Antigens shared by malignant plasma cells and normal B cells may be involved in graft versus myeloma

Cytotoxic T cells play an important role in graft-versus-host-disease (GvHD) and graft-versus-leukaemia/myeloma, which may occur in patients treated with an allogeneic stem cell transplantation (ASCT). Here, we describe the selection of a myeloma reactive CD4+ cytotoxic T cell-line (CTL) and two CD4+ clones from this CTL. The CTL was generated from the blood from a patient with multiple myeloma (MM) with graft versus myeloma/GvHD, following an ASCT. The CTL was stimulated using irradiated peripheral blood mononuclear cells and EBV transformed B cells from the myeloma patient (EBVp), both of which were obtained prior to ASCT. Both the CTL and the two T cell clones specifically lysed EBVp and secreted IFN-gamma after coculture with EBVp and autologous myeloma tumour cells in a class II restricted fashion. These results show that myeloma tumour cells and autologous B cells present a common polymorphic peptide that functions as a target for graft derived cytotoxic T cells. Identification of these proteins will give insight into the relationship between graft versus myeloma (GvM) and GvHD and may provide immunotherapeutical targets in the treatment of MM.