Specifically, at 7 days post irradiation, a linear combination of Th1 and Th17 cell numbers was revealed to be a significant predictor for the degree of pulmonary fibrosis and, at the same time point, we observed the combination of Il17 and Ifnγ levels in the bronchoalveolar lavage to significantly associate with late stage fibrosis. The gene discussed is IL17A; the disease is pulmonary fibrosis.