Immune checkpoint regulation is critically involved in canine cutaneous histiocytoma regression.

Introduction: Canine cutaneous histiocytoma (CCH) is a benign tumor frequently occurring in young dogs which is derived from Langerhans cells (LC). Distinguishing features of this tumor are its spontaneous regression following a rapid tumor growth. Impaired control of immune checkpoints during tumor development and progression is a widespread phenomenon which may result in an absent or ineffective immune response. The interaction between the inflammatory response and the expression of immune checkpoint molecules is only partially described in this tumor type. The aim of this study was to identify immune checkpoint molecules and molecules from the interferon-mediated immune response that are involved in the regression of CCH. Methods: Forty-eight CCH derived from dogs ≤ 4 years of age were assigned to one of four groups according to the severity and distribution of lymphocyte infiltration. Using immunohistochemistry and whole-slide image scans of consecutive sections the expression of programmed death protein ligand 1 (PD-L1), CD80, CD86, Survivin, forkhead box protein 3, Ki-67, cleaved caspase-3, CD3, and mx1 were investigated. RNA in-situ hybridization was performed for transcripts of mx1 and interferon-γ. Results: Neoplastic cells showed an expression of PD-L1, CD80, CD86, and Survivin. The density of CD80 expressing cells was negatively correlated with regression while the density of cleaved caspase-3 positive cells increased with regression. Mx1 transcripts and protein were predominantly localized in neoplastic cells while interferon-γ transcripts were most frequently detected in T-cells. Conclusion: The expression of the immune checkpoint molecules CD86 and PD-L1 and particularly the reduced expression of CD80 in groups 3 and 4 indicate an influence of the investigated immune checkpoints on tumor regression. In parallel an activation of the apoptotic cascade during regression is suggested. Finally, the detection of mx1 within the neoplasm pinpoints to a yet undisclosed role of anti-cellular signaling in tumor immunity.

Altered Monocyte and Lymphocyte Phenotypes Associated with Pathogenesis and Clinical Efficacy of Progestogen Therapy for Peritoneal Endometriosis in Adolescents.

Background: Immunological imbalances characteristic of endometriosis may develop as early as the primary manifestations of the disease in adolescence. Objective: To evaluate subpopulation dynamics of monocytes and lymphocytes in peripheral blood and peritoneal fluid of adolescents with peritoneal endometriosis at diagnosis and after 1-year progestogen therapy. Methods: This study included 70 girls, 13-17 years old, diagnosed laparoscopically with peritoneal endometriosis (n = 50, main group) or paramesonephric cysts (n = 20, comparison group). Phenotypes of monocytes and lymphocytes of the blood and macrophages of the peritoneal fluid were analyzed by flow cytometry at diagnosis and during progestogen therapy. Results: Differential blood counts of CD16+ (p < 0.001) and CD86+ (p = 0.017) monocytes were identified as independent risk factors for peritoneal endometriosis in adolescents. During the treatment, cytotoxic lymphocytes CD56dimCD16bright (p = 0.049) and CD206+ monocytes (p < 0.001) significantly increased while CD163+ monocytes decreased in number (p = 0.017). The CD56dimCD16bright blood counts before (p < 0.001) and during progestogen therapy (p = 0.006), as well as CD206+ blood counts during the treatment (p = 0.038), were associated with the efficacy of pain relief after 1-year progestogen therapy. Conclusions: Adolescents with peritoneal endometriosis have altered counts of pro- and anti-inflammatory monocytes and lymphocytes both before and after 1-year progestogen therapy, correlating with treatment efficacy and justifying long-term hormonal therapy.

Aberrant innate immune profile associated with COVID-19 mortality in Pretoria, South Africa.

