Thu0255 autoantibody Profile and Ethnicity: Risk Factors for Accelerated Development of Lupus Nephritis

Abstract

Background:Systemic Lupus Erythematosus (SLE) is a multisystem autoimmune disease. African ancestry is associated with an increased risk of Lupus Nephritis (LN). Anti-DNA autoantibodies play a major role in the development of LN and anti-Ro antibodies have also been implicated. McCarty et al suggested that women of African ancestry with the unusual autoantibody combination of anti-Sm, Ro & RNP antibodies (AB) were at increased risk of developing LN (1).Objectives:Our aim was to determine the correlation between autoantibody profile: Sm, Ro and RNP as a combination in the development of LN in patients with African ancestry. We investigated time to the development of LN from SLE onset.Methods:A retrospective case-control study was conducted at Guys and St Thomas NHS Trust, London, United Kingdom.75 patients with confirmed LN meeting the ACR classification criteria for SLE and Nephritis, were included: African (n=35), Caucasian (n=22) and Asian (n=17) ancestry. LN patients with the combination of Sm, Ro and RNP antibodies (Group 1) were compared to LN patients without this autoantibody combination (Group 2). Demographic data, pathology results and laboratory findings were collected.Anonymised data was analyzed using Statistical Package for Social Sciences (SPSS). Left censorship bias was reduced by use of a database of confirmed LN in our cohort of patients. Research and Development Office approval was obtained for this study.Results:There were 66 (88%) females and 9 (12%) males. The median age in Group 1 was 39 years (range 18-60), while in group 2 the median age was 45 years (range 24-64).We stratified our population based on their antibody status: Of the 75 (100%) patients, 32 (42.6%) patients had the combination of Sm, Ro & RNP antibodies (Group 1) while the remaining 43 (57.4%) patients did not (Group 2).In Group 1, regardless of ethnicity, 29 (90.6%) patients developed LN within 5 years or less from the onset of SLE symptoms, while the remaining 3 (9.4%) developed LN after 5 years. In contrast, in Group 2, 24 (55.8%) patients developed LN within 5 years or less while 19 (44.2%) developed LN after 5 years. (P value = 0.002)Further stratification was based on ethnicity and antibody (AB) status to investigate the time to develop LN from SLE symptom onset: African ancestry with positive AB, African with negative AB, Asian with positive AB, Caucasian with positive AB and Asian & Caucasian with negative Ab. Analysis showed that of 29 (38.7%) African ethnicity patients with the autoantibody combination, 19 (65.5%), developed LN within 5 years. In comparison, 46 (61.3%) patients, independent of ethnicity and AB status, developed LN after 5 years (P value = 0.01).Conclusion:Patients with the unusual autoantibody combination of Sm, Ro & RNP developed LN significantly earlier than patients who did not have this combination. This autoantibody combination was significantly over represented in the African ancestry patients. Our data suggests that African ancestry patients with this autoantibody combination are at increased risk of developing LN soon after SLE symptom onset and merit close monitoring for the development of renal disease.References:[1]McCarty GA, Harley JB, Reichlin M. A distinctive autoantibody profile in Black female patients with lupus nephritis. Arthritis & Rheumatism. 1993; 36:1560-1565Table 1.1Ethnicity with Autoantibody status showing the rate of progression into Lupus Nephritis.Duration of LN onsetTotalLess than 5 years after SLE onsetMore than 5 years after SLE onsetEthnicity with AB statusAfrican with positive19322African with negative9413Asian with positive505Caucasian with positive505Other negatives151530Total532275Graph 1.Ethnicity with Autoantibody status showing the rate of progression into Lupus Nephritis (P value= 0.01)Disclosure of Interests:Majed Albirdisi: None declared, David d’cruz Grant/research support from: GlaxoSmithKline, Shirish Sangle: None declared, Natasha Jordan: None declared