Hematopoietic Cell Transplantation Cures Adenosine Deaminase 2 Deficiency: Report on 30 Patients.

Purpose: Deficiency of adenosine deaminase 2 (DADA2) is an inherited inborn error of immunity, characterized by autoinflammation (recurrent fever), vasculopathy (livedo racemosa, polyarteritis nodosa, lacunar ischemic strokes, and intracranial hemorrhages), immunodeficiency, lymphoproliferation, immune cytopenias, and bone marrow failure (BMF). Tumor necrosis factor (TNF-α) blockade is the treatment of choice for the vasculopathy, but often fails to reverse refractory cytopenia. We aimed to study the outcome of hematopoietic cell transplantation (HCT) in patients with DADA2.

Coronavirus disease 2019 in patients with inborn errors of immunity: An international study.

Background: There is uncertainty about the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in individuals with rare inborn errors of immunity (IEI), a population at risk of developing severe coronavirus disease 2019. This is relevant not only for these patients but also for the general population, because studies of IEIs can unveil key requirements for host defense.

Objective: We sought to describe the presentation, manifestations, and outcome of SARS-CoV-2 infection in IEI to inform physicians and enhance understanding of host defense against SARS-CoV-2.

New perspectives in gene therapy for inherited disorders.

Gene therapy has become promising in many fields of medicine, as a single treatment could allow long-lasting and curative benefits. New medicines based on cell gene correction are expected to occur in upcoming years and will be hopefully part of the therapeutic armamentarium for inherited and acquired diseases. Issues related to the costs of these new therapies and access to care for all patients, and procedures and expertise needed to facilitate their application worldwide require to be addressed, together with long-term safety and efficacy monitoring.

Total loss of GM3 synthase activity by a normally processed enzyme in a novel variant and in all ST3GAL5 variants reported to cause a distinct congenital disorder of glycosylation.

ST3GAL5-CDG is a rare syndrome which is caused by variant GM3 synthases, the enzyme involved in the biosynthesis of a-b-c-series gangliosides. Here we report a novel homozygous ST3GAL5 variant, p.Gly342Ser, in a patient suffering from failure to thrive, severe hearing, visual, motor, and cognitive impairment, and respiratory chain dysfunction.

Manufacturing Mesenchymal Stromal Cells for the Treatment of Graft-versus-Host Disease: A Survey among Centers Affiliated with the European Society for Blood and Marrow Transplantation.

The immunosuppressive properties of mesenchymal stromal cells (MSC) have been successfully tested to control clinical severe graft-versus host disease and improve survival. However, clinical studies have not yet provided conclusive evidence of their efficacy largely because of lack of patients' stratification criteria. The heterogeneity of MSC preparations is also a major contributing factor, as manufacturing of therapeutic MSC is performed according to different protocols among different centers.

Neutrophils drive type I interferon production and autoantibodies in patients with Wiskott-Aldrich syndrome.

Background: Wiskott-Aldrich syndrome (WAS) is a rare primary immunodeficiency caused by mutations in Wiskott-Aldrich syndrome protein (WASp), a key regulator of cytoskeletal dynamics in hematopoietic cells. A high proportion of patients experience autoimmunity caused by a breakdown in T- and B-cell tolerance. Moreover, excessive production of type I interferon (IFN-I) by plasmacytoid dendritic cells (pDCs) contributes to autoimmune signs; however, the factors that trigger excessive innate activation have not been defined.

Reversible immortalisation enables genetic correction of human muscle progenitors and engineering of next-generation human artificial chromosomes for Duchenne muscular dystrophy.

Transferring large or multiple genes into primary human stem/progenitor cells is challenged by restrictions in vector capacity, and this hurdle limits the success of gene therapy. A paradigm is Duchenne muscular dystrophy (DMD), an incurable disorder caused by mutations in the largest human gene: dystrophin. The combination of large-capacity vectors, such as human artificial chromosomes (HACs), with stem/progenitor cells may overcome this limitation.

Efficacy of lentivirus-mediated gene therapy in an Omenn syndrome recombination-activating gene 2 mouse model is not hindered by inflammation and immune dysregulation.

