ECP 2023 Abstracts

S322 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 Methods: FI/TA was diagnosed in 50 renal allograft biopsy specimens (BS) obtained fron 85 renal transplant recipients under follow-up in our department in the last 5 years (2018- 2023). The biopsies were digitized for visualization. Results: FI/TA was diagnosed at a mean of 33.5 months after trans- plant. Among the 85 patients with FI/TA, 29 (44%) had history of acute rejection. Among the 85 BS with IF/TA, FI/TA was grade I in 53, II in 29, and III in 3. Arteriosclerosis of medium-sized arteries was observed in 73 BS (86%). The 85 patients were then classi- fied according to general histopathological characteristics: FI/TA alone (15 BS; 18%), FI/TA+ medullary injury (30 BS; 32%), and FI/TA + rejection (32 BS; 36%). Renal allograft loss occurred in two of the patients (4%). Of the remaining patients with functioning grafts, deterioration of allograft function after biopsies occurred in 22 patients (26%). Conclusion: The results of our study suggest that rejection contributes to FI/TA in 20-30% of cases, medullary injury in 30-40% of cases, and non-specific injury in 20% of cases. FI/TA significantly contributes to impaired renal allograft function. E-PS-16-013 Sarcoidosis and COVID-19: is there a link? E. Theodoropoulou*, E. Chelioti, K. Palamaris, G. Christofilidis, M. Kaniadaki, A. Stofas, M. Papadaki, H. Gakiopoulou *Nephrology Department, Tzaneio General Hospital of Pireaus, Greece Background & objectives: COVID-19 and sarcoidosis share common pathophysiologic mechanisms including dysregulation of renin-angio- tensin-system, exacerbation of immune responses involving increased cytokine levels, and cell-death pathways. Although the causal associa- tion is not well established, case reports depict time-association and interaction between these two diseases. Methods: A 50-year-old male presented with malaise, anorexia, and cough starting one month ago as well as vomiting in the last few days. Two months ago, he suffered from mild to moderate COVID-19 with fever and dry cough without hypoxemia and normal X-ray. The symp- toms lasted for about a week. He received no special treatment. He was not vaccinated against Sars-COVID-19. Results: At presentation, painless brownish symmetrical plaques were noted in both knees. Initial work-up was significant for cre- atinine (11.2mg/dL), urea (228mg/dL) and calcium (13.8mg/dL). PTH was low at 21pg/mL. Urine sediment was inactive and pro- teinuria minimal (448mg/24h). Central hypothyroidism was noted with low TSH/T4/T3. Renal ultrasound demonstrated increased kidney volume bilaterally and multiple hyperechoic depositions scattered throughout the renal parenchyma. Chest-CT-scan showed nodular lung lesions, bilateral hilar lymphadenopathy and multiple enlarged mediastinal lymph nodes. Brain-CT-scan showed hetero- geneity of the pituitary gland. Serum-Angiotensin-Converting- Enzyme (SACE) was high at 130Units/L. A kidney biopsy was performed revealing non-caseating granulomatous interstitial nephritis accompanied by severe acute tubular injury and nephro- calcinosis. Clinicopathologic correlation suggested the diagnosis of sarcoidosis. Conclusion: Haemodialysis was started, and 3 boluses of methyl- prednisolone were administered followed by 1mg/kg prednisolone. Eleven haemodialysis sessions were totally performed. Urine output gradually increased, and values of creatinine, urea and calcium sub- sequently decreased to normal levels. Three months later, SACE had been normalized at 45Units/L. Chest-CT-scan showed no evidence of pulmonary lesions or lymphadenopathy. Our case represents a rare case of sarcoidosis with multi-organ involvement (lung, lymph-nodes, skin, kidney and pituitary gland) following and probably triggered by COVID-19 infection. E-PS-16-014 Cryoglobulinemic vasculitis in a patient with HCV infection and IgMk paraproteinemia E. Theodoropoulou*, E. Chelioti, G. Christofilidis, K. Palamaris, M. Kaniadaki, M. Papadaki, A. Stofas, H. Gakiopoulou *Nephrology Department, Tzaneio General Hospital of Pireaus, Greece Background & objectives: Several glomerular diseases have been associated with HCV infection including mixed cryoglobulinemia syn- drome (MCS) which is a systemic vasculitis. Methods: A 51-year-old female diagnosed with mild ulcerative coli- tis one month earlier, presented with weakness, leg oedema, palpable purpura in lower legs, anaemia, pericardial effusion and reduced ejec- tion fraction, peripheral neuropathy, pulmonary fibrosis, ground glass opacities, impaired renal function with reduced urine output, glomeru- lar haematuria and proteinuria (3,1gr/day). Complement was low and rheumatoid factor was positive. A renal biopsy was performed. Results: Renal biopsy showed glomerulonephritis with membrano- proliferative-pattern and endocapillary hyaline thrombi with hyper- microscopic features suggestive of cryoglobulines. Immunofluores- cence showed IgG/IgM/ C3/ C1q and both light chains κ and λ. Τype II cryoglobulins (monoclonal IgM and polyclonal IgG) were posi- tive. Serum and urine immunofixation revealed monoclonal IgMκ. Fur- ther evaluation revealed HCV positivity, genotype 4, with liver fibrosis grade-3 albeit with normal liver function tests. The work-up for non- Hodgkin lymphoma or lymphoproliferative disease was negative. The patient initially received high dose methylprednisolone and hae- modialysis treatments. After the biopsy result, she underwent 6 plasma- pheresis treatments and started direct-acting-antivirals/DAAs (elbasvir- grazoprevir) and rituximab. Gradually, kidney function improved and all manifestations of MCS subsided. Conclusion: MCS diagnosis should be raised in any patient who pre- sents with one or more of the following clinical features: palpable pur- pura, skin ulcers, arthralgias and/or arthritis, peripheral neuropathy, and/or microscopic haematuria or proteinuria with or without chronic kidney disease. The index of suspicion for MCS should be raised further if these occur in the setting of viral infection (eg, HCV, HBV, or HIV), connective tissue disease (systemic lupus erythematosus, Sjögren syn- drome, or rheumatoid arthritis), or lymphoproliferative disorder. E-PS-16-015 Prognostic value of histological parameters in acute tubulointer- stitial nephritis (ATIN) C. Vieru*, M.L. Abascal Camacho, P. Nuñez Ramos, Y. Gómez Nav- arro, M. Goicoechea Diezhandino., M.R. Melero Martin, T. Bada Bosch, I.G. Arenas Moncaleano, J.C. De la flor, Ú. Verdalles Guz- man, J.M. Lara Martínez, F. Arias, F.J. Díaz Crespo *Hospital General Universitario Gregorio Marañón, Spain Background & objectives: ATIN is a varied aetiology and increasing incidence entity and it is a frequent cause of acute kidney injury (AKI). Renal biopsy is not always used to diagnose it and scarce histological studies of prognostic value are available. Methods: We searched the pathology archives of our department between 2017 and 2023. We retrospectively analysed sociodemo- graphic (age and sex), clinical (biopsy date, microhaematuria, leu- kocyturia, renal function at diagnosis, AKI, acute dialysis, protein/ creatinine, 24h proteinuria, renal recovery) and histological data (number of glomeruli and inflammatory infiltrate percentage, dis- tribution and components, tubulitis degree, tubular destruction and acute tubular necrosis). Results: 34 cases were retrospectively studied, 20 males (58.8%) and 14 females (41.2%) with mean age of 62,15 +/- years. All patients received standard corticotherapy. Patients were divided into two groups based