Background/Purpose: Anti-ribosomal P antibody (anti-P) in patients with systemic lupus erythematosus (SLE) is associated with neuropsychiatric manifestation. Of interest, recent studies have suggested that anti-P is a marker for renal flare and disease activity and is associated with renal histopathologic findings in patients with lupus nephritis (LN). However, the clinical relevance and prognostic value of anti-P in patients with LN are not well characterized. Therefore, we examined the association of the presence of anti-P with the identification of clinical, histopathologic, and prognostic values in Korean patients with biopsy-proven LN.

Methods: Seventy-nine patients with LN were included in this study based on the availability of kidney biopsy specimens. Sociodemographic, clinical, laboratory, and treatment-related data at the time of kidney biopsy and during follow-up were obtained by reviewing patients’ charts. Renal biopsy specimens were reclassified according to the ISN-RPS classification by two renal pathologists blinded to the previous classification. Anti-P was measured by immunoblot assay at the time of renal biopsy. Kaplan-Meier analysis was performed to estimate the probability of progression to chronic kidney disease (CKD) according to the presence of anti-P.

Results: Twenty-eight (35.4%) of 79 patients were positive for anti-P. Patients with anti-P had an earlier age at LN onset (26.6 ± 10.1 versus 34.7 ± 12.1, P = 0.005), higher SLEDAI 2000 score (12.7 ± 4.2 versus 10.5 ± 4.8, P = 0.029), and higher eGFR level (129.0 ± 47.6 versus 102.2 ± 41.5, P = 0.005) at the time of renal biopsy than those without. The autoantibody profiles in patients with anti-P were not different from those without; however, anti-Sm antibodies were more common in patients with anti-P (71.4% versus 37.3%, P = 0.004). The renal histopathologic findings showed that patients with anti-P had less interstitial inflammation (67.9% versus 94.1%, P = 0.003) in the activity index and less glomerular sclerosis (21.4% versus 45.1%, P = 0.037), less tubular atrophy (42.9% versus 66.7%, P = 0.040), and less interstitial fibrosis (57.1% versus 78.4%, P = 0.046) in the chronicity index. In addition, anti-P positivity was significantly associated with lower chronicity scores (1.29 ± 1.24 versus 2.25 ± 1.63, P = 0.006). Although 13 of 51 (25.5%) patients without anti-P progressed to CKD after a median follow-up of 47 (6–108) months, only 1 of 28 (3.6%) patients with anti-P developed CKD (P = 0.015).

Conclusion: Our findings have shown that although anti-P is associated with an earlier age of onset and higher disease activity at the time of LN diagnosis, anti-P has a protective role in the development of CKD in patients with LN.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/anti-ribosomal-p-antibody-has-a-protective-role-in-the-development-of-chronic-kidney-disease-in-patients-with-lupus-nephritis/