A RETROSPECTIVE STUDY ON LUPUS NEPHRITIS: EXAMINING CLINICAL, SEROLOGICAL, AND PROGNOSTIC DIFFERENCES BETWEEN PEDIATRIC AND ADULT-ONSET PATIENTS IN A TERTIARY MEDICAL CENTER

Background: Systemic Lupus Erythematosus (SLE) renal involvement occurs in approximately 40-50% of adult patients. Compared to adult-onset SLE cases, pediatric-onset SLE nephritis is reported to be more prevalent and often results in more severe outcomes. Objectives: This study seeks to evaluate the distinctive features of renal involvement and compare the clinical outcomes between childhood-onset and adult-onset SLE cases. Methods: This retrospective study, conducted at a tertiary center specializing in adult and pediatric rheumatology clinics, included 178 cases of biopsy-proven lupus nephritis. The study retrieved comprehensive demographic, clinical, and laboratory information, along with details about treatment protocols, from patient files and electronic records. Renal pathology assessments were conducted in accordance with the 2018 International Society of Nephrology/Renal Pathology Society (ISN/RPS) classification criteria. Activity score, chronicity index, endocapillary hypercellularity, leucocyte infiltration, subendothelial hyaline deposits, fibrinoid necrosis/karyorrhexis, cellular crescents, glomerular sclerosis, interstitial inflammation, tubular atrophy, interstitial fibrosis, and fibrous crescents were compared between the adult- and pediatric-onset SLE nephritis group. In addition, out of ISN/RPS criteria, thrombotic microangiopathy was also compared among the groups. For the cases biopsied before 2018, pathology reports were reassessed and scored by a single pathologist who has over twenty years of experience in the field. Differences between the preferred treatment protocols and the goals for therapeutic achievement were assessed among the groups. In addition, multiple correlation analyses were performed between the relevant clinicopathologic parameters and the presence of chronic kidney disease (CKD). Results: In this study, 178 patients diagnosed with lupus nephritis were included, with 43 from the pediatric rheumatology clinic and 128 from the adult rheumatology clinic. The female-to-male ratio was 99/29 (F/M) in the adult-onset group and 33/10 in the pediatric-onset group (p>0.05). The median time interval from SLE diagnosis to biopsy-proven lupus nephritis was 10 (IQR 0-60) months in adult-onset cases and 1.75 (IQR 0-7.04) months in childhood-onset cases (p>0.05). ISN/RPS Class IV was the most encountered pathological subgroup both in adult-onset SLE (N=38, 29.7%) and childhood-onset SLE (N=20, 50.0%) nephritis (Table 1). There were no significant differences in renal biopsy chronicity indices between the two groups (p>0.05). In terms of the treatment method, Rituximab was more preferred in adult-onset SLE nephritis (p=0.005), while Cyclophosphamide and Mycophenolate Mofetil selection were not different among the groups (p>0.05). Demographic and clinical findings were presented in Table 1. Seventeen patients (18.9%) in adults and 16 patients (50%) in children achieved prednisolone-free status and had proteinuria < 500 mg/day during treatment (p = 0.001). End-stage renal failure occurred in 35 patients (27.8%) in adults and 3 patients (7.3%) in children (p = 0.007). Conclusion: As opposed to current literature, our study reveals that childhood-onset lupus nephritis has a lower likelihood of progressing to end-stage renal disease with a more favorable treatment response, while the clinical manifestations are not different from adult-onset SLE nephritis. Additionally, endocapillary hypercellularity and glomerular sclerosis are slightly correlated with CKD, while the presence of fibrinoid necrosis/karyorrhexis is negatively correlated with CKD. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests: None declared. DOI: 10.1136/annrheumdis-2024-eular.5058 Keywords: Kidneys, Autoantibodies Citation: , volume 83, supplement 1, year 2024, page 1008Session: Systemic lupus erythematosus (Poster View)

Kidneys, Autoantibodies