Intriguingly, CD20+ B cells forming lymphoid follicles were found within the fibrotic interstitium in areas adjacent to fibroblastic foci in CPFE patients with positive serum ANA and p-ANCA profile whereas CD20+ cells were almost absent in biopsy samples from patients with CPFE and negative ANA profile as well as in control lung samples. The gene discussed is BTG3; the disease is combined pulmonary fibrosis-emphysema syndrome.