Association of HCMV specific IgG subclass antibody levels with gender and age

Infection with human cytomegalovirus (HCMV), a ubiquitously distributed herpesvirus, has been associated with human immune system aging. Especially total HCMV specific IgG antibody (AB) titres have been correlated with human frailty and mortality. The aim of this study was to further assess to which extent HCMV specific subclass AB titres differ between individuals and whether this is associated with age and gender. ELISA tests detecting HCMV specific IgG subclass 1 and 3 ABs, the main subclass ABs directed against HCMV, were developed. Using these ELISAs, 145 (73 female and 72 male) age-matched patients, aged 17 to 87 years, were tested. The results showed that the IgG1 and 3 subclass distribution was highly variable among individuals, and that female persons had significantly higher IgG3 titres than age-matched male persons (p=0.0073). A correlation of the IgG3 subclass titres with age was found in female persons (Spearman r=0.305, p=0.0088). Thus the total HCMV specific IgG level appears to consist of a variable and gender associated distribution of IgG subclass ABs developed against persistent HCMV infection. The analysis of IgG subclass titres therefore could further be used to refine previously established clinical associations of aging with total HCMV specific IgG AB titres.