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Impaired survival of regulatory T cells in pulmonary sarcoidosis.

Broos CE, van Nimwegen M, Kleinjan A, ten Berge B, Muskens F, in 't Veen JC, Annema JT, Lambrecht BN, Hoogsteden HC, Hendriks RW, Kool M, van den Blink B - Respir. Res. (2015)

Bottom Line: Patients with pulmonary sarcoidosis (n = 58) were included at time of diagnosis.Rather, increased proportions of circulating Tregs were observed, most prominently in patients developing chronic disease.In untreated patients with active pulmonary sarcoidosis, Tregs show impaired survival and enhanced apoptotic susceptibility towards CD95L.

View Article: PubMed Central - PubMed

Affiliation: Department of Pulmonary Medicine, Erasmus MC, 's Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands.

ABSTRACT

Background: Impaired regulatory T cell (Treg) function is thought to contribute to ongoing inflammatory responses in sarcoidosis, but underlying mechanisms remain unclear. Moreover, it is not known if increased apoptotic susceptibility of Tregs may contribute to an impaired immunosuppressive function in sarcoidosis. Therefore, the aim of this study is to analyze proportions, phenotype, survival, and apoptotic susceptibility of Tregs in sarcoidosis.

Methods: Patients with pulmonary sarcoidosis (n = 58) were included at time of diagnosis. Tregs were analyzed in broncho-alveolar lavage fluid and peripheral blood of patients and healthy controls (HC).

Results: In sarcoidosis patients no evidence was found for a relative deficit of Tregs, neither locally nor systemically. Rather, increased proportions of circulating Tregs were observed, most prominently in patients developing chronic disease. Sarcoidosis circulating Tregs displayed adequate expression of FoxP3, CD25 and CTLA4. Remarkably, in sarcoidosis enhanced CD95 expression on circulating activated CD45RO(+) Tregs was observed compared with HC, and proportions of these cells were significantly increased. Specifically sarcoidosis Tregs--but not Th cells--showed impaired survival compared with HC. Finally, CD95L-mediated apoptosis was enhanced in sarcoidosis Tregs.

Conclusion: In untreated patients with active pulmonary sarcoidosis, Tregs show impaired survival and enhanced apoptotic susceptibility towards CD95L. Increased apoptosis likely contributes to the insufficient immunosuppressive function of sarcoidosis Tregs. Further research into this field will help determine whether improvement of Treg survival holds a promising new therapeutic approach for chronic sarcoidosis patients.

No MeSH data available.


Related in: MedlinePlus

Impaired survival of sarcoidosis Tregs. Isolated Tregs (purity >97 %) were cultured with recombinant human IL-2. a Percentage alive Tregs at 72 hours of culture. Horizontal line indicates the median. Significance was determined using a Mann–Whitney U test, **p < 0.01. b Representative flow cytometry analysis of an HC and SRC patient after 12 hours co-culture with autologous Th cells to determine Treg survival and apoptosis. c Survival (above) and apoptosis (below) graph of Tregs cultured for 48 hours with autologous Th cells. Dots indicate mean +/− SEM of 3 HCs and 3 SRC patients. One representative experiment is shown of 3 independent experiments. HC healthy control, SRC sarcoidosis
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Fig4: Impaired survival of sarcoidosis Tregs. Isolated Tregs (purity >97 %) were cultured with recombinant human IL-2. a Percentage alive Tregs at 72 hours of culture. Horizontal line indicates the median. Significance was determined using a Mann–Whitney U test, **p < 0.01. b Representative flow cytometry analysis of an HC and SRC patient after 12 hours co-culture with autologous Th cells to determine Treg survival and apoptosis. c Survival (above) and apoptosis (below) graph of Tregs cultured for 48 hours with autologous Th cells. Dots indicate mean +/− SEM of 3 HCs and 3 SRC patients. One representative experiment is shown of 3 independent experiments. HC healthy control, SRC sarcoidosis

Mentions: Isolated cells were cultured with IL-2 and spontaneous survival was measured at 72 hours. Both healthy- and sarcoidosis-derived Tregs showed decreased survival compared with isolated Th cells (Additional file 4: Figure S3), confirming that Tregs are an apoptotic-prone population. Importantly, patient-derived Tregs showed significantly decreased survival compared with healthy control Tregs (Fig. 4a). This impaired survival was Treg-specific, since sarcoidosis-derived Th cells showed comparable survival to their healthy counterparts (Additional file 4: Figure S3). The survival defect of sarcoidosis Tregs was not restored when co-cultured with autologous Th cells (Fig. 4b and c(upper plot)). Moreover, increased proportions of apoptotic Tregs (annexin V+ and low FSC values) were observed in sarcoidosis (Fig. 4b and c(lower plot)).Fig. 4


Impaired survival of regulatory T cells in pulmonary sarcoidosis.

