Figure 1

Age-dependent changes of circulating leukocytes. Box plots display absolute numbers of circulating total leukocytes (A), neutrophils (B), monocytes (C), lymphocytes (D) and lymphocyte subsets (E) in 10⁹/L for the different groups of young (<30 years, n = 51), middle-aged (30-50 years, n = 70) and old (>50 years, n = 60) healthy volunteers. The bold black line indicates the median per group, the box represents 50% of the values, and horizontal lines show minimum and maximum values of the calculated non-outlier values; open circles indicate outlier values. Significant differences (Kruskal-Wallis and U-test) are marked by *p < 0.05.