0000000000707973
AUTHOR
Beatrix Grubeck-loebenstein
Human immunosenescence: is it infectious?
Morbidity and mortality due to infectious disease is greater in the elderly than in the young, at least partly because of age-associated decreased immune competence, which renders individuals more susceptible to pathogens. This susceptibility is particularly evident for novel infectious agents such as in severe acute respiratory syndrome but is also all too apparent for common pathogens such as influenza. Many years ago, it was noted that the elderly possessed oligoclonal expansions of T cells, especially of CD8(+) cells. At the same time, it was established that cytomegalovirus (CMV) seropositivity was associated with many of the same phenotypic and functional alterations to T-cell immunit…
Immunosenescence and Cytomegalovirus
Since Looney at al. published their seminal paper a decade ago [1] it has become clear that many of the differences in T cell immunological parameters observed between young and old people are related to the age-associated increasing prevalence of infection with the persistent β-herpesvirus HHV-5 (Cytomegalovirus). Ten years later, studies suggest that hallmark age-associated changes in peripheral blood T cell subset distribution may not occur at all in people who are not infected with this virus [[2]; Derhovanessian et al., in press]. Whether the observed changes are actually caused by CMV is an open question, but very similar, rapid changes observed in uninfected patients receiving CMV-in…
Is immunosenescence infectious?
Abstract Herpes viruses are endemic. Once established, the virus is never eliminated but persists throughout life. The fraction of infected individuals gradually increases with age, such that the majority of elderly people are cytomegalovirus (CMV) + , Epstein–Barr virus (EBV) + and Varicella + . Clinically relevant reactivation of Varicella causes painful shingles; CMV reactivation can cause fatal pneumonia. Overt reactivation, even in the very elderly, occurs only in immunocompromised individuals; however, the necessity for maintaining immunity to these viruses is costly. We argue that this cost is not only reflected in the requirement for continuous immunosurveillance against these virus…