Table 1: Characteristics of the patients. HZ pts (n = 66) Controls (n = 226) Age 54 (IQR 41-64) 45 (IQR 37-54) <0.001 Sex (female) 92.4% (61/66) 88.5% (199/226) 0.22 Histological Class Proliferative forms (III & IV) 81.0% (51/63) 74.9% (158/211) 0.26 Non proliferative forms (II & V) 19.0% (12/63) 25.1% (53/211) Activity index 6 (IQR 3-10) 6 (IQR 3-9) 0.79 Chronicity index 2 (IQR 1-4) 1 (IQR 0-3) 0.03 Creatinine (mg/dL) 0.9 (IQR 0.7-1.4) 0.9 (IQR 0.7-1.3) 0.91 Proteinuria (g/24h) 4.0 (IQR 1.8-5.3) 3.2 (IQR 2.0-5.4) 0.94 WBC (n/mmc) 5800 (IQR 4100-7600) 5600 (IQR 3900-7490) 0.63 C3 (mg/dL) 54.0 (IQR 46.0-73.0) 58.5 (IQR 48.0-79.0) 0.41 C4 (mg/dL) 11.0 (IQR 5.5-14.6) 9.8 (IQR 5-14) 0.54 IS at induction Cyclophosphamide 54.7% (29/53) 47.7% (83/174) 0.11 Azathioprine 5.7% (3/53) 15.5% (27/174) Mycophenolate 18.9% (10/53) 24.7% (43/174) Cyclosporin 9.4% (5/53) 3.5% (6/174) Rituximab 11.3% (6/53) 8.6% (15/174) Cumulative CS dose (grams) 48.9 (IQR 20.6-87.3) 21.5 (IQR 10.4-45.5) < 0.0001 Cumulative CS dose > 100 grams 15.2% (10/56) 3.1% (7/223) 0.001 Table 2: Univariate and multivariate logistic regression. Univariate logistic regression OR 95% CI P Age 1.032 1.013 1.053 0.04 Sex (female) 1.655 0.611 4.483 0.004 Proliferative form at renal biopsy 1.426 0.707 2.876 0.004 Activity index 1.01 0.948 1.076 0.0004 Chronicity index 1.094 0.956 1.253 0.007 Creatinine 1.028 0.791 1.334 0.0001 Proteinuria 0.966 0.884 1.056 0.002 Cumulative CS dose > 100 grams 5.510 2.008 15.123 0.04 Multivariate logistic regression OR 95% CI p Age 1.031 1.011 1.052 0.0002 Sex (female) 1.582 0.553 4.519 Proliferative form at renal biopsy 1.333 0.648 2.772 Cumulative CS dose > 100 grams 5.193 1.821 14.819 #3585 FAT1 ANTIGEN IN PATIENTS WITH MEMBRANOUS NEPHROPATHY AFTER HEMATOPOIETIC STEM CELL ALLOTRANSPLANTATION: A CASE SERIES Ines Bosni´ c Kovaˇ ci´ c 1 , Mario Laganovic 2 ,3 , Zivka Dika 3 ,4 , Marijana ´ Cori´ c 3 ,5 , Stela Bulimbasic 3 ,5 , Zinaida Peric 3 ,6 , Lana Grkovic 6 , Radovan Vrhovac 3,6 , Nadira Durakovic 3 ,6 , Bojan Jelakovic 3 ,4 and Ivana Vukovic Brinar 3 ,4 1 Clinical Hospital “Sveti Duh”, Department of Nephrology, Zagreb, Croatia, 2 Merkur Clinical Hospital, Department of Nephrology, Zagreb, Croatia, 3 School of Medicine, University of Zagreb, Zagreb, Croatia, 4 University Hospital Centre Zagreb, Department of Nephrology, Arterial Hypertension, Dialysis and Transplantation, Zagreb, Croatia, 5 University Hospital Centre Zagreb, Department of Pathology and Citology, Zagreb, Croatia and 6 University Hospital Centre Zagreb, Department of Haematology, Zagreb, Croatia Background and Aims: Nephrotic syndrome (NS) is a rare complication of haematopoietic stem cell transplantation (HSCT). When it occurs, it usually develops after cessation of immunosuppressive therapy, which is why it is commonly denominated as a renal form of chronic graft-versus-host disease. Membranous nephropathy (MN) is the most common pathological finding. The protocadherin FAT1 antigen is a novel antigen identified only in patients with MN who have undergone allogeneic HSCT. PLA2R and NELL1 antigens can also be found, even though they are rare and not specific to HSCT- associated MN. The aim of this study was to present a case series of allogeneic HSCT-associated MN, the treatment, outcomes and presence of a novel antigen specifically detected in this population. Method: All patients with full blown NS due to MN after HSCT in UHC Zagreb were enrolled. Kidney biopsy was performed and examined by light, immunofluorescence and electron microscopy. Biopsy samples were sent to Renal Pathology Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic for detection of FAT1 antigen in biopsy tissue samples Results: In last 30 years there had been 1302 HSCT in UHC Zagreb and three of them developed MN. The first two patients were treated with allogeneic HSCT for acute myeloid leukaemia (AML). Both developed NS after cessation of GVHD prophylaxis, after 1 and 8 months respectively. The first patient’s kidney function was preserved, while the second patient’s was reduced. Kidney biopsy showed MN. Thorough examination found no secondary cause of the disease. In the first patient, complete remission (CR) was achieved after 5 months of steroids, 2 boluses of cyclophosphamide (CP) and cyclosporine treatment. The second patient reached partial remission (PR) after 6 months of steroid treatment and oral CP. Immunosuppression was terminated due to infectious complications. CR was achieved after an additional 8 months while the patient was not taking immunosuppressants. Both patients remained in CR during the follow-up period. The third patient with acute lymphoblastic leukaemia (ALL) underwent a related peripheral blood HSCT. Sixteen years later, he developed NS with preserved renal function and was diagnosed with MN. Apart from thyroid disease, no secondary cause was detected and he was treated with rituximab. Partial remission (PR) was achieved after 24 months of therapy. i294 Abstracts Downloaded from https://academic.oup.com/ndt/article/38/Supplement_1/gfad063c_3585/7196843 by guest on 16 June 2023