Aflatoxin B1 albumin adduct levels and cellular immune status in Ghanaians
Although aflatoxins (AFs) have been shown to be immune-suppressive agents in animals, the potential role of AFs in modifying the distribution and function of leukocyte subsets in humans has never been assessed. We examined the cellular immune status of 64 Ghanaians in relation to levels of aflatoxin B1 (AFB1)-albumin adducts in plasma. The percentages of leukocyte immunophenotypes in peripheral blood, CD41 T cell proliferative response, CD41 T h and CD81 T cell cytokine profiles and monocyte
... les and monocyte phagocytic activity were measured using flow cytometry. NK cell cytotoxic function was determined by perforin and tumor necrosis factor-a expression in CD3ÿCD561 NK cells. AFB1-albumin adducts levels ranged from 0.3325 to 2.2703 (mean 5 0.9972 6 0.40, median 5 0.9068) pmol mg ÿ1 albumin. Study participants with high AFB1 levels had significantly lower percentages of CD31 and CD191 cells that showed the CD691 activation marker (CD31CD691 and CD191CD691) than participants with low AFB1 levels (P 5 0.002 for both). Also, the percentages of CD81 T cells that contained perforin or both perforin and granzyme A were significantly lower in participants with high AFB1 levels compared with those with low AFB1 (P 5 0.012 for both). Low levels of CD31CD691 (r 5 ÿ0.32, P 5 0.016) and CD191CD691 (r 5 ÿ0.334, P 5 0.010) cells were significantly associated with high AFB1 levels using correlation analysis. By multivariate analysis, there were strong negative correlations between the percentages of these cells (CD31CD691: b 5 ÿ0.574, P 5 0.001, and CD191CD691: b 5 ÿ0.330, P 5 0.032) and AFB1 levels. These alterations in immunological parameters in participants with high AFB1 levels could result in impairments in cellular immunity that could decrease host resistance to infections.