Exam 4 Flashcards
(261 cards)
1
Q
Major clinical uses for immunosuppressiveagents
A
- Transplantation induction and maintenance
- autoimmune disorders
- hypersensitivity- pathological antigen antibody reaction
- they dampen the immune response
2
Q
Which immune responses are more effectively suppressed?
A
Primary, more than secondary
3
Q
Limitations of immunosuppressive therapy:
A
- increased risk of infections of all types
- increased risk of lymphomas and related malignancies
4
Q
Induction therapy: Depleting agents
A
- used to get rid of T cells
1. Lymphocyte immune globulin (ALG and ATG)
2. Anti-CD3 antibodies
5
Q
Induction therapy: Modulators
A
- do not deplete T cells
- blocks IL2 mediated T cell activation, takes advantage of the fact that resting T cells don’t have IL2R
6
Q
ALG
A
anti-lymphocyte globulin
7
Q
ATG
A
anti-thymocyte globulin
8
Q
Major classes of immunosuppressive therapy
A
- Calcineurin inhibitors (cyclosporine, tacrolimus)
- anti-proliferative/antimetabolic drugs (sirolimus, myco. mofetil)
- antibodies (ATG, ALG, Anti-CD3: muromonab, teplizumab. Anti-IL2R modulators: Daclizumab, Basiliximab)
- glucocorticoids: Anti-inflammatory steroids (predisone, dexamethasone, etc)
9
Q
Calcineurin inhibitors: cyclosporine
A
-binds to a cytoplasmic receptor protein called cyclophilin, resulting in the inhibition of calcineurin activity
- this blocks dephosphorylation events required for cytokine gene expression/T cell activation
10
Q
How is cyclosporine metabolized?
A
- in the liver, can lead to numerous Drug-drug interactions
11
Q
Major adverse effects of cyclosporine
A
- renal toxicity/nephrotoxicity
- may appear as a similar reaction for graft rejection
12
Q
Calcineurin inhibitors: Tacrolimus (FK506)
A
- binds to a cytoplasmic receptor protein (FKBP) resulting in the inhibition of calcineurin activity which blocks dephosphorylation critical for cytokine gene expression and T cell activation
13
Q
Major adverse effects of Tacrolimus
A
- 100x more potent than cyclosporine
- nephrotoxicity/renal tox
- drug drug interactions
- glucose intolerance
- diabetes
14
Q
Antiproliferative/antimetabolic drugs
A
- prevent the clonal expansion of both B and T lymphocytes
- Sirolimus
- mycophenolate mofetil
- other (azathioprine, methotrexate, cyclophosphamide)
15
Q
Sirolimus
A
- Rapamycin
- Mech: binds to FKBP to inhibit key enzyme in cell cycle progression (mTOR), blocking progression from G1 to S phase in IL2 driven T cell proliferation
16
Q
Sirolimus toxicity
A
- dose dependent increase in cholesterol and triglycerides
- nephrotoxicity
- increased risk of lymphomas and infections
- drug drug interactions with CYP3A4
17
Q
Mycophenolate mofetil (MMF)
A
- organ transplantation drug
- Mech: a metabolite of MMF is an inhibitor of inosine monophosphate dehydrogenase (IMPDH), important for guanine nucleotide synthesis required for B and T cells
18
Q
Toxicity of mycophenolate mofetil (MMF)
A
- hematologic (leukopenia)
- gastrointestinal (diarrhea, vomiting)
19
Q
Antibodies for immunosuppressive therapy
A
- Depleting agents eliminate lymphocytes
- anti-thymocyte globulin
- anti-CD3 antibodies
- Muromonab-CD3 mAb
- Teplizumab-CD3 mAb
20
Q
Antibody modulators that affect cell function
A
- anti-IL2R mAb including:
- daclizumab
- basiliximab
21
Q
Anti-thymocyte globulin
A
- purified Igs prepared commercially from hyperimmune serum of animals following immunization with human thymocytes
- Igs bind to thymocytes in circulation, resulting in lymphopenia and impaired T cell immune responses
22
Q
Toxicity of Anti-thymocyte globulin
A
- Ig being recognized as foreign resulting in serum sickness and nephritis
- anaphylaxis (rare)
23
Q
Anti-CD3
A
- Muromonab Cd3
- a mouse monoclonal antibody that binds to the alpha chain of the Cd3 glycoprotein that is part of the T cell receptor complex on T cells –> T cell receptor complex is internalized and it prevents antigen recognition
24
Q
Cytokine release syndrome
A
- Mild flu-like illness to life threatening shock
- occurs with Anti-CD3 as an initial interaction of Muromonab-CD3 with T cells combined with the Fc mediated crosslinking
- Frequent, negative side effect
25
Administration of what before anti-Cd3 can reduce the risk of cytokine release syndrome?
- glucocorticoids. It reduces the symptoms considerably
26
Newer Anti-CD3 antibodies:
- teplizumab CD3 mAb
- delays onset of Type 1 diabetes (autoimmune disease)
- does not bind Fc receptors, minimal mouse antibody structure (it is humainzed)
- very expensive
27
Daclizumab and Basiliximab
- Anti-CD25
- mouse antibody made to the IL2 receptor (CD25)
- Mech: binds IL2 receptor present on activated but not rested T cells to block IL2 mediated events
28
Daclizumab and Basiliximab, anti-CD25 toxicity
- no cytokine release syndrome
- lower incidence of lymphoproliferative disroders and infection
- However, anaphylactic reactions can occur
29
Steroids produced in the body
Corticosteroids (21C)
- mineralcorticosteroids (electrolyte balance)
- glucocorticoids (carb metabolism, anti-inflam)
Androgens (19C)
- body building steroids
30
Sodium retention
- ability of the steroid to reduce sodium excretion by the kidney in an adrenalectomized animal
31
Liver glycogen deposition
- ability of the steroid to cause hepatic deposition of glycogen in a fasted adrenal adrenalectomized animal
32
Why do we use anti-inflammatory steroid drug therapy?
