<p>(A) In patients with SLE (n = 185) but not with RA (n = 92) or normal healthy donors (NHD, n = 74) serum autoAbs to LL-37 are detected. Shown are optical density (OD) indices, which are the ratios of the OD in the individual donor to the mean OD in NHD sera. One dot represents one patient, horizontal bars show the means. ***P<0.001, as determined by Kruskal-Wallis test with Dunn’s post-hoc test. Dashed line shows cutoff OD (1,93). (B) Sera of SLE patients (n = 21) were preincubated with saturating concentrations of LL-37 peptide before reactivity to plate-bound LL-37 was determined by ELISA. IgG reactivity to LL-37 can be blocked by preincubation with LL-37 peptide. ***P<0.001, as determined by Mann-Whitney U test. (C) Serum levels of LL-37 peptide are raised in a subgroup of SLE and RA patients. One dot represents one donor. Dashed line shows cutoff OD (2,77 ng/ml). (D) No correlation is found between SLE anti-LL-37 autoAbs and disease parameters of SLE. X-Y scatter plots of correlations between OD indices of anti-LL-37 autoAbs in SLE patients and SLEDAI (n = 163), anti-dsDNA autoAbs (n = 73), or serum levels of C-reactive protein (CRP, n = 74) or of IFNα (n = 28), respectively. Spearman coefficients (r) are depicted within the graphs. N.s., not significant. (E) Serum levels of LL-37 peptide are not linked to SLE disease activity. X-Y scatter plot of correlation between serum LL-37 levels and SLEDAI in 110 patients with SLE. Spearman coefficient (r) is depicted within the graph. N.s., not significant.</p
