Several alterations in immune function and a concomitant progressive increase in pro-inflammatory status are the major characteristics of ageing process.
Cytokines play a key role during ageing acting both in regulatory communications among cells and in effector activity during an immune response.
The impact of age on intracellular Type 1 (IFN-gamma and TNF-alpha) and Type 2 (IL-4) cytokines, after stimulation with PMA/ionomycin, was determined in three CD4+ T subsets, i.e. CD95- CD28+ (virgin), CD95+ CD28+ (activated/memory), and CD95+ CD28- (effector/memory) from 47 subjects aged between 21 and 99 years.
The percentage of IFN-gamma positive cells significantly decreased in virgin CD4+ subset both in old and nonagenarian subjects, as well as in activated/memory T cells from old in comparison with young subjects.
The percentage of TNF-alpha positive cells significantly decreased in activated/memory CD4+ subset from old people.
Regarding Type 2 cytokines, IL-4 positive cells significantly increased in activated/memory CD4+ subset from nonagenarians.
On the whole scientific data indicate that:
- different Type 1 and Type 2 cytokine-positive CD4+ T subsets are differently affected by ageing process;
- activated/memory T cells appear to be the most affected subset;
- a shift towards an increased role of Type 2 cytokines and a diminished role of Type 1 cytokines emerges with ageing.
Keywords: cytokines, memory T cells, TNF-alpha.