Hallmarks of immune response in COVID-19: Exploring dysregulation and exhaustion.

One and half year following the occurrence of COVID-19 pandemic, significant efforts from laboratories all over the world generated a huge amount of data describing the prototypical features of immunity in the course of SARS-CoV-2 infection. In this Review, we rationalize and organize the main observations, trying to define a "core" signature of immunity in COVID-19. We identified six hallmarks describing the main alterations occurring in the early infection phase and in the course of the disease, which predispose to severe illness. The six hallmarks are dysregulated type I IFN activity, hyperinflammation, lymphopenia, lymphocyte impairment, dysregulated myeloid response, and heterogeneous adaptive immunity to SARS-CoV-2. Dysregulation and exhaustion came out as the trait d'union, connecting abnormalities affecting both innate and adaptive immunity, humoral and cellular responses.

Clonally expanded PD-1-expressing T cells are enriched in synovial fluid of juvenile idiopathic arthritis patients.

Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic condition in childhood. The disease etiology remains largely unknown; however, a key role in JIA pathogenesis is surely mediated by T cells. T-lymphocytes activity is controlled via signals, known as immune checkpoints. Delivering an inhibitory signal or blocking a stimulatory signal to achieve immune suppression is critical in autoimmune diseases. However, the role of immune checkpoints in chronic inflammation and autoimmunity must still be deciphered. In this study, we investigated at the single-cell level the feature of T cells in JIA chronic inflammation, both at the transcriptome level via single-cell RNA sequencing and at the protein level by flow cytometry. We found that despite the heterogeneity in the composition of synovial CD4+ and CD8+ T cells, those characterized by PD-1 expression were clonally expanded tissue-resident memory (Trm)-like cells and displayed the highest proinflammatory capacity, suggesting their active contribution in sustaining chronic inflammation in situ. Our data support the concept that novel therapeutic strategies targeting PD-1 may be effective in the treatment of JIA. With this approach, it may become possible to target overactive T cells regardless of their cytokine production profile.

Disseminated nocardiosis and anti-GM-CSF antibodies.

Infections that are unusually severe or caused by opportunistic pathogens are a hallmark of primary immunodeficiency (PID). Anti-cytokine autoantibodies (ACA) are an emerging cause of acquired immunodeficiency mimicking PID. Nocardia spp. are Gram-positive bacteria generally inducing disseminated infections in immunocompromised patients, but seldom also occurring in apparently immunocompetent hosts. Anti-GM-CSF autoantibodies are associated with autoimmune pulmonary alveolar proteinosis (PAP). In those patients, an increased incidence of disseminated nocardiosis and cryptococcosis has been observed. It is unclear whether the PAP or the autoantibodies predispose to the infection. We report an apparently immunocompetent woman presenting with disseminated nocardiosis without any evidence of PAP. Clinical data and radiological images were retrospectively collected. Lymphocyte populations were analyzed by flow cytometry. Anti-GM-CSF autoantibodies were measured by ELISA. A 55-year-old otherwise healthy woman presented with cerebral and pulmonary abscesses. Personal and familial history of infections or autoimmunity were negative. After extensive examinations, a final diagnosis of disseminated nocardiosis was made. Immunologic investigations including neutrophilic function and IFN-γ/IL-12 circuitry failed to identify a PID. Whole-exome sequencing did not find pathogenic variants associated with immunodeficiency. Serum anti-GM-CSF autoantibodies were positive. There were no clinical or instrumental signs of PAP. Trimethoprim-sulfamethoxazole and imipenem were administered, with progressive improvement and recovery of the infectious complication. We identified anti-GM-CSF autoantibodies as the cause of disseminated nocardiosis in a previously healthy and apparently immunocompetent adult. This case emphasizes the importance of including ACA in the differential diagnosis of PID, especially in previously healthy adults. Importantly, anti-GM-CSF autoantibodies can present with disseminated nocardiosis without PAP.

Optimization of the diagnosis and characterization of gibberellin-regulated protein sensitization: An Italian cohort study.

