Rituximab-induced serum sickness: A systematic review

Area of Science:

• Immunology
• Rheumatology
• Pharmacology

Background:

• Rituximab is a chimeric monoclonal antibody used in treating autoimmune diseases and hematological malignancies.
• Serum sickness is a hypersensitivity reaction that can occur following exposure to foreign proteins.
• Rituximab-induced serum sickness (RISS) is a recognized but less common adverse event associated with rituximab therapy.

Observation:

• A systematic review identified 33 cases of RISS, with a mean age of 39.1 years and a female predominance.
• The majority of RISS cases (51.5%) were associated with underlying rheumatologic conditions, most commonly Sjögren's syndrome.
• The classic triad of fever, rash, and arthralgia occurred in 48.5% of patients.

Findings:

• Symptom onset was significantly delayed after the first rituximab dose compared to subsequent doses (10.00 vs. 4.05 days).
• Resolution of symptoms was slower in patients with rheumatologic indications versus hematological malignancies (2.50 vs. 1.00 days).
• Corticosteroids were the primary treatment, leading to complete symptom resolution in all cases within approximately 2.15 days.

Implications:

• RISS can mimic flares of underlying rheumatologic conditions, necessitating careful clinical evaluation.
• While typically self-limited, RISS underscores the importance of monitoring for adverse reactions to rituximab.
• Avoiding further rituximab administration is recommended to prevent potentially more severe reactions in patients who have developed RISS.