. 2010 Aug;35(8 Section 2):2–4.

TABLE 2.

Classifications of Component Defects

Type of component defect	Description of defect(s)	% of PIDDs	Common associated disorder(s)
B cell defects	Antibody production deficiencies Decreased antibody titers B cell dysfunction	50–60%	Selective IgA deficiency XLA CVID IgG subclass deficiency Specific antibody deficiency Autosomal recessive agammaglobulinemia Selective IgM deficiency Good’s syndrome
T cell defects	Immunoglobulin deficiencies	5–10%	DiGeorge syndrome ZAP-70 deficiency X-linked lymphoproliferative syndrome Chronic mucocutaneous candidiasis
Combined B and T cell defects	Impaired antibody formation	20%	Severe combined immunodeficiency Ataxia Telangiectasia Wiskott-Aldrich syndrome
Natural killer defects	Probable predisposition to viral infection and tumors (very rare)	NA	NA
Phagocytic cell defects	Impaired pathogen destruction	10–15%	Chronic granulomatous disease Leukocyte adhesion deficiency syndrome Chédiak-Higashi syndrome
Complement defects	Deficiencies of complement components or inhibitors	≤2%	Systemic lupus erythematosus Pyogenic infections Autoimmune disorders Angioedema Paroxysmal nocturnal hemoglobinuria Leukocyte adhesion deficiency syndrome