Autologous Peripheral Blood Mononuclear Cell Recognition of Autologous Proliferating Tumor Cells in the Context of a Patient-Specific Vaccine Trial

Abstract EN

Metastatic melanoma patients who were treated with patient-specific vaccines consisting of dendritic cells loaded with autologous tumor cells had a 5-year survival of over 50%.

Enzyme-linked immunospot (ELISPOT) has been used to detect antigen reactive T cells as a means of determining immune response.

We wished to determine whether IFN-gamma secretion in an ELISPOT assay was prognostic or predictive for survival following treatment.

Peripheral blood mononuclear cells (PBMCs) collected at weeks 0 and 4 were evaluated by ELISPOT assay for response to autologous tumor cells.

Overall, there was slight increase in the number of tumor reactive lymphocytes from week 0 to week 4.

Using >5 spots/100 K PBMC as the cutoff, a log-rank analysis revealed only a slight statistical significance in overall survival for patients who lacked tumor reactive PBMCs at week 4.

The sensitivity of ELISPOT in the context of patient-specific cellular vaccines is unclear.