Immunological Aspects of Kabuki Syndrome: A Retrospective Multicenter Study of the Italian Primary Immunodeficiency Network (IPINet).

Kabuki Syndrome (KS) is a multisystemic genetic disorder. A portion of patients has immunological manifestations characterized by increased susceptibility to infections and autoimmunity. Aiming to describe the clinical and laboratory immunological aspects of KS, we conducted a retrospective multicenter observational study on patients with KS treated in centers affiliated to the Italian Primary Immunodeficiency Network.Thirty-nine patients were enrolled, with a median age at evaluation of 10 years (range: 3 m-21y). All individuals had organ malformations of variable severity. Congenital heart defect (CHD) was present in 19/39 patients (49%) and required surgical correction in 9/39 (23%), with associated thymectomy in 7/39 (18%). Autoimmune cytopenia occurred in 6/39 patients (15%) and was significantly correlated with thymectomy (p < 0.002), but not CHD. Individuals with cytopenia treated with mycophenolate as long-term immunomodulatory treatment (n = 4) showed complete response. Increased susceptibility to infections was observed in 22/32 patients (69%). IgG, IgA, and IgM were low in 13/29 (45%), 13/30 (43%) and 4/29 (14%) patients, respectively. Immunoglobulin substitution was required in three patients. Lymphocyte subsets were normal in all patients except for reduced naïve T-cells in 3/15 patients (20%) and reduced memory switched B-cells in 3/17 patients (18%). Elevated CD3 + TCRαß + CD4-CD8-T-cells were present in 5/17 individuals (23%) and were correlated with hematological and overall autoimmunity (p < 0.05).In conclusion, immunological manifestations of KS in our cohort include susceptibility to infections, antibody deficiency, and autoimmunity. Autoimmune cytopenia is correlated with thymectomy and elevated CD3 + TCRαß + CD4-CD8-T-cells, and benefits from treatment with mycophenolate.

Long-term and real-world safety and efficacy of retroviral gene therapy for adenosine deaminase deficiency.

Adenosine deaminase (ADA) deficiency leads to severe combined immunodeficiency (SCID). Previous clinical trials showed that autologous CD34+ cell gene therapy (GT) following busulfan reduced-intensity conditioning is a promising therapeutic approach for ADA-SCID, but long-term data are warranted. Here we report an analysis on long-term safety and efficacy data of 43 patients with ADA-SCID who received retroviral ex vivo bone marrow-derived hematopoietic stem cell GT. Twenty-two individuals (median follow-up 15.4 years) were treated in the context of clinical development or named patient program. Nineteen patients were treated post-marketing authorization (median follow-up 3.2 years), and two additional patients received mobilized peripheral blood CD34+ cell GT. At data cutoff, all 43 patients were alive, with a median follow-up of 5.0 years (interquartile range 2.4-15.4) and 2 years intervention-free survival (no need for long-term enzyme replacement therapy or allogeneic hematopoietic stem cell transplantation) of 88% (95% confidence interval 78.7-98.4%). Most adverse events/reactions were related to disease background, busulfan conditioning or immune reconstitution; the safety profile of the real world experience was in line with premarketing cohort. One patient from the named patient program developed a T cell leukemia related to treatment 4.7 years after GT and is currently in remission. Long-term persistence of multilineage gene-corrected cells, metabolic detoxification, immune reconstitution and decreased infection rates were observed. Estimated mixed-effects models showed that higher dose of CD34+ cells infused and younger age at GT affected positively the plateau of CD3+ transduced cells, lymphocytes and CD4+ CD45RA+ naive T cells, whereas the cell dose positively influenced the final plateau of CD15+ transduced cells. These long-term data suggest that the risk-benefit of GT in ADA remains favorable and warrant for continuing long-term safety monitoring. Clinical trial registration: NCT00598481 , NCT03478670 .

Anti-Inflammatory and Immunomodulatory Effect of High-Dose Immunoglobulins in Children: From Approved Indications to Off-Label Use.

