Lymphocyte cell counts in middle age are positively associated with subsequent all-cause and cardiovascular mortality

Background: There is an association between higher white blood cell counts and all-cause and cardiovascular disease mortality. However, little is known about the prognostic significance of circulating lymphocyte and lymphocyte subset numbers. Aims: The present study examined the association between T, CD4,CD8,and B cell numbers, and the CD4:CD8 ratio, and all-cause and cardiovascular disease mortality. Methods: Lymphocyte and lymphocyte subset numbers were measured by flow cytometry in a cohort of 4256 male middle-aged Vietnam-era US veterans. Mortality was tracked for 15 years and cause of death was determined from death certificates. Results: In fully-adjusted survival analyses, high circulating T cells numbers were associated with increased risk of both all-cause (HR=1.75,95%CI 1.15 – 2.66) and cardiovascular (HR = 3.57, 95%CI 1.53 – 8.33) mortality. The former association appeared to reflect an effect for high CD8 cells numbers, the latter an effect for high CD4 cell numbers. For all-cause mortality, a high CD4:CD8 ratio was protective (HR = 0.58, 95%CI 0.41 – 0.81) Cardiovascular mortality was also predicted by high B cells numbers (HR = 1.87, 95%CI 1.10 – 3.17). Conclusion: Circulating lymphocyte and lymphocyte subset numbers may have substantial prognostic significance for both all-cause and cardiovascular disease mortality