The anti-mCRP199–206 antibodies aggravate tubulointerstitial lesions in lupus nephritis

Tubulointerstitial lesions could also be prominent in lupus nephritis, and the pathogenesis of tubulointerstitial lesions may be different from glomerular lesions. Previous studies have showed that plasma antibodies against modified /monomeric C-reactive protein (mCRP) are associated with renal tubulointerstitial lesions in patients with lupus nephritis, and amino acid (aa) 199–206 was one of the major epitopes of mCRP. However, the role of anti-mCRP_199–206 antibodies in the pathogenesis of tubulointerstitial lesions in lupus nephritis is unknown. A total of 95 patients with renal biopsy-proven lupus nephritis were enrolled in this study. Plasma levels of anti-mCRP_199–206 antibodies were screened by enzyme-linked immunosorbent assay (ELISA). A lupus prone mouse model was immunized using peptides mCRP_199–206 to explore the potential role of anti-mCRP_199–206 antibodies in tubulointerstitial lesions. The mechanism of anti-mCRP_199–206 antibodies damage to renal tubular epithelial cells was investigated in vitro. Plasma antibodies against mCRP_199–206 were associated with renal tubulointerstitial lesions and prognosis in patients with lupus nephritis. Immunization with peptides mCRP_199–206 in lupus prone mice could aggravate tubulointerstitial lesions and drive tubulointerstitial inflammation and fibrosis. Anti-mCRP _199–206 antibodies could activate the TGF-β1/Smad3 signal pathway and induce tubular damage by binding with CRP. Circulating antibodies against mCRP_199–206 could be a biomarker to reveal tubulointerstitial lesion, and participate in the pathogenesis of tubulointerstitial lesions, which might provide a potential therapeutic target for lupus nephritis.