BACKGROUND: The large-scale utilization of immunoglobulins in patients with inborn errors of immunity (IEIs) since 1952 prompted the discovery of their key role at high doses as immunomodulatory and anti-inflammatory therapy, in the treatment of IEI-related immune dysregulation disorders, according to labelled and off-label indications. Recent years have been dominated by a progressive imbalance between the gradual but constant increase in the use of immunoglobulins and their availability, exacerbated by the SARS-CoV-2 pandemic. OBJECTIVES: To provide pragmatic indications for a need-based application of high-dose immunoglobulins in the pediatric context. SOURCES: A literature search was performed using PubMed, from inception until 1st August 2023, including the following keywords: anti-inflammatory; children; high dose gammaglobulin; high dose immunoglobulin; immune dysregulation; immunomodulation; immunomodulatory; inflammation; intravenous gammaglobulin; intravenous immunoglobulin; off-label; pediatric; subcutaneous gammaglobulin; subcutaneous immunoglobulin. All article types were considered. IMPLICATIONS: In the light of the current imbalance between gammaglobulins' demand and availability, this review advocates the urgency of a more conscious utilization of this medical product, giving indications about benefits, risks, cost-effectiveness, and administration routes of high-dose immunoglobulins in children with hematologic, neurologic, and inflammatory immune dysregulation disorders, prompting further research towards a responsible employment of gammaglobulins and improving the therapeutical decisional process.

Hemophagocytic inflammatory syndrome in ADA-SCID: report of two cases and literature review.

Hemophagocytic inflammatory syndrome (HIS) is a rare form of secondary hemophagocytic lymphohistiocytosis caused by an impaired equilibrium between natural killer and cytotoxic T-cell activity, evolving in hypercytokinemia and multiorgan failure. In the context of inborn errors of immunity, HIS occurrence has been reported in severe combined immunodeficiency (SCID) patients, including two cases of adenosine deaminase deficient-SCID (ADA-SCID). Here we describe two additional pediatric cases of ADA-SCID patients who developed HIS. In the first case, HIS was triggered by infectious complications while the patient was on enzyme replacement therapy; the patient was treated with high-dose corticosteroids and intravenous immunoglobulins with HIS remission. However, the patient required HLA-identical sibling donor hematopoietic stem cell transplantation (HSCT) for a definitive cure of ADA-SCID, without HIS relapse up to 13 years after HSCT. The second patient presented HIS 2 years after hematopoietic stem cell gene therapy (GT), secondarily to Varicella-Zoster vaccination and despite CD4+ and CD8+ lymphocytes' reconstitution in line with other ADA SCID patients treated with GT. The child responded to trilinear immunosuppressive therapy (corticosteroids, Cyclosporine A, Anakinra). We observed the persistence of gene-corrected cells up to 5 years post-GT, without HIS relapse. These new cases of children with HIS, together with those reported in the literature, support the hypothesis that a major dysregulation in the immune system can occur in ADA-SCID patients. Our cases show that early identification of the disease is imperative and that a variable degree of immunosuppression could be an effective treatment while allogeneic HSCT is required only in cases of refractoriness. A deeper knowledge of immunologic patterns contributing to HIS pathogenesis in ADA-SCID patients is desirable, to identify new targeted treatments and ensure patients' long-term recovery.

Genetic bases of C7 deficiency: systematic review and report of a novel deletion determining functional hemizygosity.

Primary complement system (C) deficiencies are rare but notably associated with an increased risk of infections, autoimmunity, or immune disorders. Patients with terminal pathway C-deficiency have a 1,000- to 10,000-fold-higher risk of Neisseria meningitidis infections and should be therefore promptly identified to minimize the likelihood of further infections and to favor vaccination. In this paper, we performed a systematic review about clinical and genetic patterns of C7 deficiency starting from the case of a ten-year old boy infected by Neisseria meningitidis B and with clinical presentation suggestive of reduced C activity. Functional assay via Wieslab ELISA Kit confirmed a reduction in total C activity of the classical (0.6% activity), lectin (0.2% activity) and alternative (0.1% activity) pathways. Western blot analysis revealed the absence of C7 in patient serum. Sanger sequencing of genomic DNA extracted from peripheral blood of the patient allowed the identification of two pathogenetic variants in the C7 gene: the already well-characterized missense mutation G379R and a novel heterozygous deletion of three nucleotides located at the 3'UTR (c.*99_*101delTCT). This mutation resulted in an instability of the mRNA; thus, only the allele containing the missense mutation was expressed, making the proband a functional hemizygote for the expression of the mutated C7 allele.

