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.

Evidence for heterogeneity of T cell expansion in polymyositis and inclusion body myositis.

Vbeta usage of muscle-infiltrating T lymphocytes in polymyositis (PM) and sporadic inclusion body myositis (s-IBM) was correlated with clinical and histopathological features. Immunohistochemical analysis was combined with complementarity-determining region 3 (CDR3) length analysis in nine muscle biopsies of eight PM patients and six biopsies of five s-IBM patients. Vbeta usage was heterogeneous in seven patients. Four of these patients had definite PM with endomysial located T cell infiltrates, but T cells specifically surrounding and invading individual non-necrotic fibers were not found. In two s-IBM patients, Vbeta 2 usage was increased. In one of them, a repeat biopsy showed a heterogeneous Vbeta usage. We conclude that clonal expansion of muscle-infiltrating T cells could only be detected in part of the patients. Explanations may be that clonal expansion does not take place in all disease phases and that PM is a heterogeneous disease with respect to pathogenesis.