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Impaired T cell responsiveness to interleukin-6 in hematological patients with invasive aspergillosis.

Camargo JF, Bhimji A, Kumar D, Kaul R, Pavan R, Schuh A, Seftel M, Lipton JH, Gupta V, Humar A, Husain S - PLoS ONE (2015)

Bottom Line: While IFN-γ/STAT1 signaling was similar between groups, naïve T cells from patients with IA, but not those with mucormycosis, exhibited reduced responsiveness to IL-6 as measured by STAT3 phosphorylation.Furthermore, IL-6 increased Aspergillus-induced IL-17 production in culture supernatants from healthy and hematological controls but not in patients with IA.Altogether, these observations suggest an important role for dectin-1 and the IL-6/STAT3 pathway in protective immunity against Aspergillus.

View Article: PubMed Central - PubMed

Affiliation: Transplant Infectious Diseases, Multi-Organ Transplant Program, University Health Network, University of Toronto, Toronto, Ontario, Canada; Department of Medicine, University Health Network, Toronto, Ontario, Canada.

ABSTRACT
Invasive mold infections (IMI) are among the most devastating complications following chemotherapy and hematopoietic stem cell transplantation (HSCT), with high mortality rates. Yet, the molecular basis for human susceptibility to invasive aspergillosis (IA) and mucormycosis remain poorly understood. Herein, we aimed to characterize the immune profile of individuals with hematological malignancies (n = 18) who developed IMI during the course of chemotherapy or HSCT, and compared it to that of hematological patients who had no evidence of invasive fungal infection (n = 16). First, we measured the expression of the pattern recognition receptors pentraxin 3, dectin-1, and Toll-like receptors (TLR) 2 and 4 in peripheral blood of chemotherapy and HSCT recipients with IMI. Compared to hematological controls, individuals with IA and mucormycosis had defective expression of dectin-1; in addition, patients with mucormycosis had decreased TLR2 and increased TLR4 expression. Since fungal recognition via dectin-1 favors T helper 17 responses and the latter are highly dependent on activation of the signal transducer and activator of transcription (STAT) 3, we next used phospho-flow cytometry to measure the phosphorylation of the transcription factors STAT1 and STAT3 in response to interferon-gamma (IFN-γ) and interleukin (IL)-6, respectively. While IFN-γ/STAT1 signaling was similar between groups, naïve T cells from patients with IA, but not those with mucormycosis, exhibited reduced responsiveness to IL-6 as measured by STAT3 phosphorylation. Furthermore, IL-6 increased Aspergillus-induced IL-17 production in culture supernatants from healthy and hematological controls but not in patients with IA. Altogether, these observations suggest an important role for dectin-1 and the IL-6/STAT3 pathway in protective immunity against Aspergillus.

No MeSH data available.


Related in: MedlinePlus

Effect of IL-6 on Aspergillus-induced IL-17 production.(a) Levels IL-17 (pg/mL) measured by immunoassay on culture supernatants are shown. Left panels show the levels of IL-17 in supernatant of peripheral blood mononuclear cells (PBMCs) incubated in media alone (NS) or in the presence of Aspergillus fumigatus lysate (50 mg/mL) for 72hr. Right panels correspond to levels of IL-17 in supernatant of PBMCs incubated with Aspergillus fumigatus alone or in the presence of recombinant human IL-6 (100ng/mL). Detectable Aspergillus-induced cytokine production was defined as >2.5 fold change from baseline. Each line corresponds to an individual patient or control as indicated by the study ID number on the right. *p<0.05 using the paired two-tailed Student’s t-test. (b) Heat map for log2 scale of IL-17 levels fold change. Each row on the heat map corresponds to an individual patient or control as indicated by the study ID number on the left. Fold change was calculated by dividing the IL-17 levels produced in response to Phorbol 12-Myristate 13-Acetate and ionomycin (50 ng/mL and 1 mg/mL, respectively; depicted as PMA/Io) or Aspergillus fumigatus (50 mg/mL; depicted as Aspergillus) stimulation by those of non-stimulated cells; and by dividing IL-17 levels in response to Aspergillus (50 mg/mL) plus IL-6 (100ng/mL) by those of cells stimulated with Aspergillus lysate alone (depicted as Asp + IL-6). Heat map color scale is showed in the bottom.
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pone.0123171.g003: Effect of IL-6 on Aspergillus-induced IL-17 production.(a) Levels IL-17 (pg/mL) measured by immunoassay on culture supernatants are shown. Left panels show the levels of IL-17 in supernatant of peripheral blood mononuclear cells (PBMCs) incubated in media alone (NS) or in the presence of Aspergillus fumigatus lysate (50 mg/mL) for 72hr. Right panels correspond to levels of IL-17 in supernatant of PBMCs incubated with Aspergillus fumigatus alone or in the presence of recombinant human IL-6 (100ng/mL). Detectable Aspergillus-induced cytokine production was defined as >2.5 fold change from baseline. Each line corresponds to an individual patient or control as indicated by the study ID number on the right. *p<0.05 using the paired two-tailed Student’s t-test. (b) Heat map for log2 scale of IL-17 levels fold change. Each row on the heat map corresponds to an individual patient or control as indicated by the study ID number on the left. Fold change was calculated by dividing the IL-17 levels produced in response to Phorbol 12-Myristate 13-Acetate and ionomycin (50 ng/mL and 1 mg/mL, respectively; depicted as PMA/Io) or Aspergillus fumigatus (50 mg/mL; depicted as Aspergillus) stimulation by those of non-stimulated cells; and by dividing IL-17 levels in response to Aspergillus (50 mg/mL) plus IL-6 (100ng/mL) by those of cells stimulated with Aspergillus lysate alone (depicted as Asp + IL-6). Heat map color scale is showed in the bottom.

