Impact of ultra-low temperature storage on serum sIgE detection and allergic disease biobank feasibility.

Research has shown that the concentration and composition of biological samples may change after long-term ultra-low temperature storage. Consequently, this study examined the effect of ultra-low temperature storage on serum sIgE detection by comparing sIgE concentrations at various durations from the time of sample storage to subsequent testing. We selected 40 serum samples from the Guangzhou Medical University Affiliated First Hospital Biobank, which had been tested for house dust mites, dog hair, tobacco mold, cockroaches, and cow milk allergen sIgE. Samples were categorized by storage duration: 14 samples stored for 10 years, 12 for 5 years, and 14 for 3 years. They were also classified by sIgE positive levels: 15 samples at levels 1-2, 15 at levels 3-4, and 10 at levels 5-6. The allergen sIgE of these samples was retested using the same technology. Regardless of the type of allergen or the level of positivity, the majority of sIgE concentrations measured at the time of storage were higher than the current measurements, but the difference was not statistically significant. The correlation between the sIgE results at the time of storage and the current results was high for samples stored for 10 years (rs = 0.991, P < 0.001) and 5 years (rs = 0.964, P < 0.001). Serum allergen sIgE is stable when stored under ultra-low temperature conditions, making the construction of a biological sample bank for allergic diseases feasible. This will facilitate researchers in quickly obtaining samples, conducting technical research, and translating findings, thereby promoting the development of the field of allergy through integration of industry, academia, and research.

A study of allergen detection panel in Guangzhou, southern China based on real-world data from the past 7 years.

This study aims to reduce the cost of allergen testing for Guangzhou, China by limiting the number of allergens for which patients are tested, and provide a testing panel to improve diagnostic and therapeutic efficiency. This retrospective study of real-world data from 2012 to 2019 included 39,570 patients with suspected allergies in Guangzhou, southern China. All the patients were tested for one or more of the following allergens serum specific immunoglobulin E (sIgE): Dermatophagoides pteronyssinus, Dermatophagoides farinae, cat dander, dog dander, Artemisia vulgaris, Aspergillus fumigatus, Alternaria alternata, Blattella germanica, egg whites, milk, wheat, peanuts, soybeans, Cancer pagurus, and Penaeus monodon by PhadiaCAP 1000. Totally, only the positive rates of allergens sIgE in D. farinae, D. pteronyssinus, milk, egg whites, B. germanica, C. pagurus, A. alternata, and P. monodon were > 10%, the other allergens were between 4-7%. Moreover, among the allergic diseases, dust mites exhibited the overall highest positive rate, followed by milk and B. germanica. In children, milk was the main allergen, whereas in adults, mites, cockroaches, shrimp, and crab allergens had higher positive rates. The optimal scale analysis shows that the multiple sensitization classification of patients can be divided into three categories: I D. farinae and D. pteronyssinus; II. C. pagurus, P. monodon, and B. germanica; III. Milk and egg whites. Generally, a panel including 4 allergens can detect > 90% of the potential allergy in this local population. In Guangzhou, southern China, D. farinae, milk, B. germanica, and A. alternata as a panel screening allergy for suspected allergic patients was suggested base on this study.

Impact of Hemodialysis on Subfoveal Choroidal Thickness Measured by Optical Coherence Tomography: A Systematic Review and a Pooled Analysis of Self-Controlled Case Series.

