Ab0836 Significance of Ro52 and Pregnancy Outcomes in Anti-Ss-a Antibody Positive Rheumatic Disease Patients

Background: Anti-SS-A antibodies are associated with neonatal lupus erythematosus and congenital heart block (CHB). Ro/SS-A autoantigen is comprised of 52kDa Ro (Ro52) and 60kDa Ro (Ro60) protein, and antibodies for Ro52 has been shown to be particularly strongly associated with CHB 1. However, relationship between the positivity of Ro52 antibody and anti-SS-A antibody titers, or pregnancy outcomes have not yet been fully clarified and controversial. Objectives: To clarify the association between Ro52 and pregnancy outcomes, including CHB, in anti-SS-A antibody positive patients. Methods: We used the data of anti-SS-A positive patients who have been treated at the planning for pregnancy from a single center cohort of rheumatic disease pregnancy registry from 2007 to 2023. We analyzed pregnancy outcomes such as CHB, preterm birth (PB) and low birth weight (LBW), the titer of anti-SS-A antibody and therapeutic agents was extracted from medical records. Ro52 was measured by enzyme-linked immune sorbent assay (Anti-SS-A 52 ELISA kit, ORGENTEC). Results: Of the 244 pregnancies complicated with rheumatic diseases, 97 cases (39.8%) were positive for anti-SS-A antibodies, and mean titer of anti-SS-A antibodies was 989.7±2665.5 IU/ml. Among these SS-A antibody-positive patients, 34 cases (35.1%) were diagnosed as primary Sjogren syndrome (SS). Of the 49 cases in which Ro52 could be measured, 27 cases were positive, and mean titer of positive cases was 215.6±336.7 IU/ml. The titer of anti-SS-A antibodies was significantly higher in Ro52 positive cases (Figure 1a, PConclusion: The presence of anti-SS-A antibodies was not associated with the negative pregnancy outcomes such as PB or LBW. In anti-SS-A antibody positive pregnancies, it is important to assess and manage risks of neonatal lupus erythematosus, by testing for the presence and titer of anti-Ro52 antibodies and changing in therapeutic agents. REFERENCES: 1 Fritch C, Hoebeke J, Dali H, et al. 52-kDa Rp/SSA epitopes preferentially recognized by antibodies from mothers of children with neonatal lupus and congenital heart block. Arthritis Res Ther. 2006;8:R4. 2 Miyasato M, Waguri M, Yamada Y, et al. Anti-Ro52 antibody level is an important marker of fetal congenital heart block risk in anti-Ro/SSA antibody positive pregnancy. Mod Rheumatol. 2018;28:690-696. Acknowledgements: NIL. Disclosure of Interests: None declared.