T cell malignancy in Richter's syndrome presenting as hyper IgM. Induction and characterization of a novel CD3, CD4-, CD8 T cell subset from phytohemagglutinin-stimulated patient's CD3, CD4, CD8 leukemic T cells

Abstract

A patient is described, having Richter's syndrome and immunodeficiency with hyper IgM, who developed suppressor T cell lymphoma (CD3, CD4^‐, CD8) following untreated helper‐suppressor T cell chronic lymphocytic leukemia (CD3, CD4, CD8). The neoplastic T cells in both malignancies expressed interleukin (IL) 2 receptors but were deficient in typical CD2 and CD5 pan T antigens. Additionally, a large percentage of malignant lymph node T cells expressed HLA‐DR activation antigens. In vitro immunoglobulin‐production experiments demonstrated that the patient's leukemic blood T cells had an excess helper function for IgM synthesis but a suppressor function for IgG and IgA synthesis by normal B and T cells. The leukemic blood T cells demonstrated a poor response to phytohemagglutinin (PHA). A defect in IL 2 receptor expression was evident in PHA‐stimulated leukemic blood T cells. Of interest was the observation that PHA stimulated the induction of a novel CD3, CD4^‐, CD8 T cell subset from patient's CD3, CD4, CD8 leukemic blood T cells. These PHA‐induced CD3, CD4^‐, CD8 T cell subsets produced an elevated proliferative response to PHA and concanavalin A, had a helper cell function for IgM synthesis and produced highly elevated amounts of IL 2.