Chromosome Changes and Their Evolution in Subjects With Past Exposure to Benzene

Chromosome studies of peripheral blood lymphocytes in 25 subjects who had recovered from benzene hemopathy, in four subjects with bone marrow toxicity from benzene, and in three subjects who had recovered from acute benzene poisoning revealed significantly increased rates of “unstable” and “stable” chromosome aberrations which, In most cases, were still present several years after cessation of exposure to the toxic agent and recovery from the poisoning. The follow-up cytogenetic studies showed a tendency toward a decrease in unstable chromosome changes and, generally, a persistence or an increase in stable changes. Bn some cases there was evidence of abnormal clone formation in peripheral blood lymphocytes. Chromosomes of the G group seemed to be involved in stable changes with a frequency higher than expected.