Immunologic monitoring of clinical trials in patients with cancer: technology versus common sense.

Monitoring of CTL or helper T -cell responses to tumor antigens in the course of clinical trials is an essential and necessary component of specific immunotherapy of cancer. While a variety of new immunologic or molecular technologies are now available for measuring these responses at a single-cell level, none has been standardized or validated to meet this need. The clinical investigator is thus faced with a selection of a method that is most likely to meet the desirable objective of establishing a correlation between clinical and immunologic responses to biotherapy. Selection of a relevant assay for this purpose is not a trivial task. Furthermore, few immunologic techniques can be easily adapted to reliable serial monitoring of patients on clinical protocols. The ELISPOT assay performs well in this setting, allowing for tracking of antigen specific T cells in the peripheral blood of cancer patients who receive tumor vaccines. In our hands, this assay is sensitive, accurate and cost effective. Its reliable performance in the context of clinical vaccination trials is highly likely to provide information necessary for optimizing vaccine administration to cancer patients, including timing, route of delivery, antigen concentration and use of DC or other adjuvants.