Objective: To establish an enzyme-linked immunosorbent assay (ELISA) for detecting anti-Ki antibody, using a bovine recombinant Ki antigen, and studying its specificity.
Methods: Sera from 220 patients with various connective tissue diseases were screened, and a prospective study of fluctuations in anti-Ki antibody and clinical course of a woman with systemic lupus erythematosus (SLE) was analyzed, by ELISA:
Results: Anti-Ki antibodies were present in 18.9% of patients with SLE. The titer of anti-Ki antibody in the woman with SLE rose before the onset of pericarditis and pleuritis in this longitudinal study.
Conclusion: ELISA using a recombinant Ki antigen is useful for the diagnosis of SLE, and it might be useful in estimating disease activity in patients with SLE.