SPP1 and pulmonary fibrosis: Thus, IL-22 produced by γδ T cells may play a protective role in BLM-induced pulmonary fibrosis.30 Furthermore, BLM-induced lung inflammation and subsequent fibrosis was ameliorated in osteopontin (OPN)-deficient mice, whereas OPN was expressed ubiquitously in the lung parenchymal and bone marrow-derived components.