Dendritic Cell Subsets In Patients Research Articles

Evidence for immune activation in pathogenesis of the HLA class II associated disease, podoconiosis

Available evidences suggest that podoconiosis is triggered by long term exposure of bare feet to volcanic red clay soil particles. Previous genome-wide studies in Ethiopia showed association between the HLA class II region and disease susceptibility. However, functional relationships between the soil trigger, immunogenetic risk factors and the immunological basis of the disease are uncharted. Therefore, we aimed to characterise the immune profile and gene expression of podoconiosis patients relative to endemic healthy controls. Peripheral blood immunophenotyping of T cells indicated podoconiosis patients had significantly higher CD4 and CD8 T cell surface HLA-DR expression compared to healthy controls while CD62L expression was significantly lower. The levels of the activation markers CD40 and CD86 were significantly higher on monocytes and dendritic cell subsets in patients compared to the controls. RNA sequencing gene expression data indicated higher transcript levels for activation, scavenger receptors, and apoptosis markers while levels were lower for histones, T cell receptors, variable, and constant immunoglobulin chain in podoconiosis patients compared to healthy controls. Our finding provides evidence that podoconiosis is associated with high levels of immune activation and inflammation with over-expression of genes within the pro-inflammatory axis. This offers further support to a working hypothesis of podoconiosis as soil particle-driven, HLA-associated disease of immunopathogenic aetiology.

Aberrant Dendritic Cell Subsets in Patients with Myasthenia Gravis and Related Clinical Features

Introduction: Dendritic cells (DCs) play critical roles in the pathogenesis of myasthenia gravis (MG), and a series of DC-based experimental strategies for MG have recently been developed. However, the definite roles of different DC subsets in the mechanism of MG have scarcely been covered by previous studies. The present study aimed to investigate the levels of three main DC subsets, plasmacytoid DCs (pDCs) (CD303 positive) and two distinct subsets of conventional DCs (cDCs), namely CD1c⁺ cDCs and CD141⁺ cDCs, in MG patients and analyze related clinical features. Methods: From January 2016 to December 2020, 160 newly diagnosed MG patients and matched healthy controls (n = 160) were included in the study, and their clinical data were collected. The blood samples from MG patients before treatment and controls were collected for flow cytometry analysis. A total of 14 MG thymoma, 24 control thymoma, and 3 thymic cysts were used to immunostain the DC subsets. Results: The flow cytometry analysis showed a significantly higher frequency of circulating pDCs, CD1c⁺ cDCs, and CD141⁺ cDCs in MG patients than in healthy controls (p < 0.001 for all). Patients with early-onset MG (<50 years old) had a lower frequency of circulating pDCs but a higher frequency of circulating CD1c⁺ cDCs than those with late-onset MG (≥50 years old) (p = 0.014 and p = 0.025, respectively). The frequency of circulating pDCs was positively associated with the clinical severity of late-onset MG patients (r = 0.613, p < 0.001). 64.3% (9/14) of MG thymoma is of type B2 under the World Health Organization classification, which is higher than that in control thymoma (33.3%, 8/24) (p = 0.019). For type B2 thymoma, there were significantly more pDCs but fewer CD1c⁺ cDCs in MG thymoma than in the controls. Conclusion: The distribution of aberrant pDCs, CD1c⁺ cDCs, and CD141⁺ cDCs in MG patients displayed age- and thymoma-related differences, which may contribute to the impaired immune tolerance and lead to the onset of MG.

Evaluating the Role of Circulating Dendritic Cells in Methimazole-Treated Pediatric Graves' Disease Patients.