The African continent reported the least number of COVID-19 cases and deaths of all the continents, although the exact reasons for this are still unclear. In addition, little is known about the immunological profiles associated with COVID-19 mortality in Africa. The present study compared clinical and immunological parameters, as well as treatment outcomes in patients admitted with COVID-19 in Pretoria, South Africa, to determine if these parameters correlated with mortality in this population. The in-hospital mortality rate for the cohort was 15.79%. The mortality rate in people living with HIV (PLWH) was 10.81% and 17.16% in people without HIV (p = 0.395). No differences in age (p = 0.099), gender (p = 0.127) or comorbidities were found between deceased patients and those who survived. All four of the PLWH who died had a CD4+ T-cell count <200 cells/mm3, a significantly higher HIV viral load than those who survived (p = 0.009), and none were receiving antiretroviral therapy. Seven of 174 (4%) patients had evidence of auto-antibodies neutralizing Type 1 interferons (IFNs). Two of the them died, and their presence was significantly associated with mortality (p = 0.042). In the adjusted model, the only clinical parameters associated with mortality were: higher fraction of inspired oxygen (FiO2) (OR: 3.308, p = 0.011) indicating a greater need for oxygen, high creatinine (OR: 4.424, p = 0.001) and lower platelet counts (OR: 0.203, p = 0.009), possibly secondary to immunothrombosis. Overall, expression of the co-receptor CD86 (p = 0.021) on monocytes and percentages of CD8+ effector memory 2 T-cells (OR: 0.45, p = 0.027) was lower in deceased patients. Decreased CD86 expression impairs the development and survival of effector memory T-cells. Deceased patients had higher concentrations of RANTES (p = 0.003), eotaxin (p = 0.003) and interleukin (IL)-8 (p < 0.001), all involved in the activation and recruitment of innate immune cells. They also had lower concentrations of transforming growth factor (TGF)-ß1 (p = 0.40), indicating an impaired anti-inflammatory response. The immunological profile associated with COVID-19 mortality in South Africa points to the role of aberrate innate immune responses.

Human Dendritic Cell Maturation Is Modulated by Leishmania mexicana through Akt Signaling Pathway.

Dendritic cells (DC) along with macrophages are the main host cells of the intracellular parasite Leishmania. DC traverse a process of maturation, passing through an immature state with phagocytic ability to a mature one where they can modulate the immune response through the secretion of cytokines. Several studies have demonstrated that Leishmania inhibits DC maturation. Nevertheless, when cells are subjected to a second stimulus such as LPS/IFN-γ, they manage to mature. In the maturation process of DC, several signaling pathways have been implicated, importantly MAPK. On the other hand, Akt is a signaling pathway deeply involved in cell survival. Some Leishmania species have shown to activate MAPK and Akt in different cells. The aim of this work was to investigate the role of ERK and Akt in the maturation of monocyte-derived DC (moDC) infected with L. mexicana. moDC were infected with L. mexicana metacyclic promastigotes, and the phosphorylation of ERK and Akt, the expression of MHCII and CD86 and IL-12 transcript, and secretion were determined in the presence or absence of an Akt inhibitor. We showed that L. mexicana induces a sustained Akt and ERK phosphorylation, while the Akt inhibitor inhibits it. Moreover, the infection of moDC downregulates CD86 expression but not MHCII, and the Akt inhibitor reestablishes CD86 expression and 12p40 production. Thus, L. mexicana can modulate DC maturation though Akt signaling.

Profiling of Tumor-Infiltrating Immune Cells and Their Impact on Survival in Glioblastoma Patients Undergoing Immunotherapy with Dendritic Cells.

Glioblastomas (GBM) are the most common primary malignant brain tumors, comprising 2% of all cancers in adults. Their location and cellular and molecular heterogeneity, along with their highly infiltrative nature, make their treatment challenging. Recently, our research group reported promising results from a prospective phase II clinical trial involving allogeneic vaccination with dendritic cells (DCs). To date, six out of the thirty-seven reported cases remain alive without tumor recurrence. In this study, we focused on the characterization of infiltrating immune cells observed at the time of surgical resection. An analytical model employing a neural network-based predictive algorithm was used to ascertain the potential prognostic implications of immunological variables on patients' overall survival. Counterintuitively, immune phenotyping of tumor-associated macrophages (TAMs) has revealed the extracellular marker PD-L1 to be a positive predictor of overall survival. In contrast, the elevated expression of CD86 within this cellular subset emerged as a negative prognostic indicator. Fundamentally, the neural network algorithm outlined here allows a prediction of the responsiveness of patients undergoing dendritic cell vaccination in terms of overall survival based on clinical parameters and the profile of infiltrated TAMs observed at the time of tumor excision.

