Aging affects the proportions of T and B cells in a group of elderly men in a developing country--a pilot study from Pakistan.

Immune status is different in the elderly and the young, but whether age-associated differences are similar in developing and industrialized countries is unclear. To approach this question, peripheral blood immune cell phenotypes were analyzed by polychromatic flow cytometry in 50 young and 50 elderly men in a pilot study in a rural area of Pakistan. As a group, the elderly had a significantly lower CD4:CD8 ratio, a lower percentage of CD8+ naïve T cells, and significantly higher percentage of late-differentiated memory cells than the young. No age-associated differences were seen in B cells or NK cells. CD8+ cells as a percentage of CD3+ T cells were positively associated with plasma CRP levels but not other factors. We conclude that there are differences between the peripheral immune cell phenotypes of young and elderly Pakistani men and that these seem broadly similar to those more extensively documented in industrialized countries, despite the marked societal, nutritional, and many other differences in these populations.