Immuno: Inherited Immunodeficiencies Flashcards

1
Q

What are the 2 ways a person can be Asplenic?

A

Inherited: unknown mechanism

Acquired: Trauma/splenectomy

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2
Q

What is a person without a spleen the most susceptible to?

A

Infection with encapsulated bacteria like Strep Pneumoniae and H. Influenza.

ESPECIALLY SPETIC INFECTIONS because the spleen is one of the blood filters, and MACs in the spleen take up bacteria in the blood.

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3
Q

What is the treatment for an individual with no spleen?

A

Vaccination against encapsulated bacteria

Prophylactic antibiotics prior to dental procedures, or when patient shows signs of fever or URI

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4
Q

A patient presents with recurrent bacterial infections, neutrophilia, and delay in umbilical cord detachment. What do they have?

A

LAD: Leukocyte Adhesion Deficiency

Defective CD18, which is LFA-1.

Neutrophilia occurs because LFA-1 can’t grab onto ICAM on the vascular endothelium. Neutrophils can’t migrate into peripheral tissues so they’re stuck in the blood.

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5
Q

A defect in NAPDH oxidase results in what immunodeficiency?

A

Chronic granulomatous disease:

Phagocytes can’t make ROS (most notably SUPEROXIDE RADICAL) and can’t kill phagocytized bacteria.

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6
Q

What symptoms are common to Chronic Granulomatous Disease?

A

Chronic bacterial and intracellular fungal infections that result in granuloma formation.

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7
Q

What is the MILD version of Chronic Granulomatous DIsease that only results in impaired ROS production rather than absence of, and presents with milder symptoms. (Still have chronic fungal and bacterial infections and granulomas, but to a lesser extent)

A

G6PD Deficiency

Glucose-6-Phosphate Dehydrogenase

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8
Q

What is the random symptom that differentiated Chronic Granulomatous Disease from G6PD deficiency?

A

G6PD deficiency results in ANEMIA because G6PD is also involved in RBC metabolism as well as ROS production in Phagocytes.

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9
Q

If a person’s phagocytes can’t produce HOCl-, what enzyme is defective?

A

Myeloperoxidase - results in defective respiratory burst.

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10
Q

A patient presents with partial albinism, recurrent pyogenic infections (Staph and strep), and neurological dysfx. What does he have, and what is the cause?

A

Chediak-Higashi Syndrome - failure of phagosome/lysosome fusion within phagocytes.

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11
Q

A patient présents with VERY high IgE concentrations in blood, exzema, recurrent cold Staph Aureus abscesses, coarse facial features, and retained primary teeth. What does he have and what is the mechanism behind it?

A

Job’s syndrome : STAT-3 deficiency results in decreased IFN-gamma production. (Neutrophils don’t respond to chemotactic signals)

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12
Q

A patient is considered neutropenic if their neutrophil count is less than what?

A

500 cells/microliter. Norm is 2000 cells/microliter

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13
Q

Patients with neutropenia are especially susceptible to what?

A

Normal flora infections.

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14
Q

A patient with increased infections with the following organisms most likely has a deficiency in what?

  • Varicella zoster (chicken pox)
  • Herpes
  • Cytomegalovirus
  • EBV
  • Mycobacterium
  • Trichophyton (intracellular fungus)
A

NK cell deficiency. All the pathogens listed are intracellular.

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15
Q

People deficient in TLR-4 are more susceptible to infection with what kind of bacteria?

A

Gram (-) because TLR-4 recognized LPS

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16
Q

What disease involves intact PRRs but defective SIGNALING after they are activated?

A

NEMO - required for NFkB activity.

Most TLRs and NODs utilize NFkB, which is a TF that controls transcription of cytokines and chemokines.

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17
Q

What will a patient with NEMO deficiency present with?

A

Developmental Defects: (NEMO is required in development as well)

Deep-set eyes
Sparse/fine hair
Conical/missing teeth
Blistering/Changes in skin color (Incontinentia pigmenti)

CONICAL TEETH: Finding Nemo and the shark.

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18
Q

What bacteria is common to find in NEMO patients?

A

Mycobacterium avium (opportunistic)

The bird helps memo find his dad.

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19
Q

How do you treat NEMO?

A

Weekly Gamma Globulin injections

Bone marrow transplant

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20
Q

Complement deficiencies generally result in increased susceptibility to intracellular or extracellular bacteria?

A

Extracellular

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21
Q

Complement C3 deficiency results in susceptibility to….

A

Encapsidated bacteria (lack of opsonization)

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22
Q

Complement C5-C9 deficiency results in susceptibility to….

A

Neisseria (C5 deficiency is the worst due to the anaphylatoxin)

Need the Membrane Attack Complex to kill Neisseria

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23
Q

Complement components C1, C2, and C4 deficiency results in ….