BACKGROUND: Pru p 7 was the first gibberellin-regulated protein (GRP) to be identified as a food allergen as the basis of a pollen food allergy syndrome. OBJECTIVE: To clinically and biologically characterize a group of patients with suspected allergy to Pru p 7 to optimize the diagnostic workup of GRP sensitization. METHODS: Allergy to Pru p 7 was suspected in the presence of a systemic allergic reaction to plant food, positive skin prick test results for cypress pollen and lipid-transfer protein-enriched peach extract, and absence of Pru p 3-specific immunoglobulin E. Controls were patients with food allergies, patients sensitized to Pru p 3, and patients with cypress allergy without food allergy. Diagnostic workup included skin tests, basophil activation test, Western blot, and single and multiplex assays. RESULTS: In total, 23 patients and 14 controls were enrolled. The most implicated food was peach (91.3%). Approximately 70% of patients reacted to multiple foods. Mueller 4 reactions were 8.7%. In 26.1% of cases, a cofactor triggered the reaction. The basophil activation test results were positive for rPru p 7 in 87% of the patients. Specific immunoglobulin E to Pru p 7 was detected in 95.7% by singleplex and in 73.9% by multiplex assays in patients with suspected allergies; 73.9% of them also reacted to cypress pollen GRP (Cup s 7) in Western blot analysis. CONCLUSION: Patients with Pru p 7-Cup s 7 allergy in our cohort confirm a mild-to-severe clinical syndrome characterized by pollen and food allergy. The diagnosis may benefit from the proposed selection criteria that can be used as preliminary steps to further characterize the cross-reactive GRP sensitization.

Metabolomic/lipidomic profiling of COVID-19 and individual response to tocilizumab.

The current pandemic emergence of novel coronavirus disease (COVID-19) poses a relevant threat to global health. SARS-CoV-2 infection is characterized by a wide range of clinical manifestations, ranging from absence of symptoms to severe forms that need intensive care treatment. Here, plasma-EDTA samples of 30 patients compared with age- and sex-matched controls were analyzed via untargeted nuclear magnetic resonance (NMR)-based metabolomics and lipidomics. With the same approach, the effect of tocilizumab administration was evaluated in a subset of patients. Despite the heterogeneity of the clinical symptoms, COVID-19 patients are characterized by common plasma metabolomic and lipidomic signatures (91.7% and 87.5% accuracy, respectively, when compared to controls). Tocilizumab treatment resulted in at least partial reversion of the metabolic alterations due to SARS-CoV-2 infection. In conclusion, NMR-based metabolomic and lipidomic profiling provides novel insights into the pathophysiological mechanism of human response to SARS-CoV-2 infection and to monitor treatment outcomes.

Blood CD62Llow inflammatory eosinophils are related to the severity of asthma and reduced by mepolizumab.

BACKGROUND: Eosinophils have been divided into different subpopulations with distinct phenotypes based on CD62L expression. No data are available regarding the correlation between eosinophils subphenotypes and clinical severity of asthma, as well as the effect of anti-IL-5 therapy on these cells. The study investigates the correlation between blood CD62Llow inflammatory eosinophils (iEos) and clinical severity of severe eosinophilic asthma (SEA) and evaluates the impact of mepolizumab on iEos. METHODS: 112 patients were screened and were divided in two groups: biological-naive (n = 51) and biological-treated patients (n = 61). The Biological-naive patients were analyzed before treatment (Group A) and 19 out of 51 patients, were longitudinally analyzed before and after treatment with mepolizumab 100 mg s.c/4 weeks (Group B); 32 patients were excluded because they were being treated with other biological therapies. Blood eosinophils were analyzed by FACS and correlated with clinical scores. In vitro effect of IL-5 and mepolizumab on CD62L expression was assessed. RESULTS: A significant correlation between blood CD62Llow cells and clinical scores of asthma and nasal polyps, as well as the number of asthma exacerbations in the last year was shown in untreated patients. In longitudinally studied patients we observed a marked reduction of CD62Llow cells paralleled by an increase in the proportion of CD62Lbright cells, associated with clinical improvement of asthma control. In vitro, CD62L expression on eosinophils is modulated by IL-5 and anti-IL-5. CONCLUSION: A positive correlation between CD62Llow iEos and the baseline clinical features of SEA with CRSwNP was shown. Furthermore mepolizumab restores the healthy balance among eosinophils sub-phenotypes in SEA patients.