Broos CE, van Nimwegen M, Kleinjan A, ten Berge B, Muskens F, in 't Veen JC, Annema JT, Lambrecht BN, Hoogsteden HC, Hendriks RW, Kool M, van den Blink B - Respir. Res. (2015)

Impaired survival of sarcoidosis Tregs. Isolated Tregs (purity >97 %) were cultured with recombinant human IL-2. a Percentage alive Tregs at 72 hours of culture. Horizontal line indicates the median. Significance was determined using a Mann–Whitney U test, **p < 0.01. b Representative flow cytometry analysis of an HC and SRC patient after 12 hours co-culture with autologous Th cells to determine Treg survival and apoptosis. c Survival (above) and apoptosis (below) graph of Tregs cultured for 48 hours with autologous Th cells. Dots indicate mean +/− SEM of 3 HCs and 3 SRC patients. One representative experiment is shown of 3 independent experiments. HC healthy control, SRC sarcoidosis
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4574219&req=5

Fig4: Impaired survival of sarcoidosis Tregs. Isolated Tregs (purity >97 %) were cultured with recombinant human IL-2. a Percentage alive Tregs at 72 hours of culture. Horizontal line indicates the median. Significance was determined using a Mann–Whitney U test, **p < 0.01. b Representative flow cytometry analysis of an HC and SRC patient after 12 hours co-culture with autologous Th cells to determine Treg survival and apoptosis. c Survival (above) and apoptosis (below) graph of Tregs cultured for 48 hours with autologous Th cells. Dots indicate mean +/− SEM of 3 HCs and 3 SRC patients. One representative experiment is shown of 3 independent experiments. HC healthy control, SRC sarcoidosis
Mentions: Isolated cells were cultured with IL-2 and spontaneous survival was measured at 72 hours. Both healthy- and sarcoidosis-derived Tregs showed decreased survival compared with isolated Th cells (Additional file 4: Figure S3), confirming that Tregs are an apoptotic-prone population. Importantly, patient-derived Tregs showed significantly decreased survival compared with healthy control Tregs (Fig. 4a). This impaired survival was Treg-specific, since sarcoidosis-derived Th cells showed comparable survival to their healthy counterparts (Additional file 4: Figure S3). The survival defect of sarcoidosis Tregs was not restored when co-cultured with autologous Th cells (Fig. 4b and c(upper plot)). Moreover, increased proportions of apoptotic Tregs (annexin V+ and low FSC values) were observed in sarcoidosis (Fig. 4b and c(lower plot)).Fig. 4

Bottom Line: Patients with pulmonary sarcoidosis (n = 58) were included at time of diagnosis.Rather, increased proportions of circulating Tregs were observed, most prominently in patients developing chronic disease.In untreated patients with active pulmonary sarcoidosis, Tregs show impaired survival and enhanced apoptotic susceptibility towards CD95L.

View Article: PubMed Central - PubMed

Affiliation: Department of Pulmonary Medicine, Erasmus MC, 's Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands.

ABSTRACT

Background: Impaired regulatory T cell (Treg) function is thought to contribute to ongoing inflammatory responses in sarcoidosis, but underlying mechanisms remain unclear. Moreover, it is not known if increased apoptotic susceptibility of Tregs may contribute to an impaired immunosuppressive function in sarcoidosis. Therefore, the aim of this study is to analyze proportions, phenotype, survival, and apoptotic susceptibility of Tregs in sarcoidosis.

Methods: Patients with pulmonary sarcoidosis (n = 58) were included at time of diagnosis. Tregs were analyzed in broncho-alveolar lavage fluid and peripheral blood of patients and healthy controls (HC).

Results: In sarcoidosis patients no evidence was found for a relative deficit of Tregs, neither locally nor systemically. Rather, increased proportions of circulating Tregs were observed, most prominently in patients developing chronic disease. Sarcoidosis circulating Tregs displayed adequate expression of FoxP3, CD25 and CTLA4. Remarkably, in sarcoidosis enhanced CD95 expression on circulating activated CD45RO(+) Tregs was observed compared with HC, and proportions of these cells were significantly increased. Specifically sarcoidosis Tregs--but not Th cells--showed impaired survival compared with HC. Finally, CD95L-mediated apoptosis was enhanced in sarcoidosis Tregs.

Conclusion: In untreated patients with active pulmonary sarcoidosis, Tregs show impaired survival and enhanced apoptotic susceptibility towards CD95L. Increased apoptosis likely contributes to the insufficient immunosuppressive function of sarcoidosis Tregs. Further research into this field will help determine whether improvement of Treg survival holds a promising new therapeutic approach for chronic sarcoidosis patients.

No MeSH data available.


Related in: MedlinePlus