Search Results (198)

The development of FGFR1-driven stem cell leukemia and lymphoma syndrome (SCLL) in mouse models is accompanied by an increase in highly heterogenous myeloid derived suppressor cells (MDSCs), which promote immune evasion. To dissect this heterogeneity, we used a combination of CyTOF and scRNA-Seq to define the phenotypes and genotypes of these MDSCs. CyTOF demonstrated increased levels of circulating macrophages in the peripheral blood of leukemic mice, and flow cytometry demonstrated that these macrophages were derived from Ly6C^Hi M-MDSC as well as the Ly6C^Int and Ly6C^Low monocytic populations. Consistently, scRNA-Seq analysis demonstrated the accumulation of non-classical monocytes (ncMono) during leukemia progression, which also express macrophage markers. These leukemia-induced macrophages show continuous transcriptional reprogramming during leukemia progression, with the upregulation of cellular stress response genes Hspa1a and Hspa1b and inflammation-related gene Nfkbia. Trajectory analysis revealed a transition from classical monocytes (cMono) to ncMono, and potential genes orchestrating this transition process have been identified. Furthermore, T-cell suppression assays demonstrated the immune suppressive abilities of leukemia-induced circulatory macrophages. Targeting these macrophages with the GW2580 CSF1R inhibitor leads to restored immune surveillance and improved survival. Overall, we demonstrate that circulating macrophages are responsible, at least in part, for the immune suppression in SCLL leukemia models, and targeting macrophages in this system improves the survival of leukemic mice. Full article

Background: Bovine alphaherpesvirus 1 (BoAHV-1) is a major respiratory and reproductive pathogen in cattle worldwide. Both innate and adaptive immune responses contribute to protection against this virus; however, virus-host interactions remain partly undefined. In this study, the impact of BoAHV-1 infection on calves’ immune responses was investigated in detail. Methods: Six calves were intranasally infected with wild-type BoAHV-1, and blood samples were collected longitudinally. Leukocyte subset dynamics were assessed by complete haematological assay and flow cytometry, while multiplex ELISA was used to quantify serum levels of ten cytokines. For each parameter, post-infection values (days 2, 4, 8, 10, and 14) were compared with pre-infection baseline values (day 0). Results: Infection induced an initial phase of immunosuppression, reflected by decreased circulating αβ and γδ-T cells. However, infected animals rapidly developed a protective immune response, characterised by increased circulating classical and intermediate monocytes and elevated levels of the related chemokine MIP-1β. Early post-infection, rises in serum IFN-γ and IL-10 were also detected. Conclusions: Our data suggest that monocyte recruitment and increased serum levels of IFN-γ and IL-10 are positively associated with the ability to overcome infection. A better understanding of the immunopathogenic mechanisms underlying BoAHV-1 infection will support the development of more effective vaccines against this virus. Full article

Background/Objectives: Acne vulgaris can be non-inflammatory lesions, i.e., closed comedones, open comedones, inflammatory lesions, i.e., papules, pustules, cysts, and post-acne lesions. This study aimed to evaluate the expression of TLR2 and TLR4 receptors on classical, intermediate, and non-classical monocyte subpopulations in 38 women with acne vulgaris and to correlate the results with clinical features of the disease and selected skin parameters. Methods: The skin parameters were assessed: level of oiliness, hydration, pH, skin pigmentation (phototype, erythema) using a special diagnostic device (Scientific multi-probe system MPA 6, Courage + Khazaka) with simultaneous determination of monocyte subpopulations in peripheral blood expressing TLR2 and TLR4 using a CytoflexLX flow cytometer (Beckman Coulter). Results: In the study group, the percentage of non-classical monocytes expressing TLR2 was statistically significantly lower than the classical and intermediate monocytes expressing TLR2 (p < 0.001). However, the level of TLR2 receptor expression (MFI) was significantly higher on intermediate monocytes compared to the level of TLR2 expression on classical and non-classical monocytes. In the group of patients with post-acne lesions, a statistically significantly higher percentage of non-classical monocytes with TLR4 expression was observed compared to patients without post-acne lesions (p = 0.009). A statistically significant negative correlation was also observed between the percentage of intermediate and non-classical monocytes with TLR4 expression and the results of the mexameter measurements. Acne has a significant impact on the percentage of monocyte subpopulations expressing TLR2 and TLR4. A higher percentage of non-classical monocytes TLR4+ in the blood is associated with a higher incidence of post-acne lesions. Conclusions: The positive correlation between the degree of skin hydration and the level of TLR2 expression on classical monocytes suggests that these cells play an important role in skin homeostasis and defense against C. acnes. Proper acne care is not only important for aesthetic aspects, but may also have a positive impact on immunological phenomena. Full article

