T cell and T cell subset determination in normal peripheral blood: comparison of the indirect immunofluorescence and lymphocytotoxicity techniques

Effects of benzene inhalation on lymphocyte subpopulations and immune response in mice

To clarify the immunotoxicity of benzene, the effects of benzene inhalation on T and B lymphocytes and immune responses in mice were examined. BALB/c male mice were exposed to 50 or 200 ppm benzene vapor, 6 hr/day for 7 or 14 consecutive days. T and B lymphocytes, in blood and spleen, were detected by the cytotoxicity assay with anti-Thy-1.2 monoclonal antibody and the membrane immunofluorescence test with anti-immunoglobulin antibody, respectively. Humoral immune response to sheep red blood cells was determined by the hemolytic plaque-forming cell assay. Cell-mediated immune response was measured by contact sensitivity (CS) to picryl chloride. The activity of suppressor cells was evaluated in spleen by the suppressive effect on passive transfer of CS. The ratio and absolute number of T and B lymphocytes in blood and spleen were depressed after a 7-day exposure at 50 ppm benzene. The depression of B lymphocytes was dose dependent and more intense than that of T lymphocytes. The ability to form antibodies was suppressed by benzene at all exposure levels, but the CS response was resistant to benzene inhalation and rather enhanced at 200 ppm exposure for 14 days. The activity of suppressor cells could not be detected at this dose level. These data show that benzene inhalation effects on humoral and cell-mediated immune responses are a result of the selective toxicity of benzene to B lymphocytes and suppressor T cells.

T cell profiles in vitiligo

The purpose of our investigation was to quantitatively assess T cell profiles in vitiligo and to correlate any aberrations in these findings with the spectrum of clinical disease. Twenty randomly selected vitiligo patients and sixteen healthy matched control subjects were studied. The immunofluorescence and complement-mediated cytotoxicity assays were used to determine the percentages of total T (OKT3), helper (OKT4), and suppressor (OKT8) cells in the peripheral blood of patients and controls. Both assays gave comparable results. Patients with vitiligo had a statistically significant decrease in helper cells and helper/suppressor ratios in comparison with control subjects (p less than 0.01). In addition, there was a statistically significant decrease in helper cells among patients with a disease duration of less than 1 year (p less than 0.01) and in patients who produced serum autoantibodies (p less than 0.05). These findings tend to suggest that aberrations in cell-mediated immunity may be operative in the pathogenesis of vitiligo.