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. METHODS: We conducted a retrospective study on the outcome of HCT in patients with DADA2. The primary outcome was overall survival (OS). RESULTS: Thirty DADA2 patients from 12 countries received a total of 38 HCTs. The indications for HCT were BMF, immune cytopenia, malignancy, or immunodeficiency. Median age at HCT was 9 years (range: 2-28 years). The conditioning regimens for the final transplants were myeloablative (n = 20), reduced intensity (n = 8), or non-myeloablative (n = 2). Donors were HLA-matched related (n = 4), HLA-matched unrelated (n = 16), HLA-haploidentical (n = 2), or HLA-mismatched unrelated (n = 8). After a median follow-up of 2 years (range: 0.5-16 years), 2-year OS was 97%, and 2-year GvHD-free relapse-free survival was 73%. The hematological and immunological phenotypes resolved, and there were no new vascular events. Plasma ADA2 enzyme activity normalized in 16/17 patients tested. Six patients required more than one HCT. CONCLUSION: HCT was an effective treatment for DADA2, successfully reversing the refractory cytopenia, as well as the vasculopathy and immunodeficiency. CLINICAL IMPLICATIONS: HCT is a definitive cure for DADA2 with > 95% survival

Humans with inherited MyD88 and IRAK-4 deficiencies are predisposed to hypoxemic COVID-19 pneumonia

X-linked recessive deficiency of TLR7, a MyD88- and IRAK-4–dependent endosomal ssRNA sensor, impairs SARS-CoV-2 recognition and type I IFN production in plasmacytoid dendritic cells (pDCs), thereby underlying hypoxemic COVID-19 pneumonia with high penetrance. We report 22 unvaccinated patients with autosomal recessive MyD88 or IRAK-4 deficiency infected with SARS-CoV-2 (mean age: 10.9 yr; 2 mo to 24 yr), originating from 17 kindreds from eight countries on three continents. 16 patients were hospitalized: six with moderate, four with severe, and six with critical pneumonia, one of whom died. The risk of hypoxemic pneumonia increased with age. The risk of invasive mechanical ventilation was also much greater than in age-matched controls from the general population (OR: 74.7, 95% CI: 26.8–207.8, P < 0.001). The patients’ susceptibility to SARS-CoV-2 can be attributed to impaired TLR7-dependent type I IFN production by pDCs, which do not sense SARS-CoV-2 correctly. Patients with inherited MyD88 or IRAK-4 deficiency were long thought to be selectively vulnerable to pyogenic bacteria, but also have a high risk of hypoxemic COVID-19 pneumonia

Homozygous DBF4 mutation as a cause for severe congenital neutropenia

Background Severe congenital neutropenia presents with recurrent infections early in life due to arrested granulopoiesis. Multiple genetic defects are known to block granulocyte differentiation, however a genetic cause remains unknown in approximately 40% of cases. Objective We aimed to characterize a patient with severe congenital neutropenia and syndromic features without a genetic diagnosis. METHODS: Whole exome sequencing results were validated using flow cytometry, Western blotting, co-immunoprecipitation, quantitative PCR, cell cycle and proliferation analysis of lymphocytes and fibroblasts and granulocytic differentiation of primary CD34+ and HL-60 cells. Results We identified a homozygous missense mutation in DBF4 in a patient with mild extra-uterine growth retardation, facial dysmorphism and severe congenital neutropenia. DBF4 is the regulatory subunit of the CDC7 kinase, together known as DBF4-dependent kinase (DDK), the complex essential for DNA replication initiation. The variant allele demonstrated impaired ability to bind CDC7, resulting in decreased DDK-mediated phosphorylation, defective S phase entry and progression and impaired differentiation of granulocytes associated with activation of the p53-p21 pathway. The introduction of WT DBF4 into patient CD34+ cells rescued the promyelocyte differentiation arrest. Conclusion Hypomorphic DBF4 mutation causes autosomal recessive severe congenital neutropenia with syndromic features

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

Correction; Early Access: ' DOI: 10.1007/s10875-022-01280-y Early Access: APR 2022Purpose 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-alpha) 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. Methods We conducted a retrospective study on the outcome of HCT in patients with DADA2. The primary outcome was overall survival (OS). Results Thirty DADA2 patients from 12 countries received a total of 38 HCTs. The indications for HCT were BMF, immune cytopenia, malignancy, or immunodeficiency. Median age at HCT was 9 years (range: 2-28 years). The conditioning regimens for the final transplants were myeloablative (n = 20), reduced intensity (n = 8), or non-myeloablative (n = 2). Donors were HLA-matched related (n = 4), HLA-matched unrelated (n = 16), HLA-haploidentical (n = 2), or HLA-mismatched unrelated (n = 8). After a median follow-up of 2 years (range: 0.5-16 years), 2-year OS was 97%, and 2-year GvHD-free relapse-free survival was 73%. The hematological and immunological phenotypes resolved, and there were no new vascular events. Plasma ADA2 enzyme activity normalized in 16/17 patients tested. Six patients required more than one HCT. Conclusion HCT was an effective treatment for DADA2, successfully reversing the refractory cytopenia, as well as the vasculopathy and immunodeficiency. Clinical Implications HCT is a definitive cure for DADA2 with > 95% survival.Peer reviewe

Correction to: Hematopoietic cell transplantation cures adenosine deaminase 2 deficiency: report on 30 patients

