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MS – Anti-CD20 Hypogammaglobulinaemia — SCE Neurology MCQ

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ModerateMultiple Sclerosis & CNS InflammationMS – Anti-CD20 HypogammaglobulinaemiaSCE Neurology

A 40-year-old woman with MS on ocrelizumab develops a urinary tract infection. Her lymphocyte count is normal but her immunoglobulin G level is 3.2 g/L (normal 6–16 g/L). She has had 3 significant infections in the past year. What does this finding represent and what should be considered?

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Correct answer: D — Hypogammaglobulinaemia secondary to anti-CD20 therapy — consider immunoglobulin replacement if recurrent infections persist

Anti-CD20 therapies (ocrelizumab, rituximab) deplete B cells, which can lead to secondary hypogammaglobulinaemia (low IgG) over time, increasing infection risk. Regular monitoring of immunoglobulin levels is recommended. If IgG is persistently low (<4 g/L) and the patient has recurrent significant infections, immunoglobulin replacement therapy should be considered. The decision to continue, modify, or stop the anti-CD20 therapy should be made by the MS MDT. A: Hypogammaglobulinaemia with recurrent infections requires action. C: Three significant infections warrants prompt assessment. D: IgG can be affected. E: Switching without addressing hypogammaglobulinaemia is premature.

Reference: ABN MS Guidelines (2022); Ocrelizumab SmPC; NHS England IgG Monitoring in MS