VIENNA — Anti-Ro/SSA antibodies may help predict which patients with systemic sclerosis (SSc) are at a greater risk for interstitial lung disease (ILD) and may serve as a biomarker to guide screening, according to an analysis of data from a large European cohort.
The researchers were led by Blaž Burja, MD, PhD, a physician-scientist at the Center of Experimental Rheumatology, University Hospital Zürich, Switzerland, who reported that anti-Ro/SSA antibodies are a risk factor for ILD, with an odds ratio of 1.24, in patients with SSc.
At the annual European Congress of Rheumatology, he presented the findings of the study that aimed to find out if SSc-nonspecific antibodies might help better risk-stratify patients with SSc, focusing on lung involvement. “Among them, anti-Ro/SSA antibodies have been shown to be associated with interstitial lung disease in different connective tissue diseases,” Dr. Burja pointed out.
“A total of 15% of all patients in the SSc cohort presented with anti-Ro/SSA antibodies, and this subgroup presented with distinct clinical features: Importantly, higher prevalence of ILD and lower DLCO% [diffusing capacity of the lungs for carbon monoxide] in patients with established ILD,” reported Dr. Burja. “However, these anti-Ro/SSA antibodies do not predict ILD progression, death, or overall disease progression.”
Based on the findings, Dr. Burja suggested that these antibodies be incorporated into routine clinical practice to identify patients with SSc who have a high risk for ILD. He noted that “this has specific importance in clinical settings without availability of high-resolution computed tomography (HRCT), where anti-Ro/SSA antibodies could represent an additional biomarker to guide the screening process, in particular, in patients without SSc-specific antibodies.”
Caroline Ospelt, MD, PhD, co-moderator of the session and scientific program chair of EULAR 2024, told this news organization that the study was unique in its approach to studying ILD risk by “looking outside the box, so not just at specific antibodies but whether cross-disease antibodies may have value in stratifying patients and help predict risk of lung involvement and possibly monitor these patients.”
Dr. Ospelt, professor of experimental rheumatology at University Hospital Zürich, who was not involved in the study, noted: “It might also be the case that we could adapt this concept and use these antibodies in other rheumatic diseases, too, not just systemic sclerosis, to predict lung involvement.”
Risk-Stratifying With SSc-Nonspecific Antibodies
Dr. Burja explained that despite better stratification of patients with SSc with SSc-specific antibodies, “in clinical practice, we see large heterogeneity, and individual prognosis with regards to outcomes is still unpredictable, so we wanted to know whether by using nonspecific autoantibodies we might be better able to risk-stratify these patients.”
A study population of 4421 with at least one follow-up visit, including 3060 patients with available follow-up serologic data, was drawn from the European Scleroderma Trials and Research group database (n = 22,482). Of these 3060 patients, 461 were positive for anti-Ro/SSA antibodies and 2599 were negative. The researchers analyzed the relationships between baseline characteristics and the development or progression of ILD over 2.7 years of follow-up. Incident, de novo ILD was defined based on its presence on HRCT, and progression was defined by whether the percentage of predicted forced vital capacity (FVC%) dropped ≥ 10%, FVC% dropped 5%-9% in association with a DLCO% drop ≥ 15%, or FVC% dropped > 5%. Deaths from all causes and prognostic factors for the progression of lung fibrosis during follow-up were recorded.