Autoantibodies against monomeric C-reactive protein in sera from patients with lupus nephritis are associated with disease activity and renal tubulointerstitial lesions.
Serum levels of C-reactive protein (CRP) often remain low despite high disease activity in systemic lupus erythematosus (SLE). Sera from 96 patients with renal biopsy-proven active lupus nephritis, 24 of 96 patients in remission, and 49 patients with SLE with negative urinalysis (nonrenal SLE) was collected. Immunoglobulin G autoantibodies against monomeric CRP (mCRP) were screened by enzyme-linked immunosorbent assay with purified human CRP. Associations with clinical features, pathological data, and laboratory findings were investigated. The prevalence of mCRP autoantibodies in active lupus nephritis (57/96, 59.4%) was significantly higher than that in patients with SLE without clinical evidence of kidney involvement (20/49, 40.8%, p = 0.034). For the 13 patients with positive mCRP autoantibodies and sequential sera, their positive mCRP autoantibodies in active phase turned negative in remission (13/13, 100%). Patients with mCRP autoantibodies had significantly higher SLEDAI scores than patients without mCRP autoantibodies (18.3 +/- 5.2 vs 15.8 +/- 4.0, p = 0.013), who were more likely to experience acute renal failure (14/55 vs 2/33, p = 0.022), oral ulcer (15/57 vs 3/39, p = 0.022), and delayed activated partial thromboplastin time (18/52 vs 2/38, p = 0.001). Positive correlations between levels of mCRP autoantibodies and semiquantitative scores of renal histologic features were first observed in lupus nephritis as follows: interstitial inflammation (r = 0.328), tubular atrophy(r = 0.276), interstitial fibrosis (r = 0.211), and chronicity index score (r = 0.243). Autoantibodies against mCRP are prevalent in patients with lupus nephritis and are associated with disease activity and renal tubulointerstitial lesions.
Renal Division, Department of Medicine, Peking University First Hospital, Institute of Nephrology, Peking University, and Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China.
Ying
Y
Tan
Feng
F
Yu
Haizhen
H
Yang
Min
M
Chen
Qiying
Q
Fang
Ming-hui
MH
Zhao
D000328:Adult; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D015415:Biomarkers; D002097:C-Reactive Protein / Q000096:biosynthesis / Q000276:immunology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D007668:Kidney / Q000276:immunology / Q000473:pathology / Q000503:physiopathology; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000276:immunology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012075:Remission, Spontaneous; D012720:Severity of Illness Index
D001323:Autoantibodies; D015415:Biomarkers; D002097:C-Reactive Protein