Heightened levels of antimicrobial response factors in patients with systemic lupus erythematosus

Abstract

Abstract Systemic lupus erythematosus (SLE) is a complex autoimmune disorder characterized by immune system abnormalities and severe inflammation leading to multi-organ damage. Compromised gut permeability and microbial translocation is suggested to be associated with SLE. The objective of this study was to assess whether SLE subjects have increased systemic exposure to bacteria. Plasma from 30 SLE patients and 30 age and sex matched healthy controls were assessed for a series of clinically relevant antimicrobial response factors (ARFs) including sCD14, EndoCAbs, LBP, lysozyme, CXCL16, FABP2, galectin-3, and LL-37. The levels of sCD14 (P<0.0001), lysozyme (P<0.0001) and CXCL16 (P=0.001) were significantly elevated in SLE subjects compared to healthy controls. sCD14 exhibited a positive correlation with SELENA-SLEDAI score. EndoCAbs are antibodies directed against the endotoxin core of LPS. Interestingly, the ratio of EndoCAb IgM:total IgM was significantly decreased in SLE (P=0.006) and this ratio was negatively correlated with sCD14 levels (P=0.030, r=-0.396). We observed significant positive correlations between lysozyme levels and sCD14 (r=0.499, P=0.005), LBP (r=0.434, P=0.016), and FABP2 (r=0.396, P=0.030). Levels of CXCL16 was also positively correlated with the levels of sCD14 in SLE cohort (r=0.551, P=0.001). Moreover, Galectin-3 levels also positively correlated with lysozyme (r=0.447, P=0.013), sCD14 (r=0.425, P=0.019), and LBP (r=0.416, P=0.022). Overall, these changes in the levels and relationships between ARFs link microbial exposure and SLE. Thus, our study results are relevant to clinical SLE that will help to define better therapeutic strategies for SLE patients.