- exogenous glucocorticoids will turn off the immune system. The endogenous ones are not doing enough
- we want to: minimized the drug action on mineralcorticosteroids and maximize drug action on the glucocorticoid receptor
33
Metabolism of the anti-inflammatory steroids
- administered orally, parenterally, or topically
- metabolized in the liver and excreted by kidneys
- inhaled glucocorticoids: enhanced uptake and prolonged tissue binding in the airway (also GI first pass inactivation)
34
Glucocorticoid effect on neutrophils
- more circulating neutrophils
- release from bone marrow is accelerated
- half time in circulation is increased
- blockage of neutrophil migration to inflammatory sites (decrease in adherence capabilities)
35
Glucocorticoid effect on lymphocytes
- profound transient lymphopenia
- cells are not lysed, but move to extravascular compartments like spleen, lymph nodes, thoracic duct, and bone marrow
36
Glucocorticoid effects on Monocytes and eosinophils
- decreased in peripheral blood
37
Systemic administration of anti-inflammatory therapy can cause:
- life-threatening effects (suppresses infection/inflammation reaction --> unknown causes result)
- host resistance to microbial and fungal infection is lowered
38
What can cause toxicity when using glucocorticoids?
- systemic administration
- continued use of large doses
- withdrawal or discontinuation of long term use
39
Continued use of large dose corticosteroids can cause:
- increased infection
- peptic ulceration
- behavioral disturbances
- cataracts
- osteoporosis and vertebral compression fractures
- inhibition of growth
40
withdrawal or discontinuation from long term corticosteroid use can cause:
- symptoms of acute adrenal insufficiency (fever, myalgia, arthralgia, malaise)
- death can occur with hypotension and shock
41
Immune checkpoint inhibitors attack what aspect of cancer hallmarks?
Avoiding immune destruction
42
Which protein-protein interactions (Co-stimulatory molecules) inhibit the activation of T cells?
1. PD1 and PD1L
2. CTLA4 and CD80/86
43
During tumor development, what types of cell receptors are selected for?
- decreased expression of MHC 1 (makes tumor cells less immunogenic)
2. increased expression of PD1L (to inhibit T cell activation)
44
Activating signals from the T cell receptor and co-receptors result in activation of what?
- AP-1
- NFAT
- NF-kB
- transcription factors
45
PD1 interaction with PDL1 or PDL2 does what?
- blunts the T cell receptor signal and serves as a checkpoint on T cell activation
46
Increased expression of PDL1/PDL2 on cancer calls can be the result of:
1. oncogene activation
2. IFN signaling from the T cell
47
Mechanisms of resistance for immune checkpoint therapies
1. Increased expression of other immune checkpoint proteins (TIGIT, TIM3)
2. Tumor infiltration of immune suppressive cells (Tregs, M2 macrophages)
2. Increased cytokine signaling within the tumor microenvironment
48
Pembrolizumab
- Monoclonal antibody against human PD1
- checkpoint inhibitor
- Indicated in lung, breast, and melanoma cancers
- Acts by blocking the PD1, allowing cytotoxic T cells to kill tumor cells
- given via IV
- Side effects include: GI, colitis, dyspnea, and cough
49
Atezolizumab
- monoclonal antibody against human PDL1
- checkpoint inhibitor
- indicated in lung, breast, urothelial cancers
- Acts by blocking the PDL1, allowing cytotoxic T cells to kill tumor cells
- given via IV
- side effects include: GI, colitis, dyspnea, cough
50
Ipilimumab
- monoclonal antibody against human CTLA-4
- checkpoint inhibitor
- indicated in lung, breast, and urothelial cancers
- Acts by blocking the CTLA-4 interaction with CD80/86. allowing cytotoxic T cells to kill tumor cells
- given via IV
- side effects include: GI, colitis, fatigue, and anorexia
51
What hallmark of cancer is attacked by CDK4/6 inhibitors?
Sustaining proliferative signaling
52
The G1/S phase checkpoint is controlled by the activity of:
cyclin dependent kinase 4 and 6 (CDK4/6), which become hyperactive in cancer and contribute to uncontrolled proliferation
53
In a healthy cell without mitogenic signaling, E2F gene transcription is inhibited by:
the retinoblastoma protein (Rb)
54
Pathway of mitogenic signaling
Mitogen signal --> increased cyclin D1 --> formation of CDK4/6 --> phosphorylation of Rb --> activating E2F --> gene expression --> cell cycle progresses to S phase
55
Cyclin dependent kinase inhibitors:
block the activity of CdK4/6 and arrest cells in G1 -- tumor suppressors
56
E2F regulates the activity of:
Cyclin E --> activates CDK2 --> phosphorylates Rb --> increased progression through S phase
57
Breast cancer diverse changes in molecules/receptors and their effects:
1. p16 - loss of CDKIs
2. p21 - loss of p53
3. ER/PR/AR - estrogen receptor signaling
4. MAPK/PI3K/AKT - Her2, EGFR signaling
5. Cyclin D1 - CDND1 gene amplification
58
How do CDK4/6 inhibitors work?
they keep Rb in its unphosphorylated state
- resistance occurs via loss of Rb protein and aberrant activity of p27
59
Ribociclib/palbociclib
- CDK4/6 inhibitor works by inhibiting CDK4/6 complexes (keep Rb unphosphorylated) preventing transition through the G1 checkpoint into S phase
- given orally
- Metabolized via CYP3A4
- side effects include: neutropenia, fatigue, increased risk of upper respiratory infections
60
Oxygen can be reduced to water through:
- four single electron transfers
- intermediates include superoxide, hydrogen peroxide, and hydroxyl radicals which are highly reactive
61
What are the 3 main sources of ROS?
1. Coenzyme Q on the electron transport chain
2. oxidases, peroxidases, and oxygenases
3. ionizing radiation
62
Coenzyme Q reaction:
- accepts 2 electrons from NADH dehydrogenase, and transfers them to cytochrome b-c complex (cytochrome c reductase)
- semiquinone intermediate can leak single electrons to molecular O2, forming SUPEROXIDE
63
When is superoxide a signaling molecule?