Primary antibody deficiencies represent an underestimated comorbidity in asthma patients: efficacy of immunoglobulin replacement therapy in asthma control.

OBJECTIVE: Primary antibody deficiencies (PAD) are an underestimated comorbidity in asthma and its treatment could improve disease control. METHODS: a retrospective cohort of asthmatics, affected by IgG subclass deficiency or unclassified antibody deficiency and treated with low-dose intravenous immunoglobulin replacement therapy (IRT) was recruited. Demographic and clinical data, chest CT scan, blood eosinophils, atopy, chronic oral corticosteroid (OCS) therapy were evaluated at baseline. Asthma exacerbations, lower respiratory tract infections (LRTI), upper respiratory tract infections (URTI) and asthma-related hospitalizations were assessed after one and two years of IRT. RESULTS: 57 moderate-to-severe asthmatics were enrolled, mostly affected by T2 low asthma (39/57, 68.4%). After one year, IRT was effective in improving, irrespective of bronchiectasis, atopy, eosinophils and PAD type: 1) trough IgG (826.9 ± 221.3 vs 942.2 ± 195.1 mg/dl; p < 0.0001) and IgG subclasses (IgG1 355.4 ± 88.4 vs 466.7 ± 122.3, p < 0.0001; IgG2 300.1 ± 130.1 vs 347.6 ± 117.3, p < 0.0005) serum levels. 2) asthma exacerbations (6.4 ± 4.1 vs 2.4 ± 1.9, p < 0.0001), LRTI (4.3 ± 3.9 vs 1.3 ± 1.5, p < 0.0001) and hospitalization rate (0.26 ± 0.7 vs 0.05 ± 0.2, p < 0.01). These results persisted after 2 years of therapy. Estimated mean cumulative OCS exposure was reduced by 4500 mg over the 2-year period. CONCLUSIONS: low-dose IRT is effective in improving asthma control and lessening OCS burden in asthmatics affected by PAD.

Clinical and Immunological Features of SARS-CoV-2 Breakthrough Infections in Vaccinated Individuals Requiring Hospitalization.

BACKGROUND AND PURPOSE: Waning immunity and the surge of SARS-CoV-2 variants are responsible for breakthrough infections, i.e., infections in fully vaccinated individuals. Although the majority of vaccinated infected subjects report mild or no symptoms, some others require hospitalization. The clinical and immunological features of vaccinated hospitalized COVID-19 patients are currently unknown. METHODS: Twenty-nine unvaccinated and 36 vaccinated hospitalized COVID-19 patients were prospectively enrolled and clinical and laboratory data were gathered. Immunophenotyping of leukocytes' subsets, T and B cell SARS-CoV-2-specific responses were evaluated via flow cytometry. Anti-IFN-α autoantibodies were measured via ELISA. RESULTS: Despite vaccinated patients were older and with more comorbidities, unvaccinated subjects showed higher levels of pro-inflammatory markers, more severe disease, and increased mortality rate. Accordingly, they presented significant alterations in the circulating leukocyte composition, typical of severe COVID-19. Vaccinated patients displayed higher levels of anti-Spike IgGs and Spike-specific B cells. Of all participants, survivors showed higher levels of anti-Spike IgGs and Spike-specific CD4+ T cells than non-survivors. At hospital admission, 6 out of 65 patients (9.2%) displayed high serum concentrations of autoantibodies targeting IFN-α. Remarkably, 3 were unvaccinated and eventually died, while the other 3 were vaccinated and survived. CONCLUSION: Despite more severe pre-existing clinical conditions, vaccinated patients have good outcome. A rapid activation of anti-SARS-CoV-2-specific immunity is fundamental for the resolution of the infection. Therefore, prior immunization through vaccination provides a significant contribution to prevention of disease worsening and can even overcome the presence of high-risk factors (i.e., older age, comorbidities, anti-IFN-α autoantibodies).