Chikungunya fever (CF), caused by the Chikungunya virus (CHIKV), is characterized by disabling symptoms such as joint pain that can last for months. Monocytes play a central role in immune modulation and viral replication during infection. This study evaluated the clinical and immunological profiles of patients with laboratory-confirmed CF. Fever and joint pain were the most frequently reported symptoms, whereas edema was more common in women. CHIKV-infect individuals exhibited increased TLR4 expression in non-classical monocytes (CD14+CD16++). Additionally, intermediate (CD14+CD16+) and non-classical (CD14+CD16++) monocytes expressing TLR7 were enriched during the acute phase and in some chronic patients, thereby suggest prolonged TLR7 pathway activation. Levels of soluble CD163 (sCD163)—a marker of monocyte/macrophage activation—were elevated as well, indicating sustained immune activation. Coagulation-related mediators—including Tissue factor (TF) and Tissue factor pathway inhibitor (TFPI)—also increased, despite the rarity of hemorrhagic events or thrombocytopenia. Patients with arthritis demonstrated higher frequencies of TLR7+ intermediate monocytes and elevated Epidermal growth factor (EGF) levels, whereas those with edema exhibit increased Vascular endothelial growth factor (VEGF) levels. Overall, these findings highlighted the differential activation of CD16+ monocytes and suggested that sCD163 is a marker of monocyte/macrophage activation during CHIKV infection. Full article

Alpha-1 antitrypsin deficiency (AATD) represents a paradigmatic genetic disorder with well-characterized hepatic manifestations but relatively underexplored pulmonary implications. While liver involvement has been extensively reviewed, the underlying mechanisms of lung disease progression remain poorly understood, particularly regarding immunological pathways and inflammatory processes. The pathophysiology involves defective alpha-1 antitrypsin (AAT) production, including AAT variants that induce neutrophil elastase activity, causing progressive alveolar destruction and sustained inflammation, leading to emphysema, as one of the main components of chronic obstructive pulmonary disease (COPD). AATD and smoking represent major risk factors for COPD, the third leading cause of death worldwide at present. In AATD patients, neutrophils, which constitute the majority of circulating leukocytes, become dysregulated. Under normal conditions, cells perform essential functions, including phagocytosis and neutrophil extracellular trap formation (NETosis); in AATD, however, they accumulate excessively in alveolar spaces due to impaired elastase control. The accumulation of Z-AAT polymers within epithelial cells creates a pathological cycle, acting as chemoattractants that sustain pro-inflammatory responses and contribute to chronic obstructive pulmonary disease development. In addition, monocytes, representing a smaller fraction of leukocytes, migrate to inflammatory sites and differentiate into macrophages while secreting AAT with anti-inflammatory properties. However, in PiZZ patients, this protective mechanism fails, as polymer accumulation within cells reduces both AAT secretion and the number of protective human leukocyte antigen(HLA)-DR-monocyte subsets. In particular, macrophages demonstrate remarkable plasticity, switching between pro-inflammatory M1 (classically activated macrophages) and tissue-repairing M2 (alternatively activated macrophages) phenotypes based on environmental cues. In AATD, this adaptive capability becomes compromised due to intracellular polymer accumulation, leading to impaired phagocytic function and dysregulated cytokine production and ultimately perpetuating chronic inflammation and progressive tissue damage. Recent advances in induced pluripotent stem cell (iPSC) technology have facilitated alveolar epithelial cell (AEC) generation, in addition to the correction of AATD mutations through gene editing systems. Despite the limitations of AAT correction, iPSC-derived organoid models harboring AATD mutations can deliver important insights into disease pathophysiology, while gene editing approaches help demonstrate causality between specific mutations and observed phenotypes. Therefore, in this review, we investigated recent studies that can serve as tools for gene editing and drug development based on recently developed iPSC-related technologies to understand the pathogenesis of AATD. Full article

