Suboptimal function of an aged immune system may significantly contribute to morbidity and mor-tality in the elderly. In contrast to lymphocytes, only little is known about changes of cells from the monocyte/macro-phage lineage. Especially the changes of their accessory function, which are necessary for optimal T cell stimulation are controversally discussed.
Methods
We measured the accessory function of mono-cytes (PBM) and alveolar macrophages (AM) and correlat-ed their accessory function with the age of the patients.
Results
We found a significant decrease in accessory function of AM with the age (rs = −0.5, P < 0.006) but not of PBM (rs = −0.4, P > 0.1). Additionally, we found a significant decrease in the percentage of AM (rs = 0.3, P<0.005) and an increase in the percentage of lymphocytes (rs = 0.3, P < 0.02) in the bronchoalveolar lavage. No correlations could be found with other lavage parameters or with unstimulated in vitro TNF-α, TGF-β, and IL-6 release of bronchoalveo-lar lavage cells; however, in stimulated BAL-cell cultures we found a weak but significant correlation between TNF-α release and the age (rs = −0.3, P<0.02).
Conclusions
Impairment of accessory cell function of alveolar macrophages may contribute to an increased risk of pulmonary infection of elderly persons.
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