Figure 2

Age-dependent changes of circulating monocyte subsets. (A) Representative FACS plots display an increase of CD14⁺CD16⁺ monocytes (grey gate) in comparison to classical CD14⁺⁺CD16^- monocytes (black gate) among freshly isolated PBMC from old (right plot, 51 years-old male) versus young (left plot, 24 years-old female) volunteers. (B) Box plots display absolute numbers of circulating CD14⁺⁺CD16^- monocytes (left), CD14⁺CD16⁺ monocytes (middle) and the relative percentage of CD14⁺CD16⁺ from total monocytes (right) 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, **p < 0.01 and ***p < 0.0015.