Background: Omenn syndrome (OS) is a rare severe combined immunodeficiency associated with autoimmunity and caused by defects in lymphoid-specific V(D)J recombination. Most patients carry hypomorphic mutations in recombination-activating gene (RAG) 1 or 2. Hematopoietic stem cell transplantation is the standard treatment; however, gene therapy (GT) might represent a valid alternative, especially for patients lacking a matched donor.

AQP8 transports NOX2-generated H2O2 across the plasma membrane to promote signaling in B cells.

HO acts as a second messenger in key signaling circuits, transiently modulating tyrosine phosphatases and kinases. We investigated its origin, membrane transport, and functional role during B cell activation and differentiation. Our data identified NADPH-oxidase 2 as the main source of HO and aquaporin 8 as a transport facilitator across the plasma membrane.

Oligophrenin-1 regulates number, morphology and synaptic properties of adult-born inhibitory interneurons in the olfactory bulb.

Among the X-linked genes associated with intellectual disability, Oligophrenin-1 (OPHN1) encodes for a Rho GTPase-activating protein, a key regulator of several developmental processes, such as dendrite and spine formation and synaptic activity. Inhibitory interneurons play a key role in the development and function of neuronal circuits. Whether a mutation of OPHN1 can affect morphology and synaptic properties of inhibitory interneurons remains poorly understood.

Deconstructing IgG4-related disease involvement of midline structures: Comparison to common mimickers.

Objective: A series of destructive and tumefactive lesions of the midline structures have been recently added to the spectrum of IgG4-related disease (IgG4-RD). We examined the clinical, serological, endoscopic, radiological, and histological features that might be of utility in distinguishing IgG4-RD from other forms of inflammatory conditions with the potential to involve the sinonasal area and the oral cavity.

Methods: We studied 11 consecutive patients with erosive and/or tumefactive lesions of the midline structures referred to our tertiary care center.

In Vivo Tracking of Human Hematopoiesis Reveals Patterns of Clonal Dynamics during Early and Steady-State Reconstitution Phases.

Hematopoietic stem/progenitor cells (HSPCs) are capable of supporting the lifelong production of blood cells exerting a wide spectrum of functions. Lentiviral vector HSPC gene therapy generates a human hematopoietic system stably marked at the clonal level by vector integration sites (ISs). Using IS analysis, we longitudinally tracked >89,000 clones from 15 distinct bone marrow and peripheral blood lineages purified up to 4 years after transplant in four Wiskott-Aldrich syndrome patients treated with HSPC gene therapy.

Angiopoietin 2 expression in the cornea and its control of corneal neovascularisation.

Purpose: To define proangiogenic angiopoietin 2 (ANG2) expression and role(s) in human and mouse vascularised corneas. Further, to evaluate the effect of ANG2 inhibition on corneal neovascularisation (CNV).

Methods: CNV was induced in FVB mice by means of intrastromal suture placement.

Current Approaches and Future Perspectives for In Vivo Clonal Tracking of Hematopoietic Cells.

Over the past years, clonal tracking has gained the center stage as a unique technology capable to unveil population dynamics and hierarchical relationships in vivo. We here highlighted the main open questions related to the in vivo clonal behavior of hematopoietic cells with a particular focus on hematopoietic stem and progenitor cells and T cells as main targets of cell- and gene-therapies. We walked through the current methods applied for tracing in vivo dynamics and functions of hematopoietic cells in animal models and we described the results of early studies conducted on humans.

Transcriptional, epigenetic and retroviral signatures identify regulatory regions involved in hematopoietic lineage commitment.

Genome-wide approaches allow investigating the molecular circuitry wiring the genetic and epigenetic programs of human somatic stem cells. Hematopoietic stem/progenitor cells (HSPC) give rise to the different blood cell types; however, the molecular basis of human hematopoietic lineage commitment is poorly characterized. Here, we define the transcriptional and epigenetic profile of human HSPC and early myeloid and erythroid progenitors by a combination of Cap Analysis of Gene Expression (CAGE), ChIP-seq and Moloney leukemia virus (MLV) integration site mapping.

