IL-33 receptor expression on myeloid and plasmacytoid dendritic cells after allergen challenge in patients with allergic rhinitis

The diversity of immune responses in allergic diseases is critically mediated by dendritic cells (DCs), including myeloid and plasmacytoid DCs. Allergen inhalation increased the release of IL-33 from patients with allergic rhinitis (AR), which affecting the downstream cells by binding to its receptor (ST2). However, the effects of inhaled allergens on the expression of ST2 by DCs and IL-33 on the function of mDCs are unknown. The levels of ST2⁺mDCs and ST2⁺pDCs in the blood from patients with AR and healthy subjects were examined using flow cytometry. Moreover, the patients were challenged using the allergens and the levels of ST2⁺mDCs and ST2⁺pDCs were investigated at different time points. We found that there were higher levels of ST2⁺ mDCs and ST2⁺ pDCs in patients with AR, and these levels were further increased 0.5 h after allergen inhalation. Additionally, the type 2 immune response was upregulated after challenge. IL-33 treatment increased the expression of ST2 on mDCs. Our study demonstrated that ST2 was upregulated on DCs after allergen inhalation and that mDCs responded directly to IL-33 through ST2, suggesting that the IL-33/ST2 axis might play an important role in the pathogenesis of allergic rhinitis by DCs.

Dendritic cells and their associated pro-inflammatory cytokines augment to the inflammatory milieu in vitiligo skin

BACKGROUND AND AIM

Vitiligo is a progressive, autoimmune, hypomelanotic acquired disorder of skin which is characterized by depigmentation. The initial immunological events of this diseases are still at enigma that includes breach of immune tolerance, and defect in antigen presentation. Hence, we aimed to explore role of Dendritic cells (DCs) and its associated cytokines in the pathogenesis of generalized vitiligo (GV) patients.

METHODOLOGY

For this case-control study, 20 active patients and controls were enrolled. Phenotypic characterization of myeloid and plasmacytoid DCs (mDCs, pDCs) were done by flow-cytometry. Primary culture of DCs was done by monocyte differentiation supplemented with rIL-4 and rGM-CSF. Functional analysis DCs related cytokines and co-stimulatory molecules (CD80, CD40) was done by ELISA and qPCR respectively. Tissue localization of DCs was evaluated by immunohistochemistry.

RESULT

The frequency of mDCs (0.3715% v/s 0.188%) and pDCs (0.2331% v/s 0.1156%) were elevated in patients as compared to controls. Circulatory level of IL-12, TNF-α were significantly higher whereas IFN-α was decreased in patients than controls. Similar results were obtained in the culture supernatants of patients. Relative mRNA expression profiling of co-stimulatory molecules (CD80, CD40) were found to be up regulated in patient's skin. Tissue localization of Langerhans cells (Langerin, CD1a⁺) were found to be significantly higher in patients.

CONCLUSION

Elevated frequency of mDCs and pDCs along with elevated levels of IL-12, TNF-α and CD80, CD40 may contribute in defective antigen presentation of DCs. Altered pro-inflammatory and anti-inflammatory cytokines along with tissue localization of Langerhans cells might be involved in the pathogenesis of GV. These DCs associated cytokines can be explored as a therapeutic target in future.

Dendritic cell responses to Plasmodium falciparum in a malaria-endemic setting

Background

Plasmodium falciparum causes the majority of malaria cases worldwide and children in sub-Saharan Africa are the most vulnerable group affected. Non-sterile clinical immunity that protects from symptoms develops slowly and is relatively short-lived. Moreover, current malaria vaccine candidates fail to induce durable high-level protection in endemic settings, possibly due to the immunomodulatory effects of the malaria parasite itself. Because dendritic cells play a crucial role in initiating immune responses, the aim of this study was to better understand the impact of cumulative malaria exposure as well as concurrent P. falciparum infection on dendritic cell phenotype and function.

Methods

In this cross-sectional study, the phenotype and function of dendritic cells freshly isolated from peripheral blood samples of Malian adults with a lifelong history of malaria exposure who were either uninfected (n = 27) or asymptomatically infected with P. falciparum (n = 8) was assessed. Additionally, plasma cytokine and chemokine levels were measured in these adults and in Malian children (n = 19) with acute symptomatic malaria.

Results

With the exception of lower plasmacytoid dendritic cell frequencies in asymptomatically infected Malian adults, peripheral blood dendritic cell subset frequencies and HLA-DR surface expression did not differ by infection status. Peripheral blood myeloid dendritic cells of uninfected Malian adults responded to in vitro stimulation with P. falciparum blood-stage parasites by up-regulating the costimulatory molecules HLA-DR, CD80, CD86 and CD40 and secreting IL-10, CXCL9 and CXCL10. In contrast, myeloid dendritic cells of asymptomatically infected Malian adults exhibited no significant responses above the uninfected red blood cell control. IL-10 and CXCL9 plasma levels were elevated in both asymptomatic adults and children with acute malaria.

