Global mortality of chronic liver diseases attributable to Hepatitis B virus and Hepatitis C virus infections from 1990 to 2019 and projections to 2030.

BACKGROUND: The burden of chronic liver disease (CLD) deaths attributable to the hepatitis B virus (HBV) and hepatitis C virus (HCV) remains unknown. Further research is required to elucidate the extent of this burden in the eventual elimination of these diseases. METHODS: Data on liver cancer, cirrhosis, and other CLD among 204 countries and territories between 1990 and 2019 was extracted from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) published in 2019. The Bayesian age-period-cohort model was used to analyze the temporal trend and predict the disease burden by 2030. RESULTS: The number of HCV-related CLD deaths surpassed that of CLD deaths caused by HBV in 2019 (536833 deaths versus 523003 deaths) and is expected to be maintained until 2030 (689124 deaths versus 628824 deaths). East Asia had the highest burden of chronic HBV and HCV infections during the study period. In 2019, the largest age-standardized death rates (ASDR) of CLD deaths caused by HBV and HCV were mainly observed in Western Sub-Saharan Africa (18.75%) and Eastern Sub-Saharan Africa (16.42%), respectively. South Asia and East Asia are predicted to have the highest number of CLD deaths related to HCV and HBV by 2030. Eastern Europe and South Asia show the largest expected increase in disease burden caused by HCV or HBV between 2019 and 2030. No GBD region is projected to achieve the WHO target of a 65% reduction in mortality from chronic HBV and HCV infections by 2030. CONCLUSIONS: Although the mortality of CLD caused by HBV and HCV decreased in the last three decades (from 1990 to 2019), the number of deaths will continue to increase until 2030. Therefore, governments and international organizations need to strengthen the effectiveness of vaccines, screening, and treatment, especially in potential emerging hotspot regions.

Suggested Flowchart Through Integrated C-Reactive Protein and White Blood Cell Count Analysis for Screening for Early Complications After Gastric Bypass: a Single-Center Retrospective Study.

INTRODUCTION: Early leakage detection following bariatric procedures is crucial, but a standardized evaluation method is lacking. The aim was to validate the potential benefits of postoperative day 1 (POD1) C-reactive protein (CRP) levels and white blood cell (WBC) counts in distinguishing at-risk patients following Roux-en-Y gastric bypass (RYGB) while considering the impact of obesity-related chronic inflammation. METHODS: Retrospective analysis of 261 consecutive patients aged 18-65 years with a body mass index (BMI) of 32.5-50 kg/m2 who underwent primary RYGB between 2017 and 2022. Sequential changes in CRP levels and WBC counts measured 48 h preoperatively and on POD1 morning were collected and compared between patients with/without complications and in patients without complications stratified by preoperative CRP levels. RESULTS: Female patients and those with a higher BMI tended to have higher baseline CRP levels, which were positively related to postoperative CRP. Patients experiencing complications had higher WBC counts and a higher prevalence of WBC counts >14,000/µl (77.8% vs. 25.4%; p<0.001) than those without complications. Baseline CRP ≥ 0.3 mg/dl, a longer operative time, and blood loss >10 ml were significantly more common with WBC counts above 14,000/µl; a reasonable range of change in WBC count (∆WBC) derived from its positive correlation to postoperative WBC count (r=0.6695) may serve as a useful complementary indicator. CONCLUSION: An individualized CRP threshold setting and integrated interpretation of the WBC count can be more appropriate than using static criteria for differentiating at-risk patients after RYGB. Further studies are needed to validate these findings and determine their generalizability.

Effectiveness of a preoperative orlistat-based weight management plan and its impact on the results of one-anastomosis gastric bypass: A retrospective study.