Th17 lymphocyte-dependent degradation of joint cartilage by synovial fibroblasts in a humanized mouse model of arthritis and reversal by secukinumab.

How T-helper (Th) lymphocyte subpopulations identified in synovial fluid from patients with juvenile idiopathic arthritis (JIA) (Th17, classic Th1, or nonclassic Th1) drive joint damage is of great interest for the possible use of biological drugs that inhibit the specific cytokines. Our objective was to clarify the role of such Th subpopulations in the pathogenesis of articular cartilage destruction by synovial fibroblasts (SFbs), and the effect of Th17 blockage in an animal model. SFbs were isolated from healthy subjects and patients with JIA, and peripheral blood Th lymphocytes subsets were obtained from healthy subjects. Fragments of human cartilage from healthy subjects in a collagen matrix containing JIA or normal SFbs grafted underskin in SCID mice were used to measure cartilage degradation under the effects of Th supernatants. JIA SFbs overexpress MMP9 and MMP2 and Th17 induce both MMPs in normal SFbs, while nonclassic Th1 upregulate urokinase plasminogen activator (uPA) activity. In vitro invasive phenotype of normal SFbs is stimulated with conditioned medium of Th17 and nonclassic-Th1. In the in vivo "inverse wrap" model, normal SFbs stimulated with supernatants of Th17-lymphocytes and nonclassic Th1 produced a cartilage invasion and degradation similar to JIA SFbs. Secukinumab inhibits the cartilage damage triggered by factors produced by Th17.

Guidelines for the use of flow cytometry and cell sorting in immunological studies (third edition).

The third edition of Flow Cytometry Guidelines provides the key aspects to consider when performing flow cytometry experiments and includes comprehensive sections describing phenotypes and functional assays of all major human and murine immune cell subsets. Notably, the Guidelines contain helpful tables highlighting phenotypes and key differences between human and murine cells. Another useful feature of this edition is the flow cytometry analysis of clinical samples with examples of flow cytometry applications in the context of autoimmune diseases, cancers as well as acute and chronic infectious diseases. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid. All sections are written and peer-reviewed by leading flow cytometry experts and immunologists, making this edition an essential and state-of-the-art handbook for basic and clinical researchers.

Mild/Moderate Asthma Network in Italy (MANI): a long-term observational study.

OBJECTIVE: The prevalence of asthma in Italy is estimated to be around 4%; it affects approximately 2,000,000 citizens, and up to 80-90% of patients have mild-to-moderate asthma. Despite the clinical relevance of mild-to-moderate asthma, longitudinal observational data are very limited, including data on disease progression (worsening vs. improvement), the response to treatment, and prognosis. Studies are needed to develop long-term, observational, real-life research in large cohorts. The primary outcomes of this study will be based on prospective observation and the epidemiological evolution of mild and moderate asthma. Secondary outcomes will include patient-reported outcomes, treatments over time, disease-related functional and inflammatory patterns, and environmental and life-style influences. METHODS: This study, called the Mild/Moderate Asthma Network of Italy (MANI), is a research initiative launched by the Italian Respiratory Society and the Italian Society of Allergology, Asthma and Clinical Immunology. MANI is a cluster-based, real world, cross-sectional, prospective, observational cohort study that includes 20,000 patients with mild-to-moderate asthma. (ClinicalTrials.gov Identifier: NCT04796844). RESULTS AND CONCLUSION: Despite advances in asthma care, several research gaps remain to be addressed through clinical research. This study will add important new knowledge about long-term disease history, the transferability of clinical research results to daily practice, the efficacy of currently recommended strategies, and their impact on the burden and evolution of the disease. ABBREVIATIONS: MANI:Mild/Moderate Asthma Network of ItalySANI:Severe Asthma Network ItalyGINA:Global Initiative for AsthmaSABA:short acting ß2-agonistsICS:inhaled corticosteroidsCRF:Case Report Form.

