The CD27+ memory B cells display changes in the gene expression pattern in elderly individuals

Memory B cells (MBCs) have a long lifespan compared with naive B cells (NBCs), remaining viable for years. This could predispose them to suffer misbalances in the gene expression pattern in the long term, which might be involved in the development of age-related B-cell disorders. In order to identify genes whose expression might change during life, we analysed the gene expression patterns of CD27(-) NBCs versus CD27(+) MBCs in young and old subjects. Using microarray assays we observed that the expression pattern of CD27(-) NBCs versus CD27(+) MBCs is significantly different. Furthermore, to evaluate the age effect, we compared the gene expression pattern of young versus aged subjects in both cell populations. Interestingly, we did not find significant differences in the CD27(-) NBC population between young and aged individuals, whereas we found 925 genes differentially expressed in CD27(+) MBCs. Among these genes, 193 were also differentially expressed in CD27(+) MBCs compared with CD27(-) NBCs, most of them involved in cell survival, cell growth and proliferation, cellular development and gene expression. We conclude that gene expression profiles of CD27(-) NBCs and CD27(+) MBCs are different. Moreover, whereas the gene expression pattern of CD27(+) MBCs varies with age, the same does not happen in CD27(-) NBCs. This suggests that MBCs undergo time-dependent changes, which could underlie a higher susceptibility to dysfunction with age.