Serum biomarkers of inflammation and vascular damage upon SARS-Cov-2 mRNA vaccine in patients with thymic epithelial tumors.

OBJECTIVES: Thymic epithelial tumors (TET) patients are at high risk of autoimmune and hypoimmune complications. Limited evidence is available on the potential risk of immune-related and inflammatory reactions induced by SARS-Cov-2 vaccine in this patient population. METHODS: In order to identify subjects at higher risk for vaccine complications, we prospectively evaluated a panel of serum biomarkers related to inflammation (TNF-α, IL-1ß, -6, -10, -12, and -17A, IFN-α, ß and γ, MPO, MMP-9), and vascular damage (E- and P-selectin, VEGF-A, P-ANCA and MCP-1) in 44 TET patients and in 30 healthy controls along the whole SARS-Cov-2 vaccine cycle. RESULTS: About 50 % of subjects (either TET and controls) showed an increase of serum biochemical markers of inflammation and endothelial damage with a large heterogeneity of values. Such increase appeared early, after the first dose in control subjects and later, after the second dose in TET patients (in which we observed mainly an increase of inflammatory biomarkers). The values normalized after about 3 months and did not increase after the third, booster dose. No autoimmune or vascular complications were observed in the study subjects and no difference was observed in terms of vaccine response among subjects showing serum biomarkers increase and those who experienced no changes. CONCLUSIONS: Our data highlight the relevance of Sars-Cov-2 vaccine in TET patients, as it resulted safe and prevented severe COVID-19. However, further studies are awaited to explore the mechanisms and the potential consequences of the observed increase of serum inflammatory and vascular damage biomarkers.

Heterozygous FOXN1 Variants Cause Low TRECs and Severe T Cell Lymphopenia, Revealing a Crucial Role of FOXN1 in Supporting Early Thymopoiesis.

FOXN1 is the master regulatory gene of thymic epithelium development. FOXN1 deficiency leads to thymic aplasia, alopecia, and nail dystrophy, accounting for the nude/severe combined immunodeficiency (nu/SCID) phenotype in humans and mice. We identified several newborns with low levels of T cell receptor excision circles (TRECs) and T cell lymphopenia at birth, who carried heterozygous loss-of-function FOXN1 variants. Longitudinal analysis showed persistent T cell lymphopenia during infancy, often associated with nail dystrophy. Adult individuals with heterozygous FOXN1 variants had in most cases normal CD4+ but lower than normal CD8+ cell counts. We hypothesized a FOXN1 gene dosage effect on the function of thymic epithelial cells (TECs) and thymopoiesis and postulated that these effects would be more prominent early in life. To test this hypothesis, we analyzed TEC subset frequency and phenotype, early thymic progenitor (ETP) cell count, and expression of FOXN1 target genes (Ccl25, Cxcl12, Dll4, Scf, Psmb11, Prss16, and Cd83) in Foxn1nu/+ (nu/+) mice and age-matched wild-type (+/+) littermate controls. Both the frequency and the absolute count of ETP were significantly reduced in nu/+ mice up to 3 weeks of age. Analysis of the TEC compartment showed reduced expression of FOXN1 target genes and delayed maturation of the medullary TEC compartment in nu/+ mice. These observations establish a FOXN1 gene dosage effect on thymic function and identify FOXN1 haploinsufficiency as an important genetic determinant of T cell lymphopenia at birth.

Cytometric analysis of patients with COVID-19: what is changed in the second wave?