Effectiveness and safety of dupilumab in patients with chronic rhinosinusitis with nasal polyps and associated comorbidities: a multicentric prospective study in real life.

BACKGROUND: Biologics are currently one of the main treatment options for a number of diseases. The IgG4 monoclonal antibody dupilumab targets the Interleukin-4 receptor alpha chain, thus preventing the biological effects of the cytokines IL-4 and IL-13, that are essential for the Th2 response. Several controlled trials showed that dupilumab is effective and safe in patients with atopic dermatitis (AD), severe asthma and chronic rhinosinusitis with nasal polyps (CRSwNP), thus resulting in approval by regulatory agencies. Aim of the study was to evaluate the efficacy and safety of dupilumab in adult patients with CRSwNP stratified by common overlapping comorbid conditions. METHODS: We performed a multicenter, observational, prospective study enrolling adult patients with severe CRSwNP who had started dupilumab treatment in the context of standard care from January 2021 to October 2021. Data were collected from twentynine Italian secondary care centers for allergy and clinical immunology, all of which were part of the Italian Society of Allergy, Asthma and Clinical Immunology (SIAAIC). A number of efficacy parameters were used. Patient data were compared using the Wilcoxon test for paired data. All statistical analyses were performed with SPSS version 20 (IBM, Armonk, NY, USA). RESULTS: In total, 82 patients with nasal polyposis were identified. A significant improvement was detected for all the applied efficacy parameters, i.e. 22-item Sino-Nasal Outcome Test (SNOT-22) and bilateral endoscopic nasal polyp score (NPS) scores for CRSwNP, Rhinitis Control Scoring System (RCSS) and Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) scores for allergic perennial rhinitis, Forced Expiratory Volume in the 1st second (FEV1) and Asthma Quality of Life Questionnaire (AQLQ) scores for asthma, Eczema Area and Severity Index (EASI) and Dermatology Life Quality Index (DLQI) scores for AD. A non-significant improvement was also obtained in the Urticaria Activity Score over 7 days (UAS7) for chronic spontaneous urticaria. Treatment with dupilumab was well tolerated. CONCLUSIONS: These data suggest that dupilumab treatment in patients suffering from CRSwNP and associated comorbidities may be suitable. Such outcome, although confirmation by trials is warranted, suggests the possibility to treat different disorders with a single therapy, with favorable effects especially under the cost-effectiveness aspect.

Human T cells interacting with HNSCC-derived mesenchymal stromal cells acquire tissue-resident memory like properties.

Tissue-resident memory (Trm) cells are specialized components of both CD4+ and CD8+ T cell subsets that persist in peripheral nonlymphoid tissues following infections and provide fast response in case of a secondary invasion by the same pathogen. Trm cells express the surface markers CD69, CD103, and the immune checkpoint molecule PD-1. Trm cells develop not only in the context of infections but also in tumors, where they can provide a line of defense as suggested by the positive correlation between the frequency of tumor-infiltrating Trm cells and patients' survival. Trm cells persistence in peripheral tissues depends on their adaptation to the local microenvironment and the presence of survival factors, mainly IL-7, IL-15, and Notch ligands. However, the cell sources of these factors are largely unknown, especially in the context of tumors. Here, we show that head-neck squamous cell carcinoma (HNSCC) is enriched in CD4+ and CD8+ T cells with a Trm phenotype. Moreover, we show that mesenchymal stromal cells that accumulate in HNSCC are a source of survival factors and allow proper expression of Trm-typical markers in a VCAM1-dependent manner.

Cell-mediated and humoral adaptive immune responses to SARS-CoV-2 are lower in asymptomatic than symptomatic COVID-19 patients.

