Effects of lepromatous leprosy (LL) serum factor(s) on normal blood lymphocytes

To investigate the clastogenic activity of sera from leprosy patients, normal peripheral blood lymphocytes were cultured in both inactivated and noninactivated lepromatous leprosy (LL) sera. An increase in the frequency of chromosome aberrations was observed in normal lymphocyte cultures supplemented with both inactivated (5.2%) and noninactivated (5.0%) LL serum compared to that of cultures supplemented with normal human AB+ serum (2.4%). An enhanced frequency of sister chromatid exchanges (SCEs) was also observed in normal lymphocyte cultures supplemented with both inactivated (8.2 +/- 3.85) (mean +/- S.D.) and noninactivated (8.3 +/- 4.61) LL serum compared to that of controls (6.8 +/- 3.45). The normal blood lymphocyte cultures with LL serum have revealed a slow cell-cycle kinetics at a 48-hr incubation period, but a slightly faster proliferation rate was observed at 72 hr compared to cultures supplemented with normal human AB+ serum, indicating a depressive effect of LL serum on normal blood lymphocyte proliferation. The results obtained from the inactivated LL serum showed that the factor(s) which induce chromosomal damage, depress the mitotic index and the cell proliferation rate were not destroyed at 56 degrees C. These results are the first documentation of cytogenetic effects of LL sera on normal human peripheral blood lymphocytes.