Rituximab was effective on refractory thrombotic thrombocytopenic purpura but induced a flare of hemophagocytic syndrome in a patient with systemic lupus erythematosus.

We report the case of a patient with systemic lupus erythematosus (SLE) who first revealed hemophagocytic syndrome (HPS), which was treated successfully with glucocorticoid and intravenous cyclophosphamide. The patient then demonstrated refractory thrombotic thrombocytopenic purpura (TTP) with normal a disintegrin and metalloprotease with thrombospondin motifs (ADAMTS)-13 activity that responded well to rituximab. After rituximab treatment, the patient showed a flare of HPS that was controlled by additional intravenous cyclophosphamide treatment. This case showed that TTP with normal ADAMTS-13 activity is B-cell dependent and indicated that B-cell depletion might exacerbate some autoimmune conditions in SLE.