Deciphering perivascular macrophages and microglia in the retinal ganglion cell layers.

Introduction: The classically defined two retinal microglia layers are distributed in inner and outer plexiform layers. Although there are some reports that retinal microglia are also superficially located around the ganglion cell layer (GCL) in contact with the vitreous, there has been a lack of detailed descriptions and not fully understood yet. Methods: We visualized the microglial layers by using CX3CR1-GFP (C57BL6) transgenic mice with both healthy and disease conditions including NaIO3-induced retinal degeneration models and IRBP-induced auto-immune uveitis models. Result: We found the GCL microglia has two subsets; peripheral (pph) microglia located on the retinal parenchyma and BAM (CNS Border Associated Macrophage) which have a special stretched phenotype only located on the surface of large retinal veins. First, in the pph microglia subset, but not in BAM, Galectin-3 and LYVE1 are focally expressed. However, LYVE1 is specifically expressed in the amoeboid or transition forms, except the typical dendritic morphology in the pph microglia. Second, BAM is tightly attached to the surface of the retinal veins and has similar morphology patterns in both the healthy and disease conditions. CD86+ BAM has a longer process which vertically passes the proximal retinal veins. Our data helps decipher the basic anatomy and pathophysiology of the retinal microglia in the GCL. Discussion: Our data helps decipher the basic anatomy and pathophysiology of the retinal microglia in the GCL.

Erratum: Microglial reactivity in brainstem chemosensory nuclei in response to hypercapnia.

[This corrects the article DOI: 10.3389/fphys.2024.1332355.].

Microglial reactivity in brainstem chemosensory nuclei in response to hypercapnia.

Microglia, the resident immune cells of the CNS, surveil, detect, and respond to various extracellular signals. Depending on the nature of these signals, an integrative microglial response can be triggered, resulting in a phenotypic transformation. Here, we evaluate whether hypercapnia modifies microglia phenotype in brainstem respiratory-related nuclei. Adult C57BL/6 inbred mice were exposed to 10% CO2 enriched air (hypercapnia), or pure air (control), for 10 or 30 min and immediately processed for immunohistochemistry to detect the ubiquitous microglia marker, ionized calcium binding adaptor molecule 1 (Iba1). Hypercapnia for thirty, but not 10 min reduced the Iba1 labeling percent coverage in the ventral respiratory column (VRC), raphe nucleus (RN), and nucleus tractus solitarius (NTS) and the number of primary branches in VRC. The morphological changes persisted, at least, for 60 min breathing air after the hypercapnic challenge. No significant changes were observed in Iba1+ cells in the spinal trigeminal nucleus (Sp5) and the hippocampus. In CF-1 outbred mice, 10% CO2 followed by 60 min of breathing air, resulted in the reduction of Iba1 labeling percent coverage and the number and length of primary branches in VRC, RN, and NTS. No morphological change was observed in Iba1+ cells in Sp5 and hippocampus. Double immunofluorescence revealed that prolonged hypercapnia increased the expression of CD86, an inflammatory marker for reactive state microglia, in Iba1+ cells in VRC, RN, and NTS, but not in Sp5 and hippocampus in CF-1 mice. By contrast, the expression of CD206, a marker of regulatory state microglia, persisted unmodified. In brainstem, but not in hippocampal microglia cultures, hypercapnia increased the level of IL1ß, but not that of TGFß measured by ELISA. Our results show that microglia from respiratory-related chemosensory nuclei, are reactive to prolonged hypercapnia acquiring an inflammatory-like phenotype.

Anti-allergic effect of vitamin C through inhibiting degranulation and regulating TH1/TH2 cell polarization.