BACKGROUND: Coronavirus disease 2019 (COVID-19) pandemic had a 1st wave in Europe from March to May 2020 and a 2nd wave since September 2020. We previously studied 35 hospitalized COVID-19 patients of the 1st wave demonstrating a cytokine storm and the exhaustion of most lymphocyte subpopulations. Herein, we describe the results obtained from COVID-19 patients of the 2nd wave. METHODS: We analyzed interleukin (IL)-6 by human-specific enzyme-linked immunosorbent assay and a large set of lymphocyte subpopulations by flow cytometry in 274 COVID-19 patients hospitalized from September 2020 to May 2021. RESULTS: Patients of 2nd wave compared with those of 1st wave showed lower serum IL-6 levels and a higher number of B and most T lymphocyte subpopulations in advanced stages, in relation with the age and the gender. On the other hand, we observed in 2nd wave patients: (i) a reduction of most lymphocyte subpopulations at mild and moderate stages; (ii) a reduction of natural killer cells and T regulatory cells together with a higher number of activated T helper (TH) 17 lymphocytes in all stages, which were mainly related to steroid and azithromycin therapies before hospitalization. CONCLUSIONS: COVID-19 had a less severe impact in patients of the 2nd wave in advanced stages, while the impact appeared more severe in patients of mild and moderate stages, as compared with 1st wave patients. This finding suggests that in COVID-19 patients with milder expression at diagnosis, steroid and azithromycin therapies appear to worsen the immune response against the virus. Furthermore, the cytometric profile may help to drive targeted therapies by monoclonal antibodies to modulate specific IL/lymphocyte inhibition or activation in COVID-19 patients.

In Ataxia-Telangiectasia, Oral Betamethasone Administration Ameliorates Lymphocytes Functionality through Modulation of the IL-7/IL-7Rα Axis Paralleling the Neurological Behavior: A Comparative Report of Two Cases.

Ataxia-Telangiectasia (A-T) is characterized by cerebellar neurodegeneration and immunodeficiency. Recent studies suggest that very low glucocorticoids (GCs) doses may help improve A-T neurological phenotype in some patients. Interestingly, in GCs studies an unexpected improvement of lymphocytes proliferation in some A-T patients has been observed. GCs are able to upregulate IL-7 Rα expression and rescue it from the recycling. In this study, we compared several immunological functions, including PBMC proliferative responses, cell activation events and IL-7/IL-7 Rα axis functionality, with the neurological behavior during an in-vivo GCs treatment between the most Responder patient to GC and the Non-Responder at all. During in-vivo GC treatment, we observed an increase of lymphocyte proliferation upon stimulation with PHA or IL-7 only in the Responder. This finding paralleled the increase in the surface expression of IL-7 R and up-regulation of the CD69 T-cell activation marker. Internalization and recycling of IL-7 R occurred properly only in the Responder. Microarray analysis revealed a remarkable difference in the DE-genes levels among Responder and Non-Responder, mostly concerning miRNAs and Multiple Complex families. Our findings suggest that the improvement of lymphocyte functionality, which correlates to the neurological behavior, is mediated through an effect of GCs on the IL-7/IL-7 Rα axis.

Lipopolysaccharide-Elicited TSLPR Expression Enriches a Functionally Discrete Subset of Human CD14+ CD1c+ Monocytes.

Thymic stromal lymphopoietin (TSLP) is a cytokine produced mainly by epithelial cells in response to inflammatory or microbial stimuli and binds to the TSLP receptor (TSLPR) complex, a heterodimer composed of TSLPR and IL-7 receptor α (CD127). TSLP activates multiple immune cell subsets expressing the TSLPR complex and plays a role in several models of disease. Although human monocytes express TSLPR and CD127 mRNAs in response to the TLR4 agonist LPS, their responsiveness to TSLP is poorly defined. We demonstrate that TSLP enhances human CD14+ monocyte CCL17 production in response to LPS and IL-4. Surprisingly, only a subset of CD14+ CD16- monocytes, TSLPR+ monocytes (TSLPR+ mono), expresses TSLPR complex upon LPS stimulation in an NF-κB- and p38-dependent manner. Phenotypic, functional, and transcriptomic analysis revealed specific features of TSLPR+ mono, including higher CCL17 and IL-10 production and increased expression of genes with important immune functions (i.e., GAS6, ALOX15B, FCGR2B, LAIR1). Strikingly, TSLPR+ mono express higher levels of the dendritic cell marker CD1c. This evidence led us to identify a subset of peripheral blood CD14+ CD1c+ cells that expresses the highest levels of TSLPR upon LPS stimulation. The translational relevance of these findings is highlighted by the higher expression of TSLPR and CD127 mRNAs in monocytes isolated from patients with Gram-negative sepsis compared with healthy control subjects. Our results emphasize a phenotypic and functional heterogeneity in an apparently homogeneous population of human CD14+ CD16- monocytes and prompt further ontogenetic and functional analysis of CD14+ CD1c+ and LPS-activated CD14+ CD1c+ TSLPR+ mono.

