Impact of aging on cancer immunity and immunotherapy

Excerpt

The highest incidence of human cancers is seen in older people. Many parameters of immunity decrease in an age-associated manner. These two statements are each uncontroversial. However, whether the reason for the increased frequency of cancers in the elderly is due to alterations of the immune system in the old is much more controversial. Considering that the concept of immunosurveillance against spontaneously arising tumors is itself still controversial, this is hardly surprising. However, the efficacy of certain immunotherapy protocols in preclinical models and the much less reproducible but nonetheless occasionally highly effective therapeutic successes achieved in humans encourages the belief that the immune system could be exploited to control tumor growth. The following “Symposium-in-Writing” was inspired by the belief that either active or adoptive immunotherapy or a combination of both will one day soon be entering standard clinical practice. Given that most studies, preclinical and clinical both, have most often been conducted in younger individuals, it is imperative to consider the effect of age on outcome. Most obviously, the effect of age on T cell response to vaccination will be of great importance, and also the effect of the old host environment on the efficacy of adoptively transferred immune effectors needs consideration. …