During hypoxia/ low O2 levels
64
How does the cardiomyopathy occur from Doxorubicin?
- it can accept single electrons to form a semiquinone and undergo redox cycling like CoQ --> the oxidative damage to mitochondria causes the cardiomyopathy
65
Sulfamethoxazole gets metabolized by what?
1. CYP2C9
2. myeloperoxidase (MPO)
3. cyclooxygenase (COX)
-- forms sulfamethoxazole hydroxylamine --> reduces O2 to superoxide and bonds sulfhydryl groups on proteins to form adducts
66
CYP2E1 oxidizes what?
Ethanol --> acteylaldehyde in the MEOS reaction
67
Ethanol metabolism by CYP2E1 contributes to oxidative stress by:
1. Generation of superoxide
2. depletion of NADPH
68
Monoamine oxidase catalyzes the conversion of an amino group containing carbon --> aldehyde, this reaction produces what?
Hydrogen peroxide
69
What is the rate limiting step in converting purine nucleotides to uric acid?
- Xanthine oxidase
- this pathway produces ROS and plays a key role in reperfusion injury after tissue ischemia
70
Without oxygen, what accumulates?
Hypoxanthine and xanthine (O2 is a substrate for both of them to move along)
71
Low versus high concentrations of O2 and what gets produced by xanthine oxidase:
LOW: hydrogen peroxide
HIGH: superoxide
72
Where are VLCFAs oxidized?
- Peroxisomes, unlike regular FA beta-oxidation, which is in the mitochondria
- this forms hydrogen peroxide
73
Ionizing radiation splits water into:
- hydrogen atoms and a hydroxyl radical
74
Where does ionizing radiation come from?
1. Radon and cosmic
2. nuclear power generation
3. nuclear weapons
4. materials testing equipment
5. medical diagnostics/treatment
75
The Haber-Weiss reaction
Superoxide + hydrogen peroxide --> oxygen, water, hydroxyl radical
76
The Fenton reaction
H2O2 (hydrogen peroxide) + Fe2+ --> Hydroxyl radical + hydroxyl ion + Fe3+
77
Superoxide dismutase
superoxide --> hydrogen peroxide + O2
- has 3 isoforms (SOD1, 2, 3)
78
SOD1
- cytosolic
- uses copper and zinc
79
SOD2
- mitochondrial
- uses manganese
80
SOD3
- extracellular
- used copper and zinc
81
What does reactive oxygen and reactive nitrogen species damage?
1. Cell membranes (lipids- targets unsaturated FAs)
2. DNA
3. proteins
82
Initiation and propagation of lipid cell membrane destruction via ROS
Initiation: hydroxyl radical takes electron from carbon on unsaturated fatty acid forming LIPID RADICAL
Propagation: lipid radical reacts with O2 to form LIPID PEROXYL RADICAL --> lipid peroxyl radical takes single electron from adjacent FA forming LIPID PEROXIDE and a new LIPID RADICAL
83
What is a breakdown product of lipid peroxides that can be measured?
Malondialdehyde, measured in the blood
84
What is a marker of oxidative stress in tissues?
8-hydroxyguanine (an oxidation mutation of guanine that base pairs with adenine resulting in G-->T mutations)
85
Oxidative damage to proteins:
1. oxidized side chains form cross links with other side chains --> aggregates of misfolded proteins
2. Iron sulfur cluster proteins in the ETC --> loses iron --> non-functional protein AND ROS generation
86
What does Nitric oxide synthase (NOS) do?
- catalyzes the cleavage of nitric oxide from the amino acid arginine
- 3 isoforms (iNOS, eNOS, nNOS)
87
nNOS
neuronal
88
eNOS
endothelial
89
iNOS
inducible NOS in immune cells (intentional)
90
Nitric oxide's physiological function is to:
- bind iron in heme in soluble guanylyl cyclase, activating it. cGMP is produced, leading to activation of protein kinase G and promotion of VASODILATION
91
What happens when NO binds ferrous iron in heme in guanylyl cyclase and other enzymes?
- it changes the enzyme activity to depend on NO concentration (biphasic effect)
92
Derivatives of NO can:
Form adducts on amino acid side chains in proteins, interfering with protein function
93
When neutrophils encounter pathogens:
they undergo a respiratory burst, producing NADPH to power the generation of ROS and RNOS
94
Chronic granulomatous disease:
- inherited deficiency of NADPH oxidase causing deficient production of superoxide in the phagosome
- engulfs pathogens but cannot kill them
- characterized by recurrent infections
- mutations in transmembrane or cytoplasmic subunits can cause CGD
95
What are secreted into phagocytic vacuoles?
Myeloperoxidase (MPO) containing granules
- they convert hydrogen peroxide and chloride ion to hypochlorous acid (HOCl- bleach) which damages pathogen
96
Inducible nitric oxide synthase (iNOS)
- produces NO and combines with superoxide to form PEROXYNITRITE (ONOO-) which decays into nitrogen dioxide radical
- this destroys pathogen via oxygenation and peroxidation of lipids, DNA, and protein
97
In peroxisomes, hydrogen peroxide is neutralized by:
Catalase
98
Intracellularly, hydrogen peroxide is neutralized by:
- accepting electrons from reduced glutathione
- selenium dependent enzyme (selenocysteine acid in active site)
99
Which vitamins can accept single electron transfers to neutralize free radicals and limit oxidative damage?