Mentions: As STAT3 mutations result in impaired Th17 cell responses [29], we next evaluated cytokine production by Aspergillus-specific T cells. The magnitude of Aspergillus-induced cytokine production was variable across groups (S3 Fig). IFN-γ in response to Aspergillus fumigatus lysate was detectable in culture supernatants from 5 of 5 (100%) healthy controls, 5 of 7 (71.4%) IA cases and 1 of 4 (25%) non-IFI hematological controls (S4 Fig). Aspergillus-induced IL-17 production was detectable in 3 of 5 (60%) healthy controls, 4 of 7 (57%) IA cases, and none of the non-IFI hematological controls (Fig 3A and 3B). These results are consistent with the notion that among hematological patients, fungus-specific T cells are detectable only in the context of a sizeable, clinically evident, fungal burden [30]. Addition of IL-6 to the culture supernatants resulted in increased production of IL-17, as compared to Aspergillus fumigatus lysate alone, in healthy (388 ± 242 vs. 256 ± 257, pg/mL; p = 0.02) and non-IFI hematological controls (87 ± 30 vs. 57 ± 33, pg/mL; p = 0.016). However, this IL-17 boosting effect of IL-6 was not seen in IA patients (76 ± 37 vs. 83 ± 40, pg/mL; p = 0.66) (Fig 3A). IL-6 did not influence Aspergillus-induced IFN-γ production in any group (S4 Fig).


Impaired T cell responsiveness to interleukin-6 in hematological patients with invasive aspergillosis.

Camargo JF, Bhimji A, Kumar D, Kaul R, Pavan R, Schuh A, Seftel M, Lipton JH, Gupta V, Humar A, Husain S - PLoS ONE (2015)

Effect of IL-6 on Aspergillus-induced IL-17 production.(a) Levels IL-17 (pg/mL) measured by immunoassay on culture supernatants are shown. Left panels show the levels of IL-17 in supernatant of peripheral blood mononuclear cells (PBMCs) incubated in media alone (NS) or in the presence of Aspergillus fumigatus lysate (50 mg/mL) for 72hr. Right panels correspond to levels of IL-17 in supernatant of PBMCs incubated with Aspergillus fumigatus alone or in the presence of recombinant human IL-6 (100ng/mL). Detectable Aspergillus-induced cytokine production was defined as >2.5 fold change from baseline. Each line corresponds to an individual patient or control as indicated by the study ID number on the right. *p<0.05 using the paired two-tailed Student’s t-test. (b) Heat map for log2 scale of IL-17 levels fold change. Each row on the heat map corresponds to an individual patient or control as indicated by the study ID number on the left. Fold change was calculated by dividing the IL-17 levels produced in response to Phorbol 12-Myristate 13-Acetate and ionomycin (50 ng/mL and 1 mg/mL, respectively; depicted as PMA/Io) or Aspergillus fumigatus (50 mg/mL; depicted as Aspergillus) stimulation by those of non-stimulated cells; and by dividing IL-17 levels in response to Aspergillus (50 mg/mL) plus IL-6 (100ng/mL) by those of cells stimulated with Aspergillus lysate alone (depicted as Asp + IL-6). Heat map color scale is showed in the bottom.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4383538&req=5