A

Immune complex accumulation.

C1, C2, and C4 are especially important for the elimination of immune complexes, because C3b deposition on immune complexes is necessary for their clearance. If you don’t have the first components of the classical pathway of complement, how will C3b be deposited effectively?

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24
Q

Factor D deficiency results in susceptibility to….

A

Neisseria again. Not sure why, but Factor D is required for the alternative pathway of complement, responsible for the amplification of C3b deposition.

If there is less C3b, there is less formation of Membrane Attack Complexes?

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25
Q

Patients who lack DAF and CD59 are more susceptible to….

A

DAF and CD59 protect host cells from complement deposition.

People with deficiencies in these factors destroy their own RBCs.

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26
Q

Deficiency in what leads to Paroxysmal Nocturnal Hemoglobinurea?

A

DAF and CD59 - destroy their own RBCs cause they are’t protected from complement deposition by DAF and CD59

27
Q

C1-inhibitor deficiency leads to what disease with what symptoms?

A

HANE: hereditary andioneurotic edema

Caused by inappropriate activation of classical complement. C2b is a vasoactive fragment and elicits fluid accumulation and epiglottal swelling when it is cleaved uncontrollably.

28
Q

MBL deficiency results in….

A

No Lectin pathway.
Severe bacterial infections
ACUTE PHASE REPONSE IS IMPAIRED because MBL is one of the 3 acute phase response proteins. (MBL, Fibrin, and CRP)

29
Q

A patient with Btk deficiency will be more susceptible to what?

A

Extracellular bacteria infections (No antibodies, lack of opsonization, except for alternative PW of complement)

And some viral infections that use Abs for clearance (Flu)

30
Q

What does Btk do?

A

Bruton’s Tyrosine kinase - in the Bone Marrow, it’s involved in signal transdustion from cell surface receptors during B cell development.

31
Q

What is BTK deficiency formally called?

A

XLA - X-linked Agammablobulinemia

32
Q

Lambda5 deficiency. What is it? what happens?

A

Lambda5 is a componen of the surrogate light chain that holds onto the heavy chain of an Immunoglobulin during B cell development.

If you don’t have BCRs, you won’t have B cells. They all undergo APOPTOSIS

33
Q

A patient has little to no IgA in their bloodstream but higher levels of the other Antibodies. When they are given a blood transfusion, they develop anaphylactic shock. What immune deficiency do they have? What is the disease frequency?

A

Selective IgA deficiency - 1 in 500 white people have the disease. MOST COMMON GENETIC IMMUNODEFICIENCY

Anaphylaxis develops because the recipient has never seen IgA

34
Q

How much of the IgG in the adult bloodstream is IgG1?

A

60-70%

35
Q

CD40 ligand deficiency results in what disease?

A

X-linked Hyper IgM syndrome

  • CD40L on activated T-cells can’t interact with CD40 on B cells, so no B-cell activation
  • Th1 cells also can’t activate macrophages

Results in BOTH cell-mediated and antibody-mediated deficiencies

36
Q

A patient has high serum levels of IgM, and very low [ ] of other antibody isotopes. There are no germinal centers present. What syndrome does the person have and what causes it?

A

X-linked Hyper IgM syndrome

Most commonly a defect in CD40L

No macrophage activation (No CD40L)
No B cell activation (No CD40L)

37
Q

What is another disease that causes normal/high levels of IgM in the blood, but very low concentrations of other Abs, but GERMINAL CENTERS CAN STILL FORM?

A

AID deficiency. (Activation-induced Cytidine Deminase)

Necessary for class switching of Abs, but has nothing to do with Macrophage activation.

Still considered X-linked hyper IgM though.

38
Q

What is the most common primary immunodeficiency Disorder? Why?

A

CVID - Common Variable Immunodeficiency

It’s a group of 150 isn immunodeficiencies with common features that typicallyinclude reduced antibody levels.

39
Q

Hypogammaglobulinemia means what?

A

Low levels of antibodies

40
Q

TAP-1 and TAP-2 deficiencies result in very low numbers of what type of cell?

A

CTLS (CD8+ T cells)

Deficiency in MHC-1 presentation.

41
Q

CD8 alpha chain deficiency results in low numbers of ___________ and increased susceptibility to ______________.

A

CD8 T cells (same as TAP deficiencies)

increased susceptibility to viruses and intracellular pathogens

42
Q

Perforin defects effect which cell populations?

A

NK and CD8 T’s.

Susceptibility to viral and intracellular pathogens

43
Q

Recurrent candidiasis infections can be caused by what immunodeficiency? What is the disease called?

A

Chronic mucucutaneous candidiasis

Caused by lack of cytokines from T cells that are essential to T-cell mediated immensity to Candida.