- vitamin E (vegetable oil, liver, egg yolks)
- vitamin A (carrots- beta-carotene)
- vitamin C (citrus fruits)- scavenger, accepts 2 single electrons
100
What hallmark of cancer is attacked by CAR-T therapy?
avoiding immune destruction
101
Cancer cells evade the immune system by:
1. downregulating MHC 1
2. upregulated PDL1
102
Chimeric antigen receptors (CAR)
genetically engineered hybrid receptors that bind specific tumor antigen domains, has constructs with:
1. an extracellular ligand binding domain with specificity for a tumor antigen (cloned from scFV fragment of a monoclonal antibody gene)
2. Cytoplasmic domains that contain elements of TCR co-stimulatory domains (ex: from the zeta chain of the TCR— requires tyrosine kinase)
103
Tisaganlecleucal
- derives its extracellular domain form a monoclonal antibody that binds CD19
- CD19 marks the B cell lineage and is retained in B cell leukemia/lymphoma
104
Current CAR-T therapy utilizes:
- autologous transplant
- T cells isolated from patients --> transduced with CAR-T gene via lentiviral vector --> expanded in vitro --> lymphodepleting chemo --> infusion of T cells back into patient
105
Chimeric antigen receptor interacting with tumor antigen activates the CAR-T cell and:
target cells are killed through granzyme and Fas:FasL mediated apoptosis
106
Problems with initial CAR-T therapy:
- fatal neurotoxicity
- cerebral edema
107
Common toxicity of CAR-T therapy:
Cytokine release syndrome
- can cause breakdown of BBB and loss of endothelial integrity
108
Tocilizumab
- anti-IL6 monoclonal antibody that is used as treatment for cytokine release syndrome in CAR-T treated patients
109
TRUCKs:
- T cell redirected for universal cytokine mediated killing
- these consist of CAR-T cells with chimeric antigen receptors and domains that induce cytokines like IL-12
110
What does IL12 do in a tumor?
- makes an immunologically COLD tumor, HOT by:
1. activation of CD8 T cells
2. inhibition of Tregs
3. recruitment of NK cells
4. increases Fas:FasL expression on tumor cells
111
Tisagenlecleucel
- chimeric antigen receptor T cell based therapy (CAR-T) that works by chimeric antigen receptor binds CD19 on ALL cells causing Fas:FasL and granzyme killing
- indicated for pediatric and young adults with refractory or relapsed B cell ALL
- used with fludarabine and cyclophosphamide usually
- given via infusion IV
- side effects include: cytokine release syndrome, neurotoxicity
112
Axicabtagene ciloleucel
- chimeric antigen receptor T cell based therapy (CAR-T) that works by chimeric antigen receptor binds CD19 on ALL cells causing Fas:FasL and granzyme killing
- indicated for refractory of relapsed large B cell lymphoma
- used with fludarabine and cyclophosphamide usually
- given via infusion IV
- side effects include: cytokine release syndrome, neurotoxicity
113
Radioactivity
energy emitted from a source (Becquerel or Curie)
114
Exposure
energy traveling through air (Roentgen or Coulomb/Kg)
115
Absorbed dose
energy absorbed by a person or object (rad or gray)
116
Dose equivalent
normalizes biologic effects of absorbed dose to reference x-rays (roentgen equivalent man (rem) or Sievert)
117
Electromagnetic radiation
- spectrum from radio waves to cosmic waves
- photons with 33ev or greater energy can ionize water (high energy UV and above)
- radioactive isotopes can also emit particles such as alpha or beta particles and high energy photons
118
Diagnostic X-ray energy is:
10keV to 50keV
119
Therapeutic X-ray energy is:
6-18 MeV
120
When does ionizing radiation begin to ionize water?
33 eV
121
Sources of radiation in modern life
1. environmental (altitude, flights, radon)
2. medical (imaging, therapeutic)
3. occupational
122
Most common radiation exposures
- Radon and thoron (37%)
- Computed tomography (CT) (24%)
- nuclear medicine (12%)
- interventional fluoroscopy (7%)
- conventional radiography/fluoroscopy (5%)
-space (5%)
- internal (5%)
123
Average annual dose of radiation per person in the USA is:
6.2 mSv
124
Effects of radiation on tissue:
Direct: ionization of biochemicals
Indirect: ionization of water to form superoxide and peroxides that go on to cause further damage. Indirect effects are much more coommon
125
Biologic effects of radiation
- similar to endogenous ROS, but stronger
- typically exceeds the anti-oxidant capacity of the body
126
Targets of radiation in tissue
1. proteins
2. membranes
3. nucleic acids
4. endothelial cell injury leads to vascular injury, hypoperfusion, and secondary damage to exposed tissues
127
When using radiation as treatment,
occasionally it can cause secondary malignancy. The most common is breast cancer, and this usually happens after of an avg latency of 4 years
128
What is the increase of cancer incidence with CT exposure?
24%
129
Linear no threshold model
- high dose exposure leads to more cancers that low dose exposure in a population
- linear relationship between dose and cancer formation
130
ALARA
- As low as reasonably achievable
- safety revolves around procedures to keep exposure minimized
- reduce time and increase distance from exposure
131
Radioactive cures:
- radioactive isotopes (radium) first used to treat cancer 1890
- cured Hodgkins in 1960s
- 60% of cancer patients undergo radiotherapy
132
Radiotherapy
- X-rays
- electrons
- protons
- isotopes (oral/injectable- permanent or temporary implant)
133
Fractionation
- at low doses, radiation is preferentially toxic to rapidly proliferating tissue
- repeating multiple small doses amplifies these differences, leading to large differences in toxicity in cancer vs normal tissue
134
CML arises from:
defects in normal neutrophil differentiation pathway
135
What is the basis of CML?
BCR-ABL transfusion gene creating a constitutively active tyrosine kinase
136
What happens to neutrophils in CML?
1. differentiation of the neutrophil lineage during normal development
2. changes in neutrophil differentiation during chronic phase of CML
3. changes in neutrophil differentiation during the accelerated/blast phase of CML
137
What are neutrophils?
