Severe autoimmune hemolytic anemia following rituximab therapy in a patient with a lymphoproliferative disorder.

Rituximab (chimeric anti-CD20 IgG1 monoclonal antibody) is effective in the treatment of relapsed/refractory low-grade lymphomas of B-cell origin as well as in diffuse large B-cell lymphoma. Several reports also demonstrated the efficacy of rituximab for the treatment of autoimmune cytopenia, especially for cold agglutinin disease. We report the first case, to our knowledge, of rituximab-related autoimmune hemolytic anemia. The pathophysiological mechanisms remain unknown, although the drug could act through massive cytokines liberation after destruction of CD20 positive cells by rituximab.