Telomere length-heterogeneity among myeloid cells is a predictor for chronological ageing.

We have previously shown that mean telomere length (TL) of granulocytes reflects TL of myeloid bone marrow cells extremely well. Here we analysed the distribution of TL from peripheral blood granulocytes and lymphocytes in 61 female and 68 age-matched male healthy volunteers. We show that the age-dependent decline in TL occurs more rapid in peripheral blood lymphocytes (53 bp/year) than in granulocytes (39 bp/year; p<0.001), while women having longer telomeres than men. We also observed the best correlation for age and telomere length to be present in lymphocytes. The coefficient variation (CV) of TL distribution in granulocytes and monocytes was significantly higher in older compared to younger individuals, indicating an increase in telomere length heterogeneity of myeloid cells and their bone marrow residing precursors during ageing. In a multivariate statistical model, CV and lymphocyte TL were able to explain 50% of chronological ageing.