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Secondary Hypogammaglobulinaemia — RACP Adult Medicine MCQ

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HardRheumatologySecondary HypogammaglobulinaemiaRACP Adult Medicine

A 55-year-old woman with rheumatoid arthritis on methotrexate and adalimumab develops recurrent lower respiratory tract infections. Serum immunoglobulins show IgG of 3.5 g/L (low). What is the most appropriate management?

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Correct answer: D — Immunoglobulin replacement therapy

Secondary hypogammaglobulinaemia can occur with B-cell depleting therapies (rituximab most commonly) and other immunosuppressants. When IgG is significantly reduced (<4 g/L) with recurrent infections, immunoglobulin replacement therapy (IVIg or SCIg) should be considered. This allows continuation of effective immunosuppressive therapy while reducing infection risk. Simply stopping immunosuppression may lead to disease flare without resolving the hypogammaglobulinaemia.

Reference: eTG – 2025 – Immunology; ASCIA – 2024 – Secondary Immunodeficiency Guidelines