DiGeorge-like syndrome in a child with a 3p12.3 deletion involving MIR4273 gene born to a mother with gestational diabetes mellitus.

Chromosome 22q11.2 deletion is the most common chromosomal alteration associated with DiGeorge syndrome (DGS), even though this is not the only underlying cause of DGS. In rare patients, mutations in a single gene, TBX1, have been described resulting in a DGS phenotype. Recently, it has been reported that at least part of the TBX1 mutant phenotype is due to excessive bone morphogenetic proteins (BMP) signaling. Evidence suggests that miRNA may modulate the expression of critical T-box transcriptional regulators during midface development and Bmp-signaling. We report on a 7-year-old Caucasian male born to a mother affected with gestational diabetes (GDM) who had a 371Kb-interstitial deletion of 3p12.3 identified by array CGH, involving the ZNF717, MIR1243, and 4273 genes. The child presented with a DiGeorge anomaly (DGA) associated with unilateral renal agenesis and language delay. The immunological evaluation revealed a severe reduction and impairment of T lymphocytes. FISH analysis and TBX1 sequencing were negative. Among the miRNA-4273 predicted target genes, we found BMP3, which is involved in several steps of embryogenesis including kidney and lung organogenesis and in insulin gene expression. Since, DGA is not commonly found in newborns of diabetic mothers, we hypothesize that the pathogenesis of DGA associated with GDM is multifactorial, involving both genetic and/or epigenetic cofactors.

Human skin-derived keratinocytes and fibroblasts co-cultured on 3D poly ε-caprolactone scaffold support in vitro HSC differentiation into T-lineage committed cells.

In humans, the thymus is the primary lymphoid organ able to support the development of T cells through its three-dimensional (3D) organization of the thymic stromal cells. Since a remarkable number of similarities are shared between the thymic epithelial cells (TECs) and skin-derived keratinocytes and fibroblasts, in this study we used human keratinocytes seeded with fibroblasts on the 3D poly ε-caprolactone scaffold to evaluate their ability to replace TECs in supporting T-cell differentiation from human haematopoietic stem cells (HSCs). We observed that in the multicellular biocomposite, early thymocytes expressing CD7(+)CD1a(+), peculiar markers of an initial T-cell commitment, were de novo generated. Molecular studies of genes selectively expressed during T-cell development revealed that TAL1 was down-regulated and Spi-B was up-regulated in the cell suspension, consistently with a T-cell lineage commitment. Moreover, PTCRA and RAG2 expression was detected, indicative of a recombinant activity, required for the generation of a T-cell receptor repertoire. Our results indicate that in the multicellular biocomposite, containing skin-derived elements in the absence of thymic stroma, HSCs do start differentiating toward a T-cell lineage commitment. In conclusion, the construct described in this study exerts some properties of a lymphoid organoid, suitable for future clinical applications in cell-based therapies.

The ocrelizumab wearing-off phenomenon is associated with reduced immunomodulatory response and increased neuroaxonal damage in multiple sclerosis.

