The immune reactivity of stainless steel welders (n = 22-53) was evaluated in a three year's study. The results (phagocytic activity, cellular and humoral immunity) were statistically compared with those in control group of non-exposed persons from the same plant (n = 14-23) and with long-term laboratory reference values (LRV) (n = 14-311). In welders several changes were found when compared to the LRV: in humoral response there were higher prealbumin, lysozyme, circulating immune complexes and lower IgG. In phagocytic tests there were lower ingestion, bactericidal activity and higher metabolic activity of peripheral mononuclear leucocytes. In cellular immunity the marked lymphocytosis, higher counts of T-lymphocytes, CD4+ and CD8+ lymphocytes were noticed. After lowering the concentrations of metals in the working area there were trends to normal values in some parameters [relative numbers of T-lymphocytes, relative number of CD4+ lymphocytes, phagocytic activity, metabolic activity of leucocytes (INT index), IgA, complement C3, transferrin]. The extent and the length of the exposure to welding fumes, smoking and changed conditions at working place were followed as well.

Department of Microbiology Medical School Charles University