- first responders of innate immune response-- most abundant white blood cell circulation
- generated in the bone marrow, release and migrate to site of infection
- can kill microbes by multiple mechanisms
- short lived, generated continuously
138
Neutrophils: Stem cells
- HSC, multipotential progenitor
- undergo self renewal, pluripotent capable of generating all lineages, capable of proliferation
139
Neutrophils: Progenitor cells
- Common myeloid progenitor, granulocyte macrophage progenitor
- primarily undergo proliferation and differentiation multipotent, can generate more than one lineage
- capacity becomes narrower as progress down pathway
140
Neutrophils: committed cells
- do not proliferate
- only one fate, to differentiate to the next step in the path to the mature neutrophil
141
BCR-ABL genomic translocation leads to:
- genetic chimera of parts of BCR (breakpoint cluster region) gene and ABL1 (ableson tyrosine kinase) gene
- it is a constitutively active tyrosine kinase that activates proliferation and blocks apoptosis in absence of extracellular signals
- dysregulates normal neutrophil proliferation
142
Why is having the BCR-ABL transfusion of a selective advantage for progenitor cells
1. BCR-ABL progenitor cells proliferate more, survive longer
2. they have the opportunity to acquire more mutations which can make cells more oncogenic
143
BCR-ABL cells DO NOT:
Self renew (but they do continue to differentiate)
144
Chronic phase of CML (first phase)
- BCR-ABL translocation in HSC
- increased proliferation and survival of progenitor cells
- opportunity to acquire more mutations
145
Blast phase of CML (second phase)
- GMP requires ability to self renew
- acquires block to differentiation
- huge expansion of blasts. 30% extramedullary
146
GMP acquired self renewal capability in BCR-ABL
1.) wnt-beta catenin signaling is activated
2.) differentiation is blocked- translation of CEBP-alpha inhibited
147
What is a known oncogene?
V-ABL, works like the mutant version of c-ABL
148
Two most common breakpoints in BCR generate two different proteins:
- p210 found in CML (most common)
- p190 found in some ALL (less common)
- "recombination hot spots"
149
Common DNA repair mechanism:
- non-homologous end joining (NHEJ):
1. it does not require extensive homology
2. generates mutations at the site of the joint
150
Key functional domains for oncogenic fusion protein from BCR:
1. coiled-coil
2. tyrosine 177
Normal function: role in inhibition of some inflammatory rsponses
151
Key functional domains for oncogenic fusion protein from ABL1:
- N-terminal long fatty acid myristate maintains inhibition
- normally, kinase is held inactive unless activated by external signals
Normal function: role in DNA repair, cytoskeletal organization
152
Important differences between ABL1 and BCR-ABL:
1. ABL1 is inactivated unless activated by external signaling, while BCR-ABL is constitutively active
2. ABL1 mainly nuclear, BCR-ABL mainly cytoplasmic
3. ABL1 and BCR-ABL activate different intracellular signaling pathways
153
Structural changes in BCR-ABL1
1. coil-coiled domain is added from BCR promotes dimerization which is necessary for activation of the tyrosine kinase
2. Tyrosine-177 (Y-177) is added from BCR phosphorylation of Y-177 creates a new binding site for intracellular signaling proteins
3. Myristate attachment lost, which is normally necessary for autoinhibition of ABL1 tyrosine kinase activity
154
BCR-ABL transcription is independent of:
- JAK2, RAS, and PI3K
155
What is activated independently of external signaling in BCR-ABL fusion gene?
STAT5
- therefore progenitor cells proliferate independently of external signaling
156
Imatinib
- inactivates ABL1 kinase by blocking ATP binding
- prevents selective advantage that comes from activated oncogenic signaling pathways
- causes apoptosis in BCR-ABL cells and allows the growth of normal cells
157
Limitations of BCR-ABL tyrosine kinase inhibitors
1. Secondary resistance to imantinib due to mutations of BCR-ABL
2. not effective against blast phase --> no longer requires BCR-ABL because of genetic changes
3. Hematopoietic stem cells are quiescent so not strongly affected by inhibitors block proliferation (any stem cells left after treatment can repopulate into cancer again)
158
Hodgkin Lymphoma
- Characterized by Reed-Sternberg cells
- arises from a single lymph node or chain of lymph nodes
- spreads in a stepwise fashion to anatomically contiguous nodes (unlike most NHLs)
- Mesenteric nodes and Waldeyer ring rarely involved
159
What age does Hodgkin lymphoma occur?
- 15-34 years and >50 years, genetic susceptibility in children
160
What is the most common site of involvement for Hodgkin lymphoma
Neck region
161
Subtypes of Hodgkin lymphoma
1. Nodular sclerosis
2. Mixed cellularity
3. lymphocyte rich
4. lymphocyte depletion
5. lymphocyte predominance (non-classical)
162
Reed-sternberg cell
- derived from germinal center or post-germinal center B cells
- very large
- Two mirror-image nuclei or nuclear lobes containing acidophilic nucleolus surrounded by a clear zone (Owl-eye appearance)
- nuclear membrane is distinct
- EXPRESSES CD15 and CD30 !
163
1. Nodular sclerosing Hodgkin lymphoma
- most common Hodgkin lymphoma
- mostly adolescents or young adults
- good prognosis
- commonly involves the lower cervical, supraclavicular, and mediastinal lymph nodes
- Lacunar cell
164
2. Mixed cellularity Hodgkin lymphoma
- 25% of cases, mostly men (>55%), good prognosis
- EBV association in 60-70% of cases
- most common HL that occurs in HIV+ patients
- MANY Reed-Sternberg cells
- heterogenous inflammatory infiltrate
- lymph nodes and spleen affected
165
3. Lymphocyte rich Hodgkin lymphoma
- uncommon, males > females, older adults
- EBV association in 40%
- good prognosis
166
4. Lymphocyte depletion Hodgkin lymphoma
- least common HL (<1%)
- EBV associated, especially with HIV+
- Poorest prognosis, usually advanced stage with low survival rates
167
5. Lymphocyte predominance Hodgkin lymphoma
- 5% of HL cases, good prognosis
- Lympho-histiocytic variant Reed-Sternberg cells with delicate multilobed, puffy nucleus resembling popcorn
- NO EBV association
- Expresses CD20, BCL6,
- DOES NOT express CD15, CD30
168
Lacunar cell
- found in nodular sclerosis HL
- single, multi-lobate nucleus, multiple small nucleoli
- abundant, pale staining cytoplasm
- cytoplasm often torn away with formalin-fixed (nucleus lying in an empty space)
- Immunophenotype: CD15, CD30
169
What divides lymphoid tissue into circumscribed nodules in nodular sclerosing HL?
