Am. J. Respir. Crit. Care Med., Vol 151, No. 5, 05 1995, 1551-1558.
Subpopulations of alveolar macrophages in smokers and nonsmokers: relation to the expression of CD11/CD18 molecules and superoxide anion production
T Schaberg, U Klein, M Rau, J Eller and H Lode
Department of Pulmonary Medicine, Chest Hospital Heckeshorn-Zehlendorf, Berlin, Germany.
We were previously able to show that the number of alveolar macrophages
(AM) expressing CD11/CD18 molecules is increased in smokers compared with
nonsmokers and related to the superoxide anion (O2-) production of these
cells. Since it has been demonstrated that AM are a heterogeneous cell
population that can be separated by density, we performed this study to
investigate the expression of CD11/CD18 molecules and O2- production in
relation to cell density of AM from smokers and nonsmokers. AM were
obtained by bronchoalveolar lavage (BAL) from smokers (n = 32) and
nonsmokers (n = 20). Subpopulations were isolated using discontinuous
Percoll density-gradient centrifugation with four densities (fraction 1:
1.030; fraction 2: 1.040; fraction 3: 1.050; and fraction 4: 1.070 g/ml).
Expression of CD11/CD18 on freshly isolated cells and on AM before and
after density centrifugation was studied using peroxidase-antiperoxidase
staining. The contribution of AM subpopulations to O2- production in
smokers was determined by monitoring the reduction of ferricytochrome C to
ferrocytochrome C. We obtained 0.92 +/- 0.1 x 10(5) AM/ml BAL in nonsmokers
and 2.4 +/- 0.3 x 10(5) AM/ml in smokers. Recovery after density
centrifugation was > or = 72%. The absolute number of AM in smokers was
significantly increased in fractions 3 and 4 (median 4.37 x 10(6) and 2.05
x 10(6), respectively) compared with nonsmokers (median 1.26 x 10(6) and
0.7 x 10(6), respectively) (p < 0.05). In both smokers and nonsmokers,
fractions 3 and 4 showed a comparable increase in the percentage of
CD11/CD18-positive AM compared with fractions 1 and 2.(ABSTRACT TRUNCATED
AT 250 WORDS)