INTRODUCTION: The aim was to first investigate the efficacy of a preoperative weight management program centered on orlistat, which is mechanistically similar to gastrointestinal bypass procedures in that it restricts dietary fat absorption, and then assess its impact on the results of one-anastomosis gastric bypass (OAGB). MATERIALS AND METHODS: We retrospectively reviewed the clinical data of consecutive patients aged 20-65 years with a body mass index (BMI) ≥ 42.5 kg/m2 who underwent primary OAGB from 2014 to 2020. Eligible patients who adhered to a 10-14 day orlistat regimen as part of a 4-6-week diet/lifestyle modification plan preceding surgery were stratified into weight reduction (Group 1) and weight gain (Group 2) groups post treatment. The correlation between pre- and postoperative weight loss and perioperative outcomes was assessed. RESULTS: Of 62 eligible patients, 55 met the inclusion criteria and complied with treatment; 35 (64%) patients in Group 1 lost a median of 2.0 kg, and Group 2 had a median weight gain of 2.9 kg. Group 1 had a significantly higher initial BMI (48.9 kg/m2 vs. 44.6 kg/m2; p = 0.003), more females (54% vs. 25%) and a shorter operation time than Group 2 (107 min vs. 140 min; p = 0.109). There was no difference in the incidence of 30-day complications. Weight loss did not differ between the groups at 24 months. CONCLUSION: Effective weight control through an orlistat-containing regimen benefitted two-thirds of patients who underwent OAGB; however, further weight loss was not observed at 2 years post-surgery.

mRNA markers associated with malignant pleural effusion.

Malignant pleural effusions (MPE) commonly result from malignant tumors and represent advanced-stage cancers. Thus, in clinical practice, early recognition of MPE is valuable. However, the current diagnosis of MPE is based on pleural fluid cytology or histologic analysis of pleural biopsies with a low diagnostic rate. This research aimed to assess the diagnostic ability of eight previously identified Non-Small Cell Lung Cancer (NSCLC)-associated genes for MPE. In the study, eighty-two individuals with pleural effusion were recruited. There were thirty-three patients with MPE and forty-nine patients with benign transudate. mRNA was isolated from the pleural effusion and amplified by Quantitative real-time PCR. The logistic models were further applied to evaluate the diagnostic performance of those genes. Four significant MPE-associated genes were discovered in our study, including Dual-specificity phosphatase 6 (DUSP6), MDM2 proto-oncogene (MDM2), Ring finger protein 4 (RNF4), and WEE1 G2 Checkpoint Kinase (WEE1). Pleural effusion with higher expression levels of MDM2 and WEE1 and lower expression levels of RNF4 and DUSP6 had a higher possibility of being MPE. The four-gene model had an excellent performance distinguishing MPE and benign pleural effusion, especially for pathologically negative effusions. Therefore, the gene combination is a suitable candidate for MPE screening in patients with pleural effusion. We also identified three survival-associated genes, WEE1, Neurofibromin 1 (NF1), and DNA polymerase delta interacting protein 2 (POLDIP2), which could predict the overall survival of patients with MPE.

A Shared Decision-making Process may Affect Bariatric Procedure Selection and Alter Surgical Outcomes: a Single-unit Retrospective Study.

PURPOSE: A shared decision-making (SDM) process centered on the patient perspective may increase understanding and treatment satisfaction. This study aimed to investigate whether SDM would increase the acceptance of bariatric/metabolic surgeries, change treatment decisions, and affect 1-year results. MATERIALS AND METHODS: This retrospective analysis enrolled 315 consecutive patients with a body mass index between 32.5 and 50 kg/m2 and aged 20-65 years who underwent consultation for a primary bariatric/metabolic procedure within 2 years before (pre-SDM) or after (post-SDM) SDM program implementation to assist in the decision to undergo Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) surgery. Consent rate, procedure choice, weight loss, comorbidity remission, etc., were compared between periods and procedures. Statistical tests were two-sided, with p < 0.05 considered significant. RESULTS: More eligible patients underwent metabolic/bariatric procedures post-SDM than pre-SDM (115/159 [72%] vs. 106/156 [68%]; p = 0.395), and a stronger preference for RYGB post-SDM was observed (71% vs. 62%; p = 0.153). Significantly more patients with diabetes (28 [34.1%] vs. 5 [15.2%]; p = 0.041) chose RYGB over SG post-SDM. Patients who underwent RYGB had a higher diabetes remission rate both pre-SDM (70.0% vs. 58.3%; p = 0.571) and post-SDM (76.2% vs. 66.7%; p = 0.712) than those who underwent SG. While 1-year weight loss was similar between procedures, adherence to nutritional supplementation did not appear to be broadly enhanced post-SDM. CONCLUSION: SDM influenced procedure selection toward RYGB, which was more popular than SG among patients with diabetes. Higher diabetes remission was achieved with RYGB, although the results of other effects deserve further study.

