[en] Human peripheral blood T and B lymphocytes were separated by a method based on the stable rosette formation of T lymphocytes with neuraminidase-treated sheep erythrocytes, followed by centrifugation over a Ficoll-Hypaque gradient. Monocytes were isolated from the T-depleted B lymphocyte preparation by allowing the monocytes to ingest iron particles and by subsequent centrifugation over a Ficoll-Hypaque gradient. The T lymphocytes responded extremely well to PHA and very well to PWM, while the B lymphocytes were unresponsive to either PHA or PWM. However, when the B lymphocytes were cultured together with irradiated autologous or allogeneic T lymphocytes (1 : 1,1:2 or 1 : 4 ratio), both PHA and PWM became mitogenic to B lymphocytes. Irradiated T lymphocytes alone did not respond to either PHA or PWM, indicating that the ³H-thymidine incorporation seen in the mixed-cell culture was due to the activation of unirradiated B lymphocytes. The B lymphocytes failed to respond to these phytomitogens in the presence of lower concentrations of irradiated T lymphocytes. The monocytes were found to be incapable of helping the B lymphocytes to respond to PHA or PWM. (author)

[en] Chronic lymphocytic leukemia (CLL) of B-cell origin results in the malignant proliferation of small immunoglobulin-bearing lymphocytes. There is currently a controversy in the literature regarding both the ability of this leukemic population to differentiate into mature plasma cells, as well as the ability of apparently normal T cells from these patients to regulate allogeneic B-cell differentiation. In the present study we have examined the lymphocytes of CLL patients in various clinical stages of their disease and with different surface phenotypes of their leukemic B-cell population. Our results show that leukemic CLL B cells from all 20 patients (including one patient with a monoclonal IgM paraprotein and another with a monoclonal IgG paraprotein) are incapable of further differentiation even in the absence of suppressor T cells and the presence of helper T lymphocytes. This lack of capacity to differentiate is unaffected by clinical stage, by therapy, or by the phenotype of the malignant population. Since the leukemic B population did not suppress normal allogeneic B-cell differentiation, the maturation deficit is evidently intrinsic to the leukemic clone rather than a result of activity of non-T suppressor cells. T helper function was also variably depressed in the blood of some patients with CLL, and this depression did not correlate with clinical stage, with therapy, or with the degree of lymphocytosis. Dysfunction of radiosensitive T suppressor cells was found to be the most consistent regulatory deficit of CLL T cells. Each of 11 patients whose leukemic cell population was of the μdelta, μα, or μ phenotype had both helper and suppressor cell defects

[en] In the present study, there was a complete lack of autologous MLR between responding T cells or T subsets and unirradiated or irradiated leukemic B cells or monocytes in all 20 patients with CLL, regardless of disease status, stage, phenotype, or karyotype of the disease. The stimulating capacity of unirradiated CLL B cells and CLL monocytes or irradiated CLL B cells was significantly depressed as compared to that of respective normal B cells and monocytes in allogeneic MLR. The responding capacity of CLL T cells was also variably lower than that of normal T cells against unirradiated or irradiated normal allogeneic B cells and monocytes. The depressed allogeneic MLR between CLL B cells or CLL monocytes and normal T cells described in the present study could be explained on the basis of a defect in the stimulating antigens of leukemic B cells or monocytes. The decreased allogeneic MLR of CLL T cells might simply be explained by a defect in the responsiveness of T lymphocytes from patients with CLL. However, these speculations do not adequately explain the complete lack of autologous MLR in these patients. When irradiated CLL B cells or irradiated CLL T cells were cocultured with normal T cells and irradiated normal B cells, it was found that there was no suppressor cell activity of CLL B cells or CLL T cells on normal autologous MLR. Our data suggest that the absence or dysfunction of autoreactive T cells within the Tnon-gamma subset account for the lack of autologous MLR in patients with CLL. The possible significance of the autologous MLR, its relationship to in vivo immunoregulatory mechanisms, and the possible role of breakdown of autoimmunoregulation in the oncogenic process of certain lymphoproliferative and autoimmune diseases in man are discussed

No abstract available