The increased number of very late activation antigen-4-positive cells correlates with eosinophils and severity of disease in the induced sputum of asthmatic patients.
BACKGROUND
Lymphocyte function associate-1 (LFA-1), macrophage antigen-1 (Mac-1), and very late activation antigen-4 (VLA-4) are involved in the infiltration of leukocytes into the tissues. Experimental models of allergic inflammation suggest that VLA-4 could determine the selective recruitment of eosinophils into the inflamed airways.


OBJECTIVE
Our purpose was to evaluate the involvement of integrins in eosinophil recruitment in asthma.


METHODS
We evaluated by immunocytochemistry the expression of VLA-4, LFA-1, and Mac-1 and their relationship with inflammatory cells and severity of disease in the induced sputum of 20 mild to moderate atopic asthmatic subjects and in 8 healthy subjects.


RESULTS
The number of VLA-4+ cells is increased in asthmatic patients and VLA-4 is mainly localized on eosinophils. Furthermore, VLA-4+ cells are significantly related to eosinophils. In contrast, LFA-1 and Mac-1 cellular expressions do not differ between asthmatic and control subjects and are not related to any specific cell type. Eosinophils and VLA-4+ cells are significantly higher in moderately compared with mildly asthmatic patients (P <.01, P <.05) and with healthy control subjects (P <.0005, P <.001). Eosinophils and VLA-4+ cells are also higher in mildly asthmatic patients compared with control subjects (P <.001, P <.005).


CONCLUSIONS
This is the first report demonstrating, by a noninvasive method in humans, that VLA-4+ cells are increased and correlate with the eosinophils in the induced sputum of atopic patients with mild to moderate asthma and that VLA-4 expression is related to the severity of disease.
Bocchino
V
V
Department of Respiratory Disease, University of Parma, Parma, Italy.
Bertorelli
G
G
D'Ippolito
R
R
Castagnaro
A
A
Zhuo
X
X
Grima
P
P
Di Comite
V
V
Damia
R
R
Olivieri
D
D
D000328:Adult; D001249:Asthma / Q000276:immunology / Q000473:pathology* / Q000503:physiopathology*; D004804:Eosinophils / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D039041:Integrin alpha4beta1; D016023:Integrins / Q000032:analysis*; D016169:Lymphocyte Function-Associated Antigen-1 / Q000032:analysis; D016177:Macrophage-1 Antigen / Q000032:analysis; D008297:Male; D008875:Middle Aged; D016201:Receptors, Lymphocyte Homing / Q000032:analysis*; D012720:Severity of Illness Index; D013183:Sputum / Q000166:cytology* / Q000276:immunology*
D039041:Integrin alpha4beta1; D016023:Integrins; D016169:Lymphocyte Function-Associated Antigen-1; D016177:Macrophage-1 Antigen; D016201:Receptors, Lymphocyte Homing