Immunoregulatory properties of childhood leukemias.

Investigation of in vitro humoral immune responses and immunoregulatory properties of leukemic cell was carried out in 17 children with acute leukemia prior to therapy. Leukemias were of the non-T, non-B-cell type in 13 patients and of T-cell origin in four. Bone marrow and peripheral blood cells consisted of 24-96% lymphoblasts and were generally deficient in surface Ig-positive cells. Induction of Ig secreting cells in response to pokeweed mitogen was markedly decreased in marrow and peripheral mononuclear cell cultures of leukemic patients. Co-culture of leukemic cells with normal lymphocytes led to marked deviations from the expected Ig secreting-cell response of the cell mixtures. The predominant effect was enhancement, as was the case with eight non-T, non-B-cell and one T-cell leukemia samples. Suppression of the Ig secreting-cell response was observed in only three instances, two with non-T, non-B-cell and one with T-cell leukemia samples. These findings implicate non-T, non-B as well as more differentiated leukemic cells in having the potential for modifying Ig production by B cells.