Conclusions

The findings of this study indicate that myeloid dendritic cells of uninfected adults with a lifelong history of malaria exposure are able to up-regulate co-stimulatory molecules and produce cytokines. Whether mDCs of malaria-exposed individuals are efficient antigen-presenting cells capable of mounting an appropriate immune response remains to be determined. The data also highlights IL-10 and CXCL9 as important factors in both asymptomatic and acute malaria and add to the understanding of asymptomatic P. falciparum infections in malaria-endemic areas.

Age and sex determine CD4+ T cell stimulatory and polarizing capacity of rat splenic dendritic cells

The study investigated influence of sex and age on splenic myeloid dendritic cells (DCs) from Dark Agouti rats. Freshly isolated DCs from young males exhibited less mature phenotype and greater endocytic capacity compared with those from age-matched females. Upon LPS stimulation in vitro they were less potent in stimulating allogeneic CD4+ cells in mixed leukocyte reaction (MLR), due to lower expression of MHC II, and greater NO and IL-10 production. In accordance with higher TGF-β production, young male rat DCs were less potent in stimulating IL-17 production in MLR than those from young females. Irrespective of sex, endocytic capacity and responsiveness of DCs to LPS stimulation in culture, judging by their allostimulatory capacity in MLR decreased with age, reflecting decline in MHC II surface density followed by their greater NO production; the effects more prominent in females. Additionally, compared with LPS-stimulated DCs from young rats, those from sex-matched aged rats were more potent in stimulating IL-10 production in MLR, whereas capacity of DCs from aged female and male rats to stimulate IL-17 production remained unaltered and decreased, respectively. This reflected age-related shift in IL-6/TGF-β production level ratio in LPS-stimulated DC cultures towards TGF-β, and sex-specific age-related remodeling CD4+ cell cytokine pathways. Additionally, compared with LPS-stimulated DCs from young rats, those cells from sex-matched aged rats were less potent in stimulating IFN-γ production in MLR, the effect particularly prominent in MLRs encompassing male rat DCs. The study showed that stimulatory and polarizing capacity of DCs depends on rat sex and age.

High expression of BTLA and B7-H4 on the surface of myeloid dendritic cells has a negative regulatory effect on their anti-tuberculosis immunity activity in pleural tuberculosis patients

To investigate the effects of the surface markers B- and T-lymphocyte attenuator (BTLA) and B7 homologous body 4 (B7-H4) on expression of CD83, and Human Leukocyte Antigen-DR isotype (HLA-DR) that can activate dendritic cells (DCs). Flow cytometry was used to detect the co-expression of BTLA and B7-H4 on myeloid DCs (mDCs) in peripheral blood (PB) and pleural effusions (PE) in 15 volunteers and 20 tuberculous pleurisy (TP) patients. Co-expression of BTLA and B7-H4 (double positive (DP)) mDCs in PB and PE of TP patients were enhanced. The proportion of DP mDC in PB decreased markedly after 2 weeks treatment, but was still greater than in controls. Expression of CD83 and HLA-DR on DP mDCs was higher than on BTLA and B7-H4 double negative (DN) expressing mDCs in PB of different TP groups. Expression of CD83 on DP mDCs in PB and PE of TP patients was greater than that of controls. Expression of HLA-DR on DP mDCs in TP patient PB was lower than in TP PE and controls. In pleural tuberculosis (TB) patients, high expression of BTLA and B7-H4 promoted a high level of CD83 and HLA-DR, which had a negative regulatory effect on mDCs on anti-TB immunity.

[Anti-lung cancer effect of myeloid and plasmacytoid dendritic cell combined vaccines loaded with tumor cell lysates in vitro]

