Predominance of Th17 over regulatory T-cells in pleural effusions of patients with lung cancer implicates a proinflammatory profile.
BACKGROUND
Regulatory T-(Treg) and pro-inflammatory T-helper 17 (Th17) cells have been reported to be involved in the pathogenesis of pleural effusions caused by lung cancer. However, the presence of these subsets might not be a consequence of tumor pathogenesis, but rather a result of the pleural effusion itself, irrespective of its origin. In the present study, we analyzed the balance between these CD4+ T-cell subsets and compared them with those in non-malignant pleural effusions.


METHODS
We detected the frequencies of Treg and Th17 cells, identified as cluster of differentiation (CD)3+CD4+CD25+CD127low/- and CD3+CD4+ retinoid-related orphan receptor γt (RORγt)+ cells respectively, and proportions of interleukin (IL)17A-producing CD4+ cells in pleural effusions of patients with lung cancer, tuberculous and non-chronic pathologies by flow cytometry. The cytokine profile of stimulated CD4+ T-cells from tuberculosis and cancer groups was compared.


RESULTS
The proportion of Th17 cells were increased whereas Tregs were decreased in both tuberculosis and cancer, but not in non-chronic pathologies. Nevertheless, CD4+ T-cells from lung cancer effusions secreted interferon (IFN)γ, IL6 and IL17A, whereas CD4+ T-cells from tuberculous effusions secreted IL10 and low levels of IFNγ.


CONCLUSIONS
Although effusions from patients with chronic pathologies presented higher proportions of Th17 cells in comparison to those with non-chronic pathologies, only Th17 cells from malignant effusions maintained their proinflammatory profile after stimulation. Thus, in the pleural compartment of patients with lung cancer, a proinflammatory environment might be favored and possibly maintained by Th17 response.
Chronic-Degenerative Diseases Department, National Institute of Respiratory Diseases, Mexico City, Mexico hpradog@yahoo.com.
Heriberto
H
Prado-Garcia
Chronic-Degenerative Diseases Department, National Institute of Respiratory Diseases, Mexico City, Mexico.
Susana
S
Romero-Garcia
Clinic Service #3, National Institute of Respiratory Diseases, Mexico City, Mexico.
Uriel
U
Rumbo-Nava
Chronic-Degenerative Diseases Department, National Institute of Respiratory Diseases, Mexico City, Mexico.
Jose Sullivan
JS
Lopez-Gonzalez
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016207:Cytokines / Q000096:biosynthesis; D006801:Humans; D008175:Lung Neoplasms / Q000276:immunology*; D008875:Middle Aged; D010996:Pleural Effusion / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D058504:Th17 Cells / Q000276:immunology*
D016207:Cytokines
CD4+CD25+CD127low/− regulatory T-cells; CD4+RORγt+ Th17 cells; lung cancer; pleural effusion