Cytogenetic studies on blood lymphocytes from patients with Schistosoma mansoni.

Chromosomal aberrations and sister chromatid exchange (SCE) frequencies were studied in peripheral blood lymphocytes from 10 patients with Schistosoma mansoni prior to initiation of chemotherapy. The mean frequencies of chromatid and chromosome breaks for the patients were 1.80 and 2.30%, respectively, which were significantly higher (P less than 0.01) than the means 0.35 and 0.30%, scored for 20 healthy controls. Significant increase in the mean frequency of SCEs in the patients (9.1 +/- 0.5 SCE/cell) was noticeable when compared with the controls (6.2 +/- 0.1 SCEs/cell). Reductions in the lymphocyte divisions and replications in the patients were also observed. These results indicate that infection with S. mansoni could have in vivo mutagenic effects on human chromosomes.