Paradoxical eosinophilic and cytokine responses to oral corticosteroid treatment in patients with asthma exacerbations.

Background: Thymic stromal lymphopoietin (TSLP) orchestrates eosinophilic inflammation, which may increase during asthma exacerbations. In contrast, microRNA-1 (miR-1) inhibits TSLP-mediated eosinophil trafficking in lung endothelium. Whether the balance of TSLP and miR-1 levels determines the response to oral corticosteroids (OCSs) during the treatment of asthma exacerbations remains unknown. Objective: Our aim was to investigate the involvement of TSLP/miR-1 axis in inflammatory response to OCS treatment for asthma exacerbations. Methods: We measured the concentrations of TSLP and other inflammatory cytokines and miR-1 expression during acute asthma exacerbations treated with standard OCSs in a real-life setting. A total of 28 consecutive patients with acute asthma exacerbations treated with OCS (prednisolone 30 mg/d) for 1 week at the emergency department were studied prospectively. Steroid responders were identified by a significant reduction in blood eosinophil counts, whereas paradoxical responders (PRs) showed no markedly decreased or even increased absolute blood eosinophil counts after OCS treatment. Differential white blood cell counts, blood cytokine levels, and miR-1 expression within and between groups were compared before and after OCS treatment. The baseline cytokine concentrations in both groups were compared with those of patients with stable asthma. Results: OCS treatment significantly reduced TSLP levels in steroid responders, whereas this effect did not occur in PRs (P = .006 and P = .742, respectively). In contrast, miR-1 expression was unchanged in steroid responders in response to OCS, whereas it was markedly reduced in the PRs, despite higher expression at baseline than in patients with stable asthma, which may account for slower resolution of the exacerbation. Conclusions: In some asthmatic patients with acute exacerbations who do not suppress eosinophils after a course of OCS, there is a paradoxical decrease in plasma miR-1 level and increase in TSLP level versus in steroid responders, which may result in slower clinical recovery.

Involvement of Transforming Growth Factor-ß-Associated Kinase 1 in Fixed Airway Obstruction in Asthmatic Patients with Longer Disease Duration Independent on Airway Eosinophilia.

Objective: Transforming growth factor-ß-associated kinase 1 (TAK1) mediates non-canonical TGF-ß signalling by promoting adhesive, migratory, proliferative and contractile responses of fibroblasts to TGF-ß1. However, TAK1 expression status in asthmatic patients with or without fixed airway obstruction (FAO) is unknown. Patients and Methods: A total of 60 adult asthmatics with FAO were recruited and compared to 43 those without FAO (nFAO). TGF-ß1 concentrations, and total TAK1 and phosphorylated TAK1 (p-TAK1) levels were determined in sputum supernatants, cytospin, and whole cell lysate by ELISA, immunocytochemistry, and Western blot analysis, respectively, in asthmatics with and without FAO. Results: Asthmatic patients with FAO had much greater sputum TGF-ß1 concentrations than those without FAO. This was independent of airway eosinophilia as there was no significant difference in TGF-ß1 levels between high and low eosinophil counts within FAO and nFAO groups. In contrast, patients with FAO in the presence of sputum eosinophilia had greater expression of TAK1 and p-TAK1 than those without sputum eosinophilia (P=0.0032 and P=0.0061, respectively). The Western Blot data of total TAK1 and p-TAK1 were consistent with the immunocytochemistry, showing upregulation in all sputum cell types (neutrophils, eosinophils, macrophages, lymphocytes and airway epithelial cells). In addition, total TAK1 expression negatively correlated with pre- and post-bronchodilator FEV1/FVC ratio. Conclusion: TAK1 may play a key role in asthmatic patients with fixed airway obstruction, which was independent of eosinophilic airway inflammation. The interruption of TAK1 might have favourable clinical impact.

Transplantation of autologous cultivated oral mucosal epithelial sheets for limbal stem cell deficiency at Siriraj Hospital: a case series.