The characterization of cell-mediated and humoral adaptive immune responses to SARS-CoV-2 is fundamental to understand COVID-19 progression and the development of immunological memory to the virus. In this study, we detected T-cells reactive to SARS-CoV-2 proteins M, S, and N, as well as serum virus-specific IgM, IgA, IgG, in nearly all SARS-CoV-2 infected individuals, but not in healthy donors. Virus-reactive T cells exhibited signs of in vivo activation, as suggested by the surface expression of immune-checkpoint molecules PD1 and TIGIT. Of note, we detected antigen-specific adaptive immune response both in asymptomatic and symptomatic SARS-CoV-2 infected subjects. More importantly, symptomatic patients displayed a significantly higher magnitude of both cell-mediated and humoral adaptive immune response to the virus, as compared to asymptomatic individuals. These findings suggest that an uncontrolled adaptive immune response contribute to the development of the life-threatening inflammatory phase of the disease. Finally, this study might open the way to develop effective vaccination strategies.

Effectiveness of low-dose intravenous immunoglobulin therapy in minor primary antibody deficiencies: A 2-year real-life experience.

Primary antibody deficiencies (PAD) are the most prevalent group of primary immunodeficiencies (PID) in adults and immunoglobulin replacement therapy (IRT) is the mainstay therapy to improve clinical outcomes. IRT is, however, expensive and, in minor PAD, clear recommendations concerning IRT are lacking. We conducted a retrospective real-life study to assess the effectiveness of low-dose IRT in minor PAD on 143 patients fulfilling European Society for Immunodeficiencies (ESID) diagnostic criteria for immunoglobulin (Ig)G subclass deficiency (IgGSD) or unclassified antibody deficiency (UAD). All patients were treated with intravenous low-dose IRT (0.14 ± 0.06 g/kg/month). Immunoglobulin (Ig) classes and IgG subclasses were measured at baseline and after 1 year of IRT. The annual rate of total infections, upper respiratory tract infections (URTI), lower respiratory tract infections (LRTI) and hospitalizations was measured at baseline and after 1 and 2 years of IRT. After 1 year of IRT significant improvement was demonstrated in: (a) serum IgG (787.9 ± 229.3 versus 929.1 ± 206.7 mg/dl; p < 0.0001); (b) serum IgG subclasses (IgG1 = 351.4 ± 109.9 versus 464.3 ± 124.1, p < 0.0001; IgG2 = 259.1 ± 140 versus 330.6 ± 124.9, p < 0.0001; IgG3 = 50.2 ± 26.7 versus 55.6 ± 28.9 mg/dl, p < 0.002); (c) annual rate of total infections (5.75 ± 3.87 versus 2.13 ± 1.74, p < 0.0001), URTI (1.48 ± 3.15 versus 0.69 ± 1.27; p < 0.005), LRTI (3.89 ± 3.52 versus 1.29 ± 1.37; p < 0.0001) and hospitalizations (0.37 ± 0.77 versus 0.15 ± 0.5; p < 0.0002). The improvement persisted after 2 years of IRT. No significant improvement in URTI annual rate was noted in UAD and in patients with bronchiectasis. In conclusion, low-dose IRT can improve clinical outcomes in UAD and IgGSD patients, providing a potential economical advantage over the standard IRT dose.

Rarity of human T helper 17 cells is due to retinoic acid orphan receptor-dependent mechanisms that limit their expansion.

The reason why CD4(+) T helper 17 (Th17) cells, despite their well-known pathogenic role in chronic inflammatory disorders, are very rare in the inflammatory sites remains unclear. We demonstrate that human Th17 cells exhibit low ability to proliferate and to produce the T cell growth factor interleukin-2 (IL-2), in response to combined CD3 and CD28 stimulation. This was due to the upregulated expression of IL-4-induced gene 1 (IL4I1) mRNA, a secreted L-phenylalanine oxidase, which associated with a decrease in CD3ζ chain expression and consequent abnormalities in the molecular pathway that allows IL-2 production and cell proliferation. High IL4I1 mRNA expression was detectable in Th17 cell precursors and was strictly dependent on Th17 cell master gene, the retinoid acid related orphan receptor (RORC). Th17 cells also exhibited RORC-dependent CD28 hyperexpression and the ability to produce IL-17A after CD28 stimulation without CD3 triggering. Our findings suggest that the rarity of human Th17 cells in inflamed tissues results from RORC-dependent mechanisms limiting their expansion.

