0521779407-10 CUNY1086/Karliner 0 521 77940 7 June 7, 2007 18:40
Immunodeficiency Disorders 821➣Variable clinical manifestations
➣Functional defect in antibody responses to polysaccharide anti-
gens usually assoc w/ recurrent respiratory infections
■Common variable immunodeficiency
➣Low IgG, absent specific antibodies
➣Clinically heterogeneous group of disorders
➣Peak incidence in the 2nd or 3rd decade of life
➣Often assoc. w/ autoimmune disorders (inflammatory bowel dis-
ease, arthritis)
➣Increased incidence of lymphoid malignancies
■Hyper-IgM syndrome
➣X-linked mutation of the gene for CD40 ligand: inability of B cells
to switch from IgM to other isotypes
➣Absent IgG & IgA, normal or elevated IgM
➣Increased incidence of autoimmune neutropenia, anemia,
thrombocytopenia
■Bruton’s disease
➣X-linked agammaglobulinemia w/ absent B cells
➣Mutation in the gene for Bruton’s tyrosine kinase interferes w/
normal B-cell development
➣May develop echovirus encephalitis if untreatedT-Cell Deficiency Disorders
■DiGeorge syndrome: deletions of 22q11
➣Thymic hypoplasia (partial) or aplasia (complete), hypocal-
cemia, congenital heart disease
➣Complete DiGeorge: absent T cells or immunoglobulins
➣Partial DiGeorge: low but functional T cells w/out significant
infections
■Chronic Mucocutaneous Candidiasis
➣May be associated w/ other disorders (polyendocrinopathies,
autoimmune disorders, thymoma)
➣Absent DTH responses to Candida albicans only
➣Requires chronic antifungal therapyPhagocytic Defects
■Chronic granulomatous disease (CGD)
➣Defects in NADPH-oxidase, X-linked or autosomal recessive
➣Recurrent bacterial or fungal infections
➣Granulomas w/ GU or GI obstruction
■Complement deficiencies