Rituximab-induced Acute Thrombocytopenia in Granulomatosis with Polyangiitis.

A 72-year-old Japanese woman diagnosed with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis was admitted to our hospital with hearing loss, temporal pain, and sudden blindness. We finally diagnosed recurrent granulomatosis with polyangiitis and initiated methyl-prednisolone pulse therapy (1,000 mg) followed by prednisolone (30 mg/day) and rituximab (RTX). After the third RTX administration, she developed bloody stools along with acute thrombocytopenia and low complement levels. We diagnosed rituximab-induced acute thrombocytopenia (RIAT), and her platelet counts spontaneously recovered. This case suggests that after RTX therapy RIAT may sometimes cause severe thrombocytopenia, and that monitoring the complements may be useful for making an early diagnosis of RIAT.