THE INFLUENCE OF ANTI-SSA-52 KDA (ASSA52) ANTIBODIES ON THE CLINICAL PRESENTATION OF INTERSTITIAL LUNG DISEASE

Abstract

SESSION TITLE: Diffuse Lung Disease Posters SESSION TYPE: Original Investigation Posters PRESENTED ON: October 18-21, 2020 PURPOSE: Interstitial lung disease (ILD) is a common manifestation of idiopathic inflammatory myopathies (IIM) and is responsible for nearly 80% of the mortality from IIM. Seropositivity for myositis specific antibodies (MSA) has been strongly associated with this complication. Less is known about the correlation between myositis associated antibodies (MAA) and ILD. The anti-SSA-52 kDa (aSSA52) antibody has been of particular interest, although whether it plays a prognostic role in patients with ILD is unknown. We aimed to investigate the impact of aSSA52 on the clinical characteristics of patients with ILD. METHODS: This retrospective cohort study included patients followed by the ILD clinic at the University of Chicago who tested positive for at least one antibody in the MyoMarker Panel 3. Patients were grouped according to their serology for aSSA52 (positive or negative). Data on clinical status, serologies, pulmonary function tests (PFT), and chest computed tomography (CT) were collected. RESULTS: A total of 125 patients were included, 63% of whom were positive for aSSA52. Most patients who were positive for aSSA52 did not test positive for other MAA (P < 0.001) or MSA (P = 0.005). Other immune serologies were similar between the two groups, with the exception of anti-dsDNA and total SSA, which were more common in aSSA52 positive patients (P = 0.004). Rheumatologic diagnoses did not differ between the groups, nor did multidisciplinary consensus diagnosis of ILD. Notably, aSSA52 positive patients were more likely to have hypomyopathic myositis (P = 0.04) with a trend towards higher levels of aldolase (P = 0.07). Pulmonary function and outcomes (death or lung transplantation) were comparable. Modeling did not support aSSA52 as an independent predictor of forced vocal capacity (FVC) or diffusing capacity (DLCO) upon diagnosis, although the latter was close to statistical significance (P = 0.06). CONCLUSIONS: Our study identified that patients with aSSA52 and ILD were more likely to have laboratory evidence of skeletal muscle inflammation without associated muscle weakness at diagnosis, and most of these patients did not have other accompanying MSA or MAA. These patients had similar ILD diagnoses compared to the aSSA52 negative cohort. Surprisingly, the presence of aSSA52 across all subtypes of ILD did not impact severity of ILD at diagnosis nor was it associated with short-term outcomes. CLINICAL IMPLICATIONS: Our study supports a correlation between autoimmune-mediated hypomyopathic myositis and ILD, which although common in IIM remains excluded from diagnostic criteria. Further long-term analysis will be needed to understand whether aSSA52 is associated with accelerated loss of pulmonary function or other complications over time, particularly in the subset of patients with connective tissue disease-associated ILD. DISCLOSURES: Speaker/Speaker's Bureau relationship with Boehringer Ingelheim Please note: $20001 - $100000 Added 03/30/2020 by Ayodeji Adegunsoye, source=Web Response, value=Honoraria Removed 03/30/2020 by Ayodeji Adegunsoye, source=Web Response Speaker/Speaker's Bureau relationship with Boehringer Ingelheim Please note: $20001 - $100000 Added 03/30/2020 by Ayodeji Adegunsoye, source=Web Response, value=Grant/Research Support Removed 03/30/2020 by Ayodeji Adegunsoye, source=Web Response Advisory Committee Member relationship with Genentech Please note: $1-$1000 Added 03/30/2020 by Ayodeji Adegunsoye, source=Web Response, value=Honoraria Speaker/Speaker's Bureau relationship with Boehringer Ingelheim Please note: $20001 - $100000 Added 03/30/2020 by Ayodeji Adegunsoye, source=Web Response, value=Honoraria No relevant relationships by Iazsmin Bauer Ventura, source=Web Response No relevant relationships by Renea Jablonski, source=Web Response No relevant relationships by Cathryn Lee, source=Web Response No relevant relationships by Eleanor Phillips, source=Web Response PI relationship with Boehringer-Ingelheim Please note: >$100000 by Mary Strek, source=Web Response, value=Grant/Research Support PI relationship with Galapagos Please note: $5001 - $20000 by Mary Strek, source=Web Response, value=Grant/Research Support PI relationship with Novartis Please note: $5001 - $20000 by Mary Strek, source=Web Response, value=Grant/Research Support