Is immune senescence reversible?

Many genes have been shown to be involved in the decline in immune function of the elderly. However, normal numbers of myeloid and lymphoid colonies can be grown from elderly bone marrow under optimal conditions and some thymic function is preserved well into adult life. It may also be possible to reverse partially declining thymic function by IL-7 treatment. Peripheral B and T cells show evidence of dysregulation with production of large clones, changes in subset distribution and altered signalling and cytokine production, particularly decreased IL-2 production in the mouse. The identification of these defects may lead to relatively simple procedures to improve vaccination for the elderly. (C) 2000 Elsevier Science Ltd. All rights reserved.