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Research suggests including anti-SSA antibodies in routine clinical practice could notably improve the risk stratification of patients with SSc
In a study of the EUSTAR database of established patients with systemic sclerosis (SSc), anti-Ro/SSA antibodies were detected in 15% of patients. These SSc non-specific antibodies were shown to be predictive of more severe lung involvement, suggesting that including anti-SSA antibodies in routine clinical practice could notably improve the risk stratification of patients with SSc.
Patients with SSc are currently stratified based on SSc-specific antibodies. Yet, individual prognosis remains unpredictable, particularly in cases with interstitial lung disease (ILD). Further exploration of SSc non-specific antibodies is crucial to enhance risk assessment and refine management strategies for SSc patients.
Dr. Blaž Burja, MD, PhD, from the University Hospital Zurich, in Switzerland, and his team evaluated the prevalence of anti-Ro/SSA antibodies in patients with SSc and the association of these antibodies with disease phenotype and clinical outcomes, focusing on lung involvement. “We examined the largest available cohort of established SSc patients selected from the EUSTAR database together with available data on anti-Ro/SSA antibodies,” Dr Burja explained.
The team assessed the presence of lung fibrosis using high-resolution computer tomography (HRCT) over a median of 2.7-year follow-up, employing multivariable logistic regression to identify associated factors. In addition, the impact of anti-Ro/SSA antibodies on lung function (i.e. functional vital capacity [FVC] and diffusing capacity for carbon monoxide [DLCO]) in these patients was calculated.
Out of 4,421 patients with SSc meeting the 2013 criteria in the EUSTAR database, 661 (15.2%) tested positive for anti-Ro/SSA antibodies. These antibodies were significantly linked (P<0.001) with anti-SSB, anti-U1RNP antibodies, and rheumatoid factor. Patients with anti-Ro/SSA antibodies showed higher rates of muscular involvement (18% vs 12.5%; P<0.001) and ILD (56.2% vs 47.8%; P=0.001) compared with those without. The presence of anti-SSA antibodies independently predicted the presence of lung fibrosis during follow-up (OR 1.24; 1.07–1.44; P=0.006) and was associated with lower DLCO (regression coefficient -1.93; -3.83 to 0.02; P=0.049) in affected patients. Also, it revealed a trend for lower FVC in these patients (P=0.082). However, anti-SSA antibodies did not foresee the progression of lung fibrosis or mortality over time.
“Overall, the presence of anti-Ro/SSA antibodies in 15.2% of the SSc cohort signifies an independent risk factor for lung fibrosis development,” Dr Burja concluded. Therefore, integrating the assessment of anti-Ro/SSA antibodies into routine clinical practice is advisable to identify individuals at higher risk for ILD, particularly beneficial in settings without access to HRCT scans, where these antibodies can be crucial biomarkers for screening.
