SAT0030 A NOVEL ASSOCIATION BETWEEN ANTI-CARBAMYLATED ANTIBODIES AND INTERSTITIAL LUNG DISEASE IN PATIENTS WITH RHEUMATOID ARTHRITIS

Background:Interstitial lung disease (ILD) is associated with a significant increase in morbidity and mortality in patients with rheumatoid arthritis (RA). Therefore, an early diagnosis is fundamental. Anti-carbamylated proteins (Anti-CarP) have been described in different chronic respiratory diseases without a previous history of RA.Objectives:The aim of this study was to analyse the association between Anti-CarP and ILD in RA patients.Methods:We performed a cross-sectional study, including RA patients fulfilling the 2010 ACR/EULAR criteria. The main population comprised 2 groups: 1) RA patients diagnosed with ILD (RA-ILD group) and 2) RA patients without ILD (non-ILD RA group). ILD was diagnosed by high-resolution tomography and confirmed by a multidisciplinary committee. Three IgG Anti-CarP autoantibodies against fetal calf serum (Anti-FCS), fibrinogen (Anti-Fib), and fibrine/filagrine homocitrullinated peptide (Anti-CFFHP) and one IgA against FCS (Anti-FCS-IgA) were determined by home-made ELISA. Associations between Anti-CarPs and ILD were explored using multivariable logistic regression adjusted by a set of variables known to be related to the development of ILD: smoking, sex, age, RA disease duration, RF and ACPA. An independent replication sample was obtained to validate our findings from another hospital.Results:The main population included 179 patients: 37 were included in the RA-ILD group, and 142 in the non-ILD RA group. Most patients were female (79%), with a mean age of 59.7±13 years with a mean disease duration of 6.6±5 years. Baseline features are shown in table 1. The replication sample was composed of 25 patients in the RA-ILD group and 50 patients in the non-ILD RA group. We found that Anti-CarPs specificities were more frequent in RA-ILD patients (Anti-FCS 70% vs. 43%; Anti-Fib 73% vs. 51%; Anti-CFFHP 38% vs. 19%; Anti-CarP-IgA 51% vs. 20%, pTABLE 1.Main population demographic, clinical, therapeutic, and autoantibody status features.RA-ILDn:37Non-ILD RAn:142p valueFemale (%)25 (68)116 (82)NSAge mean (±SD)67.3 (10.1)57.7 (12.9)Mean disease duration (±SD)11.6 (7.1)5.3 (13.3)Ever smokers (%)21 (57)62 (44)NSSmoking cumulative dose (±SD)30.7 (11.1)21.8 (12)Caucasian (%)31 (84)120 (85)NSTreatmentGlucocorticoids (%)25 (68)81 (57)NScsDMARDs (%)33 (89)132 (86)NSMTX (%)20 (54)95 (67)NSbDMARDs (%)11 (30)36 (25)NSMean DAS28 (±SD)3.71 (1.35)2.74 (1.05)Erosive disease (%)26 (70)63 (44)Mean HAQ-DI (CI-95%)0.69 (0.53-0.85)0.31 (0.24-0.38)ACPA positive (%)29 (78)99 (70)NSMedian titer ACPA (IQR) CU674 (2,215)143 (1,132)NSRF positive (%)28 (76)83 (59)NSMedian titer RF (IQR) IU105 (298)34 (110)NSConclusion:A strong association between RA-ILD and Anti-CarP was found independently of cofounders, including RF and ACPA. Our findings suggest a possible link between Anti-CarP and the development of ILD.Disclosure of Interests:Raul Castellanos-Moreira Speakers bureau: Lilly, MSD, Sanofi, UCB, Sebastian Rodriguez-Garcia: None declared, Katherine Cajiao: None declared, Gabriela Jimenez: None declared, Maria Jose Gomara: None declared, Virginia Ruiz Speakers bureau: Lilly, Pfizer, Ivette Casafont-Solé: None declared, Julio Ramirez: None declared, José Gomez Puerta Speakers bureau: Abbvie, Eli Lilly, BMS, Roche and Pfizer, Susana Holgado Pérez: None declared, Juan de Dios Cañete: None declared, Isabel Haro: None declared, Raimón Sanmartí Speakers bureau: Abbvie, Eli Lilly, BMS, Roche and Pfizer