Fig. 2

Boxplot describing the BPIFB4 level in human serum by sub-phenotypes. The boxplots show the concentration of BPIFB4 protein detected. Controls (CTRLs, n = 32); frail long-living individuals affected with cancer, diabetes, cardiovascular disease, or stroke (F-LLIs, n = 7); healthy-aged long-living individuals (HA-LLIs, n = 23); all long-living individuals (LLIs, n = 30). Each boxplot describes: i) the lower bound of the non – outliers range; ii) the 25th percentile; iii) the 50th percentile (median value); iv) the 75th percentile; v) the upper bound of the non – outliers range of the BPIFB4 distribution. Each dot represents an outlier value with respect to the corresponding distribution. P-values were estimated by the non-parametric Wilcoxon Rank – Sum test. Bonferroni correction (*) was applied when testing for differences in terms of protein concentrations between F-LLIS, HA-LLIs and CTRLs