BACKGROUND: The loss of limbal stem cells owing to either corneal burn or inflammation leads to the repopulation of opaque skin over the raw surface of the cornea. It has been proposed that reconstitution of oral mucosal stem cells over this raw surface will mimic the limbal stem cells and restore vision. The efficacy and safety of applying a sheet of cultivated oral mucosal cells as an autologous graft for corneal replacement were evaluated. CASE PRESENTATION: The study was conducted during 2014-2015 and involved a total of six patients, of whom three had suffered a chemical burn and three had Stevens-Johnson Syndrome (SJS). Oral mucosal tissue was dissected from each patient, seeded onto irradiated J2 fibroblast feeder cells for 14 days, and analyzed for quality and safety 1 day before being transplanted onto the cornea of the affected eyes. After transplantation, topical antibiotic and anti-inflammatory eye drops were instilled four times daily, and the patients wore contact lenses. Subjects were clinically followed for visual acuities and adverse effects at 2, 4, and 6 weeks, 3 and 6 months, and 1 year post-transplantation. Data were presented descriptively. Visual acuities in patients improved at 2 weeks post-surgery. However, two patients with SJS had corneal ulcer at 2 weeks postoperatively. At the 1-year postoperative examination, the eyes of two patients were in good condition with decreased vascularization and epithelial defect. CONCLUSIONS: Cultivated oral mucosal epithelial sheet transplantation in limbal stem cell deficiency had a favorable efficacy. In this study, patients with chemical burn had more clinical benefit than those with SJS. Trial registration ClinicalTrials.gov: NCT02415218. Registered retrospectively 4 Apr 2015 ( https://clinicaltrials.gov/ct2/show/NCT02415218 ).

Indoleamine 2,3 dioxygenase (IDO) level as a marker for significant coronary artery disease.

BACKGROUND: Indoleamine 2,3 dioxygenase (IDO), the rate-limiting enzyme in the kynurenine (Kyn) pathway of tryptophan (Trp) degradation, is modulated by inflammation, and is regarded as a key molecule driving immunotolerance and immunosuppressive mechanisms. Little is known about IDO activity in patients with active coronary artery disease (CAD). METHODS: We prospectively enrolled patients who were scheduled to undergo coronary angiography. Measurement of IDO, high-sensitivity troponin T (hs-TnT), and high-sensitivity C-reactive protein (hs-CRP) levels was performed at baseline, and IDO activity was monitored at the 6-month follow-up. RESULTS: Three hundred and five patients were enrolled. Ninety-eight patients (32.1%) presented with recent acute coronary syndrome (ACS). Significant difference in IDO, kynurenine, and hs-TnT between patients with and without significant CAD was observed. Baseline IDO activity, kynurenine level, and hs-TnT level were all significantly higher in significant CAD patients with 3-vessel, 2-vessel, and 1-vessel involvement than in those with insignificant CAD [(0.17, 0.13, and 0.16 vs. 0.03, respectively; p = 0.003), (5.89, 4.58, and 5.24 vs. 2.74 µM/g, respectively; p = 0.011), and (18.27, 12.22, and 12.86 vs. 10.89 mg/dL, respectively; p < 0.001)]. One-year mortality was 3.9%. When we compared between patients who survived and patients who died, we found a significantly lower prevalence of left main (LM) disease by coronary angiogram (6.1% vs. 33.3%, p = 0.007), and also a trend toward higher baseline kynurenine (5.07 vs. 0.79 µM/g, p = 0.082) and higher IDO (0.15 vs. 0.02, p = 0.081) in patients who survived. CONCLUSION: Immunometabolic response mediated via IDO function was enhanced in patients with CAD, and correlated with the extent and severity of disease. Patients with LM disease had higher 1-year mortality. Lower level of IDO, as suggested by inadequate IDO response, demonstrated a trend toward predicting 1-year mortality. Trial registration TCTR Trial registration number TCTR20200626001. Date of registration 26 June 2020. "Retrospectively registered".

Role of autophagy in regulating interleukin-10 and the responses to corticosteroids and statins in asthma.

