Elevations in circulating and/or tissue CD45+Col-I+ cells have are seen in a broad array of fibrosing lung diseases including idiopathic pulmonary fibrosis (IPF) [4], asthma [5], post-transplant bronchiolitis obliterans syndrome [21], and scleroderma [6]. The gene discussed is PTPRC; the disease is idiopathic pulmonary fibrosis.