EFFECTS OF OCCUPATIONAL EXPOSURE TO MERCURY VAPORS ON T-CELL AND NK-CELL POPULATIONS

The counts of lymphocytes, (CD 3+) T-cells, (CD 4+) T-helper and (CD 8 +) T-suppressor and (CD 16+) NK-cells were determined in the periphera l blood of 81 males with a history of occupational exposure to metalli c mercury vapors and in 36 males without this exposure. For the determ ination of T-cell populations monoclonal antibodies were used in indir ect immunofluorescence tests; The weighted mean of mercury concentrati ons in air was 0.028 mg x m(-3). Mercury concentration in the urine of the exposed subjects ranged from 10 - 240 mu g x l(-1), and in blood it was from 4 - 30 mu g x l(-1). Stimulation of the T-cell line was no ted as evidenced by increased number of T-cells by 35% in the workers with exposure to mercury vapors below or by 38% in the workers over 10 years, by increased number of T-helper cells by 42% (p < 0.001) in th e workers with exposure below or by 60% (p < 0.001) in the workers ove r 10 years and by increased number of T-suppressor cells by 85% (p < 0 .001) in the workers below or by 96% (p < 0.001) in the workers over 1 0 years exposure. Lower increase of T-helper cells population than T-s uppressor cells population was the cause of decreased value of the T-h elper/T-suppressor ratio by about 21% (p < 0.01) in the workers with e xposure below and over 10 years. No changes were observed in the T-cel l populations between workers with up to 10 and those with over 10 yea rs exposure. The quantitative changes of T-helper cells and T-helper/T -suppressor ratio may represent an immunological indicator of exposure to mercury vapors. Presented changes in human T-lymphocytes populatio n associated with occupational exposure to mercury vapors have been pr oposed to explain the origin of more frequent autoimmunity induced by mercury.