Objective: To investigate the feasibility of myeloid and plasmacytoid dendritic cell combined vaccines loaded with heat-treated Lewis lung cancer cell lysates for treatment of lung cancer in mice. Methods: Bone marrow cells were induced by the recombinant mouse fms-like tyrosine kinase receptor 3 ligand (rmFlt3-L) in vitro, myeloid dendritic cells (mDC) and plasmacytoid dendritic cells (pDC) were separated by magnetic beads. The mDC, pDC, and mDC∶pDC=1∶1 were stimulated with heat-treated Lewis lung cancer cell lysates, respectively. The effects of each group on stimulating of lymphocyte proliferation and inducing of T cell to kill tumor cells in vitro were compared. The alternations of the immunophenotypes of CD80, CD86, CD40 and major histocompatibility complex Ⅱ (MHC-Ⅱ) were detected by flow cytometry. The secretion of cytokines including interlukin-12 (IL-12), interlukin-6 (IL-6), and tumor necrosis factor α (TNF-α) were detected by enzyme-linked immunosorbent assay (ELISA). Results: The lymphocyte proliferation in mice stimulated with mDC+ pDC group loaded with heat-treated Lewis lung cancer cell lysates was 10.80±0.66, significantly higher than 8.63±0.65 of mDC group and 7.10±0.46 pDC group under the same culture conditions, respectively (P<0.05). When the ratio of effector cells: target cells (E∶T) was 10∶1, the killing rate of the mDC+ pDC group loaded with heat-treated tumor cell lysate was 31.68%±2.93%, significantly higher than 17.44%±0.97% of mDC group and 10.29%±1.33% of pDC group, respectively (P<0.05). When the ratio of E∶T was 20∶1, the killing rate of the mDC+ pDC group loaded with heat-treated tumor cell lysate was 54.77%±3.28%, significantly higher than 35.25%±1.51% of mDC group and 15.52%±0.73% of pDC group, respectively (P<0.05). When the ratio of E∶T was 40∶1, the killing rate of the mDC+ pDC group loaded with heat-treated tumor cell lysate was 73.01%±0.91%, significantly higher than 51.36%±0.58% of mDC group and 22.65%±1.28% of pDC group, respectively (P<0.05). With the rate of E∶T increased, the killing rate also increased. The mean fluorescence intensities of surface molecules including CD80, CD86, CD40 and MHC-Ⅱ of mDC: pDC=1 group pulsed with heat-treated Lewis lung cancer cell lysates were higher than those of mDC group and pDC group. The IL-6 cytokine concentrations of mDC+ pDC group, mDC group and pDC group loaded with heat-treated Lewis lung cancer cell lysates were (586.67±52.52) pg/ml, (323.33±67.14) pg/ml and (166.67±16.07) pg/ml, respectively. The concentrations of IL-12 in each group were (2 568.75±119.24) pg/ml, (2 156.25±120.55) pg/ml and (672.92±31.46) pg/ml, respectively. The concentrations of TNF-α in each group were (789.33±48.08) pg/ml, (584.89±116.49) pg/ml and (291.56±40.73) pg/ml, respectively. The concentrations of IL-6, IL-12 and TNF-α secreted by mDC+ pDC group were much higher than those of mDC group and pDC group under the same culture conditions (P<0.05). Conclusions: The mDCs and pDCs combined vaccines pulsed with heat-treated Lewis lung cancer cell lysates have synergistic effects on inducing of T lymphocyte proliferation and killing tumor cells in vitro. This synergistic anti-tumor effect is related with up-regulation of co-stimulatory molecules and increased secretion of cytokines.

The Expression of ILT4 in Myeloid Dendritic Cells in Patients with Hepatocellular Carcinoma

Immunoglobulin-like transcript (ILT) 4 is an inhibitory immune receptor of the immunoglobulin superfamily, which could deliver inhibitory signals and induce immunosuppression. The significance of the expression of ILT4 in mDCs subsets in patients with hepatocellular carcinoma (HCC) remains unclear. In this study, the frequency of mDCs subsets in the peripheral blood of 121 patients with HCC and 103 normal controls, and in the tumor and tumor free liver tissues (TFL) of 43 HCC patients was analyzed by flow cytometry. Then, the expressions of ILT4 in mDCs subsets in the microenvironment of liver cancer were also analyzed. Results showed that the percentage of CD1c⁺ subset was dramatically decreased in peripheral blood mononuclear cells (PBMCs) of HCC patients compared with normal controls, and also significantly decreased in tumor tissue compared with the TFL. The decreased of CD1c⁺ subset in blood could be a diagnostic factor for HCC with the area under the receiver operating characteristic curve 0.975 (P < 0.01). The percentage of ILT4⁺CD1c⁺ subset was dramatically increased in tumor than that of TFL and blood. There were significant correlations between the percentage of ILT4⁺ in CD1c⁺ subset in tumor and that of in blood. The percentage of ILT4⁺CD1c⁺ subset in tumor tissue was strongly associated with the Edmondson-Steiner stage in HCC (P = 0.03). Furthermore, the capacity of ILT4⁺CD1c⁺ subset producing IFN-γ was lower than ILT4^- CD1c subset in PBMC of HCC patients following Poly I:C stimulation. Taken together, the increased ILT4⁺CD1c⁺ subset in tumor tissue might play an important role in immune suppression for patients with HCC.

The clinical application of cancer immunotherapy based on naturally circulating dendritic cells

Dendritic cells (DCs) can initiate and direct adaptive immune responses. This ability is exploitable in DC vaccination strategies, in which DCs are educated ex vivo to present tumor antigens and are administered into the patient with the aim to induce a tumor-specific immune response. DC vaccination remains a promising approach with the potential to further improve cancer immunotherapy with little or no evidence of treatment-limiting toxicity. However, evidence for objective clinical antitumor activity of DC vaccination is currently limited, hampering the clinical implementation. One possible explanation for this is that the most commonly used monocyte-derived DCs may not be the best source for DC-based immunotherapy. The novel approach to use naturally circulating DCs may be an attractive alternative. In contrast to monocyte-derived DCs, naturally circulating DCs are relatively scarce but do not require extensive culture periods. Thereby, their functional capabilities are preserved, the reproducibility of clinical applications is increased, and the cells are not dysfunctional before injection. In human blood, at least three DC subsets can be distinguished, plasmacytoid DCs, CD141⁺ and CD1c⁺ myeloid/conventional DCs, each with distinct functional characteristics. In completed clinical trials, either CD1c⁺ myeloid DCs or plasmacytoid DCs were administered and showed encouraging immunological and clinical outcomes. Currently, also the combination of CD1c⁺ myeloid and plasmacytoid DCs as well as the intratumoral use of CD1c⁺ myeloid DCs is under investigation in the clinic. Isolation and culture strategies for CD141⁺ myeloid DCs are being developed. Here, we summarize and discuss recent clinical developments and future prospects of natural DC-based immunotherapy.