Immune dysregulation in Kabuki syndrome: a case report of Evans syndrome and hypogammaglobulinemia.

Kabuki syndrome (KS) is a rare multisystemic disease due to mutations in the KMT2D or KDM6A genes, which act as epigenetic modulators of different processes, including immune response. The syndrome is characterized by anomalies in multiple organ systems, and it is associated with autoimmune and inflammatory disorders, and an underlying immunological phenotype characterized by immunodeficiency and immune dysregulation. Up to 17% of KS patients present with immune thrombocytopenia characterized by a severe, chronic or relapsing course, and often associated to other hematological autoimmune diseases including autoimmune hemolytic anemia, eventually resulting in Evans syndrome (ES). A 23-year-old woman, clinically diagnosed with KS and presenting from the age of 3 years with ES was referred to the Rare Diseases Centre of our Pediatric Department for corticosteroid-induced hyperglycemia. Several ES relapses and recurrent respiratory infections in the previous years were reported. Severe hypogammaglobulinemia, splenomegaly and signs of chronic lung inflammation were diagnosed only at the time of our observation. Supportive treatment with amoxicillin-clavulanate prophylaxis and recombinant human hyaluronidase-facilitated subcutaneous immunoglobulin replacement were immediately started. In KS patients, the failure of B-cell development and the lack of autoreactive immune cells suppression can lead to immunodeficiency and autoimmunity that may be undiagnosed for a long time. Our patient's case is paradigmatic since she presented with preventable morbidity and severe lung disease years after disease onset. This case emphasizes the importance of suspecting immune dysregulation in KS. Pathogenesis and immunological complications of KS are discussed. Moreover, the need to perform immunologic evaluations is highlighted both at the time of KS diagnosis and during disease follow-up, in order to allow proper treatment while intercepting avoidable morbidity in these patients.

Autoimmune Polyendocrine Syndromes in the Pediatric Age.

Autoimmune polyendocrine syndromes (APSs) encompass a heterogeneous group of rare diseases characterized by autoimmune activity against two or more endocrine or non-endocrine organs. Three types of APSs are reported, including both monogenic and multifactorial, heterogeneous disorders. The aim of this manuscript is to present the main clinical and epidemiological characteristics of APS-1, APS-2, and IPEX syndrome in the pediatric age, describing the mechanisms of autoimmunity and the currently available treatments for these rare conditions.

Immune tolerance breakdown in inborn errors of immunity: Paving the way to novel therapeutic approaches.

Up to 25% of the patients with inborn errors of immunity (IEI) also exhibit immunodysregulatory features. The association of immune dysregulation and immunodeficiency may be explained by different mechanisms. The understanding of mechanisms underlying immune dysregulation in IEI has paved the way for the development of targeted treatments. In this review article, we will summarize the mechanisms of immune tolerance breakdown and the targeted therapeutic approaches to immune dysregulation in IEI.

Vasculitis and vasculopathy associated with inborn errors of immunity: an overview.

Systemic autoinflammatory diseases (SAIDs) are disorders of innate immunity, which are characterized by unprovoked recurrent flares of systemic inflammation often characterized by fever associated with clinical manifestations mainly involving the musculoskeletal, mucocutaneous, gastrointestinal, and nervous systems. Several conditions also present with varied, sometimes prominent, involvement of the vascular system, with features of vasculitis characterized by variable target vessel involvement and organ damage. Here, we report a systematic review of vasculitis and vasculopathy associated with inborn errors of immunity.

