Attenuation of human herpesvirus 6B reactivation by aging

Abstract

Objective: There has been little research on human herpesvirus 6B (HHV-6B) in healthy adults and prevalences in different age groups have been unclear. Therefore, the major objective of this study was to evaluate seroprevalence to HHV-6 antibodies in ordinary working people and examine the effect of aging on seroprevalence. Also, as HHV-6B is reactivated in saliva, another objective was to investigate an association between age and HHV-6B reactivation based on measured salivary HHV-6 DNA levels.Methods: Our subjects were 77 ordinary office workers who underwent a health checkup. In this population, we measured anti-HHV-6 antibody titers using enzyme-linked immunosorbent assay and salivary HHV-6 DNA levels. In addition to examining an association with age, we examined associations with body mass index, smoking habit, and alcohol consumption as confounding factors.Results: There was a significant decrease in the seropositivity of HHV-6 antibodies in subjects of 50 years and older, and age was significantly negatively correlated with anti-HHV-6 antibody titers. Age and salivary HHV-6 DNA levels were also significantly negatively correlated but there were no significant correlations with other factors. Conclusions:Our results suggest that HHV-6B reactivation is attenuated by aging.Thus, HHV-6 antibodies steadily decrease in the body with aging. K E Y W O R D S human herpesvirus 6 (HHV-6), immune system, latent infection, reactivation J Med Virol. 2019;91:1335-1341.wileyonlinelibrary.com/journal/jmv

Effect of Lactococcus lactis Strain Plasma on HHV-6 and HHV-7 Shedding in Saliva: A Prospective Observational Study

“…To evaluate the effect of LC-Plasma on salivary shedding of HHV-6 and 7 DNA, baseline shedding of viral DNAs was measured in the first period. As previously demonstrated [ 8 , 12 , 14 ], the levels of these viral DNAs differed among individuals, and the pattern of salivary viral DNA shedding was associated with the subject’s background. HHV-6 DNA loads were significantly higher in the subjects under 40 years old than in those 40 or older ( P = 0.018).…”

“…Therefore, our findings were in conflict with our hypothesis. Recently, Kobayashi et al also reported a negative correlation between age and salivary HHV-6 DNA levels [ 8 ]. Regardless, the hypothalamus–pituitary–adrenal axis, which mediates the production of stress hormones, may play an important role in age-related changes of salivary viral shedding, as already demonstrated by analysis of astronauts during space flight [ 30 ].…”

“…Therefore, the immune activation effect of LC-Plasma via pDCs may be weakened in the elderly, who have reduced numbers of pDCs. In fact, several studies demonstrating that LC-Plasma intake decreases the risk of infection and fatigue were conducted in subjects under the age of 40 [ 8 , 22 , 32 ]. In addition to subject age, a seasonal effect may have influenced our assessment of viral reactivation in this study; the duration of LC-Plasma intake (second period) corresponded to the summer season in Japan (15 July 2019−11 August 2019), and heat stress negatively affects immune response [ 33 , 34 ].…”

“…These viruses can establish latency in various body sites, such as the salivary gland [ 4 ] and central nervous system [ 5 ] after primary infection [ 6 ]. Frequent viral shedding in saliva has been demonstrated, even in healthy and immunocompetent seropositive adults [ 7 , 8 ], and the dynamics of viral shedding may be associated with underlying disorders such as collagen diseases [ 9 , 10 , 11 , 12 ]. Interestingly, HHV-7 is frequently isolated from saliva, but HHV-6 is not, despite the presence of a high copy number of viral DNA [ 13 ].…”

Examination of control asymptomatic cohorts reveals heightened anti‐EBV and HHV‐6 A/B dUTPase antibodies in the aging populations

“…[10][11][12] Interestingly, a recent study by Kobayashi et al reported that HHV-6B reactivation is attenuated by aging in a cohort of asymptomatic individuals. 13 A limitation of this study however is that serological studies were performed using an enzyme-linked immunosorbent assay (ELISA) for the detection of immunoglobulin G (IgG) against an unreported HHV-6 antigen. The study also found that the amount of HHV-6 DNA in saliva negatively correlated with age.…”