AB0815 FIRST DEGREE RELATIVES OF PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS - CLINICAL, SEROLOGICAL AND IMMUNOLOGICAL CORRELATIONS

Background:Antinuclear antibodies (ANA) have been unequivocally recognized as essential for diagnosis and play both pathogenic and diagnostic roles in systemic lupus erythematosus (SLE). SLE and ANA have also been found to be more often among relatives of SLE patients. ANA and other immunological changes are known to appear prior to the clinical onset of the disease and thus can be used as predictors. Studies have reported that relatives of SLE patients who later transitioned to SLE displayed more lupus-associated autoantibody specificities and had early clinical signs. They also displayed elevated baseline plasma levels of inflammatory mediators, including B-lymphocyte stimulator (BLyS) and interferon-associated chemokines, with concurrent decreases in levels of regulatory mediators, e.g. tumor growth factor (TGF)-β. Commonly recognized risk factors for SLE are signs of past Epstein-Barr (EBV) infection, use of estrogen drugs and current smoking. It seems that ANA, immunologic changes and risk factors have not been investigated together in relatives of SLE patients.Objectives:The aim of the study was to determine the relative prevalence of clinical signs of SLE or connective tissue disease (CTD), smoking, use of estrogen drugs and levels of circulating ANA, BLyS, IFN-α, TGF-β, anti-EBV viral capsid antigen (VCA) IgM and IgG antibodies among sera of FDR, non-FDR healthy individuals and SLE patients.Methods:Forty three FDRs of SLE patients were studied along with 15 SLE patients and 15 clinically healthy subjects as control groups. The FDRs and the healthy answered a questionnaire about early clinical signs of CTD, smoking and estrogen use history. The questionnaire was developed based on the existing Screening Questionnaire for Connective Tissue Diseases and current knowledge of most early signs of CTD. Blood samples were obtained and tested for ANA, both by indirect immunofluorescence and immunoblot, anti-dsDNA by ELISA. ELISA was also performed to measure levels of BLys, IFN-α, TGF-β, anti-EBV IgM and IgG.Results:More than half of the FDRs displayed ANA in titer 1:160 or more, with predominately AC-4 type of fluorescence according to International Classification on ANA Patterns (ICAP) compared to only AC-1 and AC-0 among patients and controls respectively. A correlation between the ANA titer and the number of complaints was found. This was particularly valid or reported skin complaints and oral ulcers which appeared more frequently when ANA was 1:320 or above (p=0,018 and 0,038 respectively). Furthermore, oral ulcerations showed positive correlation with the presence of anti-Ro60. No associations were found in the healthy group between reported complaints and ANA titers. Smoking and estrogen use did not differ across the three groups. Patients showed significant differences in levels of BLys (p=0,027), TGF-β (p=0,019) and anti-EBV IgG (p=0.041) compared to both FDRs and controls. Without reaching statistical significance, levels of TGF-β tend to split the FDR group into “healthy-like” and “SLE-like”.Conclusion:Our results show that FDR ANA levels are between those of SLE patients and healthy subject groups. This is consistent with previous studies. The data also suggest that ANA positivity correlates with reported complaints, some of which could be interpreted as very early clinical signs of SLE. Of note, anti-Ro60 is known to be among the earliest ANA that appear in “future” SLE patients and in this study they are related to oral complaints that could be caused by early sicca phenomena. Immunologically, our data support previous findings [1] that the FDRs are a heterogenic group with different “lupus-developing” potential.References:[1]Munroe МE. et al, Soluble Mediators and Clinical Features Discern Risk of Transitioning to Classified Disease in Relatives of Systemic Lupus Erythematosus Patients, Arthritis Rheumatol. 2017 March; 69(3): 630–642.Disclosure of Interests:Bogdan Penev: None declared, Georgi Vasilev: None declared, Dobroslav Kyurkchiev: None declared, Simeon Monov Speakers bureau: I have been paid for giving lectures on statistical data on efficacy of many pharmaceutical products on various companies