Objective To investigate the effects of toluene diisocyanate (TDI) exposure on lymphocyte subsets in peripheral blood of workers and explore the immunotoxicity of TDI.
Methods In this cross-sectional study, we recruited 53 TDI exposed workers and 55 non-TDI exposed workers by cluster sampling in Gansu Province. The concentration of TDI in working environment and the concentration of urinary toluenediamine (TDA) in workers were measured by gas chromatography. The lymphocyte subsets in peripheral blood were analyzed by flow cytometry. Combined with lymphocyte count measured by automatic blood analyzer, major lymphocyte subsets were calculated including CD3+T cells, CD4+T cells, CD8+T cells, B cells, and NK cells.
Results The median (P25-P75) of total urinary TDA was 15.86 (7.91-29.99) μg/L in the TDI exposed workers. The lymphocyte, CD3+T cell, CD4+T cell, CD8+T cell, B cell, and NK cell counts in the control group were 1.80 (1.40-2.30)×109/L, (1.24±0.35)×109/L, 0.65 (0.53-0.75)×109/L, 0.47 (0.35-0.57)×109/L, 0.18 (0.13-0.23)×109/L, and 0.23 (0.19-0.31)×109/L, respectively. The lym phocyte, CD8+T cell, and NK cell counts in the TDI exposed workers were 1.92 (1.59-2.46)×109/L, 0.54 (0.40-0.67)×109/L, and 0.45 (0.35-0.61)×109/L, respectively, which were higher than those in the control group (P < 0.05). We classified the exposed workers into two groups by the median of total urinary TDA levels:The counts of lymphocytes, CD3+T cells, CD4+T cells, CD8+T cells, and NK cells in the low exposure group were 2.13 (1.84-2.45)×109/L, (1.42±0.34)×109/L, 0.70 (0.58-0.83)×109/L, 0.60 (0.53-0.69)×109/L, and 0.48 (0.33-0.64)×109/L, respectively, and were significantly higher than those in the control group (P < 0.05); The count of NK cells was 0.43 (0.32-0.55)×109/L in the high exposure group, higher than that in the control group (P < 0.05). However, no difference was found between the low and high exposure groups (P > 0.05). Working years and the change of lymphocyte subsets were not associated (P > 0.05).
Conclusion TDI exposure could cause the change of lymphocyte subsets in peripheral blood of occupationally exposed workers, implying potential impacts of TDI on immunological functions.
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