Immunological studies in human ageing. I. In vitro functions of T cells and polymorphs

T-cells were investigated by the E rosette assay, PHA stimulation, allogeneic MLC and CML responses, in a group of 100 healthy aged people over 70 years old, and compared to young control individuals less than 45 years old. No major difference was found between the two groups, except for PHA stimulation which was significantly reduced in old individuals when low mitogen concentration was used. These observations suggest that only some T cells subsets are affected by ageing, without modification of the total T lymphocyte number. Contrarily, the phagocytic activities of polymorphonuclear cells assessed in a group of 38 aged people were dramatically decreased, using either the NBT test or a direct phagocytosis assay.