Graves’ disease (GD) is hyperthyroidism associated with organ-specific autoimmune inflammation. GD occurs more frequently in adults than in children; however, pediatric patients are a therapeutic challenge due to cycles of remissions and relapses requiring constant monitoring at every stage of treatment administered. Dendritic cells (DCs) are considered to be a link between innate and adaptive immunity. DCs, as antigen-presenting cells (APCs), are involved in antigen presentation to T lymphocytes, thereby initiating a shift towards effector cells. In accordance, DCs also participate in the modulation of tolerance to specific antigens. To date, the data on DCs’ role in Graves’ pathological processes are scarce. Therefore, here, we evaluated the frequencies and role of circulating DCs in GD pediatric patients treated with methimazole. Flow cytometric analysis was implemented to evaluate three subsets of dendritic cells and their correlation with clinical GD-related parameters. We found significantly higher levels of DC subsets in patients at diagnosis. Furthermore, methimazole treatment seemed to effectively reduce subsets of DCs, which, in addition, were found to differentially correlate with thyroid function. Our study shed new light on DCs’ role in the pediatric GD pathomechanism. Further studies are required for the mechanistic assessment of DCs’ exact role in disease progression and influence on thyroid function.

Imbalance of the two main circulating dendritic cell subsets in patients with myasthenia gravis

Although it is well documented that circulating dendritic cells (DCs) have specialized features during many kinds of physiological and pathological conditions, there are few reports about the features of DCs in the peripheral blood of myasthenia gravis (MG) patients. We investigated the quantitative and component features of DCs and their implications in MG. Peripheral blood samples from different kinds of MG patients were collected and their clinical characteristics were recorded. Using flow cytometry, we distinguished circulating DC subsets [plasmacytoid DCs (pDCs) and myeloid DCs (mDCs)] and enumerated their densities in peripheral blood. Absolute numbers of circulating pDCs were significantly decreased in naïve MG patients compared with healthy controls, resulting in a markedly lower ratio of the pDC to mDC percentage in total circulating DCs (pDCs/mDCs), suggesting an imbalance in the proportions of the two main circulating DC subsets. The clinical status of MG patients was improved after drug treatment, together with increased pDCs/mDCs. In a longitudinal follow-up, we observed that circulating mDCs were significantly reduced after 1 month of therapy with a corticosteroid and immunosuppressant, resulting in recovery of pDCs/mDCs. Although the exact meaning of the proportion change in circulating DC subsets is unknown, pDCs/mDCs might reflect the balance between the autoimmune response and immune tolerance of a patient. Moreover, changes in pDCs/mDCs during treatment might be a promising marker to predict the efficacy of a specific drug used for MG patients.

Use of antigen-primed dendritic cells for inducing antitumor immune responses in vitro in patients with non-small cell lung cancer.

Cancer is associated with a reduction in immature and mature circulating dendritic cells (DCs), and with an impaired migratory capacity, compared with healthy donors. Therefore, modern approaches to the in vitro generation of DCs loaded with tumor antigens and their use for inducing antitumor immune responses in vivo are being investigated. The purpose of the present study was to investigate the phenotypic and functional characteristics of peripheral blood DC subsets in patients with non-small cell lung cancer (NSCLC), and the development of an antitumor cytotoxic response by mononuclear cells (MNCs) from patients using in vitro generated antigen-primed DCs. Heparinized peripheral venous blood samples were obtained from 10 healthy donors and 20 patients with a histologically verified diagnosis of NSCLC. The ability of antigen-activated DCs to stimulate the activity of MNCs against autologous tumor cells was evaluated using a cytotoxic test. Peripheral blood DC subsets from patients with NSCLC were identified to be decreased and to exhibit an impaired ability to mature, compared with healthy donors. Furthermore, DCs generated from MNCs from patients with NSCLC were able to stimulate a specific cytotoxic response when loaded with autologous tumor lysates or RNA and matured, in vitro. A perforin and granzyme B-dependent mode of cytotoxicity was primarily induced. The ability of DCs loaded with tumor antigens to increase the cytotoxic activity of MNCs against NSCLC cells in vitro indicates the effective induction and co-stimulation of T lymphocytes by the generated DCs.

Expression of dendritic cell subsets in patients with different stages of chronic HBV infection: a comparative analysis

Expression of dendritic cell subsets in patients with different stages of chronic HBV infection: a comparative analysis

Folliculotropic Mycosis Fungoides with Skewed T-cell Receptor CDR3 Motif: Suggestive of Lipid-antigen Selection?

