NEUTROPHILS AND LOW-GRADE INFLAMMATION IN THE SEEMINGLY NORMAL AGING HUMAN LUNG

Lung function deteriorates with age and is associated with elastin los s, loss of elastic recoil and decline in diffusing capacity for carbon monoxide. To determine whether increased numbers of neutrophils can b e found in the lower respiratory tract in healthy, clinically normal i ndividuals who are more advanced in age, we performed bronchoalveolar lavage (BAL) on individuals in three discontinuous age groups (Group I , 19-36 years; Group II, 45-55 years; Group III, 64-83 years). We foun d that neutrophils were increased in many individuals in Group III com pared to Group I. The neutrophil cell differential count was 1.44 +/- 0.18% (mean +/- S.E.M.) for Group I versus 3.88 +/- 0.81% for Group II I (P < 0.01) and neutrophils x 10(3)/ml BAL fluid was 1.7 +/- 0.2 vers us 7.2 +/- 1.7 for Group I versus Group III, respectively (P < 0.01). Similarly, interleukin-8 (IL-8) (8.5 +/- 1.7 vs 36.8 +/- 9.4 pg/ml, P < 0.01) and neutrophil elastase (NE) complexed to alpha(1)-antiproteas e (1.2 +/- 0.1 vs 16.6 +/- 7.1 ng/ml, P < 0.02) were significantly ele vated in the oldest versus youngest age group, although alpha(1)-antip rotease (582 +/- 86 vs 1178 +/- 148 ng/ml, P < 0.01) and elastase inhi bitory capacity (EIC) (8.1 +/- 1.3 vs 17.7 +/- 1.9 mu mol/ml, P < 0.01 ) were also significantly increased in the oldest age group. This cros s-sectional investigation suggests that low-grade inflammation exists in the air spaces of many clinically normal, older individuals. (C) 19 98 Elsevier Science Ireland Ltd. All rights reserved.