BACKGROUND: Interleukin (IL)-10 is a key anti-inflammatory cytokine that may be reduced in asthma but is enhanced by corticosteroids, especially when combined with a statin, although the mechanisms of these effects are uncertain. OBJECTIVE: To study the role of autophagy in macrophages in promoting inflammation in asthma through reducing IL-10 secretion and how corticosteroids and statins may reverse this process. METHODS: We conducted a randomised double-blind placebo-controlled study in moderate to severe asthmatic patients (n = 44) to investigate the effect of an inhaled corticosteroid (budesonide 400 µg/day) and the combination of budesonide with an oral statin (simvastatin 10 mg/day) given for 8 weeks on autophagy protein expression in sputum cells by using immunocytochemistry and measurement of IL-10 release. In in vitro experiments, we studied cross-regulation between autophagy and IL-10 release by measuring the expression of autophagy proteins in M2-like macrophages and the effects of budesonide and simvastatin on these mechanisms. RESULTS: In asthmatic patients, inhaled budesonide inhibited airway macrophage autophagy (beclin-1, LC3) as well as autophagic flux (p62), which was enhanced by simvastatin and was correlated with increased sputum IL-10 and reduced IL-4 concentrations. In macrophages in vitro, budesonide and simvastatin inhibited rapamycin-induced autophagy as well as autophagic flux, with reduced expression of beclin-1 and LC3, but enhanced the accumulation of p62 and increased expression of IL-10, which itself further inhibited autophagy in macrophages. With siRNA-mediated silencing, LC3-deficient macrophages also showed a maximal induction of IL-10 transcription. Neutralisation of IL-10 with recombinant specific blocking antibody and silencing IL-10 transcription reversed the inhibitory effects of budesonide and simvastatin on macrophage autophagy. CONCLUSION AND CLINICAL RELEVANCE: Inhibition by corticosteroids and a statin of macrophage autophagy enhances IL-10 production, resulting in the control of asthmatic inflammation.

Effects of the Ayurved Siriraj Wattana recipe on functional and phenotypic characterization of cytokine-induced killer cells and dendritic cells in vitro.

BACKGROUND: Ayurved Siriraj Wattana recipe (AVS073), has been prescribed as tonic, to increase appetite, and for pain relief. It also exhibits antioxidant, anti-inflammatory, immunomodulating and anti-cancer activities. However, the immunomodulatory effects on antigen-presenting cells and effector T cells remained elusive. We thus aimed to study the effects of AVS073 on differentiation, maturation, functions and proportions of CIK cells and monocyte-derived DCs. METHODS: CIK cells and monocyte-derived DCs were treated with AVS073, followed by the assessment of T-helper (Th) phenotypes using real-time RT-PCR and flow cytometry. RESULTS: AVS073 promoted Th1 phenotype in CD3+CD56+ subset of CIK cells through increasing STAT4, T-bet, and interferon-γ. AVS073 inhibited Th2 phenotype through decreasing STAT6. AVS073 inhibited Treg phenotype through decreasing STAT5A, STAT5B and IDO. AVS073 promoted Th17 phenotype through increasing STAT3, RORC and IL-17. AVS073 treatment of mDCs resulted in increasing Th1-prone cytokine (IL-12) and Th17-prone cytokines (IL-6 and IL-23). CONCLUSIONS: AVS073 upregulated Th1 and Th17, but downregulated Th2 and Treg phenotypes within CD3+CD56+ cells. The treatment of mDCs drove Th1 and Th17-polarizations.

Simvastatin up-regulates adenosine deaminase and suppresses osteopontin expression in COPD patients through an IL-13-dependent mechanism.

