Refractory autoimmune haemolytic anaemia following allogenic haematopoietic stem cell transplantation: successful treatment of rituximab

OBJECTIVE: To investigate the effectiveness and safety of rituximab in treating autoimmune haemolytic anaemia (AIHA) after allogeneic haematopoietic stem cell transplantation (allo-HSCT). METHODS: Patients with refractory AIHA following allo-HSCT were treated once-weekly with rituximab 375 mg/m(2) for a total of four doses. In an animal study, recipient CB6F1 mice were conditioned with busulfan/fludarabine and transplanted with splenocytes and T-cell-depleted bone marrow from C57Bl/6 mice. In this animal model, anti-CD20 monoclonal antibody (mAb) was evaluated to see if it could prevent graft versus host disease (GVHD). GVHD was monitored by body weight loss, GVHD clinical scores and the survival of each group of mice. Histopathological analyses of the skin, intestine, liver and lung were used to analyse the severity of GVHD. RESULTS: After rituximab therapy, refractory AIHA was resolved in all four patients as shown by increased haemoglobin levels. B-cell proportions were reduced with a relative increase of the proportions of T-cells following rituximab treatment. None of the four patients experienced chronic GVHD. In the animal model, anti-CD20 mAb treatment reduced GVHD. CONCLUSIONS: Rituximab therapy deserves consideration for the treatment of post-HSCT patients with refractory AIHA. Further studies are needed to define the therapeutic role of this anti-CD20 mAb.