Immunological characterization of an Italian PANDAS cohort.

This cross-sectional study aimed to contribute to the definition of Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections (PANDAS) pathophysiology. An extensive immunological assessment has been conducted to investigate both immune defects, potentially leading to recurrent Group A ß-hemolytic Streptococcus (GABHS) infections, and immune dysregulation responsible for a systemic inflammatory state. Twenty-six PANDAS patients with relapsing-remitting course of disease and 11 controls with recurrent pharyngotonsillitis were enrolled. Each subject underwent a detailed phenotypic and immunological assessment including cytokine profile. A possible correlation of immunological parameters with clinical-anamnestic data was analyzed. No inborn errors of immunity were detected in either group, using first level immunological assessments. However, a trend toward higher TNF-alpha and IL-17 levels, and lower C3 levels, was detected in the PANDAS patients compared to the control group. Maternal autoimmune diseases were described in 53.3% of PANDAS patients and neuropsychiatric symptoms other than OCD and tics were detected in 76.9% patients. ASO titer did not differ significantly between the two groups. A possible correlation between enduring inflammation (elevated serum TNF-α and IL-17) and the persistence of neuropsychiatric symptoms in PANDAS patients beyond infectious episodes needs to be addressed. Further studies with larger cohorts would be pivotal to better define the role of TNF-α and IL-17 in PANDAS pathophysiology.

Do Vegetarian Diets Provide Adequate Nutrient Intake during Complementary Feeding? A Systematic Review.

During the complementary feeding period, any nutritional deficiencies may negatively impact infant growth and neurodevelopment. A healthy diet containing all essential nutrients is strongly recommended by the WHO during infancy. Because vegetarian diets are becoming increasingly popular in many industrialized countries, some parents ask the pediatrician for a vegetarian diet, partially or entirely free of animal-source foods, for their children from an early age. This systematic review aims to evaluate the evidence on how vegetarian complementary feeding impacts infant growth, neurodevelopment, risk of wasted and/or stunted growth, overweight and obesity. The SR was registered with PROSPERO 2021 (CRD 42021273592). A comprehensive search strategy was adopted to search and find all relevant studies. For ethical reasons, there are no interventional studies assessing the impact of non-supplemented vegetarian/vegan diets on the physical and neurocognitive development of children, but there are numerous studies that have analyzed the effects of dietary deficiencies on individual nutrients. Based on current evidence, vegetarian and vegan diets during the complementary feeding period have not been shown to be safe, and the current best evidence suggests that the risk of critical micronutrient deficiencies or insufficiencies and growth retardation is high: they may result in significantly different outcomes in neuropsychological development and growth when compared with a healthy omnivorous diet such as the Mediterranean Diet. There are also no data documenting the protective effect of vegetarian or vegan diets against communicable diseases in children aged 6 months to 2-3 years.

Nutritional Assessment of Baby Food Available in Italy.

Adequate complementary feeding practices are important for short- and long-term child health. In industrialized countries, the formulation of several commercial baby foods (CBFs) and an increase in their consumption has been noticed. AIM: To update and analyze the nutritional composition of CBFs available in the Italian market. METHODS: Data collection carried out in two steps (July 2018-January 2019) and updated in May-September 2021. The information on CBFs was taken from the websites of the major CBF producers available in Italy. The collected information were: Suggested initial and final age of consumption; Ingredients; Energy value; Macronutrients (protein, lipids, and carbohydrates); Fiber; Micronutrients (sodium, iron, and calcium); Presence of salt and added sugars, flavorings, and other additives. RESULTS: Time-space for which CBFs are recommended starts too early and ends too late; protein content is adequate and even too high in some food; Amount of fats and their quality must be improved, keeping the intake of saturated fats low; Sugar content is too high in too many CBFs and salt is unnecessarily present in some of them. Finally, the texture of too many products is purée, and its use is recommended for too long, hindering the development of infants' chewing abilities.

Complementary Feeding Caregivers' Practices and Growth, Risk of Overweight/Obesity, and Other Non-Communicable Diseases: A Systematic Review and Meta-Analysis.