- Collagen bands
- cellular infiltrate contains: varying proportions of lymphocytes, eosinophils, histiocytes, and lacunar cells
170
Pathogenesis of HL
• arises from germinal center B cells
• EBV in RS cells (70% cases of mixed cellularity subtype)
• non-neoplastic inflammatory cell in infiltrate
• IL5 (attracts and activates eosinophils)
• activation of transcription factor NFkB by EBV/other factors— once activated it turns on genes that promote B cell proliferation
171
Clinical findings of Hodgkins lymphoma
1. Fever, unexplained weightloss, night sweats
2. Pruritus.
3. Pel- Ebstein fever
4. Painless enlargement of the single groups of lymph nodes in the neck region (becomes painful with alcohol)
5. Normocytic anemia (ACD)
172
People with Hodgkin’s lymphoma have an increased risk of developing what?
Second malignancies, usually acute myeloblastic leukemia, or non-Hodgkin’s lymphoma
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Staging of clinical features of Hodgkin lymphoma
Stage one: 1 node above the diaphragm
Stage two : 2 nodes above the diaphragm
stage three: 1+ node above, 1+ node below the diaphragm
Stage four : multi organ involvement
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What is the treatment for patients with refractory Hodgkin lymphoma?
Anti-CD30
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What is an M spike?
Increased Ig protein found on gel electrophoresis — secondary to albumin spike
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What are ways to describe plasma cells seen in multiple myeloma?
1.) clock face.
2.) fried egg.
— both talk about the nucleus off to the side, and the HOF area (large golgi area in the cytoplasm)
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What types of cells are present in multiple myeloma?
1. Overabundance of plasma cells
2. Flame cells
3. Russell bodies (large vacuoles, full of Ig)
4. Mott cell (multiple cytoplasmic inclusions)
5. Dutcher body (inclusion in the nucleus- light color)
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What is multiple myeloma?
• malignant neoplasm of plasma cells, bone marrow with greater than 10 to 20% of plasma cells
• most common primary malignancy of bone
• 65 years of age= mean
• bone pain in 80% of patients, anemia, elevated total protein, elevated calcium
• increased risk for infection
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What interleukin is increased in the serum of multiple myeloma patients?
IL-6 (stimulates plasma cell growth and Ig production)
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What immunoglobulins are produced in multiple myeloma?
1. IgG (60%)
2. IgA (40%)
- never IgM
- Does not differentiate (decreased level of normal immunoglobulins)
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What are lytic bone lesions in multiple myeloma?
• punched out lesions on x-ray
• due to osteoclastic activating factor
• bone pain, high calcium, fracture
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What are bone results that would be inconsistent with multiple myeloma?
- a positive bone scan (indicates blastic activity)
- Increased alkaline phosphatase (indicates blastic activity)
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Increased plasma proteins creates:
• hyperviscosity
• turbulent blood flow
• symptoms such as blurry vision and Raynaud’s
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What pattern do red blood cells require during multiple myeloma?
Rouleaux
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What stains indicates amyloidosis?
Apple green birefringence (this can indicate multiple myeloma in a lymph node biopsy)
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What is the multiple myeloma triad?
1. Anemia
2. Bone pain
3. Renal failure (caused by high levels of protein, hypercalcemia, amyloidosis)
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What symptoms does hypercalcemia cause?
• Neuro symptoms (weakness, confusion, lethargy)
• constipation
• polyuria
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What can multiple myeloma be associated with?
• primary amyloidosis
• systemic disorder due to diffuse amyloid deposits
• nephrotic syndrome/hepatomegaly
• restrictive cardiomyopathy (MOST COMMON)
• panhypopituitarism
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CRAB stands for what?
- Hypercalcemia
- Renal failure
- anemia
- bone lytic lesion/back pain
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What is the criteria for diagnosis of multiple myeloma?
1. Clonal bone marrow plasma cells >10% OR biopsy proven bony or soft tissue plasmacytoma
2. One of the following:
- end organ damage
- Hypercalcemia (>11)
- Renal insufficiency (cr>2)
- Anemia (hgb<10)
- Bone lesions (1+ that is >5mm)
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MGUS (monoclonal gammopathy of undetermined significance)
• serum IgM is found to be very high
• pts usually older than 50 years
• can develop plasma cell dyscrasia (MM) (increases by 1-2% per year)
• may also evolve into Waldenstrom’s macroglobulinemia, primary amyloidosis, B cell lymphoma, or CLL
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Waldenstrom’s macroglobulinemia (lymphoplasmacytic lymphoma)
• small lymphocytic lymphoma with plasmacytic differentiation
• cross between MM & SLL
• IgM causes M spike
• NO CRAB
• no lytic lesions
• Russell bodies, and Dutcher bodies may be present
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Symptoms of lymphoplasmacytic lymphoma
• visual abnormalities due to vascular, dilations and hemorrhages
• neurological symptoms, headache/confusion
• bleeding, and cryoglobulinemia
• raynauds
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Solitary plasmacytoma
• plasma cell dyscrasia
• soft tissue or axial skeleton affected
• skeletal —> MM frequently
Distinctions: only one lesion, BM plasma cell level <5%, protein levels normal, no end organ damage
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Dexamethasone
• treatment of multiple myeloma
• steroid, decreases interleukins (IL6)
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Melphalan
• alkylating agent
• interferes with DNA and RNA synthesis (alkylates and cross-links DNA)
• treatment of multiple myeloma
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Cyclophosphamide
• alkylating agent (G7)
• interferes with DNA synthesis
• SE: BMS, HEMORRHAGIC CYSTITIS
• treatment of multiple myeloma
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Bortezomib
• treatment of multiple myeloma
• inhibits proteasome (prevents degradation of pro-apoptotic factors)
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Thalidomide
• treatment of multiple myeloma
• inhibits TNF-alpha, IL6, IL100, IL12
• enhances production of IL2, IL4 and IL5
• extreme teratogen (Amelia, phocomelia)
200
Lenalidomide
• newer agent to treat multiple myeloma
• antiangiogenic agent (antibody)
• inhibits traffic signals to angiogenic factors in cells (decreases disease activity)
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What are the most common causes of death for multiple myeloma?