INTRODUCTION: Hemodialysis (HD) has various effects on the body, including optimizing body fluid composition and volume, which may have an impact on subfoveal choroidal thickness (SCT) in individuals with end-stage kidney disease (ESKD). However, previous studies have produced conflicting results regarding the effect of HD on SCT in patients with ESKD. Therefore, we conducted a meta-analysis to investigate the influence of HD on SCT. METHODS: A comprehensive search of relevant studies and bibliographies was conducted using Embase, PubMed, and Web of Science databases up to September 2022. Weighted mean difference (WMD) and 95% confidence interval (CI) were used to summarize the SCT change. Heterogeneity and publication bias were assessed, and a random-effects model was employed for the meta-analysis. Subgroup analyses were also performed to evaluate the influence of factors such as diabetes mellitus (DM), the severity of diabetic retinopathy (DR), diurnal variation adjustment, optical coherence tomography (OCT) types, and OCT scan modes. RESULTS: A total of 15 studies involving 1010 eyes were eligible for this meta-analysis, including 552 diabetic eyes, 230 non-diabetic eyes, and the remaining 228 eyes were uncategorized. The meta-analysis revealed a significant reduction in SCT after HD (WMD = -13.66 µm; 95% CI -24.29 to -3.03 µm; z = -5.115, P < 0.0001). Subgroup analysis indicated a significant difference between the DM and non-DM groups (WMD = -24.10 µm vs. -15.37 µm, 95% CI -27.39 to -20.80 µm vs. -19.07 to -11.66 µm; P = 0.001). Additionally, the group with proliferative diabetic retinopathy (PDR) exhibited a more pronounced reduction in SCT (WMD = -28.66 µm; 95% CI -37.10 to -20.23; z = -6.660, P < 0.0001). Adjusting for diurnal variation, different types or scan modes of OCT did not significantly affect the results. CONCLUSION: HD leads to a significant decrease in SCT among patients with ESKD, especially in patients with DM with PDR.

Positive association between stress hyperglycemia ratio and pulmonary infection in patients with ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention.

BACKGROUND: Previous studies have shown that the stress hyperglycemia ratio (SHR), a parameter of relative stress-induced hyperglycemia, is an excellent predictive factor for all-cause mortality and major adverse cardiovascular events (MACEs) among patients with ST-segment elevation myocardial infarction (STEMI). However, its association with pulmonary infection in patients with STEMI during hospitalization remains unclear. METHODS: Patients with STEMI undergoing percutaneous coronary intervention (PCI) were consecutively enrolled from 2010 to 2020. The primary endpoint was the occurrence of pulmonary infection during hospitalization, and the secondary endpoint was in-hospital MACEs, composed of all-cause mortality, stroke, target vessel revascularization, or recurrent myocardial infarction. RESULTS: A total of 2,841 patients were finally included, with 323 (11.4%) developing pulmonary infection and 165 (5.8%) developing in-hospital MACEs. The patients were divided into three groups according to SHR tertiles. A higher SHR was associated with a higher rate of pulmonary infection during hospitalization (8.1%, 9.9%, and 18.0%, P < 0.001) and in-hospital MACEs (3.7%, 5.1%, and 8.6%, P < 0.001). Multivariate logistic regression analysis demonstrated that SHR was significantly associated with the risk of pulmonary infection during hospitalization (odds ratio [OR] = 1.46, 95% confidence interval [CI] 1.06-2.02, P = 0.021) and in-hospital MACEs (OR = 1.67, 95% CI 1.17-2.39, P = 0.005) after adjusting for potential confounding factors. The cubic spline models demonstrated no significant non-linear relationship between SHR and pulmonary infection (P = 0.210) and MACEs (P = 0.743). In receiver operating characteristic curve, the best cutoff value of SHR for pulmonary infection was 1.073. CONCLUSIONS: The SHR is independently associated with the risk of pulmonary infection during hospitalization and in-hospital MACEs for patients with STEMI undergoing PCI.

Influencing factors of health resource allocation and utilisation before and after COVID-19 based on RIF-I-OLS decomposition method: a longitudinal retrospective study in Guangdong Province, China.

OBJECTIVES: To explore factors that influenced the health resource allocation and utilisation before and after COVID-19, and subsequently offer sensible recommendations for advancing the scientific distribution of health resources. DESIGN: A longitudinal survey using 2017-2020 data, which were collected for analysis. SETTING: The study was conducted based on data collected from the Health Commission of Guangdong Province's website. OUTCOME MEASURES: Eight health resource indicators and four health resource utilisation indicators were included in the factor analysis. Four indices were calculated to measure the inequality in health resource allocation and utilisation. We analysed factors for the inequality indices using the recentred influence function index ordinary least squares decomposition method. RESULTS: The health resource inequality indices peaked in 2020 (Gini coefficient (Gini): 0.578, Absolute Gini coefficient (AGini): 1.136, Concentration Index (CI): 0.417, Absolute CI (ACI): 0.821), whereas the health resource utilisation inequality indices declined year by year, thus reaching their lowest point in that same year. The majority of inequality indices in the annual change of health resource allocation were at their lowest in 2020 (Gini: -1.672, AGini: 0.046, CI: -0.189, ACI: 0.005), while the use of health resources declined dramatically, showing a negative growth trend. The inequality indices of health resource allocation and utilisation in 2020 were affected by a number of variables, including the COVID-19 level, (p<0.05), while the proportion of expenditure on public health was the most significant one. CONCLUSIONS: Guangdong Province's health resource allocation and utilisation were still concentrated in economically developed regions from 2017 to 2020. The health resource allocation inequality indices increased, especially under COVID-19, but the health resource utilisation inequality indices decreased. Measures should be taken to adjust the health resource allocation scientifically, which will fulfil the changing needs and the use of resources more efficiently. One effective measure is reasonably increasing the proportion of expenditure on public health.