Objective: Anifrolumab is approved for systemic lupus erythematosus (SLE). Its off-label use in non-systemic cutaneous lupus erythematosus (NSCLE) remains poorly characterized. We aimed to assess its effectiveness and safety in refractory NSCLE, supported by a literature review and exploratory immunologic analysis. Methods: This multicenter observational study included patients with NSCLE treated with anifrolumab. Skin disease was assessed using the Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI). CLASI scores at baseline were compared to months 1, 3, and 6. A narrative literature review was also conducted. In a subset of three patients, peripheral blood immunophenotyping was performed before and after treatment to explore immunologic surrogate markers associated with clinical response. Results: Fifteen patients (11 women; mean age 52.1 ± 11.7 years) were included. All had received topical corticosteroids and hydroxychloroquine. Most of them had failed multiple systemic therapies. Anifrolumab (300 mg IV every 4 weeks) was used in combination (n = 12) or as monotherapy (n = 3). All patients improved. Median CLASI-A decreased from 16 to 1 (p < 0.001); CLASI-D decreased from 5 to 4 (p < 0.001). The literature review identified 6 publications reporting 14 additional cases of NSCLE with similar outcomes and minimal adverse effects. Immunologic profiling pointed to an increase in intermediate and non-classical and decreased PD-1 expression in monocytes and NK cells after 12 weeks of treatment. Conclusions: Anifrolumab appears effective and relatively safe in refractory NSCLE. Preliminary immunologic data suggest changes in peripheral blood monocyte subsets and NK cells. However, these findings must be confirmed in prospective, controlled clinical trials. Full article

Background/Objectives: Inflammation-based markers have emerged as potential prognostic tools in hepatocellular carcinoma (HCC), but comparative data with classical prognostic factors in untreated HCC are limited. This study aimed to evaluate and compare the prognostic performance of inflammatory and conventional markers using Harrell’s concordance index (C-index). Methods: This retrospective study included 250 patients with untreated HCC. Prognostic variables included age, BCLC stage, Child–Pugh classification, Milan criteria, MELD score, AFP, albumin, Charlson comorbidity index, and the inflammation-based markers neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), Systemic Inflammation Response Index (SIRI), and Systemic Immune-inflammation Index (SIII). Survival was analyzed using Cox regression. Predictive performance was assessed using the C-index, Akaike Information Criterion (AIC), and likelihood ratio tests. Results: Among the classical markers, BCLC showed the highest predictive performance (C-index: 0.717), while NLR ranked highest among the inflammatory markers (C-index: 0.640), above the MELD score and Milan criteria. In multivariate analysis, NLR ≥ 2.3 remained an independent predictor of overall survival (HR: 1.787; 95% CI: 1.264–2.527; p < 0.001), along with BCLC stage, albumin, Charlson index, and Milan criteria. Including NLR in the model modestly improved the C-index (from 0.781 to 0.794) but significantly improved model fit (Δ–2LL = 10.75; p = 0.001; lower AIC). Conclusions: NLR is an accessible, cost-effective, and independent prognostic marker for overall survival in untreated HCC. It shows discriminative power comparable to or greater than most conventional predictors and may complement classical stratification tools for HCC. Full article

Background: Chronic cytomegalovirus (CMV) infection may favor the development of immunosenescence and inflammation that impair vaccine responses, including COVID-19. In addition, the polymorphism of the interferon-lambda gene (IFNλ) affects COVID-19 immune responses in older adults. Objective: We aimed to investigate the impact of IFNλ polymorphism (IL28B gene-rs12979860) on the immune/inflammatory response to vaccination with CoronaVac for COVID-19 in older adults who were CMV-seropositive. Methods: Blood samples from 42 CMV-seropositive older adults (73.7 ± 4.5 years) were collected before and 30 days after immunization with a second dose of the CoronaVac vaccine to evaluate the immune/inflammatory response. Results: At genotyping, 20 subjects were homozygous for the C/C alleles (Allele-1 group), 5 were homozygous for the T/T Alleles (Allele-2 group), and 17 were heterozygous (C/T, Alleles-1/2 group). The Allele-1 group showed higher IgG levels for COVID-19 (p = 0.0269) and intermediate monocyte percentage (p = 0.017), in contrast to a lower non-classical monocyte percentage (p = 0.0141) post-vaccination than pre-vaccination. Also, this group showed that IgG levels for CMV were positively associated with a systemic pro-inflammatory state and senescent T cells (CD4+ and CD8+). The Allele-2 group presented higher IFN-β levels at pre- (p = 0.0248) and post-vaccination (p = 0.0206) than the values in the Allele-1 and Alleles-1/2 groups, respectively. In addition, the Allele-2 and Alleles-1/2 groups showed that IgG levels for COVID-19 were positively associated with a balanced systemic inflammatory state. Conclusion: CMV-seropositivity in older adults who had Allele-1 could lead to an unbalanced systemic inflammatory state, which may impair their antibody response to COVID-19 vaccination compared to other volunteer groups. Full article