The case of an APDS patient: Defects in maturation and function and decreased in vitro anti-mycobacterial activity in the myeloid compartment.

Activated PI3-kinase delta syndrome (APDS) was recently reported as a novel primary immunodeficiency caused by heterozygous gain-of-function mutations in PIK3CD gene. Here we describe immunological studies in a 19year old APDS patient for whom genetic diagnosis was discovered by Whole Exome Sequencing (WES) analysis. In addition to the progressive lymphopenia and defective antibody production we showed that the ability of the patient's B cells to differentiate in vitro is severely reduced.

HIV-1 transcriptional silencing caused by TRIM22 inhibition of Sp1 binding to the viral promoter.

Background: Intracellular defense proteins, also referred to as restriction factors, are capable of interfering with different steps of the viral life cycle. Among these, we have shown that Tripartite motif 22 (TRIM22) suppresses basal as well as phorbol ester-induced HIV-1 long terminal repeat (LTR)-mediated transcription, independently of its E3 ubiquitin ligase activity, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) binding to the U3 region and Tat interaction with the TAR region of the HIV-1 LTR. As basal HIV-1 transcription is driven by the transcription factor specificity protein 1 (Sp1), we have investigated whether TRIM22 could interfere with Sp1-driven transcriptional activation of the HIV-1 LTR.

Mixed chimerism evolution is associated with T regulatory type 1 (Tr1) cells in a β-thalassemic patient after haploidentical haematopoietic stem cell transplantation.

In a cohort of β-Thalassemia (β-Thal) transplanted with haploidentical-HSCT we identified one transplanted patient characterized by persistent mixed chimerism (PMC) for several months after HSCT. In this unique β-Thal patient we assessed the donor engraftment overtime after transplantation, the potential loss of the non-shared HLA haplotype, and the presence of CD49b(+)LAG-3(+) T regulatory type 1 (Tr1) cells, previously demonstrated to be associated with PMC after HLA-related HSCT for β-Thal. The majority of the patient's erythrocytes were of donor origin, whereas T cells were initially mostly derived from the recipient, no HLA loss, but an increased frequency of circulating Tr1 cells were observed.

Clinical Outlook for Type-1 and FOXP3(+) T Regulatory Cell-Based Therapy.

T regulatory cells (Tregs) are subsets of T lymphocytes specialized in modulating antigen-specific immune responses in vivo. Hence, Tregs represent an ideal therapeutic tool to control detrimental immune reactions. Based on solid pre-clinical results, investigators started testing the safety and efficacy of Treg-based therapies in humans.

When diagnostics meets translational research: detection of hemoglobin fractions in cellular lysates from in vitro erythroid cultures by Capillarys 2 Flex Piercing analyzer (Sebia).

Detection of hemoglobin (Hb) variants represents an important issue for diagnosis and adequate treatment of hemoglobinopathies. The Capillarys 2 Flex Piercing analyzer (Capillarys) by Sebia is routinely used in our clinical laboratories to detect Hb variants in peripheral blood (PB). This automated method separates Hb fractions by capillary electrophoresis, giving a spectrophotometric measure of their relative proportion.

Gene therapy returns to centre stage.

Recent clinical trials of gene therapy have shown remarkable therapeutic benefits and an excellent safety record. They provide evidence for the long-sought promise of gene therapy to deliver 'cures' for some otherwise terminal or severely disabling conditions. Behind these advances lie improved vector designs that enable the safe delivery of therapeutic genes to specific cells.

Targeted Gene Correction in Osteopetrotic-Induced Pluripotent Stem Cells for the Generation of Functional Osteoclasts.

Autosomal recessive osteopetrosis is a human bone disease mainly caused by TCIRG1 gene mutations that prevent osteoclasts resorbing activity, recapitulated by the oc/oc mouse model. Bone marrow transplantation is the only available treatment, limited by the need for a matched donor. The use of induced pluripotent stem cells (iPSCs) as an unlimited source of autologous cells to generate gene corrected osteoclasts might represent a powerful alternative.