Ryu DH, et al. - Given a potential association of T cell immunosenescence (a hallmark of aging immune system) with the risk of developing cancer and other aging-related diseases, researchers investigated the possible association of organochlorine pesticides (OCPs) with T cell immunosenescence in the general population. They measured serum concentrations of β-hexachlorocyclohexane, p,p'-DDT, p,p'-DDE, and trans-nonachlor in 95 Korean adults aged 30 to 64 years. Evaluation of the frequencies of CD8+CD57+, CD8+CD28-, CD4+CD57+, and CD4+CD28- T lymphocytes in 20 ml of fresh peripheral blood was used to assess T cell immunosenescence. Based on the findings, they concluded that chronic exposure to low-dose OCPs may represent a new risk factor for T cell immunosenescence.