Noninvasive detection of therapeutic cytolytic T cells with 18F-FHBG PET in a patient with glioma.

BACKGROUND: A 57-year-old man had been diagnosed with grade IV glioblastoma multiforme and was enrolled in a trial of adoptive cellular immunotherapy. The trial involved infusion of ex vivo expanded autologous cytolytic CD8+ T cells (CTLs), genetically engineered to express the interleukin 13 zetakine gene (which encodes a receptor protein that targets these T cells to tumor cells) and the herpes simplex virus 1 thymidine kinase (HSV1 tk) suicide gene, and PET imaging reporter gene. INVESTIGATIONS: MRI, whole-body and brain PET scan with (18)F-radiolabelled 9-[4-fluoro-3-(hydroxymethyl)butyl]guanine ((18)F-FHBG) to detect CTLs that express HSV1 tk, and safety monitoring after injection of (18)F-FHBG. DIAGNOSIS: MRI detected grade III-IV glioblastoma multiforme plus two tumors recurrences that developed after resection of the initial tumor. MANAGEMENT: Surgical resection of primary glioblastoma tumor, enrollment in CTL therapy trial, reresection of glioma recurrences, infusion of approximately 1 x 10(9) CTLs into the site of tumor reresection, and (18)F-FHBG PET scan to detect infused CTLs.