Alteration in Leukocyte Subsets and Expressions of FcγR and Complement Receptors among Female Ragpickers in Eastern India

Abstract

Background: There are a million ragpickers in India who gather and trade recyclable municipal solid wastes materials for a living. The objective of this study was to examine whether their occupation adversely affects their immunity.

Methods: Seventy-four women ragpickers (median age, 30 years) and 65 age-matched control housemaids were enrolled. Flow cytometry was used to measure leukocyte subsets, and leukocyte expressions of Fcγ receptor I (CD64), FcγRIII (CD16), complement receptor 1 (CD35) and CR3 (CD11b/CD18), and CD14. Serum total immunoglobulin-E was estimated with enzyme-linked immunosorbent assay.

Results: Compared with the controls, ragpickers had significantly (p < 0.0001) higher levels of CD8+T-cytotoxic, CD16+CD56+natural killer, and CD4+CD45RO+memory T-cells, but depleted levels of CD19+B-cells. The percentage of CD4+T-helper-cells was lower than the control group (p < 0.0001), but their absolute number was relatively unchanged (p = 0.42) due to 11% higher lymphocyte counts in ragpickers. In ragpickers, the percentages of CD14+CD16+intermediate and CD14dim CD16+nonclassical monocyte subsets were elevated with a decline in CD14+CD16-classical monocytes. The expressions of CD64, CD16, CD35, and CD11b/CD18 on both monocytes and neutrophils, and CD14 on monocytes were significantly higher in ragpickers. In addition, ragpickers had 2.7-times more serum immunoglobulin-E than the controls (p < 0.0001). After controlling potential confounders, the profession of ragpicking was positively associated with the changes.

Conclusion: Ragpicking is associated with alterations in both innate (neutrophils, monocytes, and natural killer cell numbers and expression of complement and Fcγ receptors) and adaptive immunity (numbers of circulating B cells, helper, cytotoxic, and memory T cells).

Keywords: FcγR; complement receptors; lymphocyte; monocyte; ragpicker.

Fig. 1

Histograms showing relative distribution (%) of (A) classical, (B) intermediate, and (C) nonclassical monocyte subsets, and (D) absolute numbers of overall monocytes in peripheral blood among control and ragpickers. Bars indicate standard deviation of the mean. * p < 0.05 considered significant compared with controls in unpaired Student t test.

Fig. 2

Histograms showing mean fluorescence of (A) FcγRI in monocytes, (B) FcγRI in neutrophils, (C) FcγRIII in monocytes, and (D) FcγRIII in neutrophils in peripheral blood among control and ragpickers. Bars indicate standard deviation of the mean. * p < 0.05 considered significant compared with control in unpaired Student t test. AU, arbitrary unit, FcγR, Fcγ receptor; MFI, mean fluorescence intensity.