Immunosenescence and vaccination of the elderly II. New strategies to restore age-related immune impairment.

One of the greatest health-care challenges in the elderly is to ensure that vaccination against infections are optimally effective, but vaccination can only be effective if cells that are capable of responding are still present in the repertoire. The reversing of immunosenescence could be achieved by improving immune responses or altering vaccine formulation. Recent vaccination strategies in the elderly exert low effectiveness. Nutritional interventions and moderate exercise delay T cell senescence. Telomerase activity and expression of toll-like receptors can be improved by chemotherapy. Reversion of thymic atrophy could be achieved by thymus transplantation, depletion of accumulated dysfunctional naive T cells and herpesvirus-specific exhausted memory cells. Administration of immunostimulatory and anti-inflammatory cytokines show the best practical approach. Reduced dendritic cell activity and co-receptor expression might be increased by interleukin (IL)-2 administration. IL-7 protects both B and T lymphocytes, but IL-2, IL-10, keratinocyte growth factor, thymic stromal lymphopoietin, as well as leptin and growth hormone also have a stimulatory effect on thymopoiesis. In animals, several strategies have been explored to produce more efficacious vaccines including high dose vaccines, DNA vaccines with immunostimulatory patch, virosomal vaccines and vaccines containing new adjuvants. Hopefully, one of these approaches will be translated into human therapy in a short time.