1. ¹Hematology, Department of Medicine, University Hospital Basel, Basel, Switzerland
2. ²Blood Transfusion Centre, Swiss Red Cross, Basel, Switzerland
3. ³Department of Oncology, Medical University Clinic, Kantonsspital, Liestal, Switzerland

Correspondence: Dr A Buser, Blood Transfusion Centre, Swiss Red Cross, Basel, Hebelstrasse 10, 4031 Basel, Switzerland. E-mail: busera@uhbs.ch

Received 20 May 2008; Revised 2 July 2008; Accepted 2 July 2008; Published online 11 August 2008.

Abstract

Allogeneic hematopoietic SCT (HSCT) is increasingly considered an option in refractory or relapsing lymphoma. Today, most patients with B-cell lymphoma are treated with the monoclonal anti-CD20 antibody rituximab before HSCT. We hypothesized that prior therapy with rituximab might alter immune reconstitution after allogeneic transplantation due to in vivo depletion of B cells at the time of graft infusion. We studied B-cell immune reconstitution in 12 patients with lymphoma receiving rituximab 1–12 months before HSCT. Compared to an age- and sex-matched population of patients transplanted for myeloid malignancies, lymphoma patients with rituximab pretreatment showed significantly reduced B-cell counts at time of HSCT at +3, +6 and +12 months; B-cell counts reached values comparable to controls only 24 months after HSCT. In parallel, levels of immunoglobulins were markedly reduced for up to 2 years post transplant in patients with prior rituximab treatment. Two patients suffered from severe late bacterial infections to which the impaired humoral immunity may have contributed. In contrast, T- and NK-cell reconstitution was not different compared to control patients.In conclusion, B-cell reconstitution can be significantly delayed in allogeneic HSCT recipients with prior rituximab treatment. Rituximab appears to have clinical consequences beyond the immediate early post-transplant period.