biostudies-literatureCevirgel AInnovative Medicines InitiativeDutch Ministry of Health, Welfare and SportMinisterie van Volksgezondheid, Welzijn en Sporte13703https://www.ebi.ac.uk/biostudies/studies/S-EPMC9577949biostudies-literatureUnknown21(10)Immunosenescence describes immune dysfunction observed in older individuals. To identify individuals at-risk for immune dysfunction, it is crucial to understand the diverse immune phenotypes and their intrinsic functional capabilities. We investigated immune cell subsets and variation in the aging population. We observed that inter-individual immune variation was associated with age and cytomegalovirus seropositivity. Based on the similarities of immune subset composition among individuals, we identified nine immunotypes that displayed different aging-associated immune signatures, which explained inter-individual variation better than age. Additionally, we correlated the immune subset composition of individuals over approximately a year as a measure of stability of immune parameters. ImmunAging cellIdentification of aging-associated immunotypes and immune stability as indicators of post-vaccination immune activation.PMC9577949806776van Baarle DCevirgel AVos MBeckers LBuisman AMBijvank ERots NNanlohy NMShetty SAvan Beek JfalseIdentification of aging-associated immunotypes and immune stability as indicators of post-vaccination immune activation.Immunosenescence describes immune dysfunction observed in older individuals. To identify individuals at-risk for immune dysfunction, it is crucial to understand the diverse immune phenotypes and their intrinsic functional capabilities. We investigated immune cell subsets and variation in the aging population. We observed that inter-individual immune variation was associated with age and cytomegalovirus seropositivity. Based on the similarities of immune subset composition among individuals, we identified nine immunotypes that displayed different aging-associated immune signatures, which explained inter-individual variation better than age. Additionally, we correlated the immune subset composition of individuals over approximately a year as a measure of stability of immune parameters. Immun2022-01-01T00:00:00Z2022 Oct2025-04-04T07:13:19.569Z2025-04-04T07:13:19.569ZS-EPMC95779493608131410.1111/acel.13703