Enumeration of human peripheral blood dendritic cells throughout the life

TLDR

Aging induces immunosenescence, altering immune cell numbers and functions, and dendritic cells—key antigen‑presenting cells—are central to both adaptive and innate immunity. The study aimed to chart the distribution of circulating dendritic cells across the human lifespan to elucidate age‑related immune changes. Flow cytometry of healthy adults showed a pronounced age‑dependent decline in total dendritic cells and their subsets, particularly plasmacytoid cells, with concurrent reductions in Treg numbers that correlated positively with dendritic cell counts, establishing reference values for clinical comparison.

Abstract

Human aging is associated with immunosenescence, a process characterized by alterations in numerical and functional features of immune system components. Dendritic cells (DCs) are the main antigen-presenting cells, playing a pivotal role in adaptive and innate immunity. Therefore, we investigated the distribution of human circulating DCs throughout the life, in order to contribute to the knowledge of the physiological background underlying the aging of immune system. Cytofluorimetric analysis of peripheral blood samples by all-aged healthy population showed a significant decrease of circulating DCs and of their two main subsets among age. This reduction was limited to the plasmacytoid cell subtype when young and old subjects were analyzed separately. The analysis of circulating Treg cell number in a cohort of the subjects showed a significant reduction with increasing age and a positive significant correlation to myeloid or plasmacytoid absolute numbers. In conclusion, this work provides a large set of data of normal reference values of peripheral blood dendritic cells in healthy population suitable for comparative clinical studies concerning pathological immune dysfunctions.