B Cell Immunosenescence in the Elderlyand in Centenarians

The elderly suffer from an increased susceptibility to infectious disease and cancer. Aging ofthe immune system contributes to this state of affairs due to immunosenescence. Because repeatedintermittent or chronic antigen exposure may lead to lymphocyte clonal exhaustion,chronic antigenic stress plays a part in the compromised immunity of the elderly, who haveaccumulated a lifetime’s exposure to infectious agents, autoantigens, and cancer antigens. Literatureon immunosenescence has focused mainly on T cell impairment, but B cell compartmentis also affected. The age-dependent B cell changes documented by the present reviewindicate that advanced age per se is a condition characterized by lack of B clonotypic immuneresponse to new extracellular pathogens. In any event, data are suggesting that the loss ofnaive B cells could represent a hallmark of immunosenescence and could provide a biomarkerpossibly related to the life span of humans and potentially useful for the evaluation of antiagingtreatment. Since information on the senescence of B cells is of obvious interest, furtherstudies are necessary to confirm these suggestions as well as to extend the number of markersused to characterize the cells.