The clinical application of cancer immunotherapy based on naturally circulating dendritic cells

Dendritic cells (DCs) can initiate and direct adaptive immune responses. This ability is exploitable in DC vaccination strategies, in which DCs are educated ex vivo to present tumor antigens and are administered into the patient with the aim to induce a tumor-specific immune response. DC vaccination remains a promising approach with the potential to further improve cancer immunotherapy with little or no evidence of treatment-limiting toxicity. However, evidence for objective clinical antitumor activity of DC vaccination is currently limited, hampering the clinical implementation. One possible explanation for this is that the most commonly used monocyte-derived DCs may not be the best source for DC-based immunotherapy. The novel approach to use naturally circulating DCs may be an attractive alternative. In contrast to monocyte-derived DCs, naturally circulating DCs are relatively scarce but do not require extensive culture periods. Thereby, their functional capabilities are preserved, the reproducibility of clinical applications is increased, and the cells are not dysfunctional before injection. In human blood, at least three DC subsets can be distinguished, plasmacytoid DCs, CD141+ and CD1c+ myeloid/conventional DCs, each with distinct functional characteristics. In completed clinical trials, either CD1c+ myeloid DCs or plasmacytoid DCs were administered and showed encouraging immunological and clinical outcomes. Currently, also the combination of CD1c+ myeloid and plasmacytoid DCs as well as the intratumoral use of CD1c+ myeloid DCs is under investigation in the clinic. Isolation and culture strategies for CD141+ myeloid DCs are being developed. Here, we summarize and discuss recent clinical developments and future prospects of natural DC-based immunotherapy.

Circulating Plasmacytoid and Myeloid Dendritic Cells in Breast Cancer Patients: A Pilot Study

Purpose

Dendritic cells (DC) are a class of bone marrow-derived cells found in the blood, epithelia, and lymphoid tissues, and are the most efficient antigen presenting cells. The number and function of DC can change dramatically in cancer patients. The aim of this study is to correlate the levels of circulating DC subsets with clinical characteristics in breast cancer patients.

Methods

Peripheral blood samples were collected from 53 untreated breast cancer patients before surgery between January 2013 and November 2013. Forty-one healthy, age-matched volunteers served as the control group. The phenotypes of circulating plasmacytoid DCs (pDCs) and myeloid DCs (mDCs) were determined using fluorescence activated cell sorting assays. Correlations between DCs immunophenotypes and clinicopathologic characteristics of these breast cancer patients were then determined.

Results

Patients with breast cancer had higher levels of pDCs (p = 0.046). No relationships were observed with tumor stage and intrinsic subtype. Estrogen receptor (ER) positive patients had higher levels of mDCs than ER negative patients (p = 0.025) and human epidermal growth factor receptor 2 (HER-2) positive patients had higher levels of pDCs than HER-2 (p = 0.040). No relationships were observed with T stage, N stage, Ki67 index, histologic grade, nuclear grade, and lymphovascular invasion. In multiple regression analysis, patients with HER-2 positive breast cancer had higher levels of pDCs than HER-2 negative patients (p = 0.026).

Conclusion

An increase of pDCs in the peripheral blood of breast cancer patients was observed and patients with HER-2 positive breast cancer had higher levels of circulating pDCs than did HER-2 negative patients. Our results suggest that expression of DCs can differ according to breast cancer subtype and indicate that, with further investigation, DC expression has the possibility of being presented as a prognostic factor.

Expansion and activation of distinct central memory T lymphocyte subsets in complex regional pain syndrome

Background

Complex regional pain syndrome (CRPS) is a debilitating condition where trauma to a limb results in devastating persistent pain that is disproportionate to the initial injury. The pathophysiology of CRPS remains unknown; however, accumulating evidence suggests it is an immunoneurological disorder, especially in light of evidence of auto-antibodies in ~ 30% of patients. Despite this, a systematic assessment of all circulating leukocyte populations in CRPS has never been performed.

Methods

We characterised 14 participants as meeting the Budapest clinical criteria for CRPS and assessed their pain ratings and psychological state using a series of questionnaires. Next, we performed immunophenotyping on blood samples from the 14 CRPS participants as well as 14 healthy pain-free controls using mass cytometry. Using a panel of 38 phenotypic and activation markers, we characterised the numbers and intracellular activation status of all major leukocyte populations using manual gating strategies and unsupervised cluster analysis.

