Measurement of HAMA and Anti-Idiotypic Antibodies

Murine monoclonal antibodies (mAbs) when administered to patients are perceived much as any other foreign antigen: an immune response is usually mounted against them, the result of which is the generation of human antimouse antibodies (HAMA). Even in the absence of such immunization some patients may possess HAMA activity because of polyclonal IgM rheumatoid factors that crossreact with Fc epitopes on both human and mouse IgG (1 ).