Several institutions propose responsive feeding (RF) as the caregivers' relational standard when nurturing a child, from breast/formula feeding onwards. Previous systematic reviews (SRs) on caregivers' feeding practices (CFPs) have included studies on populations from countries with different cultures, rates of malnutrition, and incomes, whereas this SR compares different CFPs only in healthy children (4-24 months) from industrialized countries. Clinical questions were about the influence of different CFPs on several important outcomes, namely growth, overweight/obesity, risk of choking, dental caries, type 2 diabetes (DM2), and hypertension. The literature review does not support any Baby Led Weaning's or Baby-Led Introduction to SolidS' (BLISS) positive influence on children's weight-length gain, nor their preventive effect on future overweight/obesity. RF-CFPs can result in adequate weight gain and a lower incidence of overweight/obesity during the first two years of life, whereas restrictive styles and coercive styles, two kinds of non-RF in CF, can have a negative effect, favoring excess weight and lower weight, respectively. Choking risk: failure to supervise a child's meals by an adult represents the most important risk factor; no cause-effect relation between BLW/BLISS/RF/NRCF and choking could be found. Risks of DM2, hypertension, and caries: different CFPs cannot be considered as a risky or preventive factor for developing these conditions later in life.

Chilblain-like lesions onset during SARS-CoV-2 infection in a COVID-19-vaccinated adolescent: case report and review of literature.

BACKGROUND: COVID toes or chilblain-like skin lesions have been widely reported during COVID-19 pandemic. Most cases were described in patients with negative microbiological tests for SARS-CoV-2, therefore the possible relationship with SARS-CoV-2 infection, as well as with the nowadays broadly available mRNA-based vaccination, has not been fully elucidated.  CASE PRESENTATION: We here describe the case of a 14-year-old male who developed chilblain-like skin eruptions during SARS-CoV-2 infection despite two mRNA-based vaccine doses and review the clinical and epidemiological characteristics of chilblain-like lesions as a cutaneous presentation of COVID-19 in children. CONCLUSIONS: Most children and adolescent with COVID toes have a mild or asymptomatic SARS-CoV-2 infection. Our report aims to highlight the possible onset of these skin lesions in vaccinated children, if infection has occurred, and the potential use of systemic corticosteroids as a first line treatment. Additional evidence is required to better understand SARS-CoV-2 infection and cutaneous manifestations in children and determine the relationship between chilblain-like lesions and COVID-19 vaccination.

Timing of Complementary Feeding, Growth, and Risk of Non-Communicable Diseases: Systematic Review and Meta-Analysis.

No consensus currently exists on the appropriate age for the introduction of complementary feeding (CF). In this paper, a systematic review is conducted that investigates the effects of starting CF in breastfed and formula-fed infants at 4, 4-6, or 6 months of age (i) on growth at 12 months of age, (ii) on the development of overweight/obesity at 3-6 years of age, (iii) on iron status, and (iv) on the risk of developing (later in life) type 2 diabetes mellitus (DM2) and hypertension. An extensive literature search identified seven studies that evaluated the effects of the introduction of CF at the ages in question. No statistically significant differences related to the age at which CF is started were observed in breastfed or formula-fed infants in terms of the following: iron status, weight, length, and body mass index Z-scores (zBMI) at 12 months, and development of overweight/obesity at 3 years. No studies were found specifically focused on the age range for CF introduction and risk of DM2 and hypertension. Introducing CF before 6 months in healthy term-born infants living in developed countries is essentially useless, as human milk (HM) and formulas are nutritionally adequate up to 6 months of age.

Progressive Depletion of B and T Lymphocytes in Patients with Ataxia Telangiectasia: Results of the Italian Primary Immunodeficiency Network.