Innate immune cells appear to have an important implication in the resolution and/or the aggravation of the COVID-19 pathogenesis after infection with SARS-CoV-2. To better appreciate the role of these cells during COVID-19, changes in blood eosinophil, the neutrophil and monocyte count, and levels of surface protein markers have been reported. However, analyses at several timepoints of multiple surface markers on granulocytes and monocytes over a period of one month after a SARS-CoV-2 infection are missing. Therefore, in this study, we performed blood eosinophil, neutrophil, and monocyte phenotyping using a list of surface proteins and flow cytometry during a period of 30 days after the hospitalization of patients with severe SARS-CoV-2 infections. Blood cell counts were reported at seven different timepoints over the 30-day period as well as measures of multiple mediators in serum using a targeted multiplex assay approach. Our results indicate a 95% drop in the blood eosinophil count by D1, with eosinophils displaying a phenotype defined as CD69/CD63/CD125^high and CCR3/CD44^low during the early phases of hospitalization. Conversely, by D7 the neutrophil count increased significantly and displayed an immature, activated, and immunosuppressive phenotype (i.e., 3% of CD10/CD16^low and CD10^lowCD177^high, 6.7% of CD11b^highCD62L^low, and 1.6% of CD16^highCD62L^low), corroborated by enhanced serum proteins that are markers of neutrophil activation. Finally, our results suggest a rapid recruitment of non-classical monocytes leaving CD163/CD64^high and CD32^low monocytes in circulation during the very early phase. In conclusion, our study reveals potential very early roles for eosinophils and monocytes in the pathogenesis of COVID-19 with a likely reprogramming of eosinophils in the bone marrow. The exact roles of the pro-inflammatory neutrophils and the functions of the eosinophils and the monocytes, as well as these innate immune cell types, interplays need to be further investigated. Full article

Classical BCR-ABL-negative myeloproliferative neoplasms are a heterogeneous group of hematologic malignancies, including essential thrombocythemia, polycythemia vera, and primary myelofibrosis. Monocytes, immune cells derived from hematopoietic stem cells, exhibit significant heterogeneity and contribute to immune regulation through cytokine secretion and differentiation into dendritic cells and macrophages. Aberrant monocytes are associated with the prognosis of MPNs, particularly PMF. Furthermore, these altered monocytes play a critical role in the pathogenesis and progression of MPNs. This review aims to explore the heterogeneity of different monocyte subsets during homeostasis and focuses on the potential mechanisms by which monocytes contribute to the development and progression of MPNs. Full article

Muscle dystrophies are a group of genetic disorders characterized by progressive muscle degeneration. Prednisone is a glucocorticoid drug widely used to prevent muscle weakness in these diseases. Despite its known beneficial role, the effect of intermittent delivery on monocytes’ polarization and on dystrophic muscle microenvironment has not yet been thoroughly investigated. In this study, our aim was to identify the phenotype of monocyte subsets in blood and the expression of fibrosis-related genes in dystrophic muscle biopsies in patients receiving intermittent prednisone therapy. We found an increased rate of classical monocytes and a decreased rate of non-classical monocytes that expressed anti-inflammatory marker CD206 in treated patients. In dystrophic muscles, 21 fibrosis-related genes were altered, among which we identified CCAAT/enhancer-binding protein beta CEBPB. Both classical monocytes and CEBPB are known for their roles in stimulating collagen 1 production, a probable marker hampering monocyte/macrophage function. Hence, in some patients with muscular dystrophy, intermittent prednisone treatment could shift the monocytes’ phenotype toward an M2, senescent-like profile. This seems to decrease the inflammatory infiltrate in muscle tissue, an observation that needs to be further confirmed. Full article

Diclofenac is an effective medication for pain and inflammation. However, its use has been linked to hepatitis. To gain insight into diclofenac’s ability to cause hepatitis, we investigated the regulation of major effectors of the immune system following daily treatment of minipigs at 3 and 15 mg/kg for 28 days. Histopathology evidenced lobular inflammation, and through a combination of immunogenomics and immunopathology, we detected marked innate and adaptive immune responses. We identified 109 significantly regulated genes linked to neutrophil, monocyte, Kupffer cell, and lymphocyte responses and 32 code for cytokine- and interferon-γ-signaling. In support of wound repair, immunopathology evidenced manifest upregulation of macrophage migration inhibitory factor and CD74. Furthermore, the strong expression of IgG and IgM underscored humoral immune responses. Diclofenac caused an activation of the complement system, especially the C1 inhibitor of the classical pathway and C3 with critical functions in liver regeneration. The marked expression of complement factor B and H of the alternate pathway modulated B-cell responses. Likely, the upregulation of factor H protected hepatocytes from injury by limiting complement-mediated damage of inflamed cells. Additionally, diclofenac treatment elicited marked hepatic expression of lysozyme and KLF6. The latter earmarks M1-polarized Kupffer cells. We observed an extraordinary induction of calprotectin/S100A9 and of the monocyte/macrophage CD163 scavenger receptor, and therefore, we detected innate immune sensing of damaged cells. Lastly, we noted an unprecedented induction of the acute phase reactant SAA1 and DEC-205, which recognize apoptotic and necrotic cells. Together, our results offer mechanistic insights into immune-mediated liver injury patterns following diclofenac treatment. Full article