Results

We have shown expansion and activation of several distinct populations of central memory T lymphocytes in CRPS. The number of central memory CD8⁺ T cells was increased 2.15-fold; furthermore, this cell group had increased phosphorylation of NFkB and STAT1 compared to controls. Regarding central memory CD4⁺ T lymphocytes, the number of Th1 and Treg cells was increased 4.98-fold and 2.18-fold respectively, with increased phosphorylation of NFkB in both populations. We also found decreased numbers of CD1c⁺ myeloid dendritic cells, although with increased p38 phosphorylation. These changes could indicate dendritic cell tissue trafficking, as well as their involvement in lymphocyte activation.

Conclusions

These findings represent the first mass cytometry immunophenotyping study in any chronic pain state and provide preliminary evidence of an antigen-mediated T lymphocyte response in CRPS. In particular, the presence of increased numbers of long-lived central memory CD4⁺ and CD8⁺ T lymphocytes with increased activation of pro-inflammatory signalling pathways may indicate ongoing inflammation and cellular damage in CRPS.

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.

Immune aberrations in children with Autism Spectrum Disorder: a case-control study from a tertiary care neuropsychiatric hospital in India

Multiple studies have identified the presence of peripheral immune aberrations in subjects with Autism Spectrum Disorder (ASD). However, comprehensive assessment of these peripheral immune aberrations, in the cellular and systemic compartments, in a single group of subjects with ASD is lacking. We assessed proportions of various subsets of immune cells in peripheral blood (T helper cells, T regulatory cells, B cells, monocytes, Natural Killer cells, dendritic cells) by multi-parametric flow cytometry in 50 children with ASD and compared it with thirty healthy controls matched for age, gender, socio-economic status and body mass index. There were no significant differences noted in the proportion of T regulatory cells, B cells, monocytes and Natural Killer cells, between ASD subjects and controls. On the contrary, the proportion of activated Th17 and myeloid dendritic cells were significantly higher in children with ASD. Based on these findings, group comparison of serum levels of Th17 cytokines (interleukin-6, interleukin-17A) was performed. Elevated serum levels of interleukin-6 and interleukin-17A in children with ASD corroborated our immunophenotyping findings. We did not find any significant differences among the pro-inflammatory (interleukin-1β), Th1 (interferon-γ) and Th2 (interleukin-4) cytokines. This is the first evidence with concurrent findings from immunophenotyping and cytokine data demonstrating activation of the Th17 pathway in subjects with ASD. This finding assumes significance in the light of recent maternal immune activation mouse model study that has highlighted the role of Th17 pathway in the pathophysiology of ASD. Future longitudinal studies are needed to clarify the role of this dysregulated immune pathway in the development of ASD.

Role of relevant immune-modulators and cytokines in hepatocellular carcinoma and premalignant hepatic lesions

AIM

To assess the levels of different immune modulators in patients with hepatocellular carcinoma (HCC), in relation to other hepatic diseases.

METHODS

Eighty-eight patients were included in the current study and represented patients with HCC (20), liver cirrhosis (28) and chronic hepatitis (CH; 25), and normal controls (NC; 15). Peripheral blood was isolated for immunophenotyping of active myeloid dendritic cells (mDCs; CD1c and CD40), mature inactive myeloid cells (CD1c and HLA), active plasmacytoid cells (pDCs; CD303 and CD40), mature inactive pDCs (CD30 and HLA), active natural killer (NK) cells (CD56 and CD161), active NK cells (CD56 and CD314) and inactive NK cells (CD56 and CD158) was done by flow cytometry. Serum levels of interleukin (IL)-2, IL-10, IL-12, IL-1β, interferon (IFN)-α, IFN-γ and tumor necrosis factor (TNF)-αR2 were assessed by ELISA.

RESULTS

Active mDCs (CD1C+/CD40+) and inactive mDCs (CD1c+/HLA+) were significantly decreased in HCC patients in relation to NC (P < 0.001). CD40+ expression on active pDCs was decreased in HCC patients (P < 0.001), and its level was not significantly changed among other groups. Inactive pDCs (CD303+/HLA+), inactive NKs (CD56+/CD158+) and active NKs (CD56+/CD161+) were not statistically changed among the four groups studied; however, the latter was increased in CH (P < 0.05). NKG2D was statistically decreased in HCC, CH and cirrhosis (P < 0.001), and it was not expressed in 63% (12/20) of HCC patients. There was significant decrease of IL-2, IFN-α and IFN-γ (P < 0.001), and a significant increase in IL-10, IL-1β, and TNF-αR2 (P <0.01, P < 0.001 and P < 0.001; respectively) in HCC patients. There was inverted correlation between IL-12 and IL-1β in HCC (r = -0.565, P < 0.01), with a strong correlation between pDCs (CD303+/CD40+) and NKs (CD56+/CD161+; r = 0.512, P < 0.05) as well as inactive mDCs (CD1c+/HLA+) and inactive NK cells (CD56+/CD158+; r = 0.945, P < 0.001).

