[Changes in the humoral immune response in occupational exposure to metal aerosols]

The object of the study is to screen the state of the humoral immune response in the workers at the chemical plan Khimko AD-Vratsa who are in professional contact with metal aerosols, containing Cr, Ni, Cu, Fe, Zn, Mn, Al, nitric oxides, ammonia, carbon oxide and dust. 60 workers have been covered (exposed group) with working experience of 9.89 +/- 4.07 years and the control group consisted of 60 persons from the same region working at two other plants. A comparatively high rate was established of infections of the upper respiratory ways (rhinitis, laryngitis, chronic bronchitis, rhinopharyngitis and conjunctivitis) in the both groups: in the exposed group-in 12 persons (20%) and in the control group-in 5 (8.3%) persons. The study of the humoral immune response showed activated immune defence, expressed in increasing of the serum IgG and IgA (18.56 +/- 4.79 g/l and 3.64 +/- 1.32 g/l respectively) and of C3-fraction of the complement (1.14 +/- 0.25 g/l) in comparison to the control group 0.96 +/- 0.21 g/l, p < 0.00003). In 32 (53%) exposed workers an increased values of serum IgG have been found out. This rate is considerably higher than the one of the control group (33%, p < 0.05). An increased level of HBsAg-11.7% (7/60) and 8.3% (5/60), respectively in the exposed and control groups is reported. The authors have not found convincing evidence for autoimmune response in the exposed group of workers. These facts can be hardly interpreted at this stage as trace reaction resulting from frequent infections. It is possible that this activation of the humoral immunity is related to the environment-polluting metal aerosols which influence the immune system.