BACKGROUND: Food allergy has become a global public health problem. This study aimed to explore the possible anti-allergic effect of vitamin C (VC). A rat basophilic leukemia (RBL)-2H3 cell degranulation model was used to assess the effect of VC on degranulation in vitro, and an ovalbumin (OVA)-induced BALB/c mouse allergy model was used to assess the anti-allergy effect of VC in vivo. RESULTS: In vitro, VC significantly attenuated the release of ß-hexosaminidase, tryptase and histamine, and also reduced cytokine production (interleukins 4 and 6, tumor necrosis factor α) significantly (P < 0.05), with the inhibitory effect demonstrating a positive correlation with VC dose. In vivo, compared with the OVA group, the levels of serum immunoglobulins E and G1 of the VC low-dose (VCL) group (50 mg kg-1) and high-dose (VCH) group (200 mg·kg-1) were significantly reduced (P < 0.05). Furthermore, the plasma histamine level was also significantly decreased (P < 0.05). Moreover, TH2 cell polarization in mice of the VCL and VCH groups was significantly inhibited (P < 0.05), promoting the TH1/TH2 cell polarization balance. Additionally, VC treatment enhanced the expression of CD80 (P < 0.05) in spleen and small intestine tissues, while significantly inhibiting the expression of CD86 (P < 0.05); notably, high-dose VC treatment was more effective. CONCLUSION: VC exerted an anti-allergic effect through inhibiting degranulation and regulating TH1/TH2 cell polarization balance. © 2024 Society of Chemical Industry.

An anti-CD19/CTLA-4 switch improves efficacy and selectivity of CAR T cells targeting CD80/86-upregulated DLBCL.

Chimeric antigen receptor T cell (CAR T) therapy is a potent treatment for relapsed/refractory (r/r) B cell lymphomas but provides lasting remissions in only ∼40% of patients and is associated with serious adverse events. We identify an upregulation of CD80 and/or CD86 in tumor tissue of (r/r) diffuse large B cell lymphoma (DLBCL) patients treated with tisagenlecleucel. This finding leads to the development of the CAR/CCR (chimeric checkpoint receptor) design, which consists of a CD19-specific first-generation CAR co-expressed with a recombinant CTLA-4-linked receptor with a 4-1BB co-stimulatory domain. CAR/CCR T cells demonstrate superior efficacy in xenograft mouse models compared with CAR T cells, superior long-term activity, and superior selectivity in in vitro assays with non-malignant CD19+ cells. In addition, immunocompetent mice show an intact CD80-CD19+ B cell population after CAR/CCR T cell treatment. The results reveal the CAR/CCR design as a promising strategy for further translational study.

MARCH-I: A negative regulator of dendritic cell maturation.

The expression of costimulatory molecules such as MHC-II, CD86 and CD83 on dendritic cells (DCs) are strongly regulated during cellular activation. Ubiquitination of some of these markers by the E3 ubiquitin ligase MARCH-I affects the maturation state of DCs and subsequently modulates immune responses. The effects of MARCH-I gene overexpression on the functional activity of human DCs is not well understood. Here, we investigate how MARCH-I, regulates maturation of DCs. We now provide evidence that MARCH-I transduced DCs secrete high levels of IL10 despite low secretion of IL 6 and IL 12 in response to LPS stimulation. They are weak stimulators of T lymphocyte cells but skewed T cell polarization toward T regulatory subset. These results exhibit that reduced expression of surface costimulatory molecules suppresses DC activation. It can be concluded that overexpression of MARCH-I gene in DCs leads to the production of tolerogenic DC.

Genome-wide transcriptional profiling and functional analysis of long noncoding RNAs and mRNAs in chicken macrophages associated with the infection of avian pathogenic E. coli.

BACKGROUND: Avian pathogenic E. coli (APEC) can cause localized or systemic infections, collectively known as avian colibacillosis, resulting in huge economic losses to poultry industry globally per year. In addition, increasing evidence indicates that long non-coding RNAs (lncRNAs) play a critical role in regulating host inflammation in response to bacterial infection. However, the role of lncRNAs in the host response to APEC infection remains unclear. RESULTS: Here, we found 816 differentially expressed (DE) lncRNAs and 1,798 DE mRNAs in APEC infected chicken macrophages by RNAseq. The identified DE lncRNA-mRNAs were involved in Toll like receptor signaling pathway, VEGF signaling pathway, fatty acid metabolism, phosphatidylinositol signaling system, and other types of O-glycan biosynthesis. Furthermore, we found the novel lncRNA TCONS_00007391 as an important immune regulator in APEC infection was able to regulate the inflammatory response by directly targeting CD86. CONCLUSION: These findings provided a better understanding of host response to APEC infection and also offered the potential drug targets for therapy development against APEC infection.

