NEUTROPHIL MIGRATION, OXIDATIVE-METABOLISM, AND ADHESION IN ELDERLY AND YOUNG SUBJECTS

To evaluate neutrophil functions in the elderly. Methods. We investiga ted the PMN migration in vivo and PMN superoxide production and adhesi on in response to a variety of compounds; PMN have been isolated both from blood and from a skin experimental exudate (obtained by Senn's sk in window technique) of 25 normal elderly and of 25 normal young contr ol subjects. Results. No difference was found in PMN migration in vivo (62.9 +/- 21.3 x 10(6) and 65.5 +/- 9.1 x 10(6) PMN/cm(2)/24 hours in elderly and young subjects respectively), neither were different the adhesion under basal condition and after some stimuli and the superoxi de production in basal condition and in response to STZ and PMA in two groups. In elderly subjects superoxide production, in response to fML P, markedly resulted lower than in young controls both by circulating PMNs (3.6 +/- 2.7 and 9.3 +/- 3.3 nMOLES O-2(-)/10(6) PMN respectively , p < 0.0001) and by exudate PMNs (13.6 +/- 4.3 and 19.4 +/- 6 nMOLES O-2(-)/10(6) PMNs respectively, p < 0.005). Conclusion. Many PMN funct ions in the elderly do not differ from young people, suggesting that t he overall defense function of these cells is not affected by aging. T he only parameter that we have found to be different between the two g roups is the poor superoxide production after fMLP stimulus of PMNs. T he stimulus- and function-specificity of this defect in PMNs from elde rly subjects indicates the existence of a dysregulation of the signal transduction pathway distal to fMLP receptor and proximal to NADPH oxi dase activation.