Rituximab in the Treatment of Interstitial Lung Disease Associated with Autoimmune Diseases: Experience from a Single Referral Center and Literature Review

Abstract
In the present study, we aimed to report our experience with rituximab (RTX) in the treatment of patients with ILD associated with AD (AD-ILD) at a single center. For this purpose, clinical characteristics, radiological findings, and pulmonary function tests (PFTs) of RTX-treated AD-ILD-patients seen from May 2016 until March 2020 at a referral center for individuals with ILD were retrospectively reviewed. Additionally, an updated literature review was conducted. A total of 26 patients (mean age 58.3 ± 11.1 years at ILD diagnosis) was included. The most common ADs related to ILD were systemic sclerosis, idiopathic inflammatory myositis (including anti-synthetase syndrome) and rheumatoid arthritis. Non-specific interstitial pneumonia (n = 12) and usual interstitial pneumonia (n = 11) were the predominant radiological patterns. The sustained improvement in PFTs was observed from the start of RTX, with a statistically significant increase in DLCO from basal to one year after RTX (mean + 4.2%, p = 0.024). Overall, there were no differences when comparing PFT outcome according to the radiological pattern or the specific type of AD. In conclusion, RTX constitutes a good therapeutic option to preserve lung function in patients with AD-ILD, regardless of the radiological pattern or the underlying AD.