A better understanding of the role of the CTLA-CD80/86 axis in the treatment of autoimmune diseases.

Autoimmune diseases are diseases in which the regulatory mechanisms of the immune response are disturbed. As a result, the body loses self-tolerance. Since one of the main regulatory mechanisms of the immune response is the CTLA4-CD80/86 axis, this hypothesis suggests that autoimmune diseases potentially share a similar molecular basis of pathogenesis. Hence, investigating the CTLA4-CD80/86 axis may be helpful in finding an appropriate treatment strategy. Therefore, this study aims to investigate the molecular basis of the CTLA4-CD80/86 axis in the regulation of the immune response, and then its role in developing some autoimmune diseases, including systemic lupus erythematosus, rheumatoid arthritis, type 1 diabetes, and multiple sclerosis. As well, the main therapeutic strategies affecting the CTLA4-CD80/86 axis have been summarized to highlight the importance of this axis in management of autoimmune diseases.

Screening Allergenic Potencies of Skin-Contact Products Using the Human-Derived THP-1 Cell Activation Test.

With the prevalence of allergic contact dermatitis (ACD) from the usage of skin-contact products, like wearable, skin care, and hair care products, screening their skin sensitizing potential is necessary, for the sake of alleviating the consequent public health impact. In the present study, a total of 77 skin-contact products classified by four categories, watch bands (WBs), skin care products (SCPs), hair care products (HCPs), and rubber gloves (RGs), were investigated, using an optimized in vitro assay of human cell line activation test (h-CLAT). Extracting the products using neutral artificial sweat simulated well the practical usage scenarios, and testing the extracts showed that 26 of them were allergy test positive, including nine WBs, six SCPs, two HCPs, and nine RGs. The allergenic response was mainly characterized by the induction of CD54 expression, and diverse paradigms of CD54 and CD86 levels were observed by analyzing dose-response curves, which could also be influenced by the compromised viability of the THP-1 cells. The data implicated the intricate regulation by different contributors to suspicious ingredients in the test samples. Altogether, a promising methodology for testing skin allergy potential was well established for commonly used commodities by neutral artificial sweat extraction coupled with h-CLAT screening. The findings would be of great help in tracing the potential allergens in practical products and improving their qualities.

NK cells propagate T cell immunity following in situ tumor vaccination.

We report an in situ vaccination, adaptable to nearly any type of cancer, that combines radiotherapy targeting one tumor and intratumoral injection of this site with tumor-specific antibody and interleukin-2 (IL-2; 3xTx). In a phase I clinical trial, administration of 3xTx (with an immunocytokine fusion of tumor-specific antibody and IL-2, hu14.18-IL2) to subjects with metastatic melanoma increases peripheral CD8+ T cell effector polyfunctionality. This suggests the potential for 3xTx to promote antitumor immunity against metastatic tumors. In poorly immunogenic syngeneic murine melanoma or head and neck carcinoma models, 3xTx stimulates CD8+ T cell-mediated antitumor responses at targeted and non-targeted tumors. During 3xTx treatment, natural killer (NK) cells promote CTLA4+ regulatory T cell (Treg) apoptosis in non-targeted tumors. This is dependent on NK cell expression of CD86, which is upregulated downstream of KLRK1. NK cell depletion increases Treg infiltration, diminishing CD8+ T cell-dependent antitumor response. These findings demonstrate that NK cells sustain and propagate CD8+ T cell immunity following 3xTx.

Integrated analysis reveals the potential of cluster of differentiation 86 as a key biomarker in high-grade glioma.