BACKGROUND: Adenosine deaminase (ADA) and osteopontin (OPN) may play opposing roles in the pathogenesis of COPD. Deficiency of ADA results in enhanced adenosine signaling which up-regulates OPN expression. Although statins suppress OPN in cancer cells, little is known about their effects on ADA and OPN in COPD patients. METHODS: We extended a previous randomized double-blind placebo crossover study to investigate the effects of simvastatin (20 mg/day) on sputum ADA and OPN expression and explored the underlying signaling pathways involved by conducting in vitro experiments with cigarette smoke extract (CSE)-treated monocyte-derived macrophages (MDM) from COPD patients and healthy subjects. RESULTS: Simvastatin decreased sputum IL-13, OPN and CD73, while increasing ADA expression, irrespective of inhaled corticosteroid treatment and smoking status in parallel to increased inosine levels. The degree of simvastatin-restored ADA activity was significantly correlated with the magnitude of changes in pre-bronchodilator FEV1. Mechanistic exploration showed that CSE enhanced the expression of IL-13, which induced an increase in OPN and inhibited ADA mRNA accumulation in MDM from COPD patients but not healthy subjects through a STAT6-dependent mechanism. Simvastatin treatment inhibited IL-13 transcription in a dose-dependent manner, and therefore diminished the IL-13-induced increase in OPN and restored IL-13-suppressed ADA. There was no effect of simvastatin on adenosine receptors in CSE-stimulated MDM, indicating that its effects were on the adenosine pathway. CONCLUSION: Simvastatin reversed IL-13-suppressed ADA activity that leads to the down-regulation of adenosine signaling and therefore inhibits OPN expression through the direct inhibition of IL-13-activated STAT6 pathway. Inhibition of IL-13 may reverse the imbalance between ADA and OPN in COPD and therefore may prevent COPD progression.

Sunitinib indirectly enhanced anti-tumor cytotoxicity of cytokine-induced killer cells and CD3⁺CD56⁺ subset through the co-culturing dendritic cells.

Cytokine-induced killer (CIK) cells have reached clinical trials for leukemia and solid tumors. Their anti-tumor cytotoxicity had earlier been shown to be intensified after the co-culture with dendritic cells (DCs). We observed markedly enhanced anti-tumor cytotoxicity activity of CIK cells after the co-culture with sunitinib-pretreated DCs over that of untreated DCs. This cytotoxicity was reliant upon DC modulation by sunitinib because the direct exposure of CIK cells to sunitinib had no significant effect. Sunitinib promoted Th1-inducing and pro-inflammatory phenotypes (IL-12, IFN-γ and IL-6) in DCs at the expense of Th2 inducing phenotype (IL-13) and regulatory phenotype (PD-L1, IDO). Sunitinib-treated DCs subsequently induced the upregulation of Th1 phenotypic markers (IFN-γ and T-bet) and the downregulation of the Th2 signature (GATA-3) and the Th17 marker (RORC) on the CD3⁺CD56⁺ subset of CIK cells. It concluded that sunitinib-pretreated DCs drove the CD3⁺CD56⁺ subset toward Th1 phenotype with increased anti-tumor cytotoxicity.

Decreased indoleamine 2,3-dioxygenase activity and IL-10/IL-17A ratio in patients with COPD.

RATIONALE: Indoleamine 2,3-dioxygenase (IDO) induces generation of regulatory T cells but suppresses Th17 cells and therefore might attenuate neutrophilic inflammation. The role of IDO in neutrophilic airway diseases such as chronic obstructive pulmonary disease (COPD) remains unknown. We evaluated IDO activity and expression and interleukin (IL)-10 and IL-17A levels in sputum from patients with COPD. METHODS: IDO activity and cytokine concentrations in sputum supernatants from patients with COPD of varying severity and in smoking and non-smoking control subjects were determined by high-performance liquid chromatography and ELISA, respectively. RESULTS: Patients with COPD had reduced sputum IDO activity and expression and IL-10 levels, with increased IL-17A, IL-6 and CXCL8 concentrations and sputum neutrophils. These changes were significantly correlated with disease severity. IDO activity was decreased, but to a lesser extent, in normal smokers compared with non-smoking controls. CONCLUSIONS: Patients with COPD have a progressive reduction in IDO activity with reversal of the balance between IL-10 and IL-17A, resulting in chronic airway neutrophilic inflammation.

The Phyllanthus emblica L. infusion carries immunostimulatory activity in a mouse model.

