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Bruton's agammaglobulinemia
- X-linked recessive
- Defect: BTK (tyrosine kinase); can't turn pro-B cells into pre-B Cells
- Presentation: recurrent bacterial infections after 6 months
- Labs: normal pro-B; B cells; immunoglobulins of all classes
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Hyper Ig-M syndrome
- Defect: CD40L on helper T cells; B cells can't class switch
- Presentation: severe pyogenic infections early in life
- Labs: IgM; IgG, IgA, IgE
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Selective Ig deficiency
- Defect: isotype switching (IgA deficiency is most common)
- Presentation: Sinus & lung infections, milk allergies, and diarrhea; anaphylaxis on exposure to IgA
- Labs: IgA
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Common variable immunodeficiency
- Defect: B-cell maturation; many causes
- Presentation: can be acquired in 20s-30s; risk of autoimmune disease, lymphoma, sinopulmonary infections
- Labs: normal B-cell number; plasma cells & Ig
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Thymic aplasia (DiGeorge syndrome)
- Defect: 22q11 deletion; failure to develop 3rd and 4th pharyngeal pouches
- Presentation: tetany; recurrent viral/fungal infections; congenital heart and great vessel defects
- Labs: T-cells, PTH, Calcium, absent thymic shadow on CXR
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IL-12 receptor deficiency
- Defect: decreased Th1 response
- Presentation: disseminated mycobacterial infections
- Labs: INF-
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Hyper-IgE syndrome (Job's syndrome)
- Defects: Th cells fail to produce INF-; neutrophils can't respond to chemotactic stimuli
- Presentation: coarse Facies, cold staphylococcal Abscesses, retained primary Teeth, IgE, Dermatologic problems (eczema) ; FATED
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Labs: IgE
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Chronic mucocutaneous candidiasis
- Defect: T cell dysfunction
- Presentation: Candida albicans infections of skin and mucous membranes
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Severe combined immunodeficiency (SCID)
- Defect: IL-2 receptor (most common, X linked); adenosine deaminase deficiency; failure to synthesize MHCII antigens
- Presentation: recurrent viral, bacterial, fungal, and protozoan infections
- Labs: absence of thymic shadow, germinal centers & B-cells
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Ataxia-telangiectasia
- Defect: ATM gene which codes for DNA repair enzymes
- Presentation: cerebellar defects, spider angiomas, IgA deficiency
- Labs: IgA deficiency
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Wiskott-Aldrich syndrome
- Defect: progressive deletion of B and T cells; X linked recessive
- Presentation: thrombocytopenic purpura, infections, eczema (TIE)
- Labs: IgE, IgA, IgM
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Leukocyte adhesion deficiency (type 1)
- Defect: LFA-1 integrin protein on phagocytes
- Presentation: recurrent bacterial infections, absent pus formation, delayed separation of the umbilicus
- Labs: neutrophilia
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Chediak-Higashi syndrome
- Defect: lysosomal trafficking gene (LYST); microtubule dysfunction in phagosome-lysosome fusion
- Presentation: recurrent pyogenic infections by staphylococci and streptococci, partial albinism, peripheral neuropathy
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Chronic granulomatous disease
- Defect: lack of NADPH oxidase; absent respiratory burst
- Presentation: increased susceptibility to catalase positive organisms (S. marcescens, S.aureus, Aspergillus, Candida albicans, E. coli -SSPACE)
- Labs: negative Nitroblue tetrazolium dye reduction test
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