Use of rituximab and irradiated donor-derived lymphocytes to control Epstein-Barr virus-associated lymphoproliferation in patients undergoing related haplo-identical stem cell transplantation.

Epstein-Barr virus-associated lymphoproliferative disorder (EBV-LPD) is an uncommon but potentially fatal complication of allogeneic stem cell transplantation. We report here two patients who underwent T cell-depleted mismatched-related stem cell transplantation for hematologic malignancies and required aggressive post-transplant immunosuppression for graft-versus host disease (GVHD). Both patients subsequently developed markedly elevated EBV-DNA titers in association with monoclonal, light chain-restricted B cell populations in the blood. Although immunosuppressive medications were rapidly tapered, neither patient could receive potentially curative therapy with unmanipulated donor-derived lymphocyte infusions (DLI) because of the substantial risk of severe GVHD. Therefore, both patients received repeated courses of rituximab, an anti-CD20 monoclonal antibody, in combination with irradiated DLI. This therapeutic strategy resulted in normalization of the elevated EBV-DNA titers and disappearance of the monoclonal B cell populations. Our results suggest that rituximab and possibly irradiated DLI played an important role in controlling early EBV-LPD in these two patients and may be an effective alternative therapeutic strategy for patients who develop EBV-LPD post transplant and are unable to receive unmanipulated DLI.