Rituximab for the treatment of post-bone marrow transplantation refractory hemolytic anemia in a child with Omenn's syndrome.

Omenn's syndrome is a rare severe combined immunodeficiency that kills affected subjects before the end of the first year of life unless patients are treated with bone marrow transplantation (BMT). Unfortunately, post-BMT patients may develop autoimmune diseases, such as autoimmune hemolytic anemia (AIHA), which sometimes fails to respond to standard therapies. Rituximab is a chimeric, human, immunoglobulin G1/k monoclonal antibody specific for the CD20 antigen expressed on the surface of B lymphocytes. Rituximab is currently only labeled for treatment of B-cell lymphoproliferative disorders, such as B-cell non-Hodgkin's lymphoma and follicular lymphoma; however, it is also employed in the treatment of a variety of disorders mediated by auto-antibodies, such as AIHA and transplant-related autoimmune disorders. Herein, we describe the case of a 23-month-old male child with Omenn's syndrome, who had undergone BMT and was successfully treated with rituximab (375 mg/m(2) intravenously, weekly for three times) for refractory post-BMT hemolytic anemia. Our findings evidence that rituximab should be considered for treatment of post-BMT AIHA refractory to traditional therapy also in children with primary immunodeficiencies; furthermore, rituximab might represent a means to obtain remissions without the toxic effects associated with corticosteroid and immunosuppressive agents.