OBJECTIVE: The wearing-off phenomenon is common in people with multiple sclerosis (MS) treated with ocrelizumab. We aim to evaluate the presence and severity of wearing-off to ocrelizumab in relation to demographic and MS clinical variables, immune profiling, and a marker of neuroaxonal damage (plasma neurofilament light chain (pNfl)). METHODS: This cross-sectional study included MS patients treated with ocrelizumab from at least 1 year. Wearing-off questionnaire and blood samples were collected between 21 and 23 weeks after the previous ocrelizumab infusion. Lymphocyte subpopulations were evaluated on peripheral blood using flow cytometry. PNfl was evaluated using fully automated chemiluminescent enzyme immunoassay. RESULTS: We included 106 people with MS (age 49.5 ± 11.6 years; females 42.3%; wearing-off 57.6%). On regression models, wearing-off was associated with higher pNfl, CD8, CD3, and CD3CD27 lymphocytes. Most frequent wearing-off symptoms were cognitive, sensory, and balance problems; wearing-off started < 1 week (9.4%), 1-4 weeks (10.7%) or > 4 weeks (10.7%) before infusion; 44.8% of the complaints were moderate to severe. Severity of wearing-off was associated with higher pNfl and CD8 lymphocytes. CONCLUSIONS: Wearing-off is common in people with MS treated with ocrelizumab, and is associated with reduced immunomodulation (higher T lymphocytes) and increased neuroaxonal damage, suggesting reduced treatment response.

Effect of siponimod on lymphocyte subsets in active secondary progressive multiple sclerosis and clinical implications.

BACKGROUND: Circulating immune cells play a pathogenic role in multiple sclerosis (MS). However, the role of specific lymphocyte subpopulations is not unveiled yet, especially in progressive stages. We aimed to investigate lymphocyte changes during siponimod treatment in active secondary progressive MS (aSPMS) and their associations with clinical outcomes. METHODS: We enrolled 46 aSPMS patients starting on siponimod treatment with at least 6 months of follow-up and two visits within the scheduled timeframes and 14 sex- and age-matched healthy controls (HCs). Clinical and laboratory data were collected retrospectively at baseline, 3rd, 6th, 12th, and 24th month for MS patients, and at baseline for HCs. RESULTS: At baseline SPMS patients presented with increased naïve regulatory T lymphocytes (p = 0.02) vs. HCs. Over time, SPMS patients showed decreased T CD4+ (coeff. range = -24/-17, 95% CI range = -31.60 to -10.40), B lymphocyte (coeff. range = -3.77/-2.54, 95% CI range = -6.02 to -0.35), memory regulatory B cells (coeff. range = -0.78/-0.57, 95% CI range = -1.24 to -0.17) and CD4/CD8 ratio (coeff. range = -4.44/-0.67, 95% CI range = -1.61 to -0.17) from month 3 thereafter vs. baseline, and reduced CD3+CD20+ lymphocytes from month 12 thereafter (coeff. range = -0.32/-0.24, 95% CI range = -0.59 to -0.03). Patients not experiencing disability progression while on siponimod treatment showed B lymphocyte reduction from month 3 (coeff. range = -4.23/-2.32, 95% CI range = -7.53 to -0.15) and CD3+CD20+ lymphocyte reduction from month 12 (coeff. range = -0.32/-0.24, 95% CI range = -0.59 to -0.03) vs. patients experiencing progression. CONCLUSIONS: Patients treated with siponimod showed a T and B lymphocyte reduction, especially CD4+, CD3+CD20+ and naïve regulatory T cells and memory regulatory B cells. Disability progression while on siponimod treatment was associated with a less pronounced effect on B and CD3+CD20+ lymphocytes.

Case report: EBV-related eye orbits and sinuses lymphohistiocytic infiltration responsive to rituximab in a patient with X lymphoproliferative syndrome type 1.

Background and aims: X lymphoproliferative syndrome type 1 (XLP1) is a rare inborn error of immunity due to mutations of SH2D1A, encoding for slam-associated protein (SAP). The clinical phenotype includes severe mononucleosis, hemophagocytic lymphohistiocytosis (HLH), and B-cell lymphomas. Methods: We report the case of a child affected with XLP1 who presented with an incomplete HLH, triggered by Epstein-Barr virus (EBV) and treated with rituximab, involving orbits and paranasal sinuses. Results: The lesion was indistinguishable from lymphoma, complicating diagnosis and treatment. In addition, considering the high incidence of lymphoma in patients with XLP1, histology helped define its nature, driving therapeutic choices. Conclusion: We described an unusual presentation of incomplete HLH in a patient affected with XLP1: an EBV-driven infiltration of the orbits and paranasal sinuses. This led us to a challenging differential diagnosis of lymphoma-associated hemophagocytic syndrome, which can be frequently observed in patients with XLP1. Considering the extremely poor prognosis of this clinical finding, we sought for a prompt diagnosis and managed to obtain it and to immediately establish the right treatment on the basis of the pathological finding.