Bovine viral diarrhea virus (BVDV) is a globally prevalent pathogen causing severe detriment to the cattle industry. Vertical infection occurring before the development of the fetal adaptive immune response, before 125 days of gestation, results in an immunotolerant, persistently infected (PI) calf. It was hypothesized that epigenetic alterations observed in the splenic tissue of PI fetuses at gestational day 245 would persist into the postnatal period. White blood cell DNA from five PI and five control heifers at 4 months of age was subjected to reduced representation bisulfite sequencing and interpreted within the context of complete blood count and flow cytometry data herein. Analysis revealed 8367 differentially methylated sites contained within genes associated with the immune and cardiac system, as well as hematopoiesis. Differences observed in the complete blood counts of PI heifers include increased monocytes, microcytic anemia, and elevated platelets with decreased mean platelet volume. Flow cytometry revealed increased classical monocytes, B cells, and CD4⁺/CD8B⁺ and CD25⁺/CD127⁻ T cells, as well as decreased γδ⁺, CD4⁺, and CD4⁻/CD8B⁻ T cells. Investigation of the PI methylome provides a new perspective on the mechanisms of pathologies and provides potential biomarkers for the rapid identification of PI cattle. Full article

Elite controllers (ECs) represent a unique subset of people living with HIV (PLWHs), who can suppress viral replication without requiring antiretroviral therapy (ART). However, despite this viral control, ECs exhibit increased incidences of various comorbid conditions and heightened systemic inflammation, which has been linked to monocyte activation. In this study, we performed an in-depth phenotypic analysis of monocytes in a cohort of long-term ECs (LTECs) and compared them to non-controller patients with ART-mediated control of HIV replication and to non-controller patients with uncontrolled viral replication. A total of 67 participants were included: 22 LTECs, 15 non-controllers on ART (onART), 10 non-controllers without ART (offART), and 20 uninfected controls (UCs) as a reference group. Monocyte phenotypes were analyzed using spectral flow cytometry with a 13-marker panel. The data were analyzed using two approaches: (a) FCS Express software v.7 to define different subsets of monocytes and assess the levels of expression of eight different monocyte functional markers and (b) R software v.4.1.1 for unsupervised multidimensional analysis, including batch correction, dimensionality reduction, and clustering analysis. Monocyte phenotypic profiling was conducted using three different approaches: (1) assessment of monocyte subsets (classical, intermediate, and non-classical monocytes); (2) evaluation of the levels of expression of eight monocyte functional markers, and (3) characterization of monocyte clusters defined through the dimensionality reduction of flow cytometry data (56 different clusters). The monocyte phenotype of the onART group closely resembled that of the UC group. In contrast, LTECs exhibited important alterations in the monocyte phenotype compared to that of the UCs, including (a) an increased proportion of intermediate monocytes and a decreased proportion of classical monocytes (p < 0.01), (b) altered expressions of functional markers across monocyte subsets (p < 0.05), and (c) alterations in sixteen different monocyte clusters (twelve decreased and four increased, p < 0.05). Many of these alterations were also observed when comparing the LTEC and onART groups. Our findings suggest that monocyte-driven mechanisms may contribute to HIV control in LTECs; however, some of these alterations could also promote systemic inflammation and immune activation. These observations provide a compelling rationale for considering therapeutic interventions in this unique population of PLWHs. Full article

New roles for immune cells, overcoming the classical cytotoxic response, have been highlighted by growing evidence. The immune cells, such as neutrophils, monocytes/macrophages, and eosinophils, are versatile cells involved in the release of web-like DNA structures called extracellular traps (ETs) which represent a relevant mechanism by which these cells prevent microbes’ dissemination. In this process, many enzymes, such as elastase, myeloperoxidase (MPO), and microbicidal nuclear and granule proteins, which contribute to the clearance of entrapped microorganisms after DNA binding, are involved. However, an overproduction and release of ETs can cause unwanted and dangerous effects in the host, resulting in several pathological manifestations, among which are chronic inflammatory disorders, autoimmune diseases, cancer, and diabetes. In this review, we discuss the release mechanisms and the double-edged sword role of ETs both in physiological and in pathological contexts. In addition, we evaluated some possible strategies to target ETs aimed at either preventing their formation or degrading existing ones. Full article