Protocol for affinity enrichment of polyclonal autoantibodies from human plasma.

Autoantibodies (AAbs) contribute to various immune-mediated diseases and are valuable biomarkers for diagnosis, classification, and disease activity. Here, we present a protocol for the affinity enrichment of AAbs from human plasma samples. We describe steps to generate a human cell line lysate, which is immobilized on Sepharose beads for affinity enrichment of AAbs. We then detail the quality-control procedure of verifying autoreactivity of AAb fractions. This protocol has potential application in functional and proteomic analyses of AAbs. For complete details on the use and execution of this protocol, please refer to Hagadorn et al.(1).