Gliadin does not induce mucosal inflammation or basophil activation in patients with nonceliac gluten sensitivity.

BACKGROUND & AIMS: Nonceliac gluten-sensitive (NCGS) patients report intestinal and extra-intestinal symptoms shortly after ingesting gluten; these symptoms disappear on gluten-free diets, although these patients have no serologic markers of celiac disease or intestinal damage. In fact, there is no evidence for mucosal or serologic modifications in those individuals. We investigated immunologic responses of duodenal mucosa samples and peripheral blood basophils, isolated from NCGS patients, after exposure to gliadin. METHODS: Participants underwent a complete clinical evaluation to exclude celiac disease while on a gluten-containing diet, a skin prick test to exclude wheat allergy, and upper endoscopy (n = 119) at 2 tertiary medical centers in Italy. Patients were considered to have NCGS based on their symptoms and the current definition of the disorder. Subjects were assigned to the following groups: patients with celiac disease on gluten-free diets (n = 34), untreated patients with celiac disease (n = 35), patients with NCGS (n = 16), or controls (n = 34). Duodenal biopsy samples collected during endoscopy were incubated with gliadin peptides, and levels of inflammatory markers were assessed. Peripheral blood basophils were extracted and incubated with gliadin peptides or a mix of wheat proteins; activation was assessed based on levels of CD203c, CD63, and CD45. RESULTS: Duodenal mucosa samples collected from 69 patients with celiac disease showed markers of inflammation after incubation with gliadin. Some, but not all, markers of inflammation were detected weakly in biopsy samples from 3 controls and 3 NCGS patients (P = .00 for all markers). There were no significant increases in the levels of CD63 and CD203c in NCGS patients. CONCLUSIONS: Unlike the duodenal mucosa from patients with celiac disease, upon incubation with gliadin, mucosa from patients with NCGS does not express markers of inflammation, and their basophils are not activated by gliadin. The in vitro gliadin challenge therefore should not be used to diagnose NCGS.

The Effects of Adiponectin on the Behavior of B-Cell Leukemia Cells: Insights from an In Vitro Study.

Background: Non-Hodgkin's lymphoma (NHL), the most frequent hematological neoplasm worldwide, represents a heterogeneous group of malignancies. The etiology of NHL remains to be fully elucidated, but the role of adipose tissue (AT) in immune function via the secretion of adipokines was recently recognized. Among adipokines, adiponectin has garnered attention for its beneficial properties. This study aimed to explore the in vitro effects of AdipoRon, an adiponectin agonist, on JVM-2, a lymphoblast cell line used as a representative disease model. Methods: JVM-2 cells were treated with different concentrations of AdipoRon to evaluate its effects on viability (via an MTT test), cell cycle distribution (via an FACS analysis), invasiveness (via a Matrigel assay) and colony-forming ability; protein expression was assessed via a real-time PCR (qPCR) and/or Western blotting (WB). Results: We found that the prolonged exposure of JVM-2 cells to AdipoRon led to a reduction in their viability due to a cytostatic effect. Additionally, AdipoRon stimulated both the formation of cell colonies and the expression of E-cadherin. Interestingly, the administration of AdipoRon increased the invasive potential of JVM-2 cells. Conclusions: Our findings indicate that adiponectin is involved in the regulation of different cellular processes of JVM-2 cells, supporting its potential association with a pro-tumorigenic phenotype and indicating that it might contribute to the increased aggressiveness and metastatic potential of B lymphoma cells. However, additional studies are required to fully understand the molecular mechanisms of adiponectin's actions on lymphoblasts and whether it may represent a marker of disease.

Nutrient-Dependent Mitochondrial Fission Enhances Osteoblast Function.

