A 1 yr old boy presents with history of recurrent pneumonia. He also has eczema and a history of prolonged bleeding after circumcision. Peripheral smear shows thrombocytopenia with small platelets. Which of the following is most likely to be deficient?: (A) IgA, (B) IgE, (C) IgM, (D) IgG
Answer is C. The history here is highly suggestive of Wiskott-Aldreich syndrome. IgM levels are decreased in this condition. Wiskott-Aldrich syndrome It is an X-linked disease characterised by a traid of clinical manifestations: R - Recurrent infections E - Eczema T - Thrombocytopenia with small platelets. Serum IgM levels are low but IgE and IgA levels are normal or elevated. IgG is usually normal Reference: Ananthanarayan and Paniker&;s Textbook of Microbiology Tenth edition