A preliminary report on ^99mTc-fanolesomab imaging of renal allograft

OBJECTIVE: To evaluate the utility of ^99mTc-fanolesomab (a ^99mTc-labeled murine monoclonal immunoglobulin M antibody that specifically binds cluster designation 15 antigens on human neutrophillic leukocytes with high sensitivity and specificity) in diagnosing localized infections. METHODS: Five patients with renal allografts were imaged using ^99mTc-fanolesomab to look for a source of infection. Images were obtained between 2 and 4 h after injection of fanolesomab labeled with 15-20 mCi ^99mTc. Imaging results were correlated with patients' culture results and clinical outcome. RESULTS: Two patients showed a significant increase in renal allograft uptake and were found to have allograft pyelonephritis. One patient who developed a severe acute renal failure secondary to humoral rejection (antidonor human leukocyte antigen antibody-mediated rejection with polymorphonuclear capillaritis and glomerulitis) showed uptake similar to the lower lumbar spine. One patient with normal allograft function showed a significantly increased uptake, especially in the pelvis of the allograft, indicating normal excretion of the free ^99mTc- pertechnetate by the allograft. The fifth patient who had been off immunosuppressive therapy and on maintenance hemodialysis for 4 months showed tracer uptake similar to the lumbar spine, suggestive of chronic allograft rejection. CONCLUSION: This preliminary study describes different patterns of ^99mTc-fanolesomab scan in renal allografts during episodes of kidney infection, rejection, or normal function. It suggests that ^99mTc- fanolesomab can be used to evaluate renal allograft complications.