RT Journal Article SR Electronic T1 Detection of anti-cytokeratin 8 antibody in the serum of patients with cryptogenic fibrosing alveolitis and pulmonary fibrosis associated with collagen vascular disorders JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 969 OP 974 DO 10.1136/thx.53.11.969 VO 53 IS 11 A1 Naomi Dobashi A1 Jiro Fujita A1 Yuji Ohtsuki A1 Ichiro Yamadori A1 Takeo Yoshinouchi A1 Tadashi Kamei A1 Michiaki Tokuda A1 Satoko Hojo A1 Hiroki Okada A1 Jiro Takahara YR 1998 UL http://thorax.bmj.com/content/53/11/969.abstract AB BACKGROUND It has been suggested that the humoral immune system plays a role in the pathogenesis of cryptogenic fibrosing alveolitis (CFA). Although circulating autoantibodies to lung protein(s) have been suggested, none of the lung proteins have been characterised. The purpose of this study was to determine the antigen to which the serum from patients with pulmonary fibrosis reacted.METHODS The anti-A549 cell antibody was characterised in a patient with CFA using Western immunoblotting and immunohistochemical staining of A549 cells. As we identified that one of the antibodies against A549 cells was anti-cytokeratin 8, the expression of mRNA of cytokeratin 8 in A549 cells was evaluated. In addition, we attempted to establish an enzyme linked immunosorbent assay to measure the levels of anti-cytokeratin 8 antibody in the serum of patients with CFA and pulmonary fibrosis associated with collagen vascular disorders (PF-CVD).RESULTS Initially two anti-A549 cell antibodies were detected in the serum of patients with pulmonary fibrosis, one of which was characterised as anti-cytokeratin 8 antibody by Western immunoblotting. We were able to establish an ELISA to measure anti-cytokeratin 8 antibody and found significantly higher levels in patients with CFA and PF-CVD than in normal volunteers, patients with sarcoidosis, pneumonia, and pulmonary emphysema.CONCLUSIONS One of the anti-A549 cell antibodies in the serum of patients with CFA was against cytokeratin 8. The serum levels of anti-cytokeratin 8 antibody were increased in patients with CFA and PF-CVD. These results suggest that anti-cytokeratin 8 antibody may be involved in the process of lung injury in pulmonary fibrosis.