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 (x2 = 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 (x2 = 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.