LYMPHOCYTE REPLICATING ABILITY IN INDIVIDUALS EXPOSED TO ARSENIC VIA DRINKING-WATER

A human monitoring study was carried out to explore the effect on lymp hocyte proliferation of chronic exposure to arsenic (As) via drinking water. Blood and urine samples were taken from volunteers from a town where levels of As in the drinking water averaged 412 mu g/l, and from a matched group of individuals, with similar socioeconomic status, th at drank water with As average levels of 37.2 mu g/l. Exposure was ass essed by questionnaires and by determining the levels of As in urine a nd water samples. The evaluation of the peripheral blood lymphocyte pr oliferation was done at different culture times using labelling (LI), mitotic (MI) and replication indexes (RI) as endpoints. No significant differences were seen for either LI or MI, except for MI in 72 h cult ures and in LI in males and females with skin lesions vs. those withou t lesions. Significant differences in RI were seen for exposed females but not for males. Correlations between LI and MI showed that progres sion from the initial S- to M-phase is altered in exposed individuals. Arsenic exposure as well as lead and mercury affect cellular immune r esponse, making the endpoints of cell proliferation variables of inter est in population monitoring study design, since they might provide in formation in health impairment due to exposure, which is important in risk assessment.