Chimaeric anti-CD20 monoclonal antibody (rituximab) in post-transplant B-lymphoproliferative disorder following stem cell transplantation in children

Post-transplant lymphoproliferative disorder (PTLD) after haemopoietic stem cell transplantation is a serious complication that occurs in 8-22% of pat ients with high-risk factors. We retrospectively investigated tolerance and efficacy of humanized anti-CD20 monoclonal antibody (rituximab) as first-l ine treatment in 12 children with B-cell PTLD. At diagnosis, eight patients had tumoral involvement. The other four patients had fever, associated wit h raised Epstein-Barr virus (EBV) viral load and monoclonal gammopathy. Rit uximab was given at the dose of 375 mg/ m(2) once a week by intravenous inf usion (1-9 infusions). Only 1/48 infusions was associated with a grade 2 cl inical adverse event. Eight out of 12 (66%) patients responded to the treat ment and were in complete remission. All patients without tumoral involveme nt responded to the treatment. A rapid decrease in fever within 1 week was observed in all responders. Non-responders did not show any clinical respon se during the first week. Tumoral involvement and immunodepression seemed t o be more marked in nonresponders. Rituximab was an effective and well-tole rated treatment of B-cell PTLD. Early treatment before tumoral involvement seemed to be the most effective approach. Lack of rapid response should lea d to intensification of PTLD treatment. Pre-emptive treatment should be con sidered and evaluated in further longitudinal multicentre studies.