CONCLUSION

NKG2D, CD40, IL-2 and IL-10 are important modulators in the development and progression of HCC.

Increased frequencies of circulating CXCL10-, CXCL8- and CCL4-producing monocytes and Siglec-3-expressing myeloid dendritic cells in systemic sclerosis patients

Objective

To investigate the ex vivo pro-inflammatory properties of classical and non-classical monocytes as well as myeloid dendritic cells (mDCs) in systemic sclerosis (SSc) patients.

Methods

Spontaneous production of CXCL10, CCL4, CXCL8 and IL-6 was intracellularly evaluated in classical, non-classical monocytes and Siglec-3-expressing mDCs from peripheral blood of SSc patients and healthy controls (HC) through flow cytometry. In addition, production of these cytokines was determined upon toll-like receptor (TLR) 4 plus Interferon-γ (IFN-γ) stimulation.

Results

The frequency of non-classical monocytes spontaneously producing CXCL10 was increased in both limited (lcSSc) and diffuse cutaneous (dcSSC) subsets of SSc patients and CCL4 was augmented in dcSSc patients. The proportion of CCL4-producing mDCs was also elevated in dcSSc patients and the percentage of mDCS producing CXCL10 only in lcSSc patients. Upon stimulation, the frequency of non-classical monocytes expressing CXCL8 was increased in both patient groups and mDCs expressing CXCL8 only in lcSSc. Moreover, these parameters in unsupervised clustering analysis identify a subset of patients which are characterized by lung fibrosis and reduced pulmonary function.

Conclusions

These data point towards a role of activated non-classical monocytes and mDCs producing enhanced levels of proinflammatory cytokines in SSc, potentially contributing to lung fibrosis.

Electronic supplementary material

The online version of this article (10.1007/s00011-017-1106-7) contains supplementary material, which is available to authorized users.

Altered distribution of peripheral blood dendritic cell subsets in patients with pulmonary paracoccidioidomycosis

Paracoccidioidomycosis (PCM) is a systemic mycosis caused by fungi from the genus Paracoccidioides in Latin America. PCM-patients (PCM-p) are classified as having acute/subacute or chronic (CF) clinical forms. CF is responsible for 75%-90% of all cases, affects mainly adults over 30 years old and the clinical manifestation are associated mainly with lungs and mucosa of upper airdigestive tract. In addition, the CF patients exhibit fibrosis of the lungs, oral mucous membranes and adrenals, and pulmonary emphysema. Consequently, CF PCM-p with active disease, as well as those that have been apparently cured, seem to be an interesting model for studies aiming to understand the long-term host-fungi relationship and hypoxia. Dendritic cells (DCs) constitute a system that serve as a major link between innate and adaptive immunity composed of several subpopulations of cells including two main subsets: myeloid (mDCs) and plasmacytoid (pDCs). The present study aimed to access the distribution of PBDC subsets of CF PCM-p who were not treated (NT) or treated (apparently cured - AC). CF PCM-p were categorized into two groups, consisting of 9 NTs and 9 ACs. Twenty-one healthy individuals were used as the control group. The determination of the PBDC subsets was performed by FACS (fluorescence-activated cell sorting) and the dosage of serum TNF-α, IL1β, IL-18, CCL3, IL-10 and basic fibroblast growth factor (bFGF) by ELISA (enzyme-linked immunosorbent assay). A high count and percentage of mDCs was observed before treatment, along with a low count of pDCs in treated patients. Furthermore, the mDC:pDC ratio and serum levels of TNF-α was higher in both of the PCM-p groups than in the control group. In conclusion, our findings demonstrated that active PCM influences the distribution of mDCs and pDCs, and after treatment, PCM-p retained a lower count of pDCs associated with pro-inflammatory profile. Therefore, we identified new evidences of persistent immunological abnormalities in PCM-p after treatment. Even these patients showing fungal clearance after successful antifungal treatment; the hypoxia, triggered by the persistent pulmonary sequelae, possibly continues to interfere in the immune response.

Myeloid dendritic cells exhibit defects in activation and function in patients with multiple sclerosis

BACKGROUND

Regulatory T cells (Tregs) are functionally defective in patients with multiple sclerosis (MS) and this dysfunction is related to an imbalanced composition of naïve and memory Treg subtypes. Several lines of evidence indicate that these abnormalities might result from a premature decline in thymic-dependent Treg neogenesis. Myeloid dendritic cells (mDCs) critically determine Treg differentiation in the thymus, and thymic stromal lymphopoietin receptor (TSLPR) expressed on mDCs is a key component of the signaling pathways involved in this process. TSLPR-expression on mDCs was previously shown to be decreased in MS. We hypothesized that functional alterations in mDCs contribute to aberrant Treg neogenesis and, in turn, to altered Treg homeostasis and function in MS.