BACKGROUND: Phyllanthus emblica L. (Indian gooseberry, Ma khaam pom) has been an herbal component of Thai traditional recipes proposed to slow down the aging process. A number of methodologies have been employed to investigate the immunological aspects of the so called "anti-aging effects" of P. emblica in a BALB/c mice model. OBJECTIVE: 1) To investigate the immunological efficacy of the anti-aging effects of P. emblica infusion in a BALB/c mice model. 2) To verify the safety for the consumption of P. emblica infusion in BALB/c mice. MATERIAL AND METHOD: For in vitro studies, splenocytes were isolated from mice and examined in comparison with the human umbilical endothelial cells, fibroblasts and YAC-1 (mouse lymphoma) cells for proliferative activity upon the exposure to P. emblica infusion. For in vivo studies, mice were orally administered with P. emblica infusion at a dose range of 0, 50, 100, 200 mg/kg BW for 14 days. After the treatments, splenocytes isolated from these mice examined for proliferative and NK cell activities. RESULTS: For in vitro studies, the infusion of P. emblica could directly drive the proliferation of mouse splenocytes in a dose-dependent manner. The P. emblica infusion itself was already cytotoxic to YAC-1 in the studied dose, while sparing the human umbilical endothelial cells and fibroblasts. For in vivo studies, splenocytes isolated from these mice exhibited dose-dependent proliferative activities. Only the isolated splenocytes from mice ingesting 100 mg/kg BW exhibited an enhancement in NK cell activity. CONCLUSION: P. emblica infusion could drive proliferative activity of splenocyte in vitro and in vivo, with an enhancement in the NK cell-induced cytotoxic activity. The infusion in the aforementioned dose was safe throughout the study.

Upregulation of CYP 450s expression of immortalized hepatocyte-like cells derived from mesenchymal stem cells by enzyme inducers.

BACKGROUND: The strenuous procurement of cultured human hepatocytes and their short lives have constrained the cell culture model of cytochrome P450 (CYP450) induction, xenobiotic biotransformation, and hepatotoxicity. The development of continuous non-tumorous cell line steadily containing hepatocyte phenotypes would substitute the primary hepatocytes for these studies. RESULTS: The hepatocyte-like cells have been developed from hTERT plus Bmi-1-immortalized human mesenchymal stem cells to substitute the primary hepatocytes. The hepatocyte-like cells had polygonal morphology and steadily produced albumin, glycogen, urea and UGT1A1 beyond 6 months while maintaining proliferative capacity. Although these hepatocyte-like cells had low basal expression of CYP450 isotypes, their expressions could be extensively up regulated to 80 folds upon the exposure to enzyme inducers. Their inducibility outperformed the classical HepG2 cells. CONCLUSION: The hepatocyte-like cells contained the markers of hepatocytes including CYP450 isotypes. The high inducibility of CYP450 transcripts could serve as a sensitive model for profiling xenobiotic-induced expression of CYP450.

Inhibition of UVA-mediated melanogenesis by ascorbic acid through modulation of antioxidant defense and nitric oxide system.

Ascorbic acid (AA) has been well known as a skin whitening agent, although attempts have been made to evaluate its protective role against ultraviolet (UV)-induced skin hyperpigmentation or increased melanin production. While melanogenesis is a defense mechanism of the skin against UV irradiation, melanin overproduction may also contribute to melanoma initiation. UVA might play a role in melanogenesis through promoting oxidative stress, which occurs as the result of increased formation of oxidants and/or reactive nitrogen species (RNS) including nitric oxide (NO). Therefore, we investigated the antimelanogenic effect of AA (7.5-120 µM) in association with its inhibitory effect on UVA-induced oxidant formation, NO production through endothelial and inducible NO synthases (eNOS and iNOS) activation and impairment of antioxidant defense using G361 human melanoma cells. Our study demonstrated a comparable ability of AA with that of kojic acid, a well-known tyrosinase inhibitor in inhibiting mushroom tyrosinase. Melanin content was reduced by AA, but neither tyrosinase activity nor mRNA levels were reduced by AA at non-cytotoxic concentrations in UVA-irradiated G361 cells. AA was shown to inhibit UVA-mediated catalase (CAT) inactivation, glutathione (GSH) depletion, oxidant formation and NO production through suppression of eNOS and iNOS mRNA. We report herein that AA can protect against UVA-dependent melanogenesis possibly through the improvement of antioxidant defense capacity and inhibition of NO production through down-regulation of eNOS and iNOS mRNA.

Statins enhance the anti-inflammatory effects of inhaled corticosteroids in asthmatic patients through increased induction of indoleamine 2, 3-dioxygenase.

