In vitro-labeled leukocyte imaging is useful for the detection of
infection, but an in vivo labeling method is preferable. This study sought to evaluate the safety and efficacy of a leukocyte-avid
peptide for the detection of
infection, to determine the effects of
peptide dose on performance and to compare the
peptide with in vitro-labeled leukocytes. A 23-amino
acid peptide, P483, containing the platelet factor-4
heparin-binding sequence, was labeled with 99mTc and complexed with
heparin (P483H). Thirty patients were injected with 29 microg (n = 11), 145 microg (n = 10) or 290 microg (n = 9) of labeled
peptide, and imaged 15 min and 90-120 min later. Early and late images were interpreted individually and jointly. Twenty patients underwent (111)In-labeled leukocyte scintigraphy. Fourteen patients had
infection:
osteomyelitis (n = 7), vascular graft (n = 2),
abscess (n = 2),
joint replacement (n = 1),
surgical wound (n = 1) and
pneumonia (n = 1). There were 10 adverse events in six patients; all were mild and resolved spontaneously, and without any intervention. The sensitivity, specificity and accuracy were the same for both early and late imaging: 0.86, 0.81 and 0.83, respectively. Interpreting early and late images together did not improve the results. No relationship between
peptide dose and study accuracy was found. In patients undergoing both examinations, the accuracies of the
peptide and in vitro-labeled leukocyte imaging were identical: 0.80. In summary, 99mTc-P483H safely, rapidly and accurately detected
focal infection, was comparable with in vitro-labeled leukocyte imaging and therefore merits further investigation.