Leukocyte migration inhibition studies and neutrophil cell function during aging in Nigerians.

In this study, in vitro cell-mediated immune response was analysed in 150 healthy Nigerians between 6 and 95 years old by the leukocyte migration inhibitory factor (L-MIF) test. Lymphocytes were activated with the mitogen concanavalin A and candida, measles virus and mycobacterial antigens. Nonspecific cellular immune capacity was studied by the Nitroblue tetrazolium (NBT) test. Numerical estimates of leukocytes and lymphocyte subpopulations were done. Mean L-MIF activity obtained with the four lymphocyte activators decreased with rising age indicating a progressive decline in cellular immune function with age. There was no significant age-related change in formazan positivity rate for both unstimulated and stimulated NBT tests. No age-related change in number was observed for any of the leucocyte and lymphocyte subpopulations. These results show that cell-mediaging response in Nigerians immunity declines, but phagocyte function is unchanged during aging. Lymphocyte depletion or numerical alteration in resting T cell subsets could not be demonstrated to be responsible for depressed cell-mediated immunity in aging Nigerians.