Luminal pressure gradient and risk of arteriovenous fistula nonmaturation.

While arteriovenous fistula (AVF) nonmaturation is a major issue of hemodialysis care, an effective treatment to improve AVF maturation remains lacking. AVF introduces pulsatile arterial blood flow into its venous limb and produces high luminal pressure gradient, which may have adverse effect on vascular remodeling. As such, the aim of the present study is to investigate effect of luminal pressure gradient on AVF nonmaturation. This single-center, prospective observational study includes patients receiving autologous AVF creation. Participants received early postoperative ultrasound 5-7 days after surgery to collect parameters including diameters, flow rates, and volume at inflow and outflow sites. Luminal pressure gradient was estimated by using modified Bernoulli equation. The outcome was spontaneous AVF maturation within 8 weeks after surgery without intervention. Thirty patients were included, of which the mean age was 66.9 years and 70% were male. At the end of study, 13 (43.3%) patients had spontaneous AVF maturation. All demographic and laboratory characteristics were similar between patients with mature and nonmature AVF. Regarding ultrasonographic parameters, nonmature AVF showed significantly higher inflow/outflow diameter ratio, inflow velocity, and luminal pressure gradient. While these 3 parameters were significantly correlated, multivariate logistic regression showed their significant association with AVF nonmaturation. Receiver operating characteristic curve exhibited their high predictive value for AVF nonmaturation. Our findings showed that higher inflow/outflow ratio, inflow velocity, and AVF luminal pressure gradient in early postoperative ultrasound predicted risk of AVF nonmaturation. Reducing inflow/outflow diameter ratio or inflow rate may be an approach to improve AVF maturation. The predictive value of this early assessment might have impact on the clinical practice of AVF care.

Home Dust Mites Promote MUC5AC Hyper-Expression by Modulating the sNASP/TRAF6 Axis in the Airway Epithelium.

House dust mites (HDMs) are a common source of respiratory allergens responsible for allergic asthma and innate immune responses in human diseases. Since HDMs are critical factors in the triggering of allergen-induced airway mucosa from allergic asthma, we aimed to investigate the mechanisms of Toll-like receptors (TLR) in the signaling of the HDM extract that is involved in mucus hypersecretion and airway inflammation through the engagement of innate immunity. Previously, we reported that the somatic nuclear autoantigenic sperm protein (sNASP)/tumor necrosis factor receptor-associated factor 6 (TRAF6) axis controls the initiation of TLRs to maintain the homeostasis of the innate immune response. The present study showed that the HDM extract stimulated the biogenesis of Mucin 5AC (MUC5AC) in bronchial epithelial cells via the TLR2/4 signaling pathway involving MyD88 and TRAF6. Specifically, sNASP binds to TRAF6 in unstimulated bronchial epithelial cells to prevent the activation of TRAF6-depenedent kinases. Upon on HDMs' stimulation, sNASP is phosphorylated, leading to the activation of TRAF6 downstream of the p38 MAPK and NF-κB signaling pathways. Further, NASP-knockdown enhanced TRAF6 signaling and MUC5AC biogenesis. In the HDM-induced mouse asthma model, we found that the HDM extract promoted airway hyperresponsiveness (AHR), MUC5AC, and allergen-specific IgE production as well as IL-5 and IL-13 for recruiting inflammatory cells. Treatment with the PEP-NASP peptide, a selective TRAF6-blocking peptide, ameliorated HDM-induced asthma in mice. In conclusion, this study indicated that the sNASP/TRAF6 axis plays a regulatory role in asthma by modulating mucus overproduction, and the PEP-NASP peptide might be a potential target for asthma treatment.

Echogenic swirling pattern, carcinoembryonic antigen, and lactate dehydrogenase in the diagnosis of malignant pleural effusion.

