[The effects of occupational exposure to nitrogen dioxide (NO2) on the immunological parameters in workers]

The study of T-cell subpopulation: T CD3+, T CD4+, T CD8+; NK CD16+ and B CD19+ cells as well as of serum concentrations of immunoglobulins G, A, M, E, complement components C3c and C4, total circulating immune complexes (CIC), CRP, haptoglobin, ceruloplasmin and transferin, was carried out in 16 males, smokers and non-smokers. The control group of smokers and non-smokers comprised 36 males not exposed to any chemical compound. The study was performed also in two groups of non-smokers: 5 workers occupationally exposed and 7 non-exposed controls. For the determination of T-cells, NK- and B CD19+ cells populations monoclonal antibodies were used in indirect immunofluorescence tests. Passive sampling spectrophotometric method was employed to determine NO2 and NO concentrations in the work environment air. Their mean values were 0.0867 +/- 0,0585 mg x m-3 (from 0.0165 to 0.1960) and 0.0614 +/- 0.0263 mg x m-3 (from 0.0220 to 0.1090), respectively. The number of total leucocytes and lymphocytes in the group of 16 smokers and non-smokers exposed to NO2 and NO was increased. Stimulation T-cells line in the men exposed to NO2 and NO was evidenced by an increased number of T CD3+ cells, about two-fold increase in absolute number of T CD4+ cells (p < 0.001), an increased number of T CD8+ cells (p < 0.001) and by an enhanced value (by 24.7%) of the T CD4+/T CD8+ ratio. In the group of 16 persons exposed to NO2 and NO serum IgG concentration was elevated (p < 0.01), C3c C4 decreased (p < 0.001), and serum CIC enhanced by about two times (p < 0.001). Stimulation T-cells line in the groups of 5 non-smoking workers exposed to NO2 and NO was evidenced by an increased number of T CD3+ (p < 0.05), T CD4+ (p < 0.05) and T CD8+ cells but without any change in the value of the T CD4+/T CD8+ ratio. In addition, decreased serum C3c and C4 levels together with serum CIC elevated by 76.7% (p < 0.05) were evidenced in this group on non-smokers. Moreover, significant positive correlations between NO2 concentrations in the air and the numbers of total lymphocytes, T CD3+, TCD4+, T CD8+ cells or IgG: (magnitude of r in the range between 0.31 and 0.71), as well as significant negative correlations between NO2 concentrations in the air and C3c (r = 0.44) in the group of 16 smoking and non-smoking workers were calculated. In this group significant positive correlation between NO concentrations in the air of the workplace and counts of T CD3+, T CD8+, B CD19+ (magnitude of r in the range between 0.51 and 0.63), haptoglobin and ceruloplasmin (magnitude of r from 0.37 to 0.58), as well as significant negative correlation between NO concentrations in the air and serum levels of IgG, IgA and IgM (magnitude of r from -0.67 to -0.47) and CIC (magnitude of r = -0.39) were also observed. In the group of 5 exposed non-smoking workers, the values of correlation coefficients magnitude of r between NO2 and NO concentrations in the work environment air and immunological parameters were similar to those in the whole group. The results obtained suggest that during occupational exposure NO2 may play a more important role mainly in the process of inflammation but exogenous NO seems to act as modulating factor of this proinflammatory NO2 effect through a greater and exposure-dependent influence mainly on B CD19+ cells and other parameters of humoral immunity.