Immunoglobulin G glycans – Biomarkers and molecular effectors of aging

•IgG glycans modulate its effector functions, mainly effecting its (anti-)inflammatory capacity.•In the adult period aging is characterized by a change in the IgG glycosylation pattern: an increase in the level of agalactosylated and bisected glycans and a decrease in the level of digalactosylated and sialylated glycans.•The biogenesis of the age-related dynamics of the IgG glycoprofile is not yet clear.•IgG glycans are probably both: a biomarker and a contributor to the biological aging process.•Whether and if so, which, life-style interventions can influence biological age through modulation of IgG glycosylation on a personal level remains to be investigated. Immunoglobulin G (IgG) antibodies are post-translationally modified by the addition of complex carbohydrate molecules – glycans, which have profound effects on the IgG function, most significantly as modulators of its inflammatory capacity. Therefore, it is not surprising that the changes in IgG glycosylation pattern are associated with various physiological states and diseases, including aging and age-related diseases. Importantly, within the inflammaging concept, IgG glycans are considered not only biomarkers but one of the molecular effectors of the aging process. The exact mechanism by which they exert their function, however, remains unknown. In this review, we list and comment on, to our knowledge, all studies that examined changes in IgG glycosylation during aging in humans. We focus on the information obtained from studies on general population, but we also cover the insights obtained from studies of long-lived individuals and people with age-related diseases. We summarize the current knowledge on how levels of different IgG glycans change with age (i.e., the extent and direction of the change with age) and discuss the potential mechanisms and possible functional roles of changes in IgG glycopattern that accompany aging.