Aim: The aim of this study was to define clinical, histopathologic, and prognostic differences according to the presence of anti-ribosomal P antibody (anti-P) in Korean patients with biopsy-proven lupus nephritis (LN).
Methods: We studied 79 patients who underwent kidney biopsies prior to the start of induction treatment, and who were subsequently treated with immunosuppressive drugs for at least 6 months and followed-up for more than 6 months. Anti-P was measured by immunoblot analysis at the time of renal biopsy.
Results: Of all patients, 35.4% were anti-P-positive. Such patients exhibited earlier LN onset, a higher Systemic Lupus Erythematosus Disease Activity Index 2000 score, and a higher estimated glomerular filtration rate at the time of renal biopsy, than did those without antibodies. Upon renal histopathological analysis, patients with anti-P exhibited less interstitial inflammation in terms of the activity index, less glomerular sclerosis, less tubular atrophy, and less interstitial fibrosis in terms of the chronicity index. Furthermore, anti-P was associated with lower chronicity scores. At a median follow-up time of 47 months, renal function was preserved in 27 of 28 patients who had anti-P, but only 38 of 51 patients without such antibodies did not progress to chronic renal disease. After multivariate logistic regression, we found that anti-P positivity was associated with a reduced rate of progression to chronic kidney disease after adjusting for gender, baseline creatinine, activity and chronicity score, and treatment response (odds ratio = 0.196, 95% CI: 0.039-0.989, P = 0.048).
Conclusion: Anti-P was associated with better histological findings, and anti-P-positive patients had better renal outcomes than those without anti-P.
Keywords: anti-ribosomal P; autoantibody; lupus nephritis; systemic lupus erythematosus.
© 2019 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.