Distinct profiles of Th1 and Th2 cytokines in patients with IPF, CTD-ILD, and IPAF

Abstract

Background: Interstitial lung diseases (ILD) are characterized by inflammation and/or fibrosis of the lungs. Patients with idiopathic pulmonary fibrosis (IPF) are unlikely to respond to immunosuppressive therapy. In contrast, patients with features of connective tissue disease (CTD), CTD-ILD and interstitial pneumonia with autoimmune features (IPAF) benefit from immunosuppressive therapy. Th1 and Th2 cytokines are associated with the pathogenesis of these ILDs, however these ILD cytokine profiles remain unclear. Objective: To investigate distinct inflammatory profiles among IPF, CTD-ILD, and IPAF. Methods: We retrospectively investigated patients with IPF, CTD-ILD, and IPAF between June 2013 and May 2017 at our hospital. They were reviewed for clinical parameters and response to treatment. Serum and bronchoalveolar lavage fluid (BALF) levels of Th1 and Th2 cytokines were measured. Associations of these clinical parameters to levels of cytokines were evaluated. Results: One hundred two patients were included (IPF: 51, CTD-ILD: 16, IPAF: 35). Serum and BALF levels of Th1 cytokines (IP-10 and MIG) were significantly elevated in patients with CTD-ILD and IPAF compared to patients with IPF. Serum Th1 cytokine (IP-10 and MIG) levels were correlated with BALF levels and the proportions of lymphocytes and macrophages in BALF. The serum levels of Th1 cytokines (MIG, ITAC, TNFα, Fas-L) showed significant correlations with the change of FVC in patients with CTD-ILD and IPAF treated with immunosuppressants. Conclusion: Our results show distinct profiles of serum and BALF Th1 cytokines in IPF, CTD-ILD, and IPAF, and suggest these cytokines are potential inflammatory biomarkers in patients with CTD-ILD and IPAF.