Rituximab-induced neutropenia in a patient with inflammatory myopathy and systemic sclerosis overlap disease

Abstract

Rituximab (RTX) is a monoclonal chimeric antibody directed against the CD20 antigen of B lymphocytes. Late onset neutropenia (LON) is a recognised complication of rituximab usually occurring 4 weeks after the last dose and is reported in both haematological and rheumatological conditions. However, it has never been described in a patient with myositis and systemic sclerosis overlap disease. We describe a case of LON in a 54-year-old man who was diagnosed with myositis and then systemic sclerosis overlap disease. It resolved within 7 days, and the patient did not suffer neutropenic sepsis or any other complications. We propose similar mechanisms for LON as described in other conditions and routine blood monitoring in such patients.