The echogenic swirling pattern has a role in predicting malignant pleural effusion (MPE). However, its predictive ability is suboptimal, and its clinical utility remains to be defined. The aim of this study was to assess the diagnostic potential of the echogenic swirling pattern combined with pleural carcinoembryonic antigen (CEA) and routine laboratory tests of pleural effusion in MPE. The 80 consecutive patients with underlying malignancy and pleural effusions were recruited. All patients underwent one diagnostic thoracentesis with a cytologic examination of pleural fluid. Our study showed that the sensitivity of echogenic swirling patterns in MPE diagnosis was 67.7%, specificity was 72.2%, positive predictive value (PPV) was 89.4%, and negative predictive value (NPV) was 39.4%. Both CEA and lactate dehydrogenase (LDH) had acceptable sensitivity (71.0% and 60.7%) and specificity (72.2% and 77.8%). Combining the echogenic swirling pattern, pleural CEA, and pleural LDH, the highest sensitivity (95.2%) with a good PPV (86.8) was reached. In this clinical study, we found that combining the echogenic swirling pattern, pleural CEA, and pleural LDH had a higher sensitivity and a high positive predictive value for the diagnosis of MPE. This combination is a potentially suitable method for MPE screening in cancer patients with pleural effusions.

Factors that Hinder 24-Hour Discharge After Laparoscopic Roux-en-Y Gastric Bypass: a Retrospective Analysis at a Low-Volume Center.

PURPOSE: This study aimed to identify factors that hinder 24-h patient discharge after laparoscopic Roux-en-Y gastric bypass (LRYGB) in a low-volume practice. MATERIAL AND METHODS: Consecutive patients who fulfilled regional criteria and underwent primary LRYGB from 2018 to 2020 were retrospectively analyzed. Patients were discharged on the morning of the first postoperative day (POD1) after meeting the predefined criteria. The assessed outcome measures (POD1 vital signs, laboratory findings, pain scores and nausea/vomiting) and 30-day postoperative complications were compared between the early (stay ≤ 24 h) and delayed (>24 h) groups. RESULTS: For 107 patients who fulfilled the inclusion criteria, 48 (44.9%) were discharged within 24 h. There were no differences in the baseline demographics, except that the early group was more likely to have a previous abdominal operation (35.4% vs. 16.9%). Both groups had similar operation durations (89 min vs. 92 min), but the early group had a markedly shortened length of stay (23 (24-22) h vs. 27 (47-26) h). The POD1 parameters were the same between the groups, except that the delay group had a significantly higher visual analog scale score, with fewer patient scores of 0. Patients who were younger and female were more likely to need additional IV analgesics. No POD1 antiemesis was required throughout the study. There was no increase in the 30-day complications. CONCLUSION: Patient discharge at 24 h post-LRYGB is feasible and safe in a low-volume practice. A more comprehensive pain relief strategy may be required before generalizing this approach.

Renal protective effect of sacubitril/valsartan in patients with heart failure.

Sacubitril/valsartan is a combined neprilysin inhibitor/angiotensin II receptor blocker designed for treatment of heart failure (HF). Nonetheless, its renal protective effect remained an issue of debate. This retrospective cohort study investigated the renal protective effect of sacubitril/valsartan in HF patients. HF patients on sacubitril/valsartan or valsartan for > 30 days were matched for gender, age, estimated glomerular filtration rate (eGFR), and left ventricular ejection fraction (LVEF) to be enrolled into analysis. The follow-up period was 18 months. The outcomes included end eGFR, renal function decline defined as 20% reduction of eGFR, mortality, and HF-related hospitalization. Each group had 137 patients after matching. The mean age was 72.7 years and 65.7% were male. Mean eGFR was 70.9 mL/min/1.73 m2 and LVEF was 54.0% at baseline. Overall, the eGFR of sacubitril/valsartan groups was significantly higher than valsartan group at the end (P < 0.01). Subgroup analysis showed that the difference in eGFR was significant in subgroups with LVEF ≥ 40% or eGFR ≥ 60 mL/min/1.73 m2. Multivariate Cox regression model showed that sacubitril/valsartan group had significantly reduced risk for renal function decline (hazard ratio: 0.5, 95% confidence interval: 0.3-0.9). Kaplan-Meier curve showed no difference in the risk for cardiovascular mortality, all-cause mortality or HF-related hospitalization. We showed renal protective effect of neprilysin inhibition in HF patients and specified that subgroups with LVEF ≥ 40% or eGFR ≥ 60 mL/min/1.73 m2 were sensitive to this effect, suggesting an optimal subgroup of this treatment.