This study aimed to evaluate the potential of cluster of differentiation 86 (CD86) as a biomarker in high-grade glioma (HGG). The TCGA and TCIA databases were used to obtain the CD86 expression value, clinical data, and MRI images of HGG patients. Prognostic values were assessed by the Kaplan-Meier method, Receiver operating characteristic curve (ROC), Cox regression, logistic regression, and nomogram analyses. CD86-associated pathways were also explored. We found that CD86 was significantly upregulated in HGG compared with the normal group. Survival analysis showed a significant association between CD86 high expression and shorter overall survival time. Its independent prognostic value was also confirmed. These results suggested the possibility of CD86 as a biomarker in HGG. We also innovatively established 2 radiomics models with Support Vector Machine (SVM) and Logistic regression (LR) algorithms to predict the CD86 expression. The 2 models containing 5 optimal features by SVM and LR methods showed similar favorable performance in predicting CD86 expression in the training set, and their performance were also confirmed in validation set. These results indicated the successful construction of a radiomics model for non-invasively predicting biomarker in HGG. Finally, pathway analysis indicated that CD86 might be involved in the natural killer cell-mediated cytotoxicity in HGG progression.

A human 3D immune competent full-thickness skin model mimicking dermal dendritic cell activation.

We have integrated dermal dendritic cell surrogates originally generated from the cell line THP-1 as central mediators of the immune reaction in a human full-thickness skin model. Accordingly, sensitizer treatment of THP-1-derived CD14-, CD11c+ immature dendritic cells (iDCs) resulted in the phosphorylation of p38 MAPK in the presence of 1-chloro-2,4-dinitrobenzene (DNCB) (2.6-fold) as well as in degradation of the inhibitor protein kappa B alpha (IκBα) upon incubation with NiSO4 (1.6-fold). Furthermore, NiSO4 led to an increase in mRNA levels of IL-6 (2.4-fold), TNF-α (2-fold) and of IL-8 (15-fold). These results were confirmed on the protein level, with even stronger effects on cytokine release in the presence of NiSO4: Cytokine secretion was significantly increased for IL-8 (147-fold), IL-6 (11.8-fold) and IL-1ß (28.8-fold). Notably, DNCB treatment revealed an increase for IL-8 (28.6-fold) and IL-1ß (5.6-fold). Importantly, NiSO4 treatment of isolated iDCs as well as of iDCs integrated as dermal dendritic cell surrogates into our full-thickness skin model (SM) induced the upregulation of the adhesion molecule clusters of differentiation (CD)54 (iDCs: 1.2-fold; SM: 1.3-fold) and the co-stimulatory molecule and DC maturation marker CD86 (iDCs ~1.4-fold; SM:~1.5-fold) surface marker expression. Noteworthy, the expression of CD54 and CD86 could be suppressed by dexamethasone treatment on isolated iDCs (CD54: 1.3-fold; CD86: 2.1-fold) as well as on the tissue-integrated iDCs (CD54: 1.4-fold; CD86: 1.6-fold). In conclusion, we were able to integrate THP-1-derived iDCs as functional dermal dendritic cell surrogates allowing the qualitative identification of potential sensitizers on the one hand, and drug candidates that potentially suppress sensitization on the other hand in a 3D human skin model corresponding to the 3R principles ("replace", "reduce" and "refine").

Immune Checkpoint Pathway Expression in Lymphocyte Subpopulations in Patients with Common Variable Immunodeficiency and Chronic Lymphocytic Leukemia.

This study aims to gain a deeper understanding of chronic lymphocytic leukemia (CLL) and common variable immunodeficiency (CVID) by studying immune cells and specific immune checkpoint signaling pathways. The analysis of the percentage of selected immune points and their ligands (PD-1/PD-L1, CTLA-4/CD86, and CD200R/CD200) on peripheral blood lymphocyte subpopulations was performed using flow cytometry, and additional analyses determining the serum concentration of the above-mentioned molecules were performed using enzyme immunoassay tests. The obtained results indicate several significant changes in the percentage of almost all tested molecules on selected subpopulations of T and B lymphocytes in both CVID and CLL patients in relation to healthy volunteers and between the disease subunits themselves. The results obtained were also supported by the analysis of the serum concentration of soluble molecules tested. By uncovering valuable insights, we hope to enhance our comprehension and management of these conditions, considering both immunodeficiencies and hematological malignancies. Understanding the role of these signaling pathways in disease development and progression may lead to the development of modern, personalized diagnostic and therapeutic strategies. Ultimately, this knowledge may enable the monitoring of the immune system in patients with CVID and CLL, paving the way for improved patient care in the future.