BACKGROUND: The bone synthesizing function of osteoblasts (OBs) is a highly demanding energy process that requires nutrients. However, how nutrient availability affects OBs behavior and bone mineralization remain to be fully understood. METHODS: MC3T3-E1 cell line and primary OBs (OBs) cultures were treated with physiological levels of glucose (G; 5.5 mM) alone or with the addition of palmitic acid (G+PA) at different concentrations. Mitochondria morphology and activity were evaluated by fluorescence microscopy, qPCR, and oxygen consumption rate (OCR) measurement, and OBs function was assessed by mineralization assay. RESULTS: The addition of non-lipotoxic levels of 25 µM PA to G increased mineralization in OBs. G+25 µM PA exposure reduced mitochondria size in OBs, which was associated with increased activation of dynamin-related protein 1, a mitochondrial fission protein, enhanced mitochondria OCR and ATP production, and increased expression of oxidative phosphorylation genes. Treatment with Mdivi-1, a putative inhibitor of mitochondrial fission, reduced osteogenesis and mitochondrial respiration in OBs. CONCLUSIONS: Our results revealed that OBs function was enhanced in the presence of glucose and PA at 25 µM. This was associated with increased OBs mitochondrial respiration and dynamics. These results suggest a role for nutrient availability in bone physiology and pathophysiology.

Ocrelizumab effect on humoral and cellular immunity in multiple sclerosis and its clinical correlates: a 3-year observational study.

OBJECTIVE: We aim to evaluate 3-year effects of ocrelizumab (humanized anti-CD20 monoclonal antibody for the treatment of multiple sclerosis (MS)) on lymphocytes, neutrophils and immunoglobulins: (1) when compared with pre-infusion assessment; (2) over the course of treatment; and (3) possible clinical correlates of the observed immunological modifications. METHODS: This real-world observational cohort study has been conducted on prospectively collected data from 78 MS patients (mean age 47.8 ± 10.5 years; females 48.7%) commencing on ocrelizumab from 2018, with mean follow-up of 36.5 ± 6.8 months. Clinical data and blood samples were collected every three months. Total lymphocyte count and subpopulations were assessed on peripheral blood using flow cytometry. Serum immunoglobulins were evaluated with nephelometry. RESULTS: When compared with pre-infusion values, we observed reduction of total, CD19 and CD20 lymphocyte counts; however, after the first infusion, their levels remained substantially stable. Over time we observed a progressive reduction of CD8 lymphocytes, while no changes were observed for CD4, CD27, CD3CD27, and CD19CD27. After the first infusion, we observed reduction in IgG, which further decreased during the follow-up. Higher probability of EDSS progression was associated with reduced modulation of CD8 lymphocytes. INTERPRETATION: Ocrelizumab affects both humoral and cellular immune responses. Disability progression over the follow-up was associated with lower CD8 cytotoxic T-lymphocyte reduction. Changes in humoral response are immediate and sustained, while modulation of cellular immunity occurs progressively through regular re-treatment, and is related to clinical stability.

Immunocytometric analysis of patients with thymic epithelial tumors revealed that COVID-19 vaccine booster strongly enhanced the immune response.

