Age-related alterations in blood and colonic dendritic cell properties

Abstract

BackgroundDendritic cells (DC) determine initiation, type and location of immune responses and, in adults, show decreased Toll-like receptors and some increased cytokine levels on ageing. Few studies in children have characterised DC or explored DC-related mechanisms producing age-related immune changes.ResultsThe pDC marker BDCA2 (but not CD123) was absent in pre-pubertal children and numbers of pDC decreased with age. Blood and colonic DC were more mature and activated in adults. Decrease in pDC numbers correlated with reduced GM-CSF levels with aging, but increasing IL-4 and IL-8 levels correlated with a more activated DC profile in blood. CXCL16 levels decreased with age.MethodsBlood and colonic DC phenotypes were determined in healthy adults and children by flow cytometry and correlated with aging. Blood DC were divided into plasmacytoid (pDC) and myeloid (mDC) while only mDC were identified in colon. Serum cytokine levels were determined by multiplex cytokine assays and correlated with DC properties.ConclusionsIn children, lack of BDCA2, a receptor mediating antigen capture and inhibiting interferon induction, may be immunologically beneficial during immune development. Conversely, reduced pDC numbers, probably secondary to decreasing GM-CSF and increasing cytokine-induced maturation of DC are likely to determine deteriorating immunity with ageing.

Intestinal epithelial barrier functions in ageing

“…cholera toxin, CT) declined with age in rodents and non-human primates (McDonald et al 2011;Schmucker et al 1988;Taylor et al 1992). This could be attributed to age-associated defects in antigen presentation (Moretto et al 2008;Vora et al 2016) and T helper cell activity (Nicoletti, 1994;van der Geest et al 2014, Carvalho et al 2011Daniels et al 1988). However, the chronic low level of inflammation, or inflammageing typical of the ageing organism also contributed to dampen antibody responses by damaging the B cell development (Bulati et al 2017).…”

Lasting alterations in monocyte and dendritic cell subsets in individuals after hospitalization for COVID-19

“…A potential limitation of our study is the imperfect age and sex matching of the controls to the patients. This is of particular importance for some DC subsets such as pDC, which are decreased in older (>40 years) healthy individuals, whereas there are no significant effects on cDC 87,88 . Given that the levels of pDC returned to the levels of healthy controls we do not believe this is an issue.…”

Origin of langerin (CD207)‐expressing antigen presenting cells in the normal oral mucosa and in oral lichen planus lesions

“…However, several studies report that the numbers of circulating cDC2-precursors are unaltered in relation to age and gender [53]. Furthermore, when analyzing the composition of cDCs in the human gut, no significant changes in the frequencies of cDCs were reported in older individuals [41,54], thus indicating that mucosal DCs are not expanded merely as a function of increasing age. Moreover, our visual examinations of the non-inflamed connective tissue areas surrounding the oral lichen planus lesions revealed no overt increase in the cDC2-density as compared with normal oral mucosa (not shown).…”