Ataxia telangiectasia (AT) is a rare neurodegenerative genetic disorder due to bi-allelic mutations in the Ataxia Telangiectasia Mutated (ATM) gene. The aim of this paper is to better define the immunological profile over time, the clinical immune-related manifestations at diagnosis and during follow-up, and to attempt a genotype-phenotype correlation of an Italian cohort of AT patients. Retrospective data of 69 AT patients diagnosed between December 1984 and November 2019 were collected from the database of the Italian Primary Immunodeficiency Network. Patients were classified at diagnosis as lymphopenic (Group A) or non-lymphopenic (Group B). Fifty eight out of 69 AT patients (84%) were genetically characterized and distinguished according to the type of mutations in truncating/truncating (TT; 27 patients), non-truncating (NT)/T (28 patients), and NT/NT (5 patients). In 3 patients, only one mutation was detected. Data on age at onset and at diagnosis, cellular and humoral compartment at diagnosis and follow-up, infectious diseases, signs of immune dysregulation, cancer, and survival were analyzed and compared to the genotype. Lymphopenia at diagnosis was related per se to earlier age at onset. Progressive reduction of cellular compartment occurred during the follow-up with a gradual reduction of T and B cell number. Most patients of Group A carried bi-allelic truncating mutations, had a more severe B cell lymphopenia, and a reduced life expectancy. A trend to higher frequency of interstitial lung disease, immune dysregulation, and malignancy was noted in Group B patients. Lymphopenia at the onset and the T/T genotype are associated with a worst clinical course. Several mechanisms may underlie the premature and progressive immune decline in AT subjects.

Host Defenses to Viruses: Lessons from Inborn Errors of Immunity.

The constant battle between viruses and their hosts leads to their reciprocal evolution. Viruses regularly develop survival strategies against host immunity, while their ability to replicate and disseminate is countered by the antiviral defense mechanisms that host mount. Although most viral infections are generally controlled by the host's immune system, some viruses do cause overt damage to the host. The outcome can vary widely depending on the properties of the infecting virus and the circumstances of infection but also depends on several factors controlled by the host, including host genetic susceptibility to viral infections. In this narrative review, we provide a brief overview of host immunity to viruses and immune-evasion strategies developed by viruses. Moreover, we focus on inborn errors of immunity, these being considered a model for studying host response mechanisms to viruses. We finally report exemplary inborn errors of both the innate and adaptive immune systems that highlight the role of proteins involved in the control of viral infections.

Recommendations on Complementary Feeding as a Tool for Prevention of Non-Communicable Diseases (NCDs)-Paper Co-Drafted by the SIPPS, FIMP, SIDOHaD, and SINUPE Joint Working Group.

Adequate and balanced nutrition is essential to promote optimal child growth and a long and healthy life. After breastfeeding, the second step is the introduction of complementary feeding (CF), a process that typically covers the period from 6 to 24 months of age. This process is, however, still highly controversial, as it is heavily influenced by socio-cultural choices, as well as by the availability of specific local foods, by family traditions, and pediatrician beliefs. The Società Italiana di Pediatria Preventiva e Sociale (SIPPS) together with the Federazione Italiana Medici Pediatri (FIMP), the Società Italiana per lo Sviluppo e le Origine della Salute e delle Malattie (SIDOHaD), and the Società Italiana di Nutrizione Pediatrica (SINUPE) have developed evidence-based recommendations for CF, given the importance of nutrition in the first 1000 days of life in influencing even long-term health outcomes. This paper includes 38 recommendations, all of them strictly evidence-based and overall addressed to developed countries. The recommendations in question cover several topics such as the appropriate age for the introduction of CF, the most appropriate quantitative and qualitative modalities to be chosen, and the relationship between CF and the development of Non-Communicable Diseases (NCDs) later in life.

Inherited defects in the complement system.

The complement system plays an essential role in both innate and adaptive immune responses. Any dysregulation in this system can disturb normal host defense and alter inflammatory response leading to both infections and autoimmune diseases. The complement system can be activated through three different pathways. Inherited complement deficiencies have been described for all complement components and their regulators. Despite being rare diseases, complement deficiencies are often severe, with a frequent onset during childhood. We provide an overview of clinical disorders related to these disorders and describe current diagnostic strategies required for their comprehensive characterization and management.