Seasonal variations in the level of immunoglobulins and serum proteins of children differing by exposure to air-borne lead.

A semicohort of children, initial age about 11.5 years, from an exposure area near a secondary lead smelting plant (E group children) was examined for some humoral immune response parameters in the blood and saliva and compared to a group of control children matched by age living in a relatively unpolluted rural area (Co group children). All examinations were performed every autumn and spring over a period of 2 successive years, and the data included in the final analysis were only from children who had completed at least 3 of the 4 examination series performed. To sum up, children from area E showed a clearcut elevation of mean blood lead (Pb) levels with marked seasonal fluctuations peaking in spring; Pb levels in the blood of Co group children had no such season-related fluctuation patterns and tended to slightly decline over the two years of observation. Delta-aminolevulinic acid dehydratases (ALAD) levels in area E were of distinctly lower mean values than in area Co, but no correlation with mean blood Pb levels could be observed. Levels of IgG were more or less inversely correlative with Pb levels in both sexes, levels of IgM showed a distinct downward trend in E group children at all samplings. Total serum protein (SP) levels of children from area E showed a reverse correlation with plumbemia, secretory IgA (sIgA) concentrations showed a decrease in E group children of both sexes, but the values tended to converge with control values. Levels of alpha 1-antitrypsin (A 1-AT) showed marked season-related fluctuation patterns in Co children, the curves in E group children turned steeply upward from the third examination series on. Ceruloplasmin (CPL) levels in E group children had a clearcut upward trend at three subsequent blood samplings, the curves in Co group children continued to drop. Children from area E showed markedly higher frequency rates of abnormal values than did children from Co area.