A 40-year-old patient develops recurrent sinopulmonary infections, lymphoma, and has very low serum IgG, IgA, and IgM but normal number of B cells in peripheral blood. Germinal centers are absent on lymph node biopsy. This immunodeficiency is MOST likely:

• A X-linked agammaglobulinemia (XLA/Bruton disease)
• B IgA selective deficiency
• C Common variable immunodeficiency (CVID) ✓
• D Hyper-IgM syndrome

Explanation

Common variable immunodeficiency (CVID) presents in adulthood (typically 2nd-3rd decade) with hypogammaglobulinemia (all three major classes low), recurrent infections, and NORMAL or near-normal B cell numbers — distinguishing it from XLA where B cells are absent. B cells in CVID cannot differentiate into plasma cells (germinal center failure). Complications include autoimmunity, inflammatory bowel disease-like condition, granulomas, and significantly increased risk of lymphoma. XLA presents in infancy with absent B cells; IgA deficiency is isolated and often asymptomatic; Hyper-IgM has elevated IgM with low IgG/IgA.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.