Background: Thymic epithelial tumors (TETs) are rare malignancies with heterogeneous clinical manifestations. The high frequency of autoimmune paraneoplastic disorders observed in such patients requires caution when using COVID-19 vaccines. Furthermore, TETs are often associated with severe immunodeficiency, making it difficult to predict vaccine immunization. Therefore, we aimed to evaluate immune response to COVID-19 vaccine in patients with TETs. Methods: We conducted a prospective study enrolling patients who underwent the SARS-Cov-2 mRNA full vaccine cycle (two doses plus a booster after 6 months of BNT162b2). All patients were enrolled before receiving 1st vaccine dose and were followed over the vaccination cycle for up to 6 months after the booster dose to i) assess humoral and cellular responses, ii) define biomarkers predictive of effective immunization, and iii) evaluate the safety of the vaccine. Results: At the end of the full vaccine cycle, 27 (61.4%) patients developed humoral and 38 (86.4%) cellular responses (IFN γ release by stimulated cells) and showed an increase in activated TH1 and TH17 cells, particularly significant after the booster dose. The number of B and T lymphocytes at baseline was predictive of humoral and cellular responses, respectively. Patients with no evidence of tumor lesions had a higher probability of achieving a humoral response than those with evidence of the disease. Furthermore, the percentage of patients with immune-related disorders (75%), particularly Good's syndrome (47.7%) and myasthenia gravis (29.5%), did not change over the entire vaccine cycle. Overall, 19 of the 44 enrolled patients (43.2%) had COVID-19 during the observation period; none required hospitalization or oxygen support, and no fatalities were observed. Conclusion: SARS-Cov-2 mRNA vaccine determines the immune responses in patients with TET, particularly after the booster dose, and in patients with no evidence of tumor lesions. Preliminary analysis of B and T lymphocytes may help identify patients who have a lower probability of achieving effective humoral and cellular responses and thus may need passive immunization. The vaccine prevented severe COVID-19 infection and is safe.

Bifidobacterium affects antitumor efficacy of oncolytic adenovirus in a mouse model of melanoma.

Gut microbiota plays a key role in modulating responses to cancer immunotherapy in melanoma patients. Oncolytic viruses (OVs) represent emerging tools in cancer therapy, inducing a potent immunogenic cancer cell death (ICD) and recruiting immune cells in tumors, poorly infiltrated by T cells. We investigated whether the antitumoral activity of oncolytic adenovirus Ad5D24-CpG (Ad-CpG) was gut microbiota-mediated in a syngeneic mouse model of melanoma and observed that ICD was weakened by vancomycin-mediated perturbation of gut microbiota. Ad-CpG efficacy was increased by oral supplementation with Bifidobacterium, reducing melanoma progression and tumor-infiltrating regulatory T cells. Fecal microbiota was enriched in bacterial species belonging to the Firmicutes phylum in mice treated with both Bifidobacterium and Ad-CpG; furthermore, our data suggest that molecular mimicry between melanoma and Bifidobacterium-derived epitopes may favor activation of cross-reactive T cells and constitutes one of the mechanisms by which gut microbiota modulates OVs response.

ImageStream promyelocytic leukemia protein immunolocalization: in search of promyelocytic leukemia cells.

Acute promyelocytic leukemia (APL) is a hematological emergency in which a rapid diagnosis is essential for early administration of appropriate therapy, including all-trans retinoic acid before the onset of fatal coagulopathy. Currently, the following methodologies are widely used for rapid initial diagnosis of APL: 1) identification of hypergranular leukemic promyelocytes by using classical morphology; 2) identification of cells with diffuse promyelocytic leukemia (PML) protein distribution by immunofluorescence microscopy; 3) evidence of aberrant promyelocyte surface immunophenotype by conventional flow cytometry (FCM). Here, we show a method for immunofluorescent detection of PML localization using ImageStream FCM. This technique provides objective per-cell quantitative image analysis for statistically large sample sizes, enabling precise and operator-independent PML pattern recognition even in electronic and real dilution experiments up to 10% of APL cellular presence. Therefore, we evidence that this method could be helpful for rapid and objective initial diagnosis and the prompt initiation of APL treatment.

Lymphocyte Population Changes at Two Time Points during the Acute Period of COVID-19 Infection.

We previously observed an increase of serum interleukins (IL) and a reduction of most lymphocyte subpopulations in hospitalized COVID-19 patients. Herein, we aimed to evaluate the changes in serum IL-6, IL-10, and IL-17A levels and cytometric lymphocyte profiles in 144 COVID-19 patients at admission and after one week, also in relation to steroid treatment before hospitalization. After one week of hospitalization, we found that: (i) total lymphocytes were increased in all patients; (ii) neutrophils and IL-6 were reduced in mild/moderate patients; (iii) B lymphocytes were increased in severe patients; (iv) T lymphocyte populations increased in mild/moderate patients. In the eight patients that died during hospitalization, total leukocytes increased while T, T helper, T cytotoxic, T regulatory, and NK lymphocytes showed a reducing trend in five of the eight patients. Even if seven days are too few to evaluate the adaptive immunity of patients, we found that the steroid therapy was associated with a reduced COVID-19 inflammation and cytokine activation only in patients with severe disease, while in patients with less severe disease, the steroid therapy seems to have immunosuppressive effects on lymphocyte populations, and this could hamper the antiviral response. A better knowledge of cytokine and lymphocyte alterations in each COVID-19 patient could be useful to plan better treatment with steroids or cytokine targeting.

