Cryptogenic Organizing Pneumonia: IL-1β, IL-6, IL-8, and TGF- β1 Serum Concentrations and Response to Clarithromycin Treatment.

Cryptogenic organizing pneumonia (COP) is a distinct clinicopathological entity with unknown etiology. Inflammatory cytokines play a role in the development of the disease. The present study was performed to assess the correlation between concentrations of IL-1β, IL-6, IL-8, and TGF-β1 in the serum with response to clarithromycin (CAM) treatment in patients with COP. A total of 39 patients with COP were enrolled in to this study. An oral dose of 500 mg CAM was administered to all of the patients twice daily for 3 months. A complete response was noticed in 31 (80 %) of patients, and 8 (20 %) patients failed to respond to treatment. The concentration of cytokines were assessed by ELISAs before and after treatment. CAM treatment was associated with decreases in serum IL-6 (3.8 pg/mL [IQR 0.9-11.8] vs. 1.1 pg/mL [IQR 0.2-3.1]; p = 0.004), IL-8 (13.6 pg/mL [IQR 9.8-17.5] vs. 8.1 pg/mL [IQR 6.2-13.2]; p = 0.004), and TGF-β1 (37.1 ng/mL [IQR 31.7-46.2] vs. 25.7 ng/mL [IQR 22-41.7];p = 0.0001), which was particularly notable in the responders. We conclude that IL-6, IL-8, and TGF-β1 may play a role in the pathogenesis of COP, as their decreased concentrations were associated with a positive response to CAM treatment.