Fig. 6

Ceramide synthesis and acid sphingomyelinase activity are increased in CAP and COPD exacerbation. a Ceramide C 16:0, b ceramide C 18:0, c ceramide C 24:1, d acid sphingomyelinase activity, measured with an in vitro assay based on separate aliquots from the plasma samples used for the mass-spectrometric measurements. e–g Increased expression of SMPD1 (sphingomyelin phosphodiesterase, synonymous with acid sphingomyelinase) mRNA in CAP. Published datasets from studies on gene expression in CAP were reanalyzed for expression of SMPD1 mRNA as described in [47]. The mRNA expression data had been obtained with microarray analysis of whole blood. Y-axis units correspond to normalized expression values. e Increased expression of splicing isoform 1 in community-acquired bacterial CAP [23], available at GEO, accession no GSE40012. Diagnostic groups: Bacterial CAP (BAC), n = 16; influenza A virus CAP (IAV), n = 8; mixed infection CAP (mixed, n = 3); systemic inflammatory response syndrome (SIRS, n = 12); healthy donors (HD, n = 18). f, g Increased expression of splicing isoforms 1 and 2 in CAP at baseline (f) and decrease of both isoforms after treatment of CAP (g) [24], GEO accession no. 42830. Diagnostic groups in f: Ctrl (healthy controls, n = 38), CAP (n = 8). Diagnostic groups in g: CAP before and after treatment, n = 5 each. *p < 0.05, **p < 0.01, ***p < 0.001 (Mann–Whitney U test for paired comparisons)