Serum Immunoglobulin Levels and Complement Function of Tannery Workers in Bangladesh

BACKGROUND. Occupational exposures to chromium (Cr), which can have adverse effects on immune function, have not yet been extensively investigated. Hexavalent chromium (Cr (VI)), used in mineral tanning processes, poses a threat to the health of workers in the leather tanning industry. OBJECTIVES. The aim of the present study was to evaluate the effects of long-term Cr exposure on the physical health and immunological parameters of male tannery workers in Bangladesh compared with a control group. METHODS. A health examination was performed with tannery workers (N=195) and control subjects (N=125) by physicians, demographic data were recorded in questionnaires and peripheral blood samples were collected. Serum Cr levels were analyzed by an atomic absorption spectrophotometer (AAS), immunoglobulin (Ig)G, IgA, and complement components C3 and C4 were determined by nephelometry, IgE was measured by sandwich enzyme-linked immunosorbent assay and complement function was assayed by bactericidal activity. RESULTS. The mean duration of work exposure for the tanners was 9.4±7.1 years. Their body mass index (21.8±3.0 kg/m(2)), was not significantly different from the controls (22.7±3.2 kg/m(2)). The mean serum level of Cr in 30 long-term exposed tannery workers (26.97±21.11 μg/dL) was significantly higher than that of 30 randomly selected control subjects (7.38±6.81 μg/dL). The tannery workers had rough skin, rashes, itchy and decolorized skin, allergic diseases and respiratory illness, and had significantly lower levels of serum IgG, IgA, C3 and C4, but significantly higher levels of IgE than the controls. IgG, IgA and C3 levels were all inversely associated with Cr, while IgG, IgE and bactericidal activity showed an inverse correlation with duration of exposure. CONCLUSIONS. The results of the present study suggest that chronic exposure to Cr is associated with impaired immune function in male tannery workers. PARTICIPANT CONSENT. Obtained ETHICS APPROVAL. The present study was approved by the Ethical Review Committee of the faculty of Biological Sciences, University of Dhaka, Bangladesh. COMPETING INTERESTS. The authors declare no competing financial interests.