Parathyroid Hormone Induces Transition of Myofibroblasts in Arteriovenous Fistula and Increases Maturation Failure.

CONTEXT: Arteriovenous fistula (AVF) maturation failure remains a clinical dilemma, and its pathobiology is largely unclear. Secondary hyperparathyroidism is a complication of chronic renal failure that is associated with cardiovascular disease. While parathyroid hormone (PTH) has a prosclerotic effect on vascular smooth muscle cells (VSMCs), its role in AVF maturation failure remained unknown. OBJECTIVE: This work aimed to investigate the association between plasma PTH and AVF maturation. METHODS: Patients receiving AVF creation were enrolled retrospectively. A mouse model of secondary hyperparathyroidism and aortocaval AVF was used to investigate the effect of PTH on an AVF lesion. A cell model of VSMCs treated with PTH in a pressurized culture system was used to disclose the signaling pathway underlying the effect of PTH on an AVF lesion. RESULTS: In patients receiving AVF creation, higher PTH was associated with an increased risk for maturation failure. In a mouse model, vascular wall thickness and myofibroblasts of AVF significantly increased with higher PTH. When the same mice were treated with cinacalcet, AVF lesions were attenuated by suppression of PTH. A cell model showed that PTH increased the marker of myofibroblasts, integrin ß6 subunit (ITGB6), via the phosphorylated protein kinase B pathway. Finally, in the same model of mice AVF, higher PTH also increased the expression of ITGB6 in the smooth muscle layer of AVF, suggesting the transition to myofibroblast. CONCLUSION: Overall, our results suggest that higher PTH increased the risk of AVF maturation failure through increasing the transition of VSMCs to myofibroblasts. Lowering PTH may be a strategy to enhance AVF maturation.

Dexmedetomidine use in pediatric strabismus surgery: A systematic review and meta-analysis.

BACKGROUND: Common complications of pediatric strabismus surgery, including emergence agitation (EA), postoperative nausea and vomiting (PONV), and postoperative pain, may be prevented using dexmedetomidine, which is an anxiolytic and analgesic. This systematic review and meta-analysis assessed the effects of dexmedetomidine in patients who had undergone pediatric strabismus surgery. METHOD: Five databases were searched for randomized controlled trials published from database inception to April 2020 that compared dexmedetomidine use with placebo or active comparator use and evaluated EA, PONV, or postoperative pain incidence (main outcomes) in patients who had undergone pediatric strabismus surgery. Oculocardiac reflex (OCR) incidence and postanesthesia care unit (PACU) stay duration were considered as safety outcomes. All meta-analyses were performed using a random-effects model. RESULTS: In the nine studies meeting our inclusion criteria, compared with placebo use, dexmedetomidine use reduced EA incidence [risk ratio (RR): 0.39; 95% confidence interval (CI): 0.25-0.62, I2 = 66%], severe EA incidence (RR: 0.27, 95% CI: 0.17-0.43, I2 = 0%), PONV incidence (RR: 0.33, 95% CI: 0.21-0.54, I2 = 0%), analgesia requirement (RR: 0.38, 95% CI: 0.25-0.57, I2 = 0%), and pain scores (standardized mean difference: -1.02, 95% CI: -1.44 to -0.61, I2 = 75%). Dexmedetomidine also led to lower EA incidence in the sevoflurane group than in the desflurane group (RR: 0.26 for sevoflurane vs. 0.45 for desflurane). Continuous dexmedetomidine infusion (RR: 0.19) led to better EA incidence reduction than did bolus dexmedetomidine infusion at the end of surgery (RR: 0.26) or during the peri-induction period (RR: 0.36). Compared with placebo use, dexmedetomidine use reduced OCR incidence (RR: 0.63; I2 = 40%). No significant between-group differences were noted for PACU stay duration. CONCLUSION: In patients who have undergone pediatric strabismus surgery, dexmedetomidine use may alleviate EA, PONV, and postoperative pain and reduce OCR incidence. Moreover, dexmedetomidine use does not affect the PACU stay duration.

