The commonest primary immunodeficiency is?: (A) Common variable immunodeficiency, (B) Isolated IgA immunodeficiency, (C) Wiskott-Aldrich syndrome, (D) AIDS
Answer is B. Isolated IgA Deficiency: commonest immunodeficiency (1/600) Affected individuals have extremely low levels of both serum and secretory IgA C/F: asymptomatic, recurrent respiratory infections