Micronuclei in lymphocytes of young patients under antileukemic therapy.

The micronucleus test in peripheral blood lymphocytes was employed in the cytogenetic monitoring of children with acute lymphocytic leukemia (ALL), who had undergone chemotherapy and radiotherapy. Patients were treated with a variety of drugs, which included vincristine, methotrexate, daunomycin and prednisone; they also underwent cranial irradiation at the end of the first intensive phase of therapy. The first group under study consisted of 15 subjects on therapy, who showed a marked increase in micronucleated lymphocytes (mean: 19.96 +/- 12.96%) as a consequence of treatment compared with the control group (mean: 3.67 +/- 1.55%), while lower average values were obtained from 15 other subjects at the end of treatment (mean: 13.16 +/- 8.44%). A group of 6 patients was monitored during the entire period of therapy, namely at diagnosis, after 3 months of therapy, throughout maintenance therapy and at the end of it. The whole treatment lasted about 2 years. The results revealed a marked increase in basal micronucleus frequency, due to therapy: the micronucleated lymphocyte frequency remained significantly high throughout the treatment for almost all patients. These data clearly suggest the validity of the methodology in pointing out the role played by antileukemic agents in inducing somatic genetic damage.