A MALIGNANT PROLIFERATION OF HELPER T CELLS

Abstract

A B S T RA C T The Sezary syndrome is a frequently lethal disease characterized by circulating malignant cells of thymus-derived (T)-cell origin. The capacity of circulating malignant lymphocytes from patients with this syndrome to synthesize immunoglobulins and to function as helper or suppressor cells regulating immunoglobulin synthesis by bone marrow-derived (B) lymphocytes was determined. Peripheral blood lymphocytes from normal individuals had geometric mean immunoglobulin synthetic rates of 4,910 ng for IgM, 1,270 ng for IgA, and 1,625 ng for IgG per 2 x 106 cells in culture with pokeweed mitogen for 7 days. Purified normal B cells had geometric mean synthetic rates of 198 ng for IgM, 145 ng for IgA, and 102 ng for IgG. Leukemic cells from patients with the Sezary syndrome produced essentially no immunoglobulins. Adding normal T cells to normal B cells restored their immunoglobulin producing capacity. Leukemic cells from four of five patients tested had a similar capacity to help immunoglobulin synthesis by purified normal B cells. Additionally, Sezary cells from one patient studied induced a nearly 10-fold increase in IgA synthesis by lymphocytes from a child with ataxia telangiectasia and selective IgA deficiency. Furthermore, these Sezary cells induced more than a 500-fold increase in IgG and IgA synthesis