44
Q

A patient presents with disseminated mycobacterial infections. There are no granulomas though. Testing shows low levels of IFN-gamma, resulting in low Th1 cell levels. What is the deficiency?

A

IL-12 receptor deficiency - no IL-12 signaling, so there is VERY LITTLE Th1 ACTIVITY.

Intracellular infections are not controlled as well, and since Th1’s can’t activate macrophages, mycobacterial infections remain, and there is no formation of granuloma’s generally seen in mycobacterial infections. (MACs are responsible for this as well)

45
Q

WHich is more likely to result in a SCID phenotype: T cell or B cell deficiencies?

A

T cell deficiencies (primarily CD4+ because they are responsible for the 2nd signal of B cell activation. Without them, no B cell activity.)

46
Q

SCID patients (actually Dx with SCID, not just the phenotype) have deficiencies in which cell populations?

A

BOTH CD4+ and CD8+ T cells.

47
Q

What 2 conditions result in the accumulation of nucleotide catabolites that are toxic to developing B and T cells, therefore causing a SCID phenotype?

A

ADA (Adenosine Deaminase Deficiency)

PNP (Purine Nucleotide Phosphorylase deficiency)

48
Q

Lack of MHC-II expression on all cell types is called what? What happens as a result?

A

Bare Lymphocyte Syndrome

CD4 T-cells cannot be positively selected in the Thymus without MHC-II molecules.

Those that do develop cannot be activated anyway because APC’s don’t have MHC-II either.

B cells can’t be activated due to lack of CD4 T’s.

Patient is screwed.

49
Q

What is the difference between DiGeorge’s Syndrome and Complete DiGeorge’s Syndrome?

A

DiGeorge’s is a disease resulting from a micro deletion on Chromosome 22. Developmental abnormalities include congenital heart disease, palatal malformation, hypocalcemia, and LEARNING DISABILITIES.

COMPLETE DiGeorge’s syndrome presents the same, but is accompanied by an ABSENT or UNDERDEVELOPED THYMUS. Very few to no T cells.

Patients develop viral, fungal, and bacterial susceptibility that is characteristic of SCID.

50
Q

How do you treat Complete DiGeorge’s Syndrome?

A

Thymus transplant –> cures they SCID phenotype. There is no treatment for the developmental aspects of the disease.

51
Q

What is common gamma chain deficiency?

A

The common gamma chain is a functional component of pretty much all the interleukin RECEPTORS that matter. No IL-2 receptor (No T cell proliferation). No IL-7 receptor (no B cell development).

52
Q

What is the physiologic purpose of the gamma chain of IL-receptors?

A

Interacts with Jak3 molecules after Interleukins bind, in order to initiate signaling.

53
Q

What deficiency has the same effects as common gamma chain deficiency?

A

Jak3 deficiency. Both involved in the same process. Need both for intracellular signaling after an interleukin binds to the receptor

54
Q

What is the worst immunodeficiency you can have, according to Dr. Miller? What is deficient in this disorder?

A

Omenn Syndrome

Mis-sense mutation of RAG enzymes.

55
Q

Describe the cell populations effected by Omenn syndrome.

A

Absence of B cells and low numbers of oligoclonal AUTOREACTIVE T cells.

56
Q

Name some common clinical presentations associated with Omenn syndrome:

A

Splenomegaly
Alopecia (hair loss)
Chronic Diarrea
Lymphadenopathy

57
Q

A patient has NO CD8+ T cells, and normal levels of NONFUNCTIONAL CD4+ T cells. What disorder does he have?

A

Zap-70 deficiency

58
Q

What is Zap-70?

A

Zap-70 is a tyrosine kinase associated with the ITAMS on the signaling component of TCRs.

59
Q

What disease presents with this clinical triad?
Ataxia, spider angiomas, and IgA or IgE deficiency

Also: low numbers of lymphocytes, and presence of ALPHA-FETOPROTEIN in the blood.

A

Ataxia Telangiectasia

60
Q

Deficiency of FOXP3 expression causes what disease?

A

IPEX: no TRegs

Autoimmunity to many host cell tissues due to lack of regulation of auto reactive T cells.

61
Q

Treatment of IPEX?

A

Tx: Bone marrow transplant or aggressive immunosuppression.

62
Q

Clinical Presentation of IPEX?

A

Watery Diarrea
Exzemous Dermatitis
Endocrinopathy (Type 1 Diabetes)

63
Q

Autoimmun Lymphoproliferative Syndrome (ALPS) results from deficiency in what?

A

Fas ligand, Fas, or Caspase 10:

immune cells fail to undergo apoptosis after an immune response, resulting on overpopulation of lymph tissues.

64
Q

Characteristic presentation of ALPS?

A

Lymphadenopathy and Splenomegaly due to sheer numbers of immune cells populating them,