IMPAIRED IN-VITRO LYMPHOCYTE-RESPONSES IN PATIENTS WITH ELEVATED PENTACHLOROPHENOL (PCP) BLOOD-LEVELS

Immune parameters were examined in 188 patients who were exposed for m ore than 6 mo to pentachlorophenol-containing pesticides. Blood levels of pentachlorophenol, lymphocyte subpopulations, in-vitro responses t o mitogenic and allogeneic stimulation, plasma neopterin levels, and p lasma cytokine and cytokine receptor levels were determined. Impaired in-vitro lymphocyte stimulation responses were impaired in 65% of the patients. The likelihood of impaired lymphocyte stimulation increased significantly with levels of pentachlorophenol that exceeded 10 mu l/l (p<.05). Patients who had high blood levels of pentachlorophenol and abnormal lymphocyte stimulation also had increased proportions of bloo d monocytes in blood (p<.05), as well as increased IL-8 serum levels ( p<.02). Eleven patients who had abnormal mitogen stimulation experienc ed decreased CD4/CD8 ratios of < 1.0; 5 of these patients had decrease d CD4(+) lymphocyte counts of < 500/mu l, and 3 patients had increased plasma neopterin of > 15 nmol/l. These results indicate that increase d levels of pentachlorophenol in blood can lead to severe T lymphocyte dysfunction.