From Emollients to Biologicals: Targeting Atopic Dermatitis.

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease and significantly impacts patients' lives, particularly in its severe forms. AD clinical presentation varies over the course of the disease, throughout different age groups, and across ethnicities. AD is characterized by a spectrum of clinical phenotypes as well as endotypes. Starting from the current description of AD pathogenesis, this review explores the rationale of approved AD therapies from emollients to biologicals and introduces novel promising drugs.

Quantitative and qualitative alterations of circulating myeloid cells and plasmacytoid DC in SARS-CoV-2 infection.

SARS-CoV-2 is responsible for a new infectious disease (COVID-19) in which individuals can either remain asymptomatic or progress from mild to severe clinical conditions including acute respiratory distress syndrome and multiple organ failure. The immune mechanisms that potentially orchestrate the pathology in SARS-CoV-2 infection are complex and only partially understood. There is still paucity of data on the features of myeloid cells involved in this viral infection. For this reason, we investigated the different activation status profiles and the subset distribution of myeloid cells and their correlation with disease progression in 40 COVID-19 patients at different stages of disease. COVID-19 patients showed a decrease in the absolute number of plasmacytoid and myeloid dendritic cells, different subset distribution of monocytes and different activation patterns of both monocytes and neutrophils, coupled to a significant reduction of HLA-DR monocyte levels. We found that some of these alterations are typical of all COVID-19 patients, while some others vary at different stages of the disease and correlate with biochemical parameters of inflammation. Collectively, these data suggest that not only the lymphoid, but also the myeloid compartment, is severely affected by SARS-CoV-2 infection.

Biologicals targeting type 2 immunity: Lessons learned from asthma, chronic urticaria and atopic dermatitis.

During the last decades, progression of research has led to great achievements for treatment and therapy of several disabling disorders, particularly in the field of chronic inflammatory diseases. The increased knowledge of the molecular mechanisms operating in such diseases has represented the first step in this process, and the discovery of molecules able to interfere with the natural history of the diseases, has been the second. This review is focused on the effects of biologics on type 2 diseases such as asthma, chronic urticaria and atopic dermatitis, both biologics just approved for clinical application and also those that are currently undergoing clinical trials. We will also discuss aspects and emphasize clinical trials and recently published studies, as well as research that is currently in the progress, which will be highly relevant for basic immunologists. Likewise, we will cover aspects that are pertinent for clinical immunologists and highlight translational studies that are evaluating novel biologicals in animal models.

The intestinal expansion of TCRγδ+ and disappearance of IL4+ T cells suggest their involvement in the evolution from potential to overt celiac disease.

Celiac disease (CD) is characterized by a spectrum of intestinal inflammatory lesions. Most patients have villous atrophy (overt-CD), while others have a morphologically normal mucosa, despite the presence of CD-specific autoantibodies (potential-CD). As the mechanism responsible for villous atrophy is not completely elucidated, we investigated biomarkers specific for the different celiac lesions. Phenotype and cytokine production of intestinal mucosa cells were analyzed by flow cytometry in gut biopsies of children with overt- or potential-CD and in healthy controls. Density of TCRγδ+ T cells was found markedly enhanced in intestinal mucosa of children with overt-CD compared to potential-CD or controls. By contrast, very few IL4+ T cells infiltrated the mucosa with villous atrophy compared to morphologically normal mucosa. IL4+ T cells were classical CD4+ T-helper cells (CD161- ), producing or not IFN-γ, and negative for IL17A. Our study demonstrated that the transition to villous atrophy in CD patients is characterized by increased density of TCRγδ+ T cells, and concomitant disappearance of IL4+ cells. These findings suggest that immunomodulatory mechanisms are active in potential-CD to counteract the inflammatory cascade responsible of villous atrophy. Further studies are required to validate the use of IL4+ and TCRγδ+ T cells as biomarkers of the different CD forms.