BACKGROUND: We have previously shown that inhaled corticosteroids activate indoleamine 2, 3-dioxygenase (IDO) activity through increased IL-10 secretion. Statins might enhance the anti-inflammatory effects of corticosteroids. OBJECTIVE: In a double-blind study we added simvastatin to patients with mild asthma receiving a low dose of inhaled budesonide and evaluated sputum eosinophil counts, IL-10 secretion, and IDO activity, as well as their putative signaling pathways. METHODS: After a 2-week run-in period without treatment, 50 asthmatic patients were treated with 200 µg of budesonide and randomly assigned to either 10 mg of simvastatin or matched placebo for 8 weeks. Inflammation was evaluated through eosinophil counts, secretory signaling molecules, and immunocytochemistry of macrophages in sputum. RESULTS: Sputum eosinophil percentages were reduced significantly by the combined therapy with budesonide and simvastatin compared with budesonide alone (P = .02). Corticosteroids activated glucocorticoid-induced TNF receptor ligand, which induces activation of p52 through the noncanonical nuclear factor κB pathway, leading to the increased transcription and activation of IDO. Simvastatin enhanced corticosteroid-activated noncanonical nuclear factor κB-dependent induction of IDO by activating type I interferons and also enhanced the effect of corticosteroid on IL-10 release. CONCLUSION: A statin enhances the anti-inflammatory effect of an inhaled corticosteroid in asthma, and this was mediated through the alteration of IDO activity in macrophages.

Differential expression of Th2 chemokine receptors on T cells from atopic and nonatopic asthmatics in response to Der p 1-pulsed dendritic cells.

BACKGROUND: In vitro polarized human Th2 cells preferentially express the chemokine receptors CCR3 and CCR4 and migrate to their ligands: eotaxin, monocyte-derived chemokine (MDC) or CCL22, thymus- and activation-regulated chemokine (TARC) or CCL17. However little is known about the regulation of these chemokine receptor axes by Der p 1-pulsed dendritic cells in house dust mite (HDM)-sensitive and non-atopic asthmatics. OBJECTIVE: The aim was to investigate the modulatory effects of Der p 1-pulsed DCs on the expression of CCR3 and CCR4 on CD4+ T cells of HDM-sensitive and non-atopic asthmatics. MATERIAL AND METHOD: Using real-time RT-PCR and flow cytometry analysis, the expression of CCR3 and CCR4 were assessed in autologous CD4+ T cells after co-incubation with Der p 1-pulsed DCs from these two asthmatic groups. We also determined the mRNA expression of CCR4 ligands TARC/CCL17 and MDC/CCL22 in monocyte-derived DCs after Der p 1 pulsation. RESULTS: We performed flow cytometry analysis of CD4+ T cells from HDM-sensitive and non-atopic asthmatics, taken 24 and 48 h after co-incubation with Der p 1-pulsed DCs. We demonstrated that after co-incubation, there was a significant increase in CCR3+ and CCR4+ CD4+ T cells from HDM-sensitive asthmatics, which began to occur at 24 h and 48 h respectively, and corresponded to their expression at mRNA levels. In contrast, only CCR4 mRNA but not protein expression was increased in non-atopic CD4+ T cells. After Der p 1 pulsation, mRNA expression of CCR4-specific ligands (CCL17 and CCL22) was also markedly upregulated in HDM-sensitive DCs whereas only CCL17 gene expression was increased in non-atopic DCs. CONCLUSION: These data support the role of DCs in differential regulation of CCR3 and CCR4 on CD4+ T cells from HDM-sensitive and non-atopic asthmatics after Der p 1 exposure.

Human cytokine-induced killer cells specifically infiltrated and retarded the growth of the inoculated human cholangiocarcinoma cells in SCID mice.