Preoperative prediction of overt hepatic encephalopathy caused by transjugular intrahepatic portosystemic shunt.

PURPOSE: Preoperative prediction of overt hepatic encephalopathy (OHE) should be performed in patients with variceal bleeding treated using the transjugular intrahepatic portosystemic shunt (TIPS) procedure. A reliable prediction tool is therefore required. METHOD: Patients with cirrhosis-related variceal bleeding treated using the TIPS procedure were screened at two hospitals. Patients classified as Child-Pugh Class B were identified. The least absolute shrinkage and selection operator method and the backward stepwise selection method were used to screen the clinical and radiological characteristics of participants. Then, models were constructed accordingly to predict OHE. Area under the receiver operating characteristic curves, calibration curves, and decision curves were performed to discover the optimal model. Finally, whether clinical factors influenced the performance of our optimal model was tested. RESULTS: A total of 191 patients were included (training cohort: 127 cases; validation cohort: 64 cases). Three novel radiological independent risk factors were found. The combined model outperformed the models containing clinical factors or radiological characteristics alone. The areas under the curve for the training and validation cohorts were 0.901 and 0.903, respectively, with satisfactory calibration and decision curves. The Model for End-Stage Liver Disease score, serum sodium, albumin, total bilirubin, and age exhibited limited influence on the performance of the combined model. CONCLUSIONS: These radiological characteristics are also independent risk factors for post-TIPS OHE. Combining clinical factors and radiological characteristics was an effective means of predicting OHE. This study's model could be used for preoperative selection of appropriate patients before the TIPS procedure is performed.

Spontaneous Ventilation Video-Assisted Thoracoscopic Surgery for Non-small-cell Lung Cancer Patients With Poor Lung Function: Short- and Long-Term Outcomes.

Objective: The goal of this study was to explore the feasibility and safety of spontaneous ventilation video-assisted thoracoscopic surgery (SV-VATS) for non-small-cell lung cancer (NSCLC) patients with poor lung function. Methods: NSCLC patients with poor lung function who underwent SV-VATS or mechanical ventilation VATS (MV-VATS) from 2011 to 2018 were analyzed. 1:2 Propensity score matching (PSM) was applied, and the short- and long-term outcomes between the SV-VATS group and the MV-VATS group were compared. Results: Anesthesia time (226.18 ± 64.89 min vs. 248.27 ± 76.07 min; P = 0.03), operative time (140.85 ± 76.07 min vs. 163.12 ± 69.37 min; P = 0.01), days of postoperative hospitalization (7.29 ± 3.35 days vs. 8.40 ± 7.89 days; P = 0.04), and days of chest tube use (4.15 ± 2.89 days vs. 5.15 ± 3.54 days; P = 0.01), the number of N1 station lymph node dissection (2.94 ± 3.24 vs. 4.34 ± 4.15; P = 0.005) and systemic immune-inflammation index (3855.43 ± 3618.61 vs. 2908.11 ± 2933.89; P = 0.04) were lower in SV-VATS group. Overall survival and disease-free survival were not significantly different between the two groups (OS: HR 0.66, 95% CI: 0.41-1.07, P = 0.09; DFS: HR 0.78, 95% CI: 0.42-1.45, P = 0.43). Conclusions: Comparable short-term and long-term outcomes indicated that SV-VATS is a feasible and safe method and might be an alternative to MV-VATS when managing NSCLC patients with poor lung function.

