Abstract
Background
Adoptive immunotherapy with autologous tumor infiltrating lymphocytes (TIL) is a promising approach for cancer biotherapy. One issue, however, is whether such cells actually migrate to sites of tumor after intravenous infusion. There have been several reports of tumor uptake of radiolabeled TIL in patients with metastatic melanoma, but efforts to visualize tumor with radiolabeled TIL in other tumor types reportedly have been unsuccessful.
Methods
Eight patients with metastatic cancer (5 renal, 2 melanoma, 1 colon) received an intravenous infusion of 2 to 100 billion autologous TIL, including 50 million TIL which had been conjugated to 500 μCi Indium-111, co-administered with interleukin-2 (IL-2). One patient received 1gm/m2 of cyclophosphamide one day prior to TIL; seven patients received interferon alpha2b for 4 days prior to receiving TIL. Total body gamma camera imaging, including single photon emission computerized tomography (SPECT), was performed at 24 and 48 hours.
Results
All eight patients had demonstrable uptake of 111-Indium-labeled TIL into one or more known sites of tumor. There were no known sites of tumor which were not imaged. Metastatic sites imaged included bone, brain, mediastinal and perihilar lymph nodes, lung and liver parenchyma, abdominal periaortic nodes, and a pelvic mass. One patient served as a negative control in that the TIL scan was negative at a time when she had no evident disease, but a few weeks later had a positive TIL scan which lead to a diagnosis of axillary recurrence.
Conclusion
Uptake of radiolabeled TIL, whether CD8+ or CD4+, by metastatic renal cell carcinoma and other carcinomas was similar to that previously reported in melanoma. Pretreatment with cyclophosphamide was not a prerequisite for imaging, and TIL uptake did not predict tumor response.
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