Clinically, mouse monoclonal antibodies (IgG) and their fragments are used during in-vivo diagnosis procedures (radionuclides) and treatment for patients with various diseases. In patients, even a single dose injection of murine monoclonal IgG may induce immune response directed against this foreign protein (immunogen). In circulation, the presence of human antibody against murine IgG would bind to the injected murine IgG and therefore diminish the efficacy of either in-vivo diagnosis or treatment. HAMA is likely to increase the risk of anaphylactic complications to subsequent administration of the murine IgG-based therapy.
The presence of HAMA in patient serum or plasma specimens causes both false positive and false negative immunoassay test results depending on assay principles and monoclonal antibodies used in the assay system.