T-LYMPHOCYTES IN MERCURY-EXPOSED WORKERS

In this work we have investigated the changes in T- helper and T- supp ressor cells and T- cell proliferative response to phytohemagglutinin (PHA) in mercury-exposed workers. The study group consisted of 33 work ers from a mercury-producing plant with a mean age of 29 years and a m ean exposure period of 19 months. At the time of testing, and for the three previous months, the exposed population had urinary mercury leve ls below the currently accepted limit of 50 ug/g creatinine. A reverse CD4(+)/CD8(+) ratio was observed in the mercury-exposed individuals w hich was characterized by a reduction in the number of CD4(+) lymphocy tes. No changes were observed in the proliferative response of lymphoc ytes from exposed individuals to PHA. Similarly, no proliferative resp onse was observed when lymphocytes from normal individuals were cultiv ated in the presence of serum from the exposed workers. We found no co rrelations between lymphocytes changes and urinary mercury concentrati ons, time of exposure or the age of the workers.