Today's open access paper discusses possible approaches to the treatment of immunosenescence, the age-related decline in effectiveness of the immune system. Unfortunately it is largely a tour of compensatory treatments, ways to force the cells of the immune system into greater or more useful activity without addressing any of the underlying causes of immunosenescence. Many of these methodologies have serious side-effects, are disruptive of normal immune function and overall health, and cannot be applied for the long term. Checkpoint inhibition, or the delivery of recombinant IL-7, for example, both of which are used as short term interventions to treat cancer.

The path to actually fixing the aged immune system by addressing causes is quite different. It would involve restoring the thymus from atrophy in order to restore a more youthful pace of production of T cells. Replacing the hematopoietic stem cell population to ensure that the right balance of immune cells are produced in the bone marrow. Reversing the degeneration of lymph nodes, where immune cells coordinate. Clearing out the populations of worn, malfunctioning, and misconfigured immune cells in tissues and bloodstream. This is a lot of work, but it is an oversight to omit these active lines of research and development from any review of ways to treat immunosenescence.

The one approach outlined at length in this open access paper that does address a plausible cause of immunosenescence is vaccination against cytomegalovirus (CMV). Near everyone is silently infected by late life, and the adaptive immune system becomes ever more devoted to trying and failing to clear this persistent viral infection. Ever more T cells are specialized to CMV, leaving ever fewer available for other tasks. As the supply of new T cells diminishes with age, this overspecialization becomes a serious issue, contributing greatly to the decline in immune function.

The authors here make the point that all of the necessary knowledge and technology already exists to put together a viable, widely used vaccine for CMV, but the will to do so is absent. We live in a world in which HPV vaccination became a reality, however, and CMV is arguably far worse when it comes to costs and suffering. Perhaps, at some point in the years ahead, the slow machineries of regulation will come to the point at which people are regularly vaccinated against CMV in order to reduce the impact of aging on immune function. I think it likely that selective destruction of CMV-specialized immune cells is more likely to emerge as a branch of therapy before that happens, however.

Immunosenescence and Its Hallmarks: How to Oppose Aging Strategically? A Review of Potential Options for Therapeutic Intervention