[Antinuclear antibody screening by an enzyme-linked immunosorbent assay using multiple nuclear antigens]

We assessed the clinical value of an enzyme-linked immunosorbent assay (ELISA) kit (MESACUP ANA, MANA) which uses multiple nuclear antigens for screening antinuclear antibody (ANA). Since the screening procedure for ANA by the indirect fluorescence method (FANA) requires trained personnel and gives rather subjective results, development of a suitable screening test for ANA by ELISA which uses specific nuclear antigens has been long awaited. Serum samples from 350 patients with connective tissue diseases (CTD), and from 300 normal subjects were assayed for ANA by ELISA and the results were compared with those of FANA and of single-antigen ELISAs for RNP, Sm, SS-A, SS-B, Scl-70, Jo-1, dsDNA, and ssDNA. For discrimination between patients with systemic lupus erythematosus and normal subjects, the sensitivity, specificity and accuracy for MANA were 85.7%, 97.5%, and 91.6%, and those for FANA were 95.8%, 77.0%, and 86.4%, respectively. Analysis of CTD sera showing discordant results between FANA and MANA using single-antigen ELISAs revealed that FANA - MANA + sera (n = 8) contained antibodies against SS-A (n = 1) or dsDNA (n = 3) or ssDNA (n = 3), and that some FANA + MANA - sera (n = 82), which were frequently found in RA patients (43/98, 43.9%), also contained antibodies against RNP (n = 3) or ssDNA (n = 13). MANA + normal sera (n = 9) were found to contain antibodies against SS-A (n = 1) or dsDNA (n = 1) or ssDNA (n = 2). In conclusion, MANA was found to be objective, much less labor intensive and suitable for screening large numbers of CTD sera for disease-specific ANAs.