Imaging infections with antibodies. A method to localize occult infections.

C ommonly, in the care of the critically ill patient, localization and anatomic delineation of an occult infectious or inflammatory focus is essential to direct further therapeutic management. An infectious or inflammatory focus can be considered occult when the usual imaging modalities (including conventional radiography, computed tomography, and ultrasonography) have failed to delineate the site and extent of the process. Although in these cases, “inflammation scanning” using Ga-citrate and “In-labeled leukocytes has occasionally been useful, more often these techniques have had very limited clinical utility. In 1988, Fischman et al’ described a method to localize focal sites of infection and inflammation using human immunoglobulin (Ig) C coupled to “In with the chelating agent diethylenetriamine pontaacetic acid (DTPA). Using this method, Rubin et a12 in 1989 described findings in 128 patients thought to have focal infections with the indications for study shown in Table 1. In 51 patients, localization of “In..labeled IgC correlated with clinical findings of abdominal or pelvic infections (21 patients), intravascular infections (11 patients), pulmonary infections (7), and skeletal infections (12) (Table 2). No focal localization of “In-labeled IgG was