Specific Immune Subsets Alternation in Metabolic and Cardiovascular Diseases in Taiwan Elderly Population

Ageing is greatly enhancing susceptibility to diverse infections due to the alternation of immune subsets which in terms of “immunosenescence”. Aim of this work was to investigate circulating T lymphocyte subsets alternations participated in ageing and the two major elderly disease categories, including E-MDs and E-CVDs. 66 elderly outpatients and 20 elderly healthy (EH) controls (age >= 60 years) were recruited, 12 young healthy (YH) volunteers (age < 40 years) were served as young controls. MDs and CVDs were diagnosed by the gerontologist at Chang Gung Memorial Hospital (CGMH) based on clinical features using the ICD-10 codes E00~90 and I00~99. Cell suspension of peripheral blood (PB) from each subject was used for immune subsets including iNKT, Treg, TN, TEM, and TEMRA analysis using flow cytometer. Serum IFN-γ, TGF-β, GDF-15 levels were determined by using commercial ELISA kits. Our results showed that normal ageing caused the induction of CD4+T cells and Tregs levels (%), whereas reduction of CD3+T cells, CD8+T cells and iNKT cells levels (%) as compared to YH control. However, comparing EH control, we observed significantly reduced expression levels (%) of CD4+T cells and Tregs in patients with E-MDs and E-CVDs. Interestingly, the CD4+-TN levels (%) tended to reduce more severely in patients with E-MDs and E-CVDs as compared to EH, whereas CD8+ -TN levels (%) were only affected in ageing and patients with E-CVDs. TEM and TEMRA were significantly increased along with ageing compared to YH. Furthermore, both TEM and TEMRA along with their loss of CD28 and regaining of CD57 markers were differently affected in ageing and patients with E-MDs and E-CVDs. Besides, serum TGF-β, IFN-γ, GDF-15 levels were remarkably altered with ageing and disease groups. We conclude that specific T-lymphocyte subsets alteration significantly involved in ageing and patients with E-MDs and E-CVDs, especially gain the opportunities to develop potential diagnostic markers for patients with E-MDs and/or E-CVDs and understand an aspect of inflamm - ageing and immunosenescence during ageing.
Keywords: Ageing, Immunosenescence, iNKT, Treg, TEM, TEMRA