Rituximab Use and Hypogammaglobulinemia

Area of Science:

• Immunology
• Rheumatology
• Pharmacology

Background:

• Rituximab, a chimeric monoclonal antibody targeting CD20 on B cells, is used for autoimmune diseases like Granulomatosis with Polyangiitis (GPA).
• Common side effects include infusion-related chills and fever.
• Emerging evidence links rituximab to reduced immunoglobulin levels and increased infection susceptibility.

Observation:

• A 59-year-old woman with GPA developed hypogammaglobulinemia after rituximab therapy.
• Her IgG and IgM levels dropped significantly after two rituximab doses.
• She subsequently experienced acute respiratory failure due to E. coli septic shock.

Findings:

• Rituximab treatment in GPA was associated with a critical decline in immunoglobulin G (IgG) and immunoglobulin M (IgM) levels.
• The patient's hypogammaglobulinemia contributed to a fatal E. coli bacteremia and septic shock.
• This case highlights a severe adverse event linked to B-cell depletion therapy.

Implications:

• Baseline and serial immunoglobulin level monitoring is essential for patients receiving rituximab.
• Proactive management of hypogammaglobulinemia may prevent life-threatening infections in patients undergoing B-cell targeted therapy.
• This underscores the need for careful risk-benefit assessment in rituximab therapy for ANCA-associated vasculitis.