Assessment of T lymphocyte cytokine production in induced sputum from asthmatics: a flow cytometry study.
BACKGROUND
Asthma results from a bronchial inflammation in which Th2 lymphocytes play a pivotal role, as shown in invasive bronchial biopsies and broncho-alveolar lavages. Induced sputum (IS) is a non-invasive method of recovery of bronchial cells, which can be repeated in the same patients. However, lymphocyte activation has not been studied in IS to date, because of the low number of T cells recovered. Herein we took advantage of flow cytometry, a method suitable for the study of small cell populations, to assess T cell cytokine production in IS.


OBJECTIVE
(1) To assess induced sputum T cell cytokine production by flow cytometry in asthmatic subjects and controls. (2) To compare the T cell cytokine production between symptomatic and non-symptomatic asthmatics.


METHODS
Thirteen asthmatics and 19 controls were included. Sputum was induced by a hypertonic saline. Sputum cells were stimulated and intracellular IL-13 and IFN-gamma were detected in T cells by flow cytometry.


RESULTS
Stimulation induced an increase of IL-13 and IFN-gamma production by T cells. This increase was higher in asthmatics. IL-13-producing T cells were increased in asthmatics after stimulation. In symptomatic asthma, IFN-gamma-producing T cells were in higher proportion than in controlled asthma.


CONCLUSIONS
IS T cell cytokine production indicates a basic Th2 bias in asthma, accompanied during symptoms by a Th1-like activation. These results open the field for longitudinal studies of the variation of T cell activation in asthma.
Boniface
S
S
UPRES EA 3287, Groupe de Recherche Clinique Pathologie respiratoire liée à l'environnement, Université de la Méditerranée, Service de Pneumo-Allergologie Hôpital Ste Marguerite, Marseilles, France.
Koscher
V
V
Mamessier
E
E
El Biaze
M
M
Dupuy
P
P
Lorec
A M
AM
Guillot
C
C
Badier
M
M
Bongrand
P
P
Vervloet
D
D
Magnan
A
A
D000328:Adult; D001249:Asthma / Q000276:immunology* / Q000378:metabolism; D002452:Cell Count; D002478:Cells, Cultured; D004804:Eosinophils / Q000276:immunology; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis*; D018793:Interleukin-13 / Q000096:biosynthesis*; D008213:Lymphocyte Activation / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000276:immunology; D012720:Severity of Illness Index; D013183:Sputum / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology
D018793:Interleukin-13; D007371:Interferon-gamma