POS0722 Histopathological Analysis of Lupus Nephritis Incorporating Banff Criteria Emphasizes the Importance of Tubulointerstitial Changes for Creatinine and Proteinuria at 12 Months after Renal Biopsy

Abstract

Background: Lupus nephritis (LN) occurs in about 30-60% of patients with systemic lupus erythematosus (SLE). LN is associated with increased mortality. Currently, the diagnosis relies on histopathologic characteristics according to the ISN/RPS classification (1). This classification relies heavily on glomerular changes and may not accurately reflect all changes occurring in LN. For the description of transplanted kidney, the BANFF classification has been established which, in addition to glomerular changes, also incorporates tubular pathologies (2). Objectives: With the present study, we aim to describe histopathologic changes according to the BANFF classification in a single-center cohort of LN patients. Methods: We retrospectively recorded epidemiological, clinical and laboratory data of 58 patients with LN over a ten-year period. Histopathologic diagnoses according to ISN/RPS classification or the former WHO classification were also documented. We then re-analyzed representative kidney samples according to the BANFF classification and performed Spearman rank correlation for BANFF findings and creatinine at biopsy and 12 months as well as proteinuria at biopsy and at 12 months. Results: We analyzed 58 patients with LN. 9 were male, 49 were female. Median age was 38 (15-78) years. According to ISN/RPS, 3 had class I LN, 6 had class II, 14 had class III, 16 had class IV, 6 had class V, and 0 had class VI. Median eGFR at biopsy was 60 ml/min/1.73m2 (13-137). According to the BANFF classification, tubulointerstitial inflammation (ti) was associated with creatinine at 12 months. Proteinuria at 12 months was associated with interstitial fibrosis (ci) (Figure 1). Conclusion: In LN, the current ISN/RPS classification puts emphasis on glomerular changes. Nevertheless, for the long-term outcome, tubulointerstitial changes (tubulointerstitial inflammation and interstitial fibrosis) may at least be as important as glomerular changes. These findings have to be corroborated in larger cohorts with prespecified renal endpoints. References: [1]Weening et al. The classification of glomerulonephritis in systemic lupus erythematosus revisited. JASN 2004. [2]Jeong HY. Diagnosis of renal transplant rejection: Banff classification and beyond. Kidney Res Clin Pract 2020. Disclosure of Interests: Marlene Plüß: None declared, Samy Hakroush: None declared, Noah Niebusch: None declared, Björn Tampe: None declared, PETER KORSTEN Speakers bureau: Abbvie, Pfizer, Chugai, Sanofi, Boehringer-Ingelheim, GSK, Novartis, Consultant of: Abbvie, Pfizer, Chugai, Sanofi, Boehringer-Ingelheim, GSK, Novartis, Lilly, Gilead, Grant/research support from: GSK

Background: Lupus nephritis (LN) occurs in about 30-60% of patients with systemic lupus erythematosus (SLE). LN is associated with increased mortality. Currently, the diagnosis relies on histopathologic characteristics according to the ISN/RPS classification (1). This classification relies heavily on glomerular changes and may not accurately reflect all changes occurring in LN. For the description of transplanted kidney, the BANFF classification has been established which, in addition to glomerular changes, also incorporates tubular pathologies (2). Objectives: With the present study, we aim to describe histopathologic changes according to the BANFF classification in a single-center cohort of LN patients. Methods: We retrospectively recorded epidemiological, clinical and laboratory data of 58 patients with LN over a ten-year period. Histopathologic diagnoses according to ISN/RPS classification or the former WHO classification were also documented. We then re-analyzed representative kidney samples according to the BANFF classification and performed Spearman rank correlation for BANFF findings and creatinine at biopsy and 12 months as well as proteinuria at biopsy and at 12 months. Results: We analyzed 58 patients with LN. 9 were male, 49 were female. Median age was 38 (15-78) years. According to ISN/RPS, 3 had class I LN, 6 had class II, 14 had class III, 16 had class IV, 6 had class V, and 0 had class VI. Median eGFR at biopsy was 60 ml/min/1.73m2 (13-137). According to the BANFF classification, tubulointerstitial inflammation (ti) was associated with creatinine at 12 months. Proteinuria at 12 months was associated with interstitial fibrosis (ci) (Figure 1). Conclusion: In LN, the current ISN/RPS classification puts emphasis on glomerular changes. Nevertheless, for the long-term outcome, tubulointerstitial changes (tubulointerstitial inflammation and interstitial fibrosis) may at least be as important as glomerular changes. These findings have to be corroborated in larger cohorts with prespecified renal endpoints. References: [1]Weening et al. The classification of glomerulonephritis in systemic lupus erythematosus revisited. JASN 2004. [2]Jeong HY. Diagnosis of renal transplant rejection: Banff classification and beyond. Kidney Res Clin Pract 2020. Disclosure of Interests: Marlene Plüß: None declared, Samy Hakroush: None declared, Noah Niebusch: None declared, Björn Tampe: None declared, PETER KORSTEN Speakers bureau: Abbvie, Pfizer, Chugai, Sanofi, Boehringer-Ingelheim, GSK, Novartis, Consultant of: Abbvie, Pfizer, Chugai, Sanofi, Boehringer-Ingelheim, GSK, Novartis, Lilly, Gilead, Grant/research support from: GSK