pone.0123171.g003: Effect of IL-6 on Aspergillus-induced IL-17 production.(a) Levels IL-17 (pg/mL) measured by immunoassay on culture supernatants are shown. Left panels show the levels of IL-17 in supernatant of peripheral blood mononuclear cells (PBMCs) incubated in media alone (NS) or in the presence of Aspergillus fumigatus lysate (50 mg/mL) for 72hr. Right panels correspond to levels of IL-17 in supernatant of PBMCs incubated with Aspergillus fumigatus alone or in the presence of recombinant human IL-6 (100ng/mL). Detectable Aspergillus-induced cytokine production was defined as >2.5 fold change from baseline. Each line corresponds to an individual patient or control as indicated by the study ID number on the right. *p<0.05 using the paired two-tailed Student’s t-test. (b) Heat map for log2 scale of IL-17 levels fold change. Each row on the heat map corresponds to an individual patient or control as indicated by the study ID number on the left. Fold change was calculated by dividing the IL-17 levels produced in response to Phorbol 12-Myristate 13-Acetate and ionomycin (50 ng/mL and 1 mg/mL, respectively; depicted as PMA/Io) or Aspergillus fumigatus (50 mg/mL; depicted as Aspergillus) stimulation by those of non-stimulated cells; and by dividing IL-17 levels in response to Aspergillus (50 mg/mL) plus IL-6 (100ng/mL) by those of cells stimulated with Aspergillus lysate alone (depicted as Asp + IL-6). Heat map color scale is showed in the bottom.
Mentions: As STAT3 mutations result in impaired Th17 cell responses [29], we next evaluated cytokine production by Aspergillus-specific T cells. The magnitude of Aspergillus-induced cytokine production was variable across groups (S3 Fig). IFN-γ in response to Aspergillus fumigatus lysate was detectable in culture supernatants from 5 of 5 (100%) healthy controls, 5 of 7 (71.4%) IA cases and 1 of 4 (25%) non-IFI hematological controls (S4 Fig). Aspergillus-induced IL-17 production was detectable in 3 of 5 (60%) healthy controls, 4 of 7 (57%) IA cases, and none of the non-IFI hematological controls (Fig 3A and 3B). These results are consistent with the notion that among hematological patients, fungus-specific T cells are detectable only in the context of a sizeable, clinically evident, fungal burden [30]. Addition of IL-6 to the culture supernatants resulted in increased production of IL-17, as compared to Aspergillus fumigatus lysate alone, in healthy (388 ± 242 vs. 256 ± 257, pg/mL; p = 0.02) and non-IFI hematological controls (87 ± 30 vs. 57 ± 33, pg/mL; p = 0.016). However, this IL-17 boosting effect of IL-6 was not seen in IA patients (76 ± 37 vs. 83 ± 40, pg/mL; p = 0.66) (Fig 3A). IL-6 did not influence Aspergillus-induced IFN-γ production in any group (S4 Fig).

Bottom Line: While IFN-γ/STAT1 signaling was similar between groups, naïve T cells from patients with IA, but not those with mucormycosis, exhibited reduced responsiveness to IL-6 as measured by STAT3 phosphorylation.Furthermore, IL-6 increased Aspergillus-induced IL-17 production in culture supernatants from healthy and hematological controls but not in patients with IA.Altogether, these observations suggest an important role for dectin-1 and the IL-6/STAT3 pathway in protective immunity against Aspergillus.

View Article: PubMed Central - PubMed

Affiliation: Transplant Infectious Diseases, Multi-Organ Transplant Program, University Health Network, University of Toronto, Toronto, Ontario, Canada; Department of Medicine, University Health Network, Toronto, Ontario, Canada.

ABSTRACT
Invasive mold infections (IMI) are among the most devastating complications following chemotherapy and hematopoietic stem cell transplantation (HSCT), with high mortality rates. Yet, the molecular basis for human susceptibility to invasive aspergillosis (IA) and mucormycosis remain poorly understood. Herein, we aimed to characterize the immune profile of individuals with hematological malignancies (n = 18) who developed IMI during the course of chemotherapy or HSCT, and compared it to that of hematological patients who had no evidence of invasive fungal infection (n = 16). First, we measured the expression of the pattern recognition receptors pentraxin 3, dectin-1, and Toll-like receptors (TLR) 2 and 4 in peripheral blood of chemotherapy and HSCT recipients with IMI. Compared to hematological controls, individuals with IA and mucormycosis had defective expression of dectin-1; in addition, patients with mucormycosis had decreased TLR2 and increased TLR4 expression. Since fungal recognition via dectin-1 favors T helper 17 responses and the latter are highly dependent on activation of the signal transducer and activator of transcription (STAT) 3, we next used phospho-flow cytometry to measure the phosphorylation of the transcription factors STAT1 and STAT3 in response to interferon-gamma (IFN-γ) and interleukin (IL)-6, respectively. While IFN-γ/STAT1 signaling was similar between groups, naïve T cells from patients with IA, but not those with mucormycosis, exhibited reduced responsiveness to IL-6 as measured by STAT3 phosphorylation. Furthermore, IL-6 increased Aspergillus-induced IL-17 production in culture supernatants from healthy and hematological controls but not in patients with IA. Altogether, these observations suggest an important role for dectin-1 and the IL-6/STAT3 pathway in protective immunity against Aspergillus.

No MeSH data available.


Related in: MedlinePlus