Folliculotropic mycosis fungoides (FMF), a variant of mycosis fungoides (MF) with distinct clinical features, is characterized by infiltration of malignant T cells in hair follicles. This raises the hypothesis that antigens in the hair follicle may contribute to the pathogenesis of FMF.T-cell receptor β gene (TRB) sequences as well as dendritic cell subsets in patients with FMF (n = 21) and control patients with MF (n = 20) were studied to explore this hypothesis. A recurrent usage of the TRB junctional genes TRBJ2-1 and TRBJ2-7 was found in patients with FMF compared with those with MF. These genes contribute to an amino acid motif in the complementarity-determining region 3 (CDR3) of the T-cell receptor. This motif was previously found in T cells stimulated by lipids bound to CD1 on antigen-presenting cells. Additional immunohistochemical analysis revealed abundant CD1c- and CD1a- expressing dendritic cells in FMF. The combined findings support a role for lipid-antigen stimulation in FMF.

AB0068 Distribution of blood dendritic cell subsets in patients with rheumatoid arthritis, spondyloarthritis and psoriatic arthritis treated with etanercept

ObjectivesDendritic cells play a pivotal role in the initiation of innate and adaptive immune responses in host reaction to microbial infection as well as in autoimmune pathology. DC subsets in...

Impact of immunotherapy on blood dendritic cells in patients with Hymenoptera venom allergy

Modulation of T-cell differentiation, which is controlled by dendritic cells (DCs), plays a crucial role in specific immunotherapy (SIT). However, the number and the characteristics of blood DCs before and during immunotherapy are unknown. To analyze the number and the characteristics of blood DC subsets in patients with Hymenoptera venom allergy before and after initiation of SIT. In this clinical trial (NCT00947908), blood myeloid and plasmacytoid DCs were analyzed in 20 patients with Hymenoptera venom allergy (bee or wasp venom) by using 4-color flow cytometry at 3 time points: directly before SIT, and 52 hours and 12 months after initiation of SIT. In addition, 20 age-matched and sex-matched controls were examined. In patients with Hymenoptera venom allergy, the number of plasmacytoid DCs before SIT was comparable to that of controls. Plasmacytoid DCs decreased markedly 52 hours after initiation of SIT and returned to control levels after 12 months of treatment. Myeloid DCs were elevated in patients with Hymenoptera venom allergy before, during, and after the first 12 months of SIT. In addition, there were changes in the expression of function-associated surface molecules on myeloid DCs (such as Fc γ receptor 2 and Toll-like receptor 2) during SIT. Numbers of blood myeloid DCs are elevated in patients with Hymenoptera venom allergy, and there are specific changes in the expression of function-associated surface molecules on these cells during SIT. Numbers of plasmacytoid DCs in blood are profoundly but are only transiently decreased after initiation of SIT.

Phenotype changes and impaired function of dendritic cell subsets in patients with sepsis: a prospective observational analysis

