Myositis specific antibodies are associated with isolated anti-Ro-52 associated interstitial lung disease

Objectives Anti-Ro-52 antibody positivity might be associated with the presence of interstitial lung disease (ILD) among patients with autoimmune features. However, the clinical significance of isolated anti-Ro-52 positivity (i.e. the presence of anti-Ro-52 antibodies but the absence of anti-Ro-60 antibodies; anti-Ro-52(+)Ro-60(-)) in patients with ILD is not clear. Methods This is a prospective and observational study of Chinese ILD patients with isolated anti-Ro-52 positivity. According to their myositis specific antibody (MSA) status, patients were split into groups, and their clinical and radiological features were compared. Results Of the 158 enrolled patients with ILD and isolated anti-Ro-52 positivity (isolated anti-Ro-52-ILD), there were 130 patients with a positive MSA status and 28 patients with a negative MSA status. Anti-synthetase antibodies (ASAs) were found in 61.5% of patients with MSA(+)-ILD, and anti-melanoma differentiation associated protein 5 (anti-MDA-5) antibodies were found in the remaining 38.5% of patients. The anti-nuclear antibody (ANA) pattern was associated with ASA and anti-MDA-5 positivity (x(2) = 70.7, P < 0.001; Cramer's value 0.47, P < 0.001): ANA negativity was associated with anti-MDA-5 positivity, and cytoplasmic ANA positivity was associated with ASA positivity. There were statistically significant differences in the high-resolution CT patterns between patients with isolated anti-Ro-52 positivity with different MSA statuses (x(2) = 29.8, P < 0.001; Cramer's value 0.31, P < 0.001): OP pattern was more common in patients with anti-MDA-5 antibodies than in those without anti-MDA-5 antibodies. Conclusions Patients with isolated anti-Ro-52-ILD showed high positivity of MSA. Isolated anti-Ro-52 positivity with cytoplasmic ANA positivity was strongly associated with ASA(+)-ILD, while ANA negativity was associated with anti-MDA-5(+)-ILD.