Diabetic retinopathy risk in patients with unhealthy lifestyle: A Mendelian randomization study.

Purpose: This study aimed to investigate the causal association between unhealthy lifestyle factors and diabetic retinopathy (DR) risk and to determine better interventions targeting these modifiable unhealthy factors. Design: Two-sample Mendelian randomization (MR) analysis was performed in this study. The inverse variance-weighted method was used as the primary method. Method: Our study included 687 single-nucleotide polymorphisms associated with unhealthy lifestyle factors as instrumental variables. Aggregated data on individual-level genetic information were obtained from the corresponding studies and consortia. A total of 292,622,3 cases and 739,241,18 variants from four large consortia (MRC Integrative Epidemiology Unit [MRC-IEU], Genetic Investigation of Anthropometric Traits [GIANT], GWAS & Sequencing Consortium of Alcohol and Nicotine Use [GSCAN], and Neale Lab) were included. Result: In the MR analysis, a higher body mass index (BMI) (odds ratio [OR], 95% confidence interval [CI] = 1.42, 1.30-1.54; P < 0.001] and cigarettes per day (OR, 95% CI = 1.16, 1.05-1.28; P = 0.003) were genetically predicted to be causally associated with an increased risk of DR, while patients with higher hip circumference (HC) had a lower risk of DR (OR, 95% CI = 0.85, 0.76-0.95; P = 0.004). In the analysis of subtypes of DR, the results of BMI and HC were similar to those of DR, whereas cigarettes per day were only related to proliferative DR (PDR) (OR, 95% CI = 1.18, 1.04-1.33; P = 0.009). In the MR-PRESSO analysis, a higher waist-to-hip ratio (WHR) was a risk factor for DR and PDR (OR, 95% CI = 1.24, 1.02-1.50, P = 0.041; OR, 95% CI = 1.32, 1.01-1.73, P = 0.049) after removing the outliers. Furthermore, no pleiotropy was observed in these exposures. Conclusion: Our findings suggest that higher BMI, WHR, and smoking are likely to be causal factors in the development of DR, whereas genetically higher HC is associated with a lower risk of DR, providing insights into a better understanding of the etiology and prevention of DR.

Evaluation of a fully automated and completely quantitative allergen-specific IgE and total IgE detection assay.

Based on the current urgent need for an in vitro quantitative detection system for allergens in most hospitals in China, we introduced a novel allergen-specific immunoglobulin E detection system that employs a solid phase enzyme-linked immunoassay and evaluated its clinical performance. The system uses a special reaction component (innovative patents) to reduce the reaction time to 12 min, achieving point-of-care testing for allergy management, which is impressive compared to the 3-18 h testing time for all other systems. In addition, the AILEX system has excellent consistency with the ImmunoCAP reference method system; therefore, we recommend the introduction of the AILEX system for clinical auxiliary diagnosis in medical units.

Distribution characteristics of cow's milk-sIgE components in children with respiratory allergic diseases in southern China.

BACKGROUND: Cow's milk (CM) is the main food allergen for toddlers and infants. Presently, studies on CM specific immunoglobulin E (sIgE) sensitization and positive distribution of CM components ALA-, CAS-, and BLG-sIgE are lacking in infants with respiratory allergic diseases, especially in southern China. This study therefore aimed to investigate the distribution of CM sensitization and the relation between its components α-lactalbumin (ALA), ß-lactoglobulin (BLG) and casein (CAS) sIgE in children with respiratory allergic diseases in southern China. METHODS: A total of 1839 children (≤12 years) with respiratory diseases and detected CM-sIgE levels were included. Serum samples were collected from the Respiratory Diseases Bioresources Center of the National Center for Respiratory Diseases in southern China from August 2012 to July 2017. ALA-, BLG-, and CAS-sIgE were detected and questionnaires were completed in 103 children. RESULTS: A total of 36.7% children were positive for CM-sIgE. CM-sIgE levels were higher in asthmatic bronchitis (AB) group than in other allergic respiratory disease groups (all P < 0.05). Among the 103 CM-sIgE-sensitized children, 64.08% had a history of family allergies. There were 84.47% of the children who tested positive for two or more sIgE components. The average ALA-, BLG-, and CAS-sIgE levels were 1.91 kU/L, 1.81 kU/L, and 0.62 kU/L, respectively. The CM-sIgE level showed a correlation with BLG-sIgE (rs = 0.833), ALA-sIgE (rs = 0.816), and CAS-sIgE (rs = 0.573) levels (all p < 0.001). CONCLUSIONS: In southern China, CM-sIgE levels were higher in children with AB than in those with other respiratory allergic diseases. ALA and BLG were the main allergenic components detected in CM-sIgE-sensitized children with respiratory allergic diseases.

