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Various immune deficiencies from First Aid for the USMLE, Step 1
Terms in this set (18)
C1 esterase inhibitor deficiency
Hereditary angioedema (C1 esterase inhibitor helps prevent C' activation on self-cells)
Severe, recurrent pyogenic sinus / resp tract infections (no opsonization by C3b; no PMN chemotaxis via C3a). Also increased susceptibility to type III hypersensitivity reactions (C3b aids in clearing immune complexes)
Neisseria bactermia. Terminal complement -> MAC; can't punch hole in capsule
DAF (decay-accelerating factor) deficiency
Paroxysmal nocturnal hematuria. DAF helps prevent C' activation on self-cells; without it, C' lysis of RBCs happens at night (when you get a little hypoxemic).
Decreased production of B-cells. X-linked rec. defect (boys!) in Bruton's tyrosine kinase (BTK) a/w low levels of all classes of Igs. Decreased number of B cells with normal numbers of pro-B cells in marrow. A/w recurrent bacterial infections after 6mo of age (mom's IgG decline).
Thymic aplasia / DiGeorge syndrome
Decreased production of T-cells. 22q11 deletion. Thymus / parathyroids don't develop (3rd/4th branchial pouches). P/W: tetany (hypocalcemia), recurrent viral / fungal infections (no T-cells), also congenital heart & great vessel defects.
Severe Combined Immunodeficiency (SCID)
Decreased production of B- and T-cells. Defect in early stem cell differentiation. Failure to make MHC II antigens; defective IL-2 receptors (X-linked recessive; most common) or adenosine deaminase deficiency. P/W recurrent bacterial / viral / fungal / protozoal infection. No allograft rejection.
IL-12 receptor deficiency
Decreased activation of T-cells. Decreased Th1 response --> disseminated mycobacterial infections
Decreased activation of B-cells. Defect in CD40 ligand on CD4 Th cells = can't class switch. P/W severe pyogenic infections, early in life. Lots of IgM, very low IgG/A/E
Decreased activation of B-cells. X-linked. Can't mount IgM response to capsular polysaccharide of bacteria. P/W recurrent pyogenic infections, thrombocytopenic purpura, eczema. Elevated IgE/A; low IgM
Decreased activation of neutrophils. No IFN-gamma production by Th cells, so PMNs don't respond to chemotactic stimuli. P/W ("FATED"): coarse Facies, cold (no inflammation) staph Abscesses, retained primary Teeth, increased IgE, Derm problems (eczema)
Leukocyte adhesion deficiency syndrome (type 1)
Phagocytic cell deficiency. LFA-1 integrin (CD18) defective on phagocytes. P/W early bacterial infections, no pus formation, neutrophilia, delayed separation of umbilicus.
Phagocytic cell deficiency. Aut rec defect in microtubular function, lysosomal emptying of phagocytic cells. P/W recurrent pyogenic infections (staph / strep), partial albinism, peripheral neuropathy.
Chronic granulomatous disease
Phagocytic cell deficiency (PMNs). No NADPH oxidase activity (or similar enzymes). P/W opportunistic infections with bacteria (S. aureus, E. coli), Aspergilus. Dx: negative nitroblue tetrazolium dye reduction test (NBT)
Chronic mucocutaneous candidiasis
Idiopathic dysfunction of T-cells; specifically against Candida albicans. Lots of candidiasis on skin / mucous membranes.
Selective immunoglobulin deficiency
Idiopathic dysfunction of B-cells. Deficiency in specific class of immunoglobulins (defect in isotype switching?). Selective IgA deficiency is most common. P/W sinus / lung infections; milk allergies / diarrhea common. Anaphylaxis if exposed to blood products with IgA.
Idiopathic dysfunction of B-cells. Defect in DNA repair enzymes with associated IgA deficiency. P/W ataxia (cerebellar probs) & spider angiomas (telangiectasia)
Common variable immunodeficiency
Idiopathic dysfunction of B-cells. Defect in B-cell maturation. Normal numbers of circulating B-cells but decreased plasma cells; decreased Ig. Can be acquired (20s-30s). Increased risk of autoimmune disease, lymphoma.
THIS SET IS OFTEN IN FOLDERS WITH...
Biochem - Diseases
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