IntroductionPatients with sepsis often demonstrate severely impaired immune responses. The hallmark of this state of immunoparalysis is monocytic deactivation characterized by decreased human leukocyte antigen (HLA)-DR expression and reduced production of proinflammatory cytokines. Recently, diminished numbers of dendritic cells (DCs) were reported in patients with sepsis. However, little is known about DC phenotype and function in human sepsis. We therefore compared phenotypic and functional changes in monocyte and DC subsets in patients with sepsis and immunoparalysis.MethodsIn a prospective observational analysis, 16 consecutive patients with severe sepsis and septic shock (age 59.2 ± 9.7 years, 13 male, Sequential Organ Failure Assessment score 6.1 ± 2.7) and immunoparalysis (monocytic HLA-DR expression < 5,000 antibodies/cell) and 16 healthy volunteers were included. Peripheral blood DC counts, HLA-DR expression and ex vivo cytokine production were evaluated in comparison with monocyte subsets over time.ResultsAt baseline, a profound reduction in the numbers of myeloid DCs (MDCs), plasmacytoid DCs (PDCs), and CD14dimCD16positive monocytes was observed in sepsis whereas CD14brightCD16negative and CD14brightCD16positive monocyte numbers were increased. HLA-DR expression was reduced on all monocyte and DC subsets. Production of proinflammatory cytokines and intracellular cytokine staining in response to lipopolysaccharide and lipoteichoic acid was impaired in monocyte subsets and MDCs, whereas IL-10 secretion was increased. IFNα response by stimulated PDCs was significantly decreased compared with controls. At day 28, HLA-DR expression and cytokine production of DC and monocyte subsets remained lower in septic patients compared with controls.ConclusionsIn sepsis, long-lasting functional deactivation is common to all circulating monocyte and DC subsets. In addition to decreased peripheral blood DC counts, functional impairment of antigen-presenting cells may contribute to an impaired antimicrobial defense in sepsis.

Dysfunctional DC subsets in RCC patients: Ex vivo correction to yield an effective anti-cancer vaccine

Dendritic cells (DCs) are potent antigen-presenting cells responsible for the activation and functional polarization of specific T cells. In patients with renal cell carcinoma (RCC) and other cancers, coordinate DC and T cell defects have been reported. In particular, DC and T cell functional subsets that are not conducive to tumor clearance are hypothesized to predominate in patients with advanced-stage disease. Two major peripheral blood DC subsets have been identified in humans: myeloid dendritic cells (mDCs) and plasmacytoid dendritic cells (pDCs) that are believed to mediate contrasting effects on cancer immunity. Given the lack of information regarding DC subsets in patients with RCC, in the present study we have investigated the comparative frequencies and activation states of mDC and pDC in peripheral blood, cancer tissues and lymph nodes of patients with RCC using flow cytometry and immunohistochemistry. Three monoclonal antibodies (mAbs) reactive against specific DC subsets (BDCA-2 or BDCA-4 for pDC and BDCA-1 and BDCA-3 which represent two distinct subsets of mDC, mDC1 and mDC2, respectively) were employed. We observed a significant reduction of both DC subsets in the peripheral blood of patients as compared to normal donors. Similarly, both mDC and pDC were recruited in large numbers into RCC tumor tissues, where they displayed an immature phenotype (DC-LAMP −) and appeared unable to differentiate into mature DC (CD83 +) that were competent to migrate to draining lymph nodes. However, we were readily able to generate ex vivo mDC from RCC patients. These DC stimulated robust anti-tumor CTL in vitro and would be envisioned for use in DC-based vaccines applied in patients with RCC whose existing immune system is judged dysfunctional, anergic or prone to undergo apoptosis.

Characterization of Dendritic Cell Subsets in Patients Undergoing Renal Transplantation

Dendritic cells (DCs) play a key role in transplantation tolerance and immune reactions to transplants. In order to ascertain whether DC levels are predictive for rejection, we examined the levels and expression patterns of DCs of renal transplant patients following immunosuppressive and/or surgical interventions. Myeloid (HLA-DR+/CD11c+) and plasmacytoid (HLA-DR+/CD123+) DCs were characterized by flow cytometry over 28 days. We demonstrated that myeloid DCs and plasmacytoid DCs in peripheral blood were discernable and dramatically decreased following renal transplantation and immunosuppression. Furthermore, the expression of CD62L was significantly up-regulated ( P = .032), while CD86 was significantly down-regulated ( P = .008) on myeloid but not plasmacytoid DCs. Although DC levels alone were not predictive for the occurrence of a rejection episode, in combination with other factors they may be indicative of rejection, thereby sparing the patient a biopsy.