Metadherin is an apoptotic modulator in prostate cancer through miR-342-3p regulation.

Prostate cancer is the second most common cancer in men worldwide. This study focused to clarify the roles of Metadherin (MTDH) and miR-342-3p in prostate cancer. We identified that MTDH was up-regulated and miR-342-3p was down-regulated in the prostate tissues, and there is an inverse correlation between MTDH and miR-342-3p. Functional studies revealed that miR-342-3p directly targets MTDH via binding to the 3' untranslated regions (UTRs) in the prostate cancer cells. Moreover, we also found MTDH overexpression in DU145 and PC3 cells inhibited apoptosis. Subsequently, miR-342-3p has been revealed to reverse the MTDH effect on the cellular apoptosis in the further studies. Our results indicate that MTDH repress apoptosis of prostate cancer in vitro and provides a new strategy for human prostate cancer therapy in the future.

The practical benefit of Phadiatop test as the first-line in vitro allergen-specific immunoglobulin E (sIgE) screening of aeroallergens among Chinese asthmatics: a validation study.

BACKGROUND: Phadiatop test is a variant of ImmunoCAP assay that covers a mixture of common aeroallergens. Its diagnostic efficiency in Chinese population remains so far inadequate. We validated Phadiatop testing with ImmunoCAP assays in a Chinese cohort. METHODS: Phadiatop test was performed for serum samples from 290 asthmatics and 92 healthy controls previously tested with "classic" ImmunoCAP for house dust mix (hx2), molds and yeasts mix (mx2), tree pollen mix (tx4) and weed mix (wx5). RESULTS: Phadiatop positivity was shown in 46.2% of 290 asthmatic patients. Using ImmunoCAP as the gold standard, the concordance rate was 91.7%; negative predictive value, 92.9%; and positive predictive value, 90.2%. The sensitivity of Phadiatop test was high for hx2 (98.2%), tx4 (100%) and wx5 (95.5%), but not for mx2 (78.4%). Yet the mx2 allergen-specific immunoglobulin E (sIgE) level in all missed cases was relatively low (0.35 to 0.90 kUA/L). The total Phadiatop sIgE level was correlated with the ImmunoCAP sIgE levels for all allergen mixes combined (rs =0.941, P<0.001) or each allergen mix, particularly the hx2 (rs =0.924) (all P<0.001), 0.53 kUA/L used as a cut-off would optimize the diagnostic performance of Phadiatop testing, yielding 89.4% sensitivity and 97.5% specificity in indentifying serums positive to any of these allergen mixes. CONCLUSIONS: Overall, Phadiatop test may efficiently detect sensitization to common aeroallergen mixes. In light of the currently rigorous administration on crude extracts for skin tests in China, using Phadiatop as the first-line test for suspected atopy can be cost-effective.

Oxygen is a master regulator of the immunogenicity of primary human glioma cells.

With recent approval of the first dendritic cell (DC) vaccine for patient use, many other DC vaccine approaches are now being tested in clinical trials. Many of these DC vaccines employ tumor cell lysates (TL) generated from cells cultured in atmospheric oxygen (∼20% O2) that greatly exceeds levels found in tumors in situ. In this study, we tested the hypothesis that TLs generated from tumor cells cultured under physiologic oxygen (∼5% O2) would be more effective as a source for DC antigens. Gene expression patterns in primary glioma cultures established at 5% O2 more closely paralleled patient tumors in situ and known immunogenic antigens were more highly expressed. DCs treated with TLs generated from primary tumor cells maintained in 5% O2 took up and presented antigens to CD8 T cells more efficiently. Moreover, CD8 T cells primed in this manner exhibited superior tumoricidal activity against target cells cultured in either atmospheric 20% O2 or physiologic 5% O2. Together, these results establish a simple method to greatly improve the effectiveness of DC vaccines in stimulating the production of tumoricidal T cells, with broad implications for many of the DC-based cancer vaccines being developed for clinical application.

