Diseases of Immune System- Nelson Flashcards Preview

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Flashcards in Diseases of Immune System- Nelson Deck (37):

Using just a few sentences, define autoimmune disease and state the key underlying immune defect.

Autoimmune disease = immune-mediated inflammatory diseases in which tissues and cell injury are due to immune reactions to self-antigens. Can be mediated by:

-Immune complexes

**Autoimmunity → LOSS of self tolerance


State the two key factors that combined together lead to autoimmune disease

-inheritance of susceptibility genes
-environmental triggers


In what ways can infections cause autoimmunity?

-may up-regulate expression of co-stimulators on APCS

-Molecular mimicry = antigens might have same amino acid sequences as self antigens

-Some viruses- polyclonal B-cell activation

-Tissue injury (from infection) can release antigens and also structurally alter self antigens so that they activate T-cells


Does presence of autoantibodies always indicate an autoimmune disease?



Define self-tolerance

the phenomenon of unresponsiveness to an individual's own antigens


Describe the pathological mechanism for Systemic Lupus Erythematosis

-production of anti-nuclear antibodies (ANAs)
-Antibodies to double stranded DNA
-Antibodies to Smith (Sm) antigen
-Systemic lesions caused my immune complex deposition (type III hypersensitivities)
-may also have auto abs to proteins complexed with phospholipids


State the potential complication of the presence of anti-phospholipid antibodies in SLE

***Complications of a hypercoaguable state
-venous and arterial thrombosis
-Spontaneous miscarriages
-Cerebral ischemia


What are the pathological features seen SLE involving the skin?

-Erythema in light exposed areas
-Typically immune complex deposition at the dermoepidermal junction


What are the pathological features seen SLE involving the kidney?

-lupus nephritis due to immune complex deposition in the glomeruli
-Variety of patterns of glomerular injury are seen


What are the pathological features seen in SLE involving the joints?

Non-erosive, non-deforming small joint inolvement


What are the pathological features seen in SLE involving the cardiovascular system?

Fibrinous pericarditis
Non bacterial verrucous endocarditis
Accelerated coronary atherosclerosis in long term disease


What does SOAP BRAIN MD stand for?

Systemic lupus erythematosis!

O=oral ulcers
P=photosensitivity, pulmonary fibrosis
B=blood cells
R=renal, raynauds
I=immunologic (anti-Sm, anti-dsDNA)
M=malar rash
D=discoid rash


In Rheumatoid arthritis what are the auto-antibodies directed against?

Citrullinated peptides (CCPs)


What is the pathogenesis for rheumatoid arthritis?

-Activation of CD4+ T cells and B cells
-Forms pannus (mass of inflammed synovium)
-Pannus grows over the joint cartilage -- inflammatory destruction of the joint


What is Sjogren syndrome?

Chronic disease = dry eyes and dry mouth resulting form immunologically mediated destruction of the lacrimal glands and salivary glands
-Can be primary or secondary


What is the auto antibody directed against in Sjogren syndrome?

Antibodies to ribonucleoproteins SS-A and SS-B (not specific)


What is CREST syndrome?

Develops from Limited scleroderma

C- calcinosis
R- Raynaud's phenomenon
E- esophagel dysmotility
S- Sclerodactylyl
T- telangiectasia


What is the difference between diffuse and limited scleroderma?

Diffuse- widespread involvement of the skin at onset, early visceral involvement

Limited- skin involvement limited to fingers, forearms and face. May develop CREST syndrome


What is the pathogenesis of Systemic sclerosis?

(aka as scleroderma)
-widespread damage to small blood vessels and progressive interstitial and perivascular fibrosis of skin and multiple organs


What are the autoantibodies to in systemic sclerosis?

Scl-70 (DNA topo I)


What are the antibodies directed to in CREST syndrome?

Anti-centromere antibodies


Pathogenesis of dermatomyositis and polymositis?

Autoimmune disease
Damage to small blood vessels and capillaries in the skeletal muscles


Antibodies in dermatomyositis/polymyositis?

Anti-Jo1 = directed against histidyl t-RNA synthetase


Difference between dermatomyositis and polymyositis?

Dermatmyositis has skin involvement, polymyositis does NOT.


Describe the difference between primary and secondary immunodeficiencies. In what patient population does one typically encounter primary immunodeficiencies

Primary = congenital, genetically determined → manifest in infancy (6 months)

Secondary = due to complications of cancer, infection, malnutrition, immunosuppression, irradiation or chemotherapy


Isolated IgA deficiency

failure of B cells to differentiate into IgA producing plasma cells

serums and secretory IgA decreased

weakend mucosal defesenses


DiGeroge Sydrome

T-cell deficiency due to failure of development of the third and fourth pharyngeal pouches


Hyper IgM syndrome

Pts able to make IgM but are deficient in their ability to make IgG, IgA, and IgE anbitodies

-defect in class switching


Severe Combined Immunodeficiency

profound defects in both humoral and cell mediated immunity (death in one year without hematopoietic cell transplant)


X-linked lymphoproliferative syndrome

inability to eliminate EBV leading to severe and sometime fatal infectious mononucleosis


State which type of infection patients without a spleen are at risk for and why.

Asplenia → loss of splenic macrophages can lead to increased risk of bacterial infection with encapsulated organisms

S. Pneumoniae
H. influenza
N. menigitidis


List the three ways that one could suspect a patient has an immunodeficiency.

Clinical history

Presents with an opportunistic infections from a “signature organism”

Presents with repeated infections


State the laboratory tests you would order to assess B-cell function, T-cell function, phagocytic function, and complement.

B-cell function → immunoglobulin levels

Phagocytic function → CB, peripheral smear, genetic tests, specific tests of neutrophil function

Complement → total serum complement


What is chediak-higashi syndrome?

Gene → defective fusion of phagosomes and lysosomes in phagocytes, resulting in defective phagocyte function and susceptibility to infections

autosomal recessive disorder, recurrent pyogenic infections, partial oculocutaneous albinism, progressive neurologic abnormalities, and mild coagulation defects


How do you make the diagnosis of chediak-higashi syndrome?

Diagnosis can be made w/ peripheral smear for pathognomonic giant cytoplasmic granule in leukocytes


Wiskott-Aldrich Syndrome

X-linked recessive disorder

Progressive deletion of B and T cells

Characterized by:
Marked vulnerability to recurrent infection


What recurrent infections would you see in a patient with complement deficiency?

Increased susceptibility for recurrent neisserial infections