Autoreactive T cell-dependent polyclonal hypergammaglobulinemia in mantle cell lymphoma.

We investigated the mechanism of polyclonal B cell differentiation in mantle cell lymphoma (MCL) using peripheral blood mononuclear cells (PBMC) from a patient with MCL in leukemic stage presenting polyclonal hypergammaglobulinemia. Patient T cells not only responded to autologous non-T cells but induced polyclonal production of IgG in vitro. Flow cytometric analysis of PBMC showed the increased conversion of CD4+ T cells from the naive to the memory state. We propose the possible mechanism that autoreactive T cells may be involved in polyclonal B cell differentiation in this monoclonal B cell disorder.