Pos0902 anti-ssa ro52 and anti-ro60 autoantibodies: association with clinical phenotypes

Background Anti-SSA autoantibodies can be differentiated according to their antigenic target proteins as anti-Ro60 (60 kDa) or anti-Ro52 (52 kDa). Anti-SSA(Ro60) are clearly associated with Connective Tissue Diseases (CTD), but the clinical significance of anti-SSA(Ro52) remains unclear. Objectives To analyze the disease phenotype of patients with anti-Ro52 and/or anti-Ro60. Methods Multicenter, cross-sectional study of anti-Ro52 and/or Ro60 positive patients followed at 10 Rheumatology centers from January 2018 until December 2021. Patients were categorised into 3 groups: group 1 (Ro52+/Ro60-); group 2 (Ro52-/Ro60+); group 3 (Ro52+/Ro60+). Antinuclear antibodies were evaluated by indirect immunofluorescence assay and further screened for anti-extractable nuclear antigen (ENA) antibodies. Demographics and clinical data were compared between the 3 groups, by patients’ medical chart review. Univariate analysis was performed using chi-square, Fisher’s exact or Kruskall-Wallis test. Subsequently, the Bonferroni test was used to identify intergroup differences (level of significance: p<0.0167). Univariate logistic regression was used to calculate the odds ratio with a 95% confidence interval (CI). Results We included 776 patients [female: 83.1%; median age: 59 (46-71) years]. Groups 1, 2 and 3 comprised 31.1%, 32.6%, and 36.3% of the patients, respectively. Characteristics of the groups are presented in Table 1. Anti-Ro52 alone is more frequently associated with non-rheumatic diseases, older age, and men (p<0.05). Among patients with CTD, the diagnosis of systemic lupus erythematosus is 3 and 2 times more prevalent in groups 2 and 3, respectively, than in group 1 [OR 2.8 (95% CI 1.60, 4.97),p=<0.001; OR 2.2 (95% CI 1.28, 3.86), p=0.007]. In group 2, the diagnosis of undifferentiated connective tissue disease is more frequent than in the other groups. The presence of isolated Ro52+ is more frequently associated with inflammatory myositis than in group 2 [OR 0.09 (95% CI 0.01, 0.33), p=<0.001] or group 3 [OR 0.08 (95% CI 0.01, 0.29), p=<0.001]. Group 1 was also more frequently associated with arthritis (p=0.006), interstitial lung disease (p=0.002), and myositis (p=0.009). Table 1. Characteristics of the study population according to the groups of anti-SSA(Ro) positivity. Group 1 (n=241) Group 2 (n=253) Group 3 (n=282) p Age, median (IQR) 64 (52-76) 56 (44-67) 57 (44-69) <0.001 Female, n (%) 185 (76.8) 214 (84.6) 246 (87.2) 0.005 Other anti-ENA, n (%) Anti-La 24 (10) 50 (19.8) 114 (40.4) <0.001 Anti-RNP 11 (4.6) 23 (9.1) 17 (6.0) 0.115 Anti-Scl70 3 (1.2) 4 (1.6) 6 (2.1) 0.146 Anti-Jo1 7 (3) 1 (0.4) 3 (1.1) 0.070 Anti-Sm 1 (0.4) 7 (2.8) 6 (2.13) 0.098 Anti-dsDNA 11 (4.6) 39 (15.4) 37 (13.1) <0.001 Anti-centromere 12 (5) 3 (1.2) 6 (2.1) 0.026 Lupus anticoagulant 10 (4.2) 32 (12.7) 23 (8.2) 0.008 Anti-cardiolipin 8 (3.3) 10 (3.9) 23 (8.2) 0.024 Anti-β2 glycoprotein 1 6 (2.5) 10 (3.9) 10 (3.6) 0.736 Rheumatoid Factor 46 (19.1) 44 (17.4) 81 (28.7) 0.001 Anti-CCP 11 (4.6) 15 (5.9) 19 (6.7) 0.327 Non-rheumatologic disease, n (%) 77 (32) 35 (13.8) 30 (10.6) <0.001 Infections 11 (14.3) 2 (5.7) 1 (3.3) 0.192 Neoplasms 22 (28.6) 3 (8.6) 6 (20.0) 0.057 Interstitial lung disease 5 (6.5) 4 (11.4) 0 0.168 Other diseases 46 (59.7) 25 (71.4) 22 (73.3) - Immune-mediated rheumatologic disease, n (%) 164 (68.1) 218 (86.2) 252 (89.4) <0.001 Sjögren syndrome 92 (56.1) 88 (40.3) 150 (59.5) <0.001 Systemic lupus erythematosus 20 (12.2) 61 (28) 59 (23.4) 0.001 Systemic sclerosis 11 (6.7) 7 (3.2) 8 (3.2) 0.150 Inflammatory myositis 15 (9.2) 2 (0.9) 2 (0.8) <0.001 Rheumatoid arthritis 18 (11) 17 (7.8) 16 (6.4) 0.234 Undifferentiated connective tissue disease 11 (6.7) 35 (16.1) 21 (8.3) 0.004 Mixed connective tissue disease 6 (3.7) 6 (2.8) 4 (1.6) 0.406 Other diseases 9 (5.5) 8 (3.7) 10 (4.0) - Conclusion Anti-Ro52+ alone is frequently found in patients with non-rheumatic diseases. In addition, anti-Ro52+ is also prevalent in patients with CTD and associated with clinical phenotypes that are different from anti-Ro60+. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests None Declared.