Immunophenotyping of peripheral blood cells allows to discriminate MIS-C and Kawasaki disease.

Background: The pathogenesis of the novel described multisystem inflammatory syndrome in children (MIS-C) and Kawasaki disease (KD) is still debated as it is not clear if they are the same or different nosological entities. However, for both the diseases a rapid and unequivocal diagnosis is mandatory to start the therapy before the onset of severe complications. In this study, we aimed to evaluate the white cell populations in MIS-C and KD as potential markers to discriminate between the two diseases. Methods: We studied white cell populations by flow cytometry in 46 MIS-C and 28 KD patients in comparison to 70 age-matched healthy children. Results: MIS-C patients had a significant lymphopenia that involved both B and T populations while KD patients showed a significant neutrophilia and thrombocythemia. Granulocyte/lymphocyte ratio helped to diagnose both MIS-C and KD with a high diagnostic sensitivity, while a multivariate analysis of granulocyte and T lymphocyte number contributed to discriminate between the two diseases. Conclusions: The relevant lymphopenia observed in MIS-C patients suggests that the disease would be a post-infectious sequel of COVID-19 immunologically amplified by a massive cytokine release, while the significant neutrophilia and thrombocythemia observed in KD confirmed that the disorder has the genesis of a systemic vasculitis. The analysis of a panel of circulating cells may help to early diagnose and to discriminate between the two diseases. Supplementary Information: The online version contains supplementary material available at 10.1186/s41231-022-00128-2.

MIS-C: A COVID-19-as sociated condition between hypoimmunity and hyperimmunity.

Multisystem inflammatory syndrome in children (MIS-C) is a rare, severe complication of COVID-19. A better knowledge of immunological, cellular, and genetic characteristics of MIS-C could help better understand the pathogenesis of the disease and contribute to identifying specific diagnostic biomarkers and develop targeted therapies. We studied 37 MIS-C children at hospital admission and 24 healthy controls analyzing serum cytokines (IFN-α, IFN-ß, IFN-γ, IL-6, IL-10, IL-17A, IL-12p70 and TNF), lymphocyte populations by flow cytometry and 386 genes related to autoimmune diseases, autoinflammation and primary immunodeficiencies by NGS. MIS-C patients showed a significant increase of serum IFNγ (despite a significant reduction of activated Th1) and ILs, even if with a great heterogeneity among patients, revealing different pathways involved in MIS-C pathogenesis and suggesting that serum cytokines at admission may help to select the inflammatory pathways to target in each patient. Flow cytometry demonstrated a relevant reduction of T populations while the percentage of B cell was increased in agreement with an autoimmune pathogenesis of MIS-C. Genetic analysis identified variants in 34 genes and 83.3% of patients had at least one gene variant. Among these, 9 were mutated in more patients. Most genes are related to autoimmune diseases like ATM, NCF1, MCM4, FCN3, and DOCK8 or to autoinflammatory diseases associated to the release of IFNγ like PRF1, NOD2, and MEF. Thus, an incomplete clearance of the Sars-CoV2 during the acute phase may induce tissue damage and self-antigen exposure and genetic variants can predispose to hyper-reactive immune dysregulation events of MIS-C-syndrome. Type II IFN activation and cytokine responses (mainly IL-6 and IL-10) may cause a cytokine storm in some patients with a more severe acute phase of the disease, lymphopenia and multisystemic organ involvement. The timely identification of such patients with an immunocytometric panel might be critical for targeted therapeutic management.