Cytokine-induced killer (CIK) cells were examined for safety and efficacy for cholangiocarcinoma treatment. Several conditions of human CIK cells were examined using ex vivo cytotoxic assay and SCID mice pre-inoculated with cholangiocarcinoma cells. We monitored the ex vivo cytotoxicity, tumor sizes and immunohistochemistry. Optimal tumor suppression was observed when CIK cells were pre-exposed to dendritic cells (DCs). Unexpectedly, pulsing of tumor RNA to DCs rendered the co-culturing CIK cells ineffective and raised the proportion of CD4(+)CD25(+) subset. The use of CD3(+)CD56(+) subset instead of the whole population of CIK cells for the co-culture with RNA-pulsed DCs restored the efficacy. Tumor-infiltrating human CD3(+) cells were observed from day 2 - 14. The CD3(+)CD56(+) cells are logical candidates for clinical trial while the DC-co-cultured CIK cells produced similar efficacy and more feasible for clinical application. The RNA pulsation of DCs up-regulated the regulatory subset of CIK cells and abrogated the anti-tumor efficacy.

Der p 1 suppresses indoleamine 2, 3-dioxygenase in dendritic cells from house dust mite-sensitive patients with asthma.

BACKGROUND: Indoleamine 2, 3-dioxygenase (IDO), a tryptophan-degrading enzyme in dendritic cells (DCs), mediates an immunosuppressive effect on activated T lymphocytes. However, little is known about the effect of Der p 1 on IDO in human DCs. OBJECTIVE: The aim was to investigate the effect of Der p 1 on the expression and activity of IDO in monocyte-derived DCs from house dust mite (HDM)-sensitive patients with asthma. METHODS: Using real-time RT-PCR and HPLC, the expression and activity of IDO were assessed in TNF-alpha-induced mature DCs from HDM-sensitive and nonatopic patients with asthma in response to Der p 1 exposure ex vivo. We also monitored the alteration of IDO activity in Der p 1-pulsed DCs after the coincubation with autologous T cells. RESULTS: With a reliance on its protease activity, Der p 1 suppressed functional IDO in DCs from HDM-sensitive patients with asthma but enhanced IDO activity in DCs from nonatopic patients with asthma. This suppression was maintained by the reciprocally induced IL-4 from the coculturing autologous HDM-sensitive T cells. Conversely, the upregulation of IDO activity in Der p 1-pulsed DCs was maintained by IFN-gamma released from autologous nonatopic T cells and the regulatory T-cell subset. Der p 1 pulsation to sensitive DCs failed to raise regulatory T cells but raised progenitor fractions from cloned HDM-sensitive CD4(+) cells through direct contact and soluble mediators. CONCLUSION: House dust mite-sensitive DCs exposed to Der p 1 downregulated IDO activity and tipped the T(H)1/T(H)2 cytokine balance toward IL-4, resulting in sustainable IDO suppression.

Sputum indoleamine-2, 3-dioxygenase activity is increased in asthmatic airways by using inhaled corticosteroids.

BACKGROUND: Indoleamine-2, 3-dioxygenase (IDO), a tryptophan-degrading enzyme, plays a key role in the regulation of T-lymphocyte function. IDO inhibits eosinophilic inflammation in a murine asthma model, but little is known about its role in asthmatic patients or the effects of corticosteroids on this key regulatory enzyme. OBJECTIVE: We studied IDO activity and the effect of inhaled corticosteroids (ICSs) in patients with asthma and how this correlated with eosinophilic inflammation. METHODS: After a 1-week run-in period on no therapy, 34 asthmatic patients were treated with only short-acting beta(2)-agonists as required or an ICS or an ICS in combination with a long-acting beta(2)-agonist, which were required for asthma control, and the treatment was continued for a further 4 weeks. Each patient underwent sputum induction at the end of the run-in and treatment periods. Sputum supernatant specimens were analyzed for IDO activity and kynurenine concentrations by using HPLC. RESULTS: All patients with mild intermittent and mild-to-moderate persistent asthma had low baseline IDO activity in induced sputum compared with that seen in age-matched nonasthmatic subjects. The IDO activity was markedly enhanced by either ICS (P = .03) or ICS/long-acting beta(2)-agonist (P < .0001) treatment, and this increase negatively correlated with sputum eosinophils but was positively associated with an increase in IL-10-positive macrophages. CONCLUSION: ICSs might exert their anti-inflammatory activity in asthmatic airways, at least in part, through the upregulation of IDO activity associated with increased IL-10 secretion from macrophages.