Here, you will find the data and R scripts reproducing the results (run 'R-scripts-for-paper.R' in subfolder 'analysis') of the corresponding manuscript published by the International Journal of Molecular Sciences (https://doi.org/10.3390/ijms241713186 , preprint https://doi.org/10.20944/preprints202308.0524.v1) Abstract: Immunological aging type definition requires establishing reference intervals from the distribution of immunosenescence biomarkers conditional on age. For 1,605 individuals (18–97 years), we determined the IMMmune Age indeX IMMAX from flow cytometry-based blood cell sub-populations, and identified age-specific centiles by fitting generalized additive models for location, scale and shape. The centiles were uncorrelated to age, and facilitated categorizing individuals as immunologically slow, or fast aging types. With its 50th percentile as reference, we rescaled IMMAX to equivalent years-of-life (EYOL), and computed the immunological age gap as difference between EYOL and chronological age. Applied to preliminary baseline and follow-up measurements from 53 participants of the Dortmund Vital Study (ClinicalTrials.gov Identifier: NCT05155397), the averaged changes in IMMAX and EYOL conformed to the 5-year follow-up period, whereas no significant changes occurred concerning IMMAX centiles and age gap. This suggested that the participants immunologically adapted to aging, and kept their relative positions within the cohort. Sex was non-significant. Methodical comparisons indicated that future confirmatory analyses employing the completed follow-up examinations could rely on percentile curves estimated by simple linear quantile regression, while the selection of the immunosenescence biomarker will greatly influence the outcome, with the comprehensive metric IMMAX representing the preferable choice.