Am. J. Respir. Crit. Care Med., Vol 154, No. 5, 11 1996, 1296-1300.
Integrin upregulation on sputum neutrophils in smokers with chronic airway obstruction
P Maestrelli, PG Calcagni, M Saetta, T Bertin, CE Mapp, A Sanna, C Veriter, LM Fabbri and D Stanescu
Institute of Occupational Medicine, University of Padova, Italy.
To determine the relationship between the expression of leukocyte- specific
integrins in the airways and the airway obstruction in smokers, we analyzed
hypertonic saline-induced sputum in 33 male subjects, age 64.7 +/- 0.5 yr
(mean +/- SEM), with a smoking history of 12 to 94 pack-years, at the end
of a 15-yr follow-up study. Average FEV1/VC ratio was 69 +/- 1% at the
beginning of the study and 66 +/- 2% at the end of the follow-up period,
and annual decline of FEV1 was 20 +/- 3 ml/yr. Fourteen individuals
exhibited airway obstruction as assessed by a FEV1/VC ratio lower than
63.3%. Differential leukocyte count was performed on cytospin preparations
and the expression of integrin alpha (CD11a, CD11b, CD11c) and beta (CD18)
chains was assessed on granulocytes and mononuclear cells by
immunocytology. The numbers of neutrophils expressing CD11b and CD18, but
not CD11c or CD11a, were increased in the subjects with airway obstruction
compared with those without airway obstruction. CD11b- and CD18-positive
neutrophils were negatively correlated with FEV1/VC ratio (p < 0.01). No
significant correlations were found between CD11a-, CD11b-, CD11c-,
CD18-positive mononuclear cells and lung function measurements. In
conclusion, our results suggest that leukocyte-specific integrin CD11b/CD18
expressed on sputum polymorphonuclear leukocytes represents a marker for
the smokers who develop chronic airway obstruction.
