The balance between lung regulatory T cells and Th17 cells is a risk indicator for the acute exacerbation of interstitial lung disease after surgery: a case control study

Abstract

Abstract Background: Acute exacerbation (AE) of interstitial lung disease (ILD) (AE-ILD) is a life-threatening condition and the leading cause of 30-day mortality among patients who underwent pulmonary resection for lung cancer in Japan. This study was conducted to clarify the characteristics of the immune environment of lung tissue before the onset of AE-ILD. Methods: This retrospective matched case-control study comparing the immune phenotype of helper T cells in the lung from patients with and without AE-ILD after surgery was conducted in 135 patients who underwent surgical resection for lung cancer and were pathologically diagnosed with ILD at our institute between 2009 and 2018. Thirteen cases of AE-ILD and 122 cases without AE (non-AE) were matched using a propensity score analysis, and 12 cases in each group were compared. We evaluated the percentage of T helper (Th)1, Th2, Th17, regulatory T cells (Treg), and CD8 cells in CD3+ T cells and the Th1:Th2, Th17: Treg, and CD8: Treg ratios in AE patients by immunostaining of lung tissue in the non-tumor area. Results: We found a significant difference in the lung Th17: Treg ratio between the AE and non-AE groups (1.47 and 0.79, p = 0.041). However, we detected no significant differences in the percentages of lung Th1 (21.3% and 29.0%), Th2 (34.2% and 42.7%), Th17 (22.3% and 21.6%), Treg (19.6% and 29.1%), and CD8+ T cells (47.2% and 42.2%) of CD3+ T cells between the AE and non-AE groups. Conclusion: The ratios of Th17: Treg cells in the lung from the AE group were higher than those in the non-AE group. Clinical Trial Registration: This study was approved by the ethics committee of our institute (2016095).