Localization of inflammatory lesions by J-123-antigranulocytes antibodies

We report on a new approach to in vivo labelling of granulocytes for scintigraphic detection of infections by using the I-123-tagged monoclonal anti-CEA antibody 47 (Mab 47). Mab 47 reacts selectively with a glycoprotein (NEA 95) present on the surface of mature granulocytes. Binding does not inhibit granulocyte functions (e.g. chemotaxis, initation of 'burst'). Up till now we have performed the search for infectious lesions in more than 110 patients. For clinical use a dose consisted of 120 mcg Mab 47 labeled with 110 to 150 MBq I-123 (specific activity: 1,85 GBq/mg). We noticed that all infectious lesions were usually highly visible after 3 to 6 hours after tracer injection or could be excluded after 24 hrs. High counting rates permitted SPECT-studies up to 24 hrs post injectionem which are very usefull for exact topographical localization of a lesion. Main clinical interest was concentrated on cases of bone and joint infections. It is concluded that there are distinct advantages of this method compared with In-111 WBC scanning. Without the need for cell separation there is a rapid in vivo labelling of granulocytes so that the method is also suitable in very acute cases. No allergic reactions have been seen, and according to our results in 42 patients in determinating HAMA factors (human antimouse antibodies) there is no clinically relevant immunization by the Mab-amount injected. In spite of these obvious advantages and the low administered dose of antibodies the indication for the immunoscintigraphy of infectious lesions should always be checked up very carefully. (Author)