TTV DNA plasma load and its association with age, gender, and HCMV IgG serostatus in healthy adults

Abstract

Understanding immunosenescence and changes in antimicrobial immune response with age is of high importance. The association of immunosenescence with gender and persistent infection with human cytomegalovirus (HCMV) is a matter of intensive research. We determined whether replication of another persistent and highly prevalent virus, Torque teno virus (TTV), is related to age, gender, and HCMV IgG serostatus of the host. TTV DNA load in plasma was assessed by real-time PCR in 313 healthy persons: 20-30 years old (young, n = 104), 50-60 years old (middle-aged, n = 101), or >80 years old (elderly, n = 108). TTV DNA loads were further associated with age-groups, gender, and HCMV IgG serostatus. TTV load was significantly higher in the elderly compared to the young group (p < 0.001; Tukey's honest significant difference (HSD)), and the higher TTV DNA levels over age were found to be gender-specific (p = 0.002; ANOVA), with young women showing the lowest TTV load compared to young men (p = 0.009, t test) and compared to the other female age-groups (middle-aged p = 0.005; elderly p < 0.001; Tukey's HSD). TTV load of HCMV IgG-seropositive persons was significantly higher than that of the HCMV IgG seronegative in the young (p = 0.005; t test) and middle-aged (p = 0.016; t test) groups. These results indicate that the host's immune control of TTV replication decreases with age and is gender-specific. Persistent HCMV infection is significantly related to higher TTV DNA loads, especially at a younger age. Therefore, the influence of gender and HCMV on immunosenescence earlier in life should be further explored.

Fig. 1

TTV DNA log10 plasma loads between three age groups. The ANOVA post hoc Tukey’s HSD test was performed to compare mean values between the age groups. Nonsignificant p values are shown as ns. Thick horizontal bars represent the median value of each group

Fig. 2

TTV DNA log10 plasma loads between three age groups divided in a female and a male population. The ANOVA post hoc Tukey’s HSD test was performed to compare mean values between the age groups. Nonsignificant p values are shown as ns. Thick horizontal bars represent the median value of each group

Fig. 3

TTV DNA log10 plasma loads between females and males within three age groups. The unpaired t test was performed to compare mean values within the age groups. Nonsignificant p values are shown as ns. Thick horizontal bars represent the median value of each group

Fig. 4

TTV DNA log10 plasma loads between three age groups divided into two populations according to HCMV IgG serostatus. The ANOVA post hoc Tukey’s HSD test was performed to compare mean values between the age groups. Nonsignificant p values are shown as ns. Thick horizontal bars represent the median value of each group

Fig. 5

TTV DNA log10 plasma loads between HCMV IgG-seropositive and IgG-seronegative people across three age groups. The unpaired t test was performed to compare mean values within the age groups. Groups are divided in being either HCMV-IgG seropositive (pos) or HCMV-seronegative (neg). Nonsignificant p values are shown as ns. Thick horizontal bars represent the median value of each group