Characterization and biological significance of peripheral blood dendritic cell subsets in patients with severe burn

To investigate the characteristics of dendritic cells (DCs) in patients with severe burn. Peripheral blood samples were obtained from 12 patients with severe burn 1, 2, 3, and 4 weeks after burn, and from 10 healthy donors as controls. Mononuclear cells were isolated, and GM-CSF 1000 and IL-4 were used to induce the transformation of DCs. Mature DCs were harvested and underwent flow cytometry to detect the expression of HLA-DR, CD80, CD83, CD86, CD14, and CD11c. 1, 2, 3, and 4 weeks after burn, the expression levels of HLA-DR were 62.1% +/- 8.4%, 65.0% +/- 6.2%, 68.4% +/- 5.7%, and 75.4% +/- 8.4% respectively; the expression levels of CD80 were 12.9% +/- 3.7%, 14.7% +/- 2.5%, 16.1% +/- 4.2%, and 16.2% +/- 4.8%; the expression levels of CD83 were 15.1% +/- 4.2%, 15.1% +/- 4.0%, 22.2% +/- 7.7%, and 21.3% +/- 7.0% respectively; the expression levels of CD86 were 69.2% +/- 7.1%, 70.5% +/- 5.4%, 75.1% +/- 6.1%, and 79.6% +/- 6.4% respectively, all significantly lower than that of the control group (84.3% +/- 8.2%, all P < 0.001). 1, 2, 3, and 4 weeks after burn, the expression levels of CD14 in the DCs of the severe burn patients were 12.7% +/- 1.9%, 12.0% +/- 1.5%, 11.3% +/- 1.3%, and 9.3% +/- 1.7% respectively, all significantly higher than that of the control group (7.3% +/- 1.5%, P < 0.001). 1, 2, 3, and 4 weeks after burn, the expression levels of CD11c in the DCs of the severe burn patients were 86.8% +/- 6.1%, 89.5% +/- 5.1%, 91.3% +/- 2.8%, and 89.4% +/- 4.0% respectively, a little lower than that of the control group, however, without significant difference (92.6% +/- 3.8%, P > 0.05). The functions of DCs in the patients with severe burn are declined, which may partly contribute to infection after burn.

Normal Functional Capacity in Circulating Myeloid and Plasmacytoid Dendritic Cells in Patients with Chronic Hepatitis C

Initial reports analyzing dendritic cell (DC) function in patients with hepatitis C virus (HCV) infection have been controversial. Here, we enumerate and characterize the function of circulating myeloid and plasmacytoid DCs. The results show lower percentages of myeloid DCs (0.62 vs. 0.83; P = .05) and plasmacytoid DCs (0.11 vs. 0.34; P = .004) in patients with chronic HCV infection than in healthy, non-HCV-infected individuals. Despite the lower numbers of circulating myeloid DCs present, no phenotypic or functional defects were identified. The lower percentage of plasmacytoid DCs resulted in decreased absolute interferon (IFN)-alpha production; however, when analyzed on a per-cell basis, plasmacytoid DCs from HCV-infected patients generated levels of IFN-alpha equivalent to those generated by DCs from healthy, non-HCV-infected individuals. Contrary to data from previous models (which attributed HCV pathogenesis to defects in the DC compartment), our data reveal functional DC subsets in patients with chronic HCV infection. These results are encouraging for DC-based HCV immunotherapy trials.

Decreased numbers and impaired function of circulating dendritic cell subsets in patients with chronic hepatitis B infection (R2)