Toll-like receptor 9 signaling by CpG-B oligodeoxynucleotides induces an apoptotic pathway in human chronic lymphocytic leukemia B cells.

Chronic lymphocytic leukemia (CLL) is the most prevalent human leukemia and is characterized by the progressive accumulation of long-lived malignant B cells. Here we show that human B-CLL cells selectively express high levels of Toll-like receptor 9 (TLR9) mRNA and proteins. Treating B-CLL cells with TLR9 agonists, type B CpG oligodeoxynucleotides (CpG-B ODNs), induces significant morphologic and phenotypic activation, altered cytokine production, reversal of signal transducer, and activator of transcription 1 (STAT1) phosphorylation state, followed by profound apoptosis of B-CLL cells that is CpG-B ODN treatment time- and dose-dependent. TLR9-CpG ODN ligation-induced apoptosis of B-CLL cells is confirmed by viable cell counts, annexin V/propidium iodide and tetramethyl-rhodamine ethylester staining, Western blots of the activation, and cleaved caspases and poly (ADP-ribose) polymerase. Triggering TLR9 by CpG-B ODN leads to nuclear factor-kappaB-dependent production of autocrine interleukin-10, which activates JAK/STAT pathway-dependent tyrosine phosphorylation of STAT1 proteins and thereby provokes an apoptosis pathway in B-CLL cells. Treating B-CLL cells in vitro or in vivo with CpG-B ODN reduces the number of leukemia cells that engraft in NOD-scid mice. These findings provide new understanding of CpG ODN-mediated antitumor effects and support for the development of TLR9-targeted therapy for human CLL.

The indoleamine 2,3-dioxygenase pathway is essential for human plasmacytoid dendritic cell-induced adaptive T regulatory cell generation.

Human plasmacytoid dendritic cells (PDCs) can drive naive, allogeneic CD4(+)CD25(-) T cells to differentiate into CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs). However, the intracellular mechanism or mechanisms underlying PDC-induced Treg generation are unknown. In this study, we show that human PDCs express high levels of IDO, an intracellular enzyme that catabolizes tryptophan degradation. Triggering of TLR 9 with CpG oligodeoxynucleotides activates PDCs to up-regulate surface expression of B7 ligands and HLA-DR Ag, but also significantly increases the expression of IDO and results in the generation of inducible Tregs from CD4(+)CD25(-) T cells with potent suppressor cell function. Blocking IDO activity with the pharmacologic inhibitor 1-methyl-D-tryptophan significantly abrogates PDC-driven inducible Treg generation and suppressor cell function. Adding kynurenine, the immediate downstream metabolite of tryptophan, bypasses the 1-methyl-D-tryptophan effect and restores PDC-driven Treg generation. Our results demonstrate that the IDO pathway is essential for PDC-driven Treg generation from CD4(+)CD25(-) T cells and implicate the generation of kynurenine pathway metabolites as the critical mediator of this process.

FLT3 ligand administration after hematopoietic cell transplantation increases circulating dendritic cell precursors that can be activated by CpG oligodeoxynucleotides to enhance T-cell and natural killer cell function.