METHODS

We recruited blood samples from 20 MS patients and 20 healthy controls to assess TSLPR expression on mDCs ex vivo by flow cytometry and by activating mDCs induced by recombinant TSLP (rhTSLP) in vitro. As previous studies documented normalization of both function and homeostasis of Tregs under immunomodulatory (IM) therapy with interferon-beta (IFN-beta) and glatiramer acetate (GA), we also tested phenotypes and function of mDCs obtained from IM-treated patients (IFN-beta: n=20, GA: n=20).

RESULTS

We found that TSLP-induced mDC activation and effector function in vitro was reduced in MS and correlated with TSLPR-expression levels on mDCs. IM treatment prompted upregulation of TSLPR on mDCs and an increase in TSLP-induced activation of mDCs together with a normalization of Treg homeostasis.

CONCLUSION

The decreased TSLP-induced activation of MS-derived mDCs in vitro, together with the reduced density of TSLPR on the cell surface of mDCs corroborates the hypothesis of mDCs being critically involved in impairing Treg development in MS.

Mesenchymal Stromal Cells Prevent Allostimulation In Vivo and Control Checkpoints of Th1 Priming: Migration of Human DC to Lymph Nodes and NK Cell Activation

Although the immunomodulatory potency of mesenchymal stromal cells (MSC) is well established, the mechanisms behind are still not clear. The crosstalk between myeloid dendritic cells (mDC) and natural killer (NK) cells and especially NK cell-derived interferon-gamma (IFN-γ) play a pivotal role in the development of type 1 helper (Th1) cell immune responses. While many studies explored the isolated impact of MSC on either in vitro generated DC, NK, or T cells, there are only few data available on the complex interplay between these cells. Here, we investigated the impact of MSC on the functionality of human mDC and the consequences for NK cell and Th1 priming in vitro and in vivo. In critical limb ischemia patients, who have been treated with allogeneic placenta-derived mesenchymal-like stromal cells (PLX-PAD), no in vivo priming of Th1 responses toward the major histocompatibility complex (MHC) mismatches could be detected. Further in vitro studies revealed that mDC reprogramming could play a central role for these effects. Following crosstalk with MSC, activated mDC acquired a tolerogenic phenotype characterized by reduced migration toward CCR7 ligand and impaired ability to stimulate NK cell-derived IFN-γ production. These effects, which were strongly related to an altered interleukin (IL)-12/IL-10 production by mDC, were accompanied by an effective prevention of Th1 priming in vivo. Our findings provide novel evidence for the regulation of Th1 priming by MSC via modulation of mDC and NK cell crosstalk and show that off-the-shelf produced MHC-mismatched PLX-PAD can be used in patients without any sign of immunogenicity.

High salt drives Th17 responses in experimental autoimmune encephalomyelitis without impacting myeloid dendritic cells

Recently, we have shown that high dietary salt intake aggravates T helper cell (Th) 17 responses and neuroinflammation. Here, we employed in vitro assays for myeloid dendritic cell (mDC) maturation, DC cytokine production, T cell activation and ex vivo analyses in murine experimental autoimmune encephalomyelitis (EAE) to investigate whether the salt effect on Th17 cells is further mediated through DCs in vivo. In cell culture, an excess of 40mM sodium chloride did neither affect the generation, maturation nor the function of DCs, but, in different assays, significantly increased Th17 differentiation. During the initiation phase of MOG35-55 EAE, we did not observe altered DC frequencies or co-stimulatory capacities in lymphoid organs, while IL-17A production and Th17 cells in the spleen were significantly increased. Complementary ex vivo analyses of the spinal cord during the effector phase of EAE showed increased frequencies of Th17 cells, but did not reveal differences in phenotypes of CNS invading DCs. Finally, adaption of transgenic mice harboring a MOG specific T cell receptor to a high-salt diet led to aggravated clinical disease only after active immunization. Wild-type mice adapted to a high-salt diet in the effector phase of EAE, bypassing the priming phase of T cells, only displayed mildly aggravated disease. In summary, our data argue for a direct effect of NaCl on Th17 cells in neuroinflammation rather than an effect primarily exerted via DCs. These data may further fuel our understanding on the dietary impact on different immune cell subsets in autoimmune diseases, such as multiple sclerosis.

Altered dendritic cell subset distribution in patients with Parkinson's disease: Impact of CMV serostatus

Parkinson's disease (PD) is characterised by low-level systemic inflammation, which may be at least partly due to pathophysiological activation of immunity. Here, the frequencies of different types of circulating dendritic cells (DCs) with and without a pro-inflammatory phenotype were determined in PD patients and controls. A high proportion of older people is infected with cytomegalovirus (CMV), which acts as a chronic antigenic stressor that could also contribute to increased inflammation. Following this idea, we found higher frequencies of myeloid DCs with a pro-inflammatory CD16+ILT2(high) phenotype in CMV-positive PD patients than controls, suggesting the potential involvement of CMV in exacerbating PD.

Sera from patients with active systemic lupus erythematosus patients enhance the toll-like receptor 4 response in monocyte subsets

Background

Systemic Lupus Erythematosus (SLE) is an auto-immune disease whose complex pathogenesis remains unraveled. Here we aim to explore the inflammatory ability of SLE patients’ sera upon peripheral blood (PB) monocyte subsets and myeloid dendritic cells (mDCs) obtained from healthy donors.