• renal failure
• sepsis/ infection
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Multiple myeloma
• 70+, African-American males
• CRAB
• Bence Jones protein: free, kappa, or Lambda light chains that are excreted in the urine
• IL-6
• punched out lytic lesions
• clock/fried egg plasma cells
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Solitary plasmacytoma
• skeletal plasmacytoma can progressed to multiple myeloma
• soft tissue plasmacytoma is in the upper respiratory tract
• low or no serum and urine M protein spike
• no malignant plasma, cells in bone marrow
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Lymphoplasmacytic lymphoma (Waldenstrom’s macroglobulinemia)
• acquired mutation of MYD88
• tumor cells, secrete IgM
• mixture of B cells ranging from small lymphocytes —> plasmacytic lymphocytes —> plasma, cells
• behaves like indolent B cell lymphoma involving lymph nodes, bone marrow and spleen
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What do myeloma cells secrete?
• IL6
• IL-1beta
• TNF
—> RANK ligand —> osteoclast activity increases —> bone resorption —> osteolytic lesions, pathological fractures, and hypercalcemia
206
What are the common infections of multiple myeloma?
1. Staphylococcus aureus
2. Streptococcus pneumonia
3. E. coli
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Renal findings in multiple myeloma
• renal insufficiency
• proteinaceous tubular casts
• nephrocalcinosis from hypercalcemia
• AL-type amyloidosis
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Immunophenotype for multiple myeloma
- CD38 +
- CD138 +
- CD56 +
- syndecan1 +
- high serum immunoglobin (IgA or IgG)
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Urine immunofixation electrophoresis
Characterizes whether Bence Jones protein is kappa or lambda. More sensitive and detecting BJ protein than the standard urine protein electrophoresis
210
Serum for free light chains
- detects and quantitates kappa in lambda light chain in serum
- More sensitive for detecting light chain than any of the other urine methodologies
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Waldenstrom macroglobulinemia
• visual: tortuosity and distention of retinal veins, retinal, hemorrhages, and exudates
• neurologic: HA/dizzy, tinnitus/deafness
• bleeding: formation of complexes between macroglobulins, and clotting factors that interfere with platelet function (Rouleax)
• cryoglobulinemia: precipitation of macroglobulins at low temp- Raynaud’s
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What treatment removes macroglobulins?
Plasmapheresis— used for WM
213
Monoclonal gammopathy of undetermined significance
• asymptomatic, monoclonal, gammopathy
• <3 g/dL monoclonal protein in serum
• precursor lesion with a tendency to evolve to MM (single lesion)
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POEMS syndrome
• paraneoplastic syndrome, including:
P- polyneuropathy
O- organomegaly
E- endocrinopathy
M- monoclonal gammopathy
S- skin changes (hypertrichosis)
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What do Langerhans cells express?
- CD1a, Langerin
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What is Langerin?
• transmembrane protein in Birbeck granules
• cytoplasmic pentalaminar rodlike tubular structures (tennis racket appearance on EM)
217
Three distinctive clinical pathological entities of Langerhans cell histiocytosis
1. Multisystem LCH: Lederer-Siwe disease
2. Unifocal unit system LCH: eosinophilic granuloma
3. Multifocal Unisystem LCH: hand-Shuller-Christian disease
— all have CD1a marker and coffee bean nucleus
218
What mutation is found in Langerhans cell histiocytosis?
BRAF— acquired mutation in serine/threonine kinase (a valine to glutamate substitution in residue 600)
219
Letterer-Siwe disease
• children younger than two years
• multifocal cutaneous lesions
• hepatosplenomegaly, lymphadenopathy, pulmonary and osteolytic lesions
• pancytopenia
• rapidly fatal if untreated
• eczematous type of rash, due to malignant histiocytes infiltrating skin and dermis
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Unisystem Langerhans cell histiocytosis
• unifocal, or multifocal
• erosive accumulations of Langerhans cells within medullary cavities of bones or skin, lungs, stomach
• variable cell types— eosinophils may be prominent
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Unifocal Unisystem disease (eosinophilic granuloma)
• benign, histiocytosis, mainly and adolescents and young adults
• unifocal lytic lesion in bone (skull, ribs, femur)
• typically seen in young smokers, resolves when smoking cessation occurs
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Hand-Schuller-Christian disease
• malignant histiocytosis, mainly affecting children
• multiple bony masses that may extend into soft tissues
HSC TRIAD:
1. Lytic lesions in skull.
2. Diabetes insipidus
3. Exophthalmos
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What are the most common TKI therapies for CML?
1. Imatinib
2. Dasatinib
- Second generation TKIs (bosutinib, nilotinib) may produce faster and deeper responses, then imatinib
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What is the mechanism of imatinib in CML?
Binds to the ATP binding site of the BCR-ABL tyrosine kinase fusion protein
225
CML therapy goals
1. Hematologic response (normalization of CBC)
2. Cytogenic response (resolution of the Philadelphia chromosome)
3. Molecular response (resolution of the BCR – ABL gene)
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What should you check before assuming a BCR-ABL mutation that makes CML unresponsive to TKI treatment?
Adherence by the patient
227
When is ponatinib used?
In CML when there is a BCR-ABL T315I mutation
* however, this causes arterial thrombosis, and hepatic toxicity as a side effect
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If a patient that has CML gets pregnant, what should you do?
Immediately stop imatinib or any TKI, they are teratogens
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What’s a unique feature of B cell lymphoma?
