Discrimination exposure and lymphocyte differentiation: Results from the health and retirement study.

Everyday discrimination is a social determinant of health linked to disease and mortality, with one potential mechanism of this link involving stress-related signaling that "weathers" immune health. Previous research has examined links between discrimination and inflammatory processes derived from innate immune cells, but little is known about the associations of everyday discrimination with lymphoid lineage cells (T cells and B cells) that mediate adaptive immunity. To better understand the potential immunological impact of everyday discrimination, we analyzed the relationship between Everyday Discrimination Scale scores and flow cytometry data from the Health and Retirement Study (n = 6337; mean age = 70 years, SD = 9 years; 58 % female; 71 % White). Primary analyses adjusted for sociodemographic factors and secondary analyses additionally controlled for health behaviors. Weighted results showed that higher levels of discrimination were significantly associated with higher total CD4 T, CD8 T, and B cell counts. Follow-up analyses of T and B cell maturity indicated a potential link between higher discrimination levels and mature "terminally differentiated" cells, including CD4 TEMRA (7.8 % elevation, 95 % CI: 3.8 %-12.0 % elevation,  < 0.001), CD8 TEMRA (2.9 % elevation, 95 CI: 0.1 %-5.9 % elevation,  = 0.040), and IgD memory B cells (3.4 % elevation, 95 CI: 0.7 %-6.0 % elevation,  = 0.012), but no significant associations with the immature "naïve" T or B cell subpopulations. Overall, these results suggest that everyday discrimination may contribute to immune aging by promoting the accumulation of terminally differentiated T and B cells, a profile consistent with accelerated immunosenescence in the adaptive immune system.