Methods

In this study we included 11 SLE patients with active disease (ASLE), 11 with inactive disease (ISLE) and 10 healthy controls (HC). PB from healthy donors was stimulated with patients’ sera, toll-like receptor (TLR) 4 ligand – lipopolysaccharide or both. The intracellular production of TNF-α was evaluated in classical, non-classical monocytes and mDCs, using flow cytometry. TNF-α mRNA expression was assessed in all these purified cells, after sera treatment.

Results

We found that sera of SLE patients did not change spontaneous TNF-α production by monocytes or dendritic cells. However, upon stimulation of TLR4, the presence of sera from ASLE patients, but not ISLE, significantly increased the intracellular expression of TNF-α in classical and non-classical monocytes. This ability was related to titers anti-double stranded DNA antibodies in the serum. High levels of anti-TNF-α in the patients’ sera were associated with increased TNF-α expression by co-cultured mDCs. No relationship was found with the levels of a wide variety of other pro-inflammatory cytokines. A slight increase of TNF-α mRNA expression was observed in these purified cells when they were cultured only in the presence of SLE serum.

Conclusions

Our data suggest that SLE sera induce an abnormal in vitro TLR4 response in classical and non-classical monocytes, reflected by a higher TNF-α intracellular expression. These effects may be operative in the pathogenesis of SLE.

Dendritic cells in hepatitis C virus infection: key players in the IFNL3-genotype response

Recently, single nucleotide polymorphisms, in the vicinity of the interferon lambda 3 (IFNL3) gene have been identified as the strongest predictor of spontaneous and treatment induced clearance of hepatitis C virus (HCV) infection. Since then, increasing evidence has implicated the innate immune response in mediating the IFNL3 genotype effect. Dendritic cells (DCs) are key to the host immune response in HCV infection and their vital role in the IFNL3 genotype effect is emerging. Reports have identified subclasses of DCs, particularly myeloid DC2s and potentially plasmacytoid DCs as the major producers of IFNL3 in the setting of HCV infection. Given the complexities of dendritic cell biology and the conflicting current available data, this review aims to summarize what is currently known regarding the role of dendritic cells in HCV infection and to place it into context of what is know about lambda interferons and dendritic cells in general.

Two functionally distinct myeloid dendritic cell subpopulations are present in bovine blood

Immature myeloid (m)DCs circulating in the blood of cattle have been defined as lineage negative (Lin(-))MHCII(+)CD11c(+)CD205(+) cells. Lin(-)MHCII(+)CD11c(+)CD205(+) mDCs (0.2% blood mononuclear cells) isolated from bovine blood were heterogeneous in cell size and CD205 expression. Using highspeed cell sorting, Lin(-)MHCII(+)CD11c(+)CD205(+) DCs were sorted into CD205(Hi) and CD205(Lo) subpopulations which were phenotypically distinct and differed significantly (P<0.01) in TLR gene expression. CD205(Hi) and CD205(Lo) mDCs were more efficient in macropinocytosis than monocytes and expressed no or little detectable non-specific esterase activity. CD205(Lo) mDCs efficiently activated purified allogeneic T cells and the addition of TLR agonists did not significantly alter this antigen presentation capacity. T cell activation by CD205(Lo) mDCs was associated with differential up-regulation of CD40, CD80, CD86 and TGFβ1 gene expression when compared to CD205(Hi) mDCs. In conclusion, two phenotypically and functionally distinct CD11c(+)CD205(+) mDCs were isolated from blood that had an equal capacity to acquire antigen but markedly different capacities to activate T cells.

Flow cytometry assay of myeloid dendritic cells (mDCs) in peripheral blood during acute hepatitis C: Possible pathogenetic mechanisms

AIM: To asses the expression of myeloid dendritic cells (CD11c+) subset during acute HCV hepatitis and its possible involvement in natural history of the infection.

METHODS: We enrolled 11 patients with acute hepatitis C (AHC) (Group A), 10 patients with acute hepatitis A (AHA) (as infective control-Group B) and 10 healthy donors (group C) in this study. All patients underwent selective flow cytometry gating strategies to assess the peripheral number of the myeloid dendritic cells (mDCs) to understand the possible role and differences during acute hepatitis.

RESULTS: Eight of 11 patients with acute HCV hepatitis did not show any increase of mDCs compared to healthy individuals, while a significant decrease of mDCs was found in absolute cell count (z = -2.37; P < 0.05) and percentage (z= -2.30; P < 0.05) as compared with AHA. On the contrary, The remaining three patients of the group A had a higher mDCs number and percentage as occur in group B. Interestingly, after six months, those patients did not show any increase of mDCs subset were chronically infected. while the three subjects with an increase of peripheral mDCs, as in HAV acute infection, resolved the illness.

CONCLUSION: The lack of increase of mDCs during acute hepatitis C might be an important factor involved in chronicization of the infection.