ECP 2023 Abstracts

S321 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 E-PS-16-009 Clinicopathological evaluation of 124 biopsy-proven lupus nephritis E. Kussever*, G. Gonlusen, K. Erdogan, B. Atmış, B. Kaya, A. Kara- bay Bayazıt, S. Paydas *Cukurova University, Turkey Background & objectives: Lupus nephritis (LN) is a common cause of kidney injury in systemic lupus erythematosus. We aimed to focused on pathological findings on LN. Methods: Totally 38 paediatric and 86 adult biopsy-proven LN were enrolled into this study. Paediatric and adult forms were evaluated comparatively. The histopathological examination was based on 2003 International Society of Nephrology/Renal Pathology Society system. Results: Paediatric patients data: the mean age was 11.5,male/female ratio was 0.4.Morphological classifications were divided into Class I(n:5),Class II(n:11),Class III(n:5),Class IV(n:15),Class V(n: 2).The mean activity scores were 2,5.6,8.5 and 1; chronicity scores were 0.09,0,0.78,1 according to Class II,III,IV and V respectively. The ultra- structural features were allowed Class II to Class III(n:1); Class III to Class III+Class V(n:1).Adult patients data: the mean age was 37, male/ female ratio was 0,2.Morphological classifications were divided into Class I(n:1),Class II(n:8),Class III(n:19),Class IV(n:51),Class V(n:7). The mean activity scores were 1,2.2,6.2,10.7,1.5; chronicity scores were 0.8,0.7,2.2,0.5 according to Class II,III,IV and V respectively. The ultrastructural features were allowed Class II to Class IV(n:1); Class III to Class III+Class V(n:2); Class IV to Class IV+V(n:3). Conclusion: Paediatric patients were summarized as: the mean age was 11,5 years old, male/female ratio was 0.4.Morphological classifications were divided into Class I(n: 5), Class II(n: 11), Class III(n: 5), Class IV(n:15), Class V(n: 2). The mean activity scores were 2, 5.6, 8.5 and 1 according to Class II, III, IV and V respectively. Chronicity scores were 0.09, 0, 0.78, 1 according to Class II,III,IV,V respectively. The ultrastructural features were allowed Class II to Class III (n:1); Class III to Class III+Class V(n:1). Funding: Çukurova University E-PS-16-010 T-cell-mediated cellular rejection and antibody-mediated rejection in HLA-DSA-negative kidney transplant recipients J. Osuna Soto*, F. Leiva-Cepas, I. Sánchez Ramírez, A. Sanz Zor- rilla, M.J. Galvez Medina, S. Haro Yuste *Hospital Universitario Reina Sofía, Spain Background & objectives: Banff 2021 categorized the previously “suspicious” Antibody Mediated Rejection (ABMR) without circulat- ing HLA Donor Specific Antibodies (DSA) in Kidney Transplant (Ktx) biopsies. Recent series describe absent HLA DSA (DSANeg-ABMR) up to 60% of ABMR histologies. Methods: To evaluate presentation and outcomes of biopsy-proven ABMRs (bpABMR) in patients with and without HLA-DSA Abs in solid-organ transplant (SOT) recipients. Single centre descriptive study of SOT patients (31KTx, 3 multiorgan) with ABMR under contempo- rary BANFF criteria between Feb 2014–Feb 2023 compared by HLA- DSA status. 34 total bpABMR were included. Results: 57,1% were DSANeg-ABMR. In this group, 55% were males, mean age of 41.8±12.6 vs 51.8±13.3 (p=0.04). 6 had preTx DSAs that vanished post-KTx and 5 developed them after the index biopsy. 47.1 % were first kidney allografts. 78,3% DSANeg-ABMR patients vs 41.7% (p=0.05) had received antibody-induction. 41.2% of DSANeg- ABMR vs 8.3% had acute TCMR (“Mixed Rejection”) (p=0.06). There were no differences in creatinine (Cr) pre-biopsy nor the 1st month postrasplant (1.87±0.73 vs 1.82±1.17mg/dl). ABMR appeared earlier in DSANeg-ABMR (median 276 vs 2487days, -p=0.04-). Survival analysis showed no significant differences between groups and 53% of allografts were lost at the second year. Conclusion: In our series, 57,1% of SOTs with ABMR had no cir- culating anti-HLA DSAs and as all ABMRs were diagnosed as per indication biopsy, this outcomes appeared earlier during follow up than in those with mensurable HLA-DSAs. The DSANeg-ABMR group showed a clear trend to present as a Mixed Rejection. Both groups entail a poor prognosis with a 53% renal survival after two years. E-PS-16-011 Stress biomarkers: from serum to tissue K. Palamaris*, A. Gkivalou, I. Theochari, E. Theodoropoulou, H. Gakiopoulou, P. Papazafiri, G. Chrousos, A. Charonis *First Department of Pathology, National and Kapodistrian University of Athens School of Medicine, Athens, Greece Background & objectives: The biological fingerprint of stress is under intensive current investigation. Stress-biomarkers like DDX6, β2-microglobulin and FKBP5 have been isolated in the serum of stressed patients. We comparatively investigated for the first time their histological expression in stressed and normal renal tissues. Methods: The study included 5 normal renal tissues derived from nephrectomy specimens and renal tissues from 15 patients (7 with hypertension without diabetes and 8 with diabetes without hyper- tension) as hypertension and diabetes constitute distinct well known stressor stimuli and their appearance is significantly influenced by the stress. Immunohistochemistry was performed with polyclonal antibod- ies against DDX6, β2-microglobulin and FKBP5. Results: In normal renal tissues no significant expression of DDX6 protein was observed. In contrast, hypertensive and diabetic kidneys showed significant increase in DDX6 expression in tubular epithelial cells, mainly in distal tubules. In normal kidneys, β2-microglobulin demonstrated diffuse immunohistochemical granular cytoplasmic expression in tubular epithelial cells, mainly proximal, and in glomeruli along the basement membranes of the capillaries. In hypertensive and diabetic kidneys there was decreased expression of β2-microglobulin in both compartments. As far as FKBP5 is concerned, its expression in normal tissues was mostly faint and cytoplasmic in some tubular cells. In contrast, in pathologic tissues a nuclear expression in tubular cells was observed. Conclusion: Although a limited number of samples were exam- ined, quantitative differences and differential patterns of expression of each protein between normal and pathological tissues, seem to exist. This is a first attempt to establish a link between serum stress- biomarkers and tissue pathology of stressed organs. The ultimate goal would be the discovery of molecular stress-algorithms with organ and/or tissue specificity in order to predict the appearance of stress, to quantify it, and to discover targeted therapies in the context of precision-medicine. E-PS-16-012 Chronic kidney graft neprhopathy. Prognostic histopathological variables? I. Sánchez Ramírez*, F. Leiva-Cepas, M.J. Galvez Medina, J. Osuna Soto, S. Haro Yuste, A. Sanz Zorrilla *Hospital Universitario Reina Sofía, Spain Background & objectives: The aim of our work was to perform an histopathological analysis of a cohort of cases presenting interstitial fibrosis (IF) and tubular atrophy (TA) after renal transplantation to clarify the mechanism underlying the development and prognostic significance of FI/TA.