Cross-reactive idiotypes on cryoprecipitating monoclonal IgMk rheumatoid factors

Shared idiotype specificities (CRIs) among monoclonal IgM rheumatoid factors from patients with essential mixed cryoglobulinemia have been demonstrated with the use of polyclonal antisera and have been confirmed, more recently, using monoclonal antibodies. In this paper we will summarize some of the work that has been performed in our laboratory using anti-idiotypic monoclonal antibodies. Such reagents allowed us to detect CRIs on cryoprecipitable rheumatoid factors, to detect idiotype-positive cells in bone marrow and peripheral blood, and to identify glomerular immune deposits.