Study protocol for a prospective observational study to investigate the role of luminal pressure on arteriovenous fistula maturation.

INTRODUCTION: Arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis due to its higher patency and lower infection rate. However, its suboptimal maturation rate is a major weakness. Although substantial risk factors for AVF maturation failure have been disclosed, modifiable risk factors remain unknown. During the AVF maturation process, an elevated luminal pressure is required for outward remodeling; however, excessively high luminal pressure may also be detrimental to AVF maturation, which remains to be defined. We hypothesized that higher AVF luminal pressure is harmful to its maturation, and investigate its potential as a modifiable factor to improve AVF maturation. METHODS AND ANALYSIS: This prospective study includes patients undergoing surgical creation for a native AVF. The exclusion criteria were as follows: age <20 years, inability to sign an informed consent, and failure to create a native AVF due to technical difficulties. Demographic and laboratory profiles will be collected before AVF surgery. Vascular sonography will be performed within 1 week of AVF creation to measure the diameters, flow rates, and flow volumes of AVF and its branched veins. The pressure gradient within AVF will be estimated from the blood flow rates using the modified Bernoulli equation. The primary outcome is spontaneous AVF maturation defined as provision of sufficient blood flow for hemodialysis within 2 months of its creation without any interventional procedures. The secondary outcome is assisted AVF maturation, which is defined as AVF maturation within 2 months from its creation aided by any interventional procedure before the successful use of AVF. DISCUSSION: While contemporary theory for AVF maturation failure focuses on disturbed wall shear stress, complicate assumptions and measurement preclude its clinical applicability. AVF luminal pressure, which may be manipulated pharmaceutically and surgically, may be a target to improve the outcome of AVF maturation. TRIAL REGISTRATION: This study has been registered at the protocol registration and results system. The Protocol ID: NCT04017806.

Functional interaction of cockroach allergens and mannose receptor (CD206) in human circulating fibrocytes.

BACKGROUND: The innate pattern recognition C-type-lectin receptors (CLRs), including mannose receptor (MRC1; CD206), have been suggested to functionally interact with allergens and are critical in controlling immune response. Fibrocytes have been considered to play a role in allergic asthma. Here we sought to investigate the functional interaction of cockroach allergens with CD206 in fibrocytes. METHODS: Profiling of N-linked glycans from natural purified cockroach allergen Bla g 2 was accomplished by MALDI-MS. The binding activity of cockroach allergens to CD206 was determined by solid-phase binding assays. Levels of CD206 expression on human fibrocytes and CD206 mediated signaling and cytokine production in Bla g 2 treated fibrocytes were determined. RESULTS: Profiling of N-linked glycans from Bla g 2 revealed a predominance of small, mannose-terminated glycans with and without fucose. Significant binding of Bla g 2 to CD206 was observed, which was inhibited by yeast mannan (a known CD206 ligand), free mannose, and a blocking antibody (anti-hMR). Flow cytometric analyses of human fibrocytes (CD45(+) and collagen-1(+)) showed selective expression of CD206 on fibrocytes. Functionally, a concentration-dependent uptake of FITC labeled Bla g 2 by fibrocytes was observed, but was significantly inhibited by anti-hMR. Bla g 2 can stimulate up-regulation of inflammatory cytokines including TNF-alpha and IL-6 and activation of nuclear factor kappa B (NF-kB/p65), p38 mitogen-activated protein kinase (p38), ERK, and JNK in cultured fibrocytes. This increased secretion of TNF-alpha and IL-6 and activation of NF-kB, ERK, and JNK was significantly inhibited by the addition of either mannan or mannose. Furthermore, Bla g 2 induced increase in TNF-alpha and IL-6 production was also inhibited by the use of NF-kB, ERK, and JNK inhibitors. CONCLUSION: These results provide evidence supporting the existence of a functional cockroach allergen-CD206 axis in human fibrocytes, suggesting a role for CD206 in regulating allergen induced allergic responses in asthma.

