Humoral immunodeficiency in T-cell chronic lymphocytic leukemia. An immunologic assessment.

The humoral antibody immunodeficiency in two patients with T-cell chronic lymphocytic leukemia (T-CLL) appeared to be the result of immunoregulatory abnormalities in the leukemic T-cell populations. Both patients had CD4+ CD45R+ "virgin" or suppressor-inducer T-CLL, but Patient 1 had hypogammaglobulinemia and Patient 2, immunoglobulin (Ig) M hypergammaglobulinemia. Although, CD25+ interleukin-2 (IL-2) receptors were present on leukemic T-cells of both patient, OKT9+ (CD71) transferrin receptors and OKT10 (CD38) activation antigens were found only on Patient 2's cells. Highly elevated amounts of IL-2 was secreted from phytohemagglutinin-stimulated and concanavalin A-stimulated T-cells in both patients. In Patient 1 with hypogammaglobulinemia, immune defects involve T-cells, first an intense suppressor activity on B-cell-induced IgM and IgG synthesis and, second, deficient production of B-cell growth factor (BCGF) and B-cell differentiation factor (BCDF). In Patient 2, highly elevated BCGF and IgM-specific BCDF was secreted by T-cells, a mechanism leading to IgM hypergammaglobulinemia in this patient. These studies stress the importance of BCGF and BCDF activity of leukemic T-cells in humoral antibody immunodeficiency disorders in T-CLL cases.