Prognostic value of CD4+ lymphocytes in pleural cavity of patients with non-small cell lung cancer

Lung T-cell subset composition at the time of surgical resection is a prognostic indicator in non-small cell lung cancer

NSCLC arises in the complex environment of chronic inflammation. Depending on lung immune polarization, infiltrating immune cells may either promote or suppress tumor growth. Despite the importance of the immune microenvironment, current staging techniques for NSCLC do not take into consideration the immune milieu in which the neoplasms arise. T-cell subset content was compared between paired tumor-bearing and contralateral lungs, patient and control peripheral blood. The relationship between T-cell subset distribution and survival were evaluated. CD4 and CD8+ T cells were subsetted by CD45RA/CD27 and analyzed for expression of activation, adhesion, and homing markers. Strikingly, T-cell content was indistinguishable between lungs. Compared with peripheral blood, naïve CD4 and CD8 T cells were rare in BAL. CD4+ BAL T cells showed increased CD95 (higher apoptotic potential) and CD103 expression (epithelial adhesion), but decreased CD38 (activation) and CCR7 expression (lymph node homing). CD8+ BAL T cells showed increased CD103 expression and decreased CD28 expression (co-stimulation). Differences in CD28, CD95, and CCR7 expression were more pronounced within memory cells, while differences in CD4+ CD103 expression were more prominent in effector/memory cells. Of these populations, the absence of lung CD4 T cells with an effector-like phenotype (CD45RA+/CD27-) emerged as a predictor of favorable outcome. Patients with a low proportion (≤0.44%) had 90% 5-year survival (n = 10, median survival 2,343 days), compared with 0% (n = 9, median survival 516 days) of patients with a higher proportion. Further study is required to confirm this association prospectively and define the function of this subpopulation.

Generation and differentiation of IL-17-producing CD4+ T cells in malignant pleural effusion

IL-17-producing CD4(+) T (Th17) cells have been found to be increased in some human cancers; however, the possible implication of Th17 cells in regulating antitumor responses in malignant pleural effusion (MPE) remains to be elucidated. In the current study, distribution and phenotypic features of Th17 cells in both MPE and peripheral blood from patients with lung cancer were determined by flow cytometry or double immunofluorescence staining. The impacts of cytokines on Th17 cell generation and differentiation were explored. The chemoattractant activity of chemokines CCL20 and CCL22 for Th17 cells in vitro was also observed. It was found that the increased Th17 cells could be found in MPE compared with blood. The in vitro experiments showed that IL-1β, IL-6, IL-23, or their various combinations could promote Th17 cell generation and differentiation from naive CD4(+) T cells. MPE was chemotactic for Th17 cells, and this activity was partly blocked by anti-CCL20 and/or CCL22 Abs. Our data also showed that the accumulation of Th17 cells in MPE predicted improved patient survival. It could be concluded that the overrepresentation of Th17 cells in MPE might be due to Th17 cell differentiation and expansion stimulated by pleural proinflammatory cytokines and to recruitment of Th17 cells from peripheral blood induced by pleural chemokines CCL20 and CCL22. Furthermore, the accumulation of Th17 cells in MPE predicted improved patient survival. These data provide the basis for developing immune-boosting strategies based on ridding the cancer patient of this cell population.

The prevalence of FOXP3+ regulatory T-cells in peripheral blood of patients with NSCLC

We have studied CD4(+)CD25(high)FOXP3(+) regulatory T-cells (T(regs)) from 51 patients with non-small-cell lung cancer (NSCLC) and 33 healthy donors. Regulatory T-cells were identified by fluorescence-activated cell sorting by using a panel of antibodies and by reverse transcriptase polymerase chain reaction analysis for FOXP3 expression. Functional studies were done to analyze their inhibitory role. Finally, regulatory T-cells were analyzed in malignant pleura effusion (PE) from patients with NSCLC. Patients with NSCLC have increased numbers of CD4(+)CD25(high) FOXP3(+) T(regs) in their peripheral blood and pleura effusion (PE), which express high levels of CTLA-4, GITR. These cells were anergic toward T-cell receptor stimulation and, when cocultured with activated CD4(+)CD25(-) cells, potently suppressed their proliferation and cytokine secretion. Our data suggest that in NSCLC patients, there is an increase of CD4(+)CD25(high)FOXP3(+) regulatory T-cells in the peripheral blood and tumor microenvironment. These T-cells might prevent effective antitumor immune responses, and the increase in frequency of CD4(+)CD25(high)FOXP3(+) Tregs might play a role in the modulation of the immune response against NSCLC and could be important in the design of immunotherapeutic approaches.