Functional interaction of common allergens and a C-type lectin receptor, dendritic cell-specific ICAM3-grabbing non-integrin (DC-SIGN), on human dendritic cells.

Fucosylated glycans on pathogens are known to shape the immune response through their interaction with pattern recognition receptors, such as C-type lectin receptors (CLRs), on dendritic cells (DCs). Similar fucosylated structures are also commonly found in a variety of allergens, but their functional significance remains unclear. To test a hypothesis that allergen-associated glycans serve as the molecular patterns in functional interaction with CLRs, an enzyme-linked immunosorbent assay-based binding assay was performed to determine the binding activity of purified allergens and allergen extracts. THP-1 cells and monocyte-derived DCs (MDDCs) were investigated as a model for testing the functional effects of allergen-CLR interaction using enzyme-linked immunosorbent assay, Western blotting, and flow cytometry. Significant and saturable bindings of allergens and allergen extracts with variable binding activities to DC-specific ICAM3-grabbing non-integrin (DC-SIGN) and its related receptor, L-SIGN, were found. These include bovine serum albumin coupled with a common glycoform (fucosylated glycan lacking the alpha1,3-linked mannose) of allergens and a panel of purified allergens, including BG60 (Cyn dBG-60; Bermuda grass pollen) and Der p2 (house dust mite). The binding activity was calcium-dependent and inhibitable by fucose and Lewis-x trisaccharides (Le(x)). In THP-1 cells and human MDDCs, BG60-DC-SIGN interaction led to the activation of Raf-1 and ERK kinases and the induction of tumor necrosis factor-alpha expression. This effect could be blocked, in part, by Raf-1 inhibitor or anti-DC-SIGN antibodies and was significantly reduced in cells with DC-SIGN knockdown. These results suggest that allergens are able to interact with DC-SIGN and induce tumor necrosis factor-alpha expression in MDDCs via, in part, Raf-1 signaling pathways.

Antigen coupled with Lewis-x trisaccharides elicits potent immune responses in mice.

BACKGROUND: Glycoproteins containing Lewis-x (Le(x)) trisaccharides are often associated with the host's adaptive T(H)2-type immunity, but the mechanisms underlying the T(H)2-biased response are at present unclear. OBJECTIVE: The modulatory effect of Le(x) or its glycoconjugates on IgE/T(H)2 responses was investigated. METHODS: The levels of serum antibodies and cytokines were analyzed by means of ELISA, RT-PCR, or both. RESULTS: In C3H mice Le(x) coupled with BSA (Le(x)-BSA) elicited higher levels of specific IgE and IgG1, but not IgG2a, which were associated with increased levels of splenic T(H)2 cytokines when compared with those seen in BSA-sensitized mice. In BALB/c mice sensitized with Le(x)-BSA or Le(x) mixed with ovalbumin, significantly increased levels of specific IgE and IgG2a antibodies were found concomitant with reduced levels of serum IL-12p70. These effects were attenuated in IL-12-deficient BALB/c mice. Le(x) and an isomer, Le(y), but not other isomers, inhibited the production of LPS-induced IL-12p70, associated with a significant reduction of nuclear NF-kappaB, in bone marrow-derived dendritic cells from BALB/c mice, suggesting that Le(x)-induced suppression of IL-12p70 results in an enhanced T(H)2 response. The addition of mannan, a known ligand for dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin, abrogated the suppressive effect of Le(x) trisaccharides. CONCLUSION: These results provide evidence for a potential role of Le(x) trisaccharides in shaping the immune responses through, at least in part, its suppressive effect on IL-12p70 production. Considering the relative ubiquity of glycoproteins with Le(x) or similar oligosaccharides, including plant-derived (or food-derived) allergens, these findings might have a broad implication. CLINICAL IMPLICATIONS: The adjuvant activity of Le(x) trisaccharides might aid in vaccine design and might be important in determining the allergenicity of proteins containing this or other similar structures.