High-Throughput Immunoassays for Cavin-4 IgG: A Diagnostic Tool for Immune-Mediated Rippling Muscle Disease.

Cavin-4 was identified as a potential autoantigen for immune-mediated rippling muscle disease (iRMD). To validate this, we developed and tested various immunoassays, including a cell-based assay (CBA), cavin-4 recombinant protein ELISA, and multi-peptide ELISA. Among 19 iRMD patients, all exhibited muscle rippling, and 13 had percussion-induced mounding. All immunoassays demonstrated clinical and analytical specificities greater than 95%. The protein ELISA had the highest sensitivity (94.7%) and specificity (99.9%), outperforming CBA (sensitivity 89.5%, specificity 99.6%) and the multi-peptide ELISA (sensitivity 79.0%, specificity 97.2%). Our results suggest that the cavin-4 protein ELISA is a promising tool for high-throughput clinical testing in iRMD.