Role of monocytes and dendritic cells in cardiac reverse remodelling after cardiac resynchronization therapy.

BACKGROUND AND AIMS: Monocytes and dendritic cells (DC) are both key inflammatory cells, with recognized effects on cardiac repair. However, there are distinct subsets of monocytes with potential for beneficial or detrimental effects on heart failure (HF) pathogenesis. The connection between reverse cardiac remodelling, the potential anti-inflammatory effect of cardiac resynchronization therapy (CRT) and monocytes and DC homeostasis in HF is far from being understood. We hypothesized that monocytes and DC play an important role in cardiac reverse remodelling and CRT response. Therefore, we aimed to assess the potential role of baseline peripheral levels of blood monocytes and DC subsets and their phenotypic and functional activity for CRT response, in HF patients. As a secondary objective, we aimed to evaluate the impact of CRT on peripheral blood monocytes and DC subsets, by comparing baseline and post CRT circulating levels and phenotypic and functional activity. METHODS: Forty-one patients with advanced HF scheduled for CRT were included in this study. The quantification and phenotypic determination of classical (cMo), intermediate (iMo) and non-classical monocytes (ncMo), as well as of myeloid (mDC) and plasmacytoid DC (pDC) were performed by flow cytometry in a FACSCanto™II (BD) flow cytometer. The functional characterization of total monocytes and mDC was performed by flow cytometry in a FACSCalibur flow cytometer, after in vitro stimulation with lipopolysaccharide from Escherichia coli plus interferon (IFN)-γ, in the presence of Brefeldina A. Comparisons between the control and the patient group, and between responders and non-responders to CRT were performed. RESULTS: Compared to the control group, HF population presented a significantly lower frequency of pDC at baseline and a higher proportion of monocytes and mDC producing IL-6 and IL-1ß, both before and 6-months after CRT (T6). There was a remarkable decrease of cMo and an increase of iMo after CRT, only in responders. The responder group also presented higher ncMo values at T6 compared to the non-responder group. Both responders and non-responders presented a decrease in the expression of CD86 in all monocyte and DC populations after CRT. Moreover, in non-responders, the increased frequency of IL-6-producing DC persisted after CRT. CONCLUSION: Our study provides new knowledge about the possible contribution of pDC and monocytes subsets to cardiac reverse remodelling and response to CRT. Additionally, CRT is associated with a reduction on CD86 expression by monocytes and DC subsets and in their potential to produce pro-inflammatory cytokines, contributing, at least in part, for the well described anti-inflammatory effects of CRT in HF patients.

Exploring the Significance of Immune Checkpoints and EBV Reactivation in Antibody Deficiencies with Near-Normal Immunoglobulin Levels or Hyperimmunoglobulinemia.

This study delves into the intricate landscape of primary immunodeficiencies, with a particular focus on antibody deficiencies characterized by near-normal immunoglobulin levels or hyperimmunoglobulinemia. Contrary to the conventional focus on genetic dysregulation, these studies investigate the key roles of immune checkpoints, such as PD-1/PD-L1, CTLA-4/CD86, and CD200R/CD200, on selected subpopulations of T and B lymphocytes and their serum concentrations of soluble forms in patients recruited for the studies in healthy volunteers. In addition, the studies also show the role of Epstein-Barr virus (EBV) reactivation and interactions with tested pathways of immune checkpoints involved in the immunopathogenesis of this disease. By examining the context of antibody deficiencies, this study sheds light on the nuanced interplay of factors beyond genetics, particularly the immune dysregulations that occur in the course of this type of disease and the potential role of EBV reactivation, which affects the clinical presentation of patients and may contribute to the development of cancer in the future, especially related to hematological malignancies.