endpoint). Participants received intravenous administration of study drug on Day 1, were discharged from the institution on Day 2, received a single intramuscular dose of vaccine at the Week 4 visit, and were followed for 16 weeks in total on an outpatient basis. Blood samples were taken at regular intervals, and anti-tetanus toxoid and anti- diphtheria toxoid IgG, IgM and IgA quantitative ELISA assays were performed. Tetanus and diphtheria anti-toxoid IgG titers 0.1 IU/mL are generally considered to be protective. RESULTS: In the vaccination cohort, 15 participants were randomized and dosed with study drug or placebo, of whom 14 completed the study, and one participant who received VIS649 was lost to follow-up prior to receiving the vaccine. Both groups (placebo and VIS649) demonstrated increased tetanus anti-toxoid IgG titers following immunization, with a mean 7.9-fold increase in IU/mL at Week 6 for placebo recipients and a mean 6.4-fold increase in IU/mL for VIS649 recipients (Figure). At visits after Week 6, tetanus anti-toxoid IgG titers declined faster in the VIS649 group than in the placebo group (consistent with the reduction in total IgG associated with VIS649 administration) but remained above the protective threshold of 0.1 IU/mL all participants throughout the study. Similar trends were observed for diphtheria toxoid IgG titers, with a mean 5.5-fold increase in IU/mL at the Week 6 visit for placebo recipients and a mean 5.1-fold increase for VIS649 recipients (Figure). was no evidence of tetanus- or diphtheria-toxoid elicited IgM responses in either the placebo or VIS649 groups, consistent with the recall nature of the vaccination. In a hoc analysis, pre-existing serum tetanus/diphtheria anti-toxoid IgA titers fell betwee Day 1 and Week 4 in the VIS649 group, consistent with the overall suppression of serum IgA, were boosted after vaccination in both groups, and declined faster in the VIS649 recipients thereafter. CONCLUSION: VIS649 treatment did not interfere with participants’ ability to an antigen-specific serum IgG or IgA boost response to tetanus and diphtheria vaccination. There was no evidence of tetanus- or diphtheria-specific IgM responses either the placebo or VIS649 groups, consistent with recall vaccination exposure. data indicate that qualitative antibody responses are preserved during APRIL suppression. MO284 UTILITY OF SERUM IGA/C3 RATIO IN PREDICTING RENAL DISEASE PROGRESSION IN IGA NEPHROPATHY Sophia Mohammed 1 , Rajkumar Chinnadurai 2 , Arvind Ponnusamy 2 1 The University of Manchester, United Kingdom and 2 Royal Preston Hospital, Department of Renal Medicine, Fulwood, United Kingdom BACKGROUND AND AIMS: : IgA nephropathy is the most prevalent and predominantly slow progressing glomerular disease. Risk prediction tools like the international IgAN help to guide the prognosis in this group of patients. The IgA/C3 ratio has been shown to be a useful predictor of poor outcomes in Chinese cohort but such a study is lacking in the Caucasians. The study aims to investigate the utility of IgA/C3 score in predicting renal outcome in 5 years (50% decline in five years or reaching ESRD) in a Caucasian cohort. METHOD: All available patients with biopsy-proven IgA nephropathy in our centre between January 2001 and December 2013 were included in this observational study (115 patients). Baseline (biopsy date) data relevant to the scores including demographics, laboratory and the histopathological features were collated at the time of biopsy. Follow up data on renal functions and renal outcome (50% decline in eGFR at 5 years) were collected until an arbitrary end date 31/12/2018. IgA/C3 ratio was available in 46 (40%) of the patients and this cohort wase split into two groups based on IgA/C3 ratio (A- ratio </=3 and B- ratio >3) and analysed. RESULTS: We had a total of 115 patients recorded over this 13-year period. The median age of our cohort at time of biopsy was 41 years with a predominance of male gender (71%). At baseline 84% were hypertensive and 11% diabetic. 77% were on a renin-angiotensin blocker, with 53% being on a statin. At 2 years follow-up the median decline in estimated glomerular filtration (eGFR) between the groups was similar (Group- A 2.65 ml/min vs Group- B 2 ml/min, p=0.557). At 5 years, the median decline in eGFR was higher in Group B though not statistically significant (9.3ml/min vs 4.6ml/min, p=0.475) (Table-1). At 5 years a higher IGA/C3 ratio was showing appositive corelation to the decline in eGFR (Figure– 2). MO285 CLINICAL PRESENTATION OF IGA NEPHROPATHY AND LONG-TERM RENAL OUTCOME Gabriel Stefan 1,2 , Simona Stancu 1,2 , Adrian Dorin Zugravu 1,2 , Nicoleta Petre 3,4 , Gabriel Mircescu 1,2 1 University of Medicine and Pharmacy Carol Davila, Nephrology, 2 Dr Carol Davila Teaching Hospital of Nephrology, Nephrology, 3 University of Medicine and Pharmacy Carol Davila, Pathology and 4 Dr Carol Davila Teaching Hospital of Nephrology, Pathology BACKGROUND AND AIMS: There is a wide range of clinical presentation of IgA nephropathy (IgAN), from asymptomatic microscopic hematuria to rapidly progressive glomerulonephritis. However, there is little epidemiologic data on the relationship between the clinical pattern at diagnosis and long-term renal outcome. METHOD: We performed a unicentric retrospective study on 299 consecutive IgAN patients (age 43 [35-56] years, 71% male, eGFR 42.1 [25.2-62.8] mL/min, proteinuria 1.3 [0.6-2.6] g/g creatinine) - kidney biopsy proven - between 2010-2017. Patients were followed until composite endpoint (doubling of serum creatinine, ESKD (dialysis or renal transplant) or death, whichever came first) or end of study (May 2018). RESULTS: Patients were followed for a mean of 41 (95%CI 38, 44) months, and 80 (27%) patients experienced the composite endpoint. The most frequent clinical presentation at diagnosis regardless of age was nephritic syndrome (68%), followed by asymptomatic urinary abnormalities (AUA) (19%), macroscopic hematuria (15%), acute kidney injury (AKI) (14%) and nephrotic syndrome (10%). The clinical pattern varied in frequency with age: macroscopic hematuria had a bimodal distribution in the 20- and 60-years groups, AKI was more frequent in the 50 Nephrology Dialysis Transplantation Abstracts 10.1093/ndt/gfab104 | i217 Downloaded from https://academic.oup.com/ndt/article/36/Supplement_1/gfab104.0043/6289681 by guest on 18 February 2022