To investigate the frequencies, numbers and function of circulating dendritic cell (DC) subsets in patients with hepatitis B virus (HBV) infection, we assayed the circulating precursor DC subsets (including pDC1 and pDC2) and their ability in patients at various stages of HBV infection in vitro. Circulating pDC1 and pDC2 frequencies in peripheral blood mononuclear cells (PBMC) were analyzed by flow cytometric analysis. Costimulatory molecule expression and allostimulatory mixed lymphocyte reaction (AMLR) of DC1, cultured from PBMC in vitro, were detected in patients with chronic hepatitis B (CHB). On behalf of pDC2, interferon (IFN)-alpha production of PBMC was determined by the ELISA method in HBV-infected patients. The number of circulating pDC1 decreased only in patients with liver cirrhosis (LC) compared with that in normal controls. However, pDC2 numbers decreased in both CHB and LC patients. DC1 from CHB patients showed lower expression of costimulatory molecules CD80, CD86 and impaired allostimulatory mixed lymphocyte reaction (AMLR) compared with those in normal controls. The ability of PBMC to secrete IFN-alpha also decreased significantly in patients with chronic HBV infection. Our results suggest that patients with chronic HBV infection have a significantly lower expression of costimulatory molecules and impaired AMLR of pDC1, as well as decreased number and impaired function of circulating pDC2, which may be partially related to HBV disease progression in these patients.

Impaired generation of bone marrow CD34-derived dendritic cells with low peripheral blood subsets in patients with myelodysplastic syndrome.

Myelodysplastic syndrome (MDS) is a stem cell disorder characterized by ineffective haematopoiesis and blood cytopenias. The present study investigated the potential of bone marrow CD34(+) progenitors in MDS patients to proliferate and differentiate into dendritic cells (DCs) in a cytokine-supplemented liquid culture system and analysed the status of blood DC subsets in these patients. CD34(+) progenitors had low potential to generate DCs in vitro, as the number of DCs obtained from one CD34(+) cell was significantly lower compared with controls (median value 0.2 vs. 4, P = 0.003). In patients, the survival and proliferation of CD34(+) cells in culture was not correlated to the degree of apoptosis. Phenotypically and functionally CD34(+)-derived DCs were similar in MDS patients and normal subjects. The percentage of both circulating DC subsets in patients was extremely diminished compared with controls (myeloid DC: 0.10 +/- 0.10% vs. 0.35 +/- 0.13%, P < 0.001; plasmacytoid DC: 0.11 +/- 0.10% vs. 0.37 +/- 0.14%, P < 0.001). In cases with the 5q deletion both CD34-derived DCs and blood DCs harboured the cytogenetic abnormality. Our results indicate that, in MDS, the production of DCs is affected by the neoplastic process resulting in ineffective 'dendritopoiesis' with low blood DC precursor numbers. This quantitative DC defect probably contributes to the poor immune response against infectious agents and to the escape of the malignant clone from immune recognition with disease progression towards acute leukaemia.

Phenotypic analysis of circulating and intrahepatic dendritic cell subsets in patients with chronic liver diseases

Background/Aims: Dendritic cells (DCs) are the most potent professional antigen-presenting cells. Although two subsets of circulating DCs, lineage −CD11c +CD4 low (CD11c +DCs) and lineage −CD11c −CD4 +CD123 + (CD123 +DCs) are identified in humans, the role of each DC subset in the immunopathogenesis of liver diseases is unknown. Methods: We examined the numbers and activation status of each DC subset in the circulation and in the inflamed livers in patients with chronic liver diseases by flow cytometry and immunohistochemistry. Results: The numbers of circulating CD11c + DCs were inversely correlated with serum alanine aminotransferase (ALT) levels in patients with chronic viral hepatitis, and that the expression of costimulatory molecules on circulating CD11c +DCs in patients with chronic viral hepatitis was significantly up-regulated in patients with high serum levels of ALT. Both DCs are also identified in the livers by flow cytometry, and the expression of costimulatory molecule CD40 on those DCs was significantly higher in liver DCs than that in circulating DCs. Moreover, the ratios of CD11c +DCs/CD123 +DCs were higher in liver DCs (mean±SD, 7.2±6.0) than those of circulating DCs (4.0±4.6). Immunohistochemically, CD11c + or CD123 + cells and CD83 + activated DCs were observed mostly in portal areas with mononuclear cell infiltration in various liver diseases. These overall data suggest that DCs, especially CD11c +DCs, could be associated with the necroinflammatory response in the liver of chronic viral liver diseases. Conclusions: DCs, especially CD11c +DCs, may be involved in the immunopathogenesis of chronic liver diseases.