Correction to: Journal of Clinical Immunology (2021) 41:1633–164

Unravelling the genetic cause of life-threatening infections in children

Despite the progress of the last century in living conditions and medical care, some previously healthy children are still affected by lethal or potentially lethal infections with pathogens that only cause mild illness in most people. Hypothesizing that monogenic defects of immunity underlie the unusual infectious phenotype in these children, we apply an unbiased diagnostic approach with next generation sequencing to identify possible causes of immunodeficiency and proceed to analyze the identified mutations to characterize their pathophysiological mechanism. First of all, we study a patient from a consanguineous family who suffered from disseminated vaccine-strain measles and another patient with viscerotropic vaccine-strain yellow fever. Whole exome sequencing (WES) identifies previously not reported biallelic variants in the gene encoding the type I interferon receptor 1 (IFNAR1), involved in anti-viral innate and intracellular responses. A complete functional analysis of the variants is performed and demonstrates their pathogenicity at the gene, protein and cellular level. In particular, we show that patients' fibroblasts are highly susceptible to viruses, including the vaccine-strain measles and yellow fever. Therefore, autosomal recessive complete IFNAR1 deficiency results in life-threatening complications of live attenuated viral vaccinations in previously healthy children, but apparently not other severe infections. This study provides new insight into the specific function and potential redundancy of a pathway of innate immunity and highlights the fact that a severe/unusual course of infection in an otherwise healthy child should always be considered as a potential immunodeficiency. Subsequently, we expand our current knowledge of STAT2 deficiency, another autosomal recessive disorder of the type I interferon response. The affected patients present with a characteristic, although not fully penetrant, risk of disseminated disease and encephalitis after inoculation with live measles-mumps-rubella (MMR) vaccine. In contrast with IFNAR1 deficiency, they also seem to be susceptible to other viral illnesses and show a more severe phenotype, with a mortality of 19% in childhood. Analyzing sixteen patients from seven unrelated kindreds with STAT2 deficiency, we find a broader infectious and non-infectious phenotype than previously described, centered on viral susceptibility. Moreover, the functional assessment of the different mutations hints at a possible incomplete form of STAT2 deficiency, where type I interferon responses are partially preserved in vitro. As with other innate immunity defects, once patients reach adulthood they seem to be protected from severe infections. Finally, we tackle another inborn error of immunity presenting with a broader phenotype than previously described. A young woman manifesting intellectual and growth delay, dysmorphisms, macrothrombocytopenia, camptodactyly, and structural brain abnormalities, suffered from immunodeficiency, severe lung infections, immune dysregulation and systemic inflammation. WES identified a de novo mutation in CDC42, causing Takenouchi-Kosaki syndrome. The extended immunophenotyping of the patient showed B cell lymphopenia with increased naïve B cells, decreased naïve T cells, and a global defect of CD8+ T cell activation. Most interestingly, the patient had signs of immune dysregulation and autoinflammation, including myelofibrosis and upregulation of inflammatory cytokines in her blood. These findings expand the phenotypic spectrum of Takenouchi-Kosaki syndrome and link autoinflammation with other CDC42 mutations than those in the C-terminal domain, recently identified as a cause of neonatal inflammation and hemophagocytic lymphohistiocytosis.status: publishe

Recent advances in primary immunodeficiency: from molecular diagnosis to treatment.

The technological advances in diagnostics and therapy of primary immunodeficiency are progressing at a fast pace. This review examines recent developments in the field of inborn errors of immunity, from their definition to their treatment. We will summarize the challenges posed by the growth of next-generation sequencing in the clinical setting, touch briefly on the expansion of the concept of inborn errors of immunity beyond the classic immune system realm, and finally review current developments in targeted therapies, stem cell transplantation, and gene therapy.status: Published onlin

Inherited and acquired errors of type I interferon immunity govern susceptibility to COVID-19 and multisystem inflammatory syndrome in children

: Since the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)/coronavirus disease 2019 (COVID-19) pandemic, global sequencing efforts have led in the field of inborn errors of immunity, and inspired particularly by previous research on life-threatening influenza, they have revealed that known and novel inborn errors affecting type I interferon immunity underlie critical COVID-19 in up to 5% of cases. In addition, neutralizing autoantibodies against type I interferons have been identified in up to 20% of patients with critical COVID-19 who are older than 80 years and 20% of fatal cases, with a higher prevalence in men and individuals older than 70 years. Also, inborn errors impairing regulation of type I interferon responses and RNA degradation have been found as causes of multisystem inflammatory syndrome in children, a life-threatening hyperinflammatory condition complicating otherwise mild initial SARS-CoV-2 infection in children and young adults. Better understanding of these immunologic mechanisms can aid in designing treatments for severe COVID-19, multisystem inflammatory syndrome in children, long COVID, and neuro-COVID

Patients with Primary lmmunodeficiencies: How Are They at Risk for Fungal Disease ?

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Purpose of Review: In this review, we focus on the inborn errors of immunity known to render the host susceptible to fungal infections, including candidias, aspergillosis, dermatophytosis, phaeohyphomycosis, pneumocystosis, fusariosis, cryptococcosis, and endemic mycoses. Recent Findings: Classically, the burden of fungal disease in humans is believed to be carried by patients with a secondary immunodeficiency, either due to malignancy, to chemotherapy, to an immunocompromised state post hematopoietic stem cell transplantation, or to treatment with anti-cytokine therapies. However, in the last decade, the study of patients affected by fungal infections without any overt risk factors has led to the unraveling of several monogenic defects of human immunity to fungi. The study of these inborn errors of immunity has added vastly to our comprehension of antifungal immunity. For example, the role of IL-17 immunity in human defense against mucocutaneous candidiasis has been extensively characterized through the analysis of IL-17F, IL-17RA, IL-17Rc, ACT1, RORγT and, indirectly, CARD9 deficiency. Summary: Many monogenic causes of susceptibility to superficial and/or invasive fungal infections have been recently unraveled. Most of these inborn errors of immunity associate with a specific type of fungal infection, and such a defect should always be suspected and sought in patients affected by fungal infection in the absence of predisposing factors.status: publishe