Pleural macrophages are the dominant cell population in the thoracic cavity with an inflammatory cytokine profile similar to peritoneal macrophages

Numerous human macrophage (mphi) subpopulations with different behavior have been identified in adults. It is well known that peritoneal mphi are activated by abdominal surgery and subsequently contribute to a systemic inflammatory response that leads to immune suppression, increased morbidity and mortality. Information on the role of pleural mphi in adults is scarce and information on their role in children is lacking. We investigated the behavior of pleural versus peritoneal mphi in children and adolescents. As a first step, we compared the cellular composition of the pleural and peritoneal surface in children and adolescents. Pleural and peritoneal lavages were performed in 21 patients undergoing non-contaminated laparoscopic and thoracoscopic surgical procedures. We observed a significantly higher percentage of mphi in the pleural compared to the peritoneal cavity with less lymphocytes, a small amount of polymorphonuclear cells (PMNs) and other cells. To further study the mphi inflammatory response, we measured the spontaneous and LPS triggered cytokine release of isolated pleural versus peritoneal mphi (IL-1beta, IL-6, and IL-10). The pattern of cytokine release was similar in both, pleural and peritoneal mphi. Directly after lavage, they showed a strong activation, with no difference between stimulated and non-stimulated cells. After 24 h resting, mphi of both compartments reacted to LPS with a similar significant increase in the cytokine release. In conclusion, our results demonstrate that pleural mphi represent the dominant cell population in the pleural cavity of the young. They show a similar inflammatory response as peritoneal mphi and should be considered to play a major role in the local inflammatory response to thoracic surgery.

CD4+CD25+ regulatory T lymphocytes in malignant pleural effusion

BACKGROUND

Active suppression by CD4(+)CD25(+) regulatory T lymphocytes plays an important role in the downregulation of T-cell responses to foreign and self-antigens.

OBJECTIVE

To analyze whether the CD4(+)CD25(+) regulatory T lymphocytes exist and function normally in malignant pleural effusion.

METHODS

The percentages of CD4(+)CD25(+) T lymphocytes in pleural effusion and peripheral blood from patients with lung cancer with malignant effusion, pleural lavage and peripheral blood from patients with lung cancer without effusion, and peripheral blood from healthy control subjects were determined by flow cytometry. The expressions of forkhead transcription factor Foxp3 and cytotoxic lymphocyte-associated antigen-4 were also examined. CD4(+)CD25(+) and CD4(+)CD25(-) T cells from pleural effusion and peripheral blood were isolated, and were cultured to observe the effects of CD4(+)CD25(+) cells on proliferation response of CD4(+)CD25(-) T cells in vitro.

MAIN RESULTS

There were increased numbers of CD4(+)CD25(+) T cells in malignant pleural effusion from patients with lung cancer compared with pleural lavage from patients with lung cancer without pleural effusion, and that these cells have constitutive high-level expression of Foxp3 and cytotoxic lymphocyte-associated antigen-4. Furthermore, CD4(+)CD25(+) T cells mediate potent inhibition of proliferation response of CD4(+)CD25(-) T cells, and anticytotoxic lymphocyte-associated antigen-4 monoclonal antibody could reduce the inhibitory activity of CD4(+)CD25(+) T cells.

CONCLUSIONS

The increased CD4(+)CD25(+) T cells found in malignant pleural effusion express high levels of Foxp3 transcription factor and potently suppress the proliferation of CD4(+)CD25(-) T cells, and cytotoxic lymphocyte-associated antigen-4 is involved in the suppressive activity of pleural CD4(+)CD25(+) T cells.