Anti-Ro52 Antibody as a Protective Factor for Pulmonary Fibrosis in Primary Sjögren's Syndrome.

Background: Pulmonary fibrosis is common in primary Sjögren's syndrome (pSS)-related interstitial lung disease (ILD). However, research is lacking on the diagnostic immunological examination of pSS-related pulmonary fibrosis. Particularly, the value of detecting anti-Ro52 antibody in pulmonary fibrosis is unclear.

Objective: To evaluate the potential diagnostic value of anti-SSA, anti-SSB, and anti-Ro52 autoantibodies as markers of pSS-related pulmonary fibrosis.

Methods: One-hundred seventy-nine patients with pSS were analyzed retrospectively at our hospital. They were divided into the fibrosis and non-fibrosis groups. Pulmonary fibrosis was classified as mild, moderate, or severe based on the patients' computed tomography (CT) findings. Laboratory examinations, including anti-SSA, anti-SSB, and anti-Ro52 antibody evaluations, were performed. The influencing factors of pulmonary fibrosis were analyzed using logistic regression.

Results: Chest CT revealed pulmonary fibrosis in 45 patients with pSS (25.1%). The positive rates of anti-SSA and anti-Ro52 antibodies in the fibrosis group were lower than in the non-fibrosis group (P=0.04, P=0.001). The frequency of anti-Ro52 antibody showed no significant differences between mild-to-moderate (53.8%) and severe (47.3%) pulmonary fibrosis. The anti-Ro52 antibody was identified as a potentially protective factor against pSS (P=0.041).

Conclusions: Patients with pSS and pulmonary fibrosis had a low frequency of anti-SSA and anti-Ro52 antibodies. In patients with pSS and negative anti-Ro52 antibody, a chest CT is recommended to further understand the patients' condition.