Dendritic cells (DCs) are key effectors in innate immunity and play critical roles in triggering adaptive immune responses. FLT3 ligand (FLT3-L) is essential for DC development from hematopoietic progenitors. In a phase I clinical trial, we demonstrated that immunotherapy with subcutaneous injection of FLT3-L is safe and well tolerated in cancer patients recovering from autologous hematopoietic cell transplantation (HCT). FLT3-L administration significantly increased the frequency and absolute number of blood DC precursors without affecting other mature cell lineages during the 6-week course of FLT3-L therapy. After 14 days of FLT3-L administration, the number of blood CD11c + DCs, plasmacytoid DCs (PDCs), and CD14 + monocytes increased by 5.3-, 2.9-, 3.8-fold, respectively, and was maintained at increased levels throughout FLT3-L therapy. FLT3-L-increased blood DCs in HCT patients were immature and had modest enhancing effects on in vitro T-cell proliferation to antigens and natural killer (NK) cell function. The addition of type B CpG oligodeoxynucleotides (ODNs) to peripheral blood mononuclear cells obtained from HCT patients receiving FLT3-L therapy induced rapid maturation of both CD11c + DCs and PDCs and enhanced T-cell proliferative responses. In addition, CpG ODN induced potent activation of NK cells from FLT3-L-treated patients with increased surface CD69 expression and augmented cytotoxicity. CpG ODN-induced activation of NK cells was primarily via an indirect mechanism through PDCs. These findings suggest that FLT3-L mobilization of DC precursors followed by a specific DC stimulus such as CpG ODN may provide a novel strategy to manipulate antitumor immunity in patients after HCT.

Human plasmacytoid dendritic cells activated by CpG oligodeoxynucleotides induce the generation of CD4+CD25+ regulatory T cells.

Plasmacytoid dendritic cells (PDCs) are key effectors in host innate immunity and orchestrate adaptive immune responses. CpG oligodeoxynucleotides (ODN) have potent immunostimulatory effects on PDCs through TLR9 recognition and signaling. Little is known about the effects of CpG ODN on human PDC-mediated T cell priming. Here we show that type B CpG ODN effectively promotes PDCs to prime allogeneic naive CD4(+)CD25(-) T cells to differentiate into CD4(+)CD25(+) regulatory T (Treg) cells. The CD4(+)CD25(+) T cells induced by CpG ODN-activated PDCs express forkhead transcription factor 3 and produce IL-10, TGF-beta, IFN-gamma, and IL-6, but low IL-2 and IL-4. These CD4(+)CD25(+) T cells are hyporesponsive to secondary alloantigen stimulation and strongly inhibit proliferation of autologous or allogeneic naive CD4(+) T cells in an Ag-nonspecific manner. CpG ODN-activated PDCs require direct contact with T cells to induce CD4(+)CD25(+) Treg cells. Interestingly, IL-10 and TGF-beta were undetectable in the supernatants of CpG ODN-stimulated PDC cultures. Both CpG-A and CpG-C ODN-activated PDCs similarly induced the generation of CD4(+)CD25(+) Treg cells with strong immune suppressive function. This study demonstrates that TLR9 stimulation can promote PDC-mediated generation of CD4(+)CD25(+) Treg cells and suggests PDCs may play an important role in the maintenance of immunological tolerance.

Thrombopoietin cooperates with FLT3-ligand in the generation of plasmacytoid dendritic cell precursors from human hematopoietic progenitors.

Type 1 interferon-producing cells (IPCs), also known as plasmacytoid dendritic cell (DC) precursors, represent the key effectors in antiviral innate immunity and triggers for adaptive immune responses. IPCs play important roles in the pathogenesis of systemic lupus erythematosus (SLE) and in modulating immune responses after hematopoietic stem cell transplantation. Understanding IPC development from hematopoietic progenitor cells (HPCs) may provide critical information in controlling viral infection, autoimmune SLE, and graft-versus-host disease. FLT3-ligand (FLT3-L) represents a key IPC differentiation factor from HPCs. Although hematopoietic cytokines such as interleukin-3 (IL-3), IL-7, stem cell factor (SCF), macrophage-colony-stimulating factor (M-CSF), and granulocyte M-CSF (GM-CSF) promote the expansion of CD34+ HPCs in FLT3-L culture, they strongly inhibit HPC differentiation into IPCs. Here we show that thrombopoietin (TPO) cooperates with FLT3-L, inducing CD34+ HPCs to undergo a 400-fold expansion in cell numbers and to generate more than 6 x 10(6) IPCs per 10(6) CD34+ HPCs within 30 days in culture. IPCs derived from HPCs in FLT3-L/TPO cultures display blood IPC phenotype and have the capacity to produce large amounts of interferon-alpha (IFN-alpha) and to differentiate into mature DCs. This culture system, combined with the use of adult peripheral blood CD34+ HPCs purified from G-CSF-mobilized donors, permits the generation of more than 10(9) IPCs from a single blood donor.