Preinfusion positron-emission tomography (PET) reveals hypermetabolic lesions in the right lung and the left inguinal–iliac node that are consistent with metastases (arrowheads); the lesions colocalized to tumor nodules on computed tomography (CT). After infusion with NY-ESO-1–specific CD4+ T cells, PET scans show that the tumor nodules have regressed, and no evidence of disease can be detected. Uptake in liver, spleen, and bladder represents normal background signal and did not colocalize to any lesions on CT scans.

Antigen-specific T-cell responses to melanoma antigen recognized by T cells (MART-1), melanoma antigen 3 (MAGE-3), NY-ESO-1, and glycoprotein 100 (GP100) were evaluated in samples of peripheral-blood mononuclear cells (PBMCs) collected before infusion and at time points up to 12 weeks after infusion. Autologous dendritic cells (DCs) that were transfected with RNA-encoding tumor antigen were used to stimulate PBMCs in enzyme-linked immunospot assays. The frequency of the antigen-specific response is presented as the number of reactive spots per 100,000 PBMCs (squares). Parallel wells with DCs transfected with control RNA were used at each time point (diamonds). Each data point is an average of the values from triplicate wells. After infusion, marked elevations in antigen-specific T-cell responses were observed for MAGE-3 (Panel A), MART-1 (Panel B), and NY-ESO-1 (Panel C) but not for GP100 (Panel D). The I bars denote standard errors.

Quantitative polymerase-chain-reaction (PCR) assay with the use of clone-specific primers flanking the TCR–CDR3 region was used to determine the frequency of infused CD4+ T-cell clones among peripheral-blood mononuclear cells (PBMCs) in samples collected before infusion and at intervals after infusion until day 90. Results are represented as the number of T-cell clones per 1 million PBMCs and as a percentage of the total number of PBMCs at peak points and low points. As expected, the NY-ESO-1–specific CD4+ T-cell clone is undetectable in preinfusion PBMCs (sensitivity of detection, 1:100,000 cells). After infusion, the frequency of the infused CD4+ T-cell clone in vivo increased to almost 2% of all PBMCs and fluctuated between 0.7 and 3.0% during the next 12 weeks. The I bars denote standard errors.