Immunophenotypic characteristics of monocytes in elderly subjects.

Since ageing is accompanied by various alterations of the immune system, the aim of the present study was to investigate the effect of age on the expression of surface markers in peripheral blood monocytes. We studied 28 healthy young subjects and 28 elderly subjects fulfilling the criteria of the SENIEUR protocol. Peripheral blood mononuclear cells were isolated and the expression of various surface markers was analysed by double colour flow cytometry. The mean fluorescence intensity of the intercellular adhesion molecule- (CD54), CD29, CD45RO and CD32 was increased significantly in CD14+ cells of elderly people when compared with the young subjects. No significant differences were found in the expression of CD11a, CD11b, CD15, CD26, CD27, CD33, CD45RA, CD45RB, CD49d, HLA-DR and CD65. In summary, we demonstrated significant increase in four monocyte surface markers in subjects of old age; this finding may be related to certain immune phenomena observed in ageing subjects such as auto-immunity.