1. Rash and/or exaggerated response to insect bites
2. Pruritus and/or alcohol intolerance (also seen in Hodgkin lymphoma)
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What are B symptoms?
1. Fever
2. Weight loss, unexplained >10% of body weight over the past six months
3. Drenching night sweats
231
Which lymphomas are aggressive and symptomatic?
• diffuse large B cell lymphoma (DLBCL)
• mantle cell lymphoma
• Burkitt lymphoma
• peripheral T cell lymphomas
• HIV associated lymphomas
• Hodgkin lymphoma
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Which lymphomas are typically indolent and asymptomatic?
• follicular lymphoma
• splenic marginal zone lymphoma
• MALT lymphoma (mucosal associated lymphoid tissue)
• extranodal marginal zone lymphoma
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If a patient with lymphoma has a GI bleed, which diagnosis should be on the differential?
Mantle cell lymphoma
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What type of diagnostic biopsies are done for lymphomas?
1. Excisional biopsy- best, but invasive
2. Incisional biopsy
3. Core-needle biopsy- least invasive for the best results
4. Fine needle aspiration (not great for lymph node architecture)
5. Bone marrow biopsy— unilateral, and >3cm
235
What are the problems with flow cytometry for lymphomas?
1. DLBCL can often come back negative, but it does not rule out the diagnosis
2. Hodgkin lymphoma: RS cells are so few, but it will not pick them up
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What is seen on diagnostic pathologic evaluation for lymphomas?
Double/triple hit:
• MYC and BCL2 and/or BCL6 gene rearrangement
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Gene expression profiling:
1.) germinal center B cell type (GCB), more indolent
2.) activated B cell type (ABC), more aggressive
238
Which cancers are FDG-avid lymphomas on PET scan?
• DLBCL
• follicular
• mantle cell
• T cell
• Hodgkin
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Which cancers are poorly FDG-avid on PET scan?
• CLL/SLL
• lymphoplasmacytic lymphoma/ Waldenstrom’s macroglobulinemia
• mycosis fungoides
• marginal zone
• extranodal marginal zone
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What is a first line treatment for a lot of lymphomas?
Bendamustine + rituximab
241
What is CLL?
• An uncontrolled clonal accumulation of mature lymphocytes
• lymphocytosis: >5000/mL required
• CD5+, CD23+ (flow cytometry)
• CD19/20+
• SMUDGE CELLS
242
What are poor prognostic factors of CLL?
• advanced age at diagnosis
• 11q- and 17p-
• elevated b2-macroglobulin
• unmutated IGVH (no somatic, hypermutation in B cells)
243
What tests should you always get in CLL?
1. WBC
2. IGVH mutational status
3. Always get FISH
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Best to worst prognosis for CLL
1. 13q-
2. Normal karyotype.
3. Trisomy 12
4. 11q-
5. 17p- (worst— almost always seen with p53)
6. p53
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Frequent therapy choices for CLL
1. Bruton tyrosine kinase inhibitors (ibrutinib, acalabrutinib, zanubrutinib)
2. BCL-2 inhibitors (venetoclax)
3. Monoclonal antibodies (anti-CD20, rituximab)
4.) chemotherapy
5.) CAR-T therapy
6.) allogenic stem cell transplantation
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What can a horse voice indicate in patients?
Problems with the recurrent laryngeal nerve— maybe from lymph node tumor pressing on it
247
What points you to autoimmune hemolytic anemia?
- Spherocytes
- high reticulocyte count
- Nucleated red blood cells
- Coomb’s +
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Monoclonal lymphocytosis of unknown significance (MBL, MLUS)
• clonal lymphocytes with ALC <5000
• absence of other signs or symptoms of lymphoproliferative disorder
• progression to CLL is around 1-2% per year
• follow up is clinical with occasional CBC monitoring
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What test do you not order in multiple myeloma and why?
Do not order a BONE SCAN, it shows you blastic activity, not lytic.
250
What tests DO you order in multiple myeloma?
• H&P
• SIELP, serum free light chains, UPEP, CBC, CMP, beta-2 microglobulin, LDH
• bone marrow biopsy with cytogenetics, and FISH
• bone survey (full body CT, PET if plasmacytoma)
251
Smoldering myeloma
• asymptomatic
• serum monoclonal protein >3 g/dL
• Bence Jones protein >500 mg/24hr
• clonal, bone marrow plasma, cells 10-59%
• absence of myeloma-defining events (CRAB) or amyloidosis
252
Paraprotein
• a monoclonal immunoglobulin or immunoglobulin light chain in the blood or urine resulting from a clonal proliferation of plasma, cells, or B lymphocytes (synonyms: M-band, M-spike, monoclonal Band, monoclonal spike, monoclonal protein)
253
How do you identify paraproteins?
• serum protein electrophoresis
• immunofixation
• urine protein electrophoresis
254
Multiple myeloma staging
1. Stage one: serum beta-2 microglobulin <3.5 g/dL
2. Stage two: not stage 1 or 3
3. Stage three: serum beta-2 microglobulin >5.5 g/dL
— staging is weighted heavily by FISH
255
How do you define treatment goals of multiple myeloma?
Performance status: who is the patient?
256
What is common treatment for multiple myeloma?
RVD: lenalidomide, bortezomib, dexamethasone
257
What makes a multiple myeloma patient high risk genetically?
• t(14;16)
• t(14;20)
• 17p- deletion
• t(4;14)
• 1q+ gain
258
What is maintenance therapy post transplant in multiple myeloma?
- lenalidomide
- bortezomib
259
What do bisphosphonates do?
• pamidronate, zoledronic acid
• block osteoclastic activity
• pamidronate < zoledronic acid for hypercalcemia
** however, good renal function needed for zoledronic acid
260
What treatment is used for multiple myeloma when patients have a renal failure?
• CyBorD
• cyclophosphamide, bortezomib, dexamethasone
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What is key to improving outcomes in cancer medicine?
Clinical trials
