Infusion parameters, safety, and practical guidance for the manual administration of subcutaneous immunoglobulin 20% (Ig20Gly).

Primary immunodeficiency diseases (PIDs), also referred to as inborn errors of immunity, constitute a group of genetic conditions that affect the immune system. The current standard of care for patients with PIDs is lifelong immunoglobulin replacement therapy, delivered by intravenous (IVIG) or subcutaneous (SCIG) infusion. Immune globulin subcutaneous (human) 20% solution stabilized with glycine (Ig20Gly) is indicated as a replacement therapy for PIDs in adults and children of any age in Europe and in patients aged 2 years and above in the USA. Typically, Ig20Gly is administered using an infusion pump; however, delivery of Ig20Gly by manual administration has recently been approved in Europe. Practical recommendations on the use of Ig20Gly manual administration are lacking; this review therefore aims to provide guidance for use of this method of administration. Additionally, we summarize the infusion parameters, safety, patient-reported outcomes, and economic benefits associated with Ig20Gly manual administration. Manual administration of Ig20Gly was shown to permit faster rates of infusion than administration via infusion pump. Patients typically infused at two or fewer infusion sites with manual administration of Ig20Gly. Safety and tolerability profiles were similar for Ig20Gly manual administration and administration by infusion pump. Overall, there were comparable levels of patient satisfaction with manual administration and infusion pump, with patient preference deemed to be a key determinator of success for either method of administration. Economic studies identified cost savings for the healthcare system through manual administration compared with IVIG or SCIG infusion by infusion pump because of the reduced equipment costs and nurse support. For infusion of Ig20Gly by manual administration, a syringe and butterfly needle are used; patients are advised to start infusion at 1-2 mL/min to prevent discomfort. Overall, manual administration of Ig20Gly offers an effective and well-tolerated alternative to administration by infusion pump.

Inborn errors of immunity and somatic variant phenocopies disrupting human JAK-STAT signaling.

The Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling cascade is an evolutionarily conserved signal transduction pathway that regulates many vital cellular processes, including immune function and hematopoiesis. Human genetic variants that disrupt JAK-STAT signaling are being found to cause a rapidly increasing number of diseases, including both germline-encoded inborn errors of immunity (IEI) and acquired somatic variants causing a 'phenocopy' of the IEI. Multiple genetic mechanisms are responsible for this growing group of JAK-STAT diseases including loss-of-function (LOF), gain-of-function (GOF), and dominant negative (DN) effects. In this review, we discuss the clinical presentation and pathogenesis of all currently described JAK/STAT defects, as well as providing an overview of the guiding principles to consider in diagnosing and treating these conditions.

Clinical exome sequencing data from patients with inborn errors of immunity: Cohort level diagnostic yield and the benefit of systematic reanalysis.

While next generation sequencing has expanded the scientific understanding of Inborn Errors of Immunity (IEI), the clinical use and re-use of exome sequencing is still emerging. We revisited clinical exome data from 1300 IEI patients using an updated in silico IEI gene panel. Variants were classified and curated through expert review. The molecular diagnostic yield after standard exome analysis was 11.8 %. Through systematic reanalysis, we identified variants of interest in 5.2 % of undiagnosed patients, with 76.7 % being (candidate) disease-causing, providing a (candidate) diagnosis in 15.2 % of our cohort. We find a 1.7 percentage point increase in conclusive molecular diagnoses. We find a high degree of actionability in patients with a genetic diagnosis (76.4 %). Despite the modest absolute diagnostic gain, these data support the benefit of iterative exome reanalysis in IEI patients, conveying the notion that our current understanding of genes and variants involved in IEI is by far not saturated.

First Brazilian Case Report of Unrelated Patients with Identical ISG15 Mutation.

BACKGROUND: ISG15 deficiency is a mixed syndrome of Mendelian susceptibility to mycobacterial infections (MSMD), a rare inherited condition characterized primarily by recurrent infections from low-virulence mycobacteria and monogenic type I interferonopathy. OBJECTIVE: To characterize the laboratory and molecular features of two patients from different families affected by the same ISG15 variant. METHODS: We began with clinical characterization and investigation, assessed IL-12/IFN-γ production, performed genetic characterization through WES and Sanger sequencing, conducted an in silico molecular analysis of the genetic ISG15 variant's protein impact, and utilized RNAseq for transcriptome analysis to understand pathway impacts on ISG15-deficient subjects from unrelated families. RESULTS: A mutation in the ISG15 gene was identified, affecting two patients treated in different hospitals and cities in Brazil (Fortaleza and Sao Paulo), who are also members of unrelated families. Both patients showed low IFN-γ production when stimulated with BCG or BCG + IL-12. ISG15 deficiency presented with two distinct clinical phenotypes: infectious and neurological. It was identified that both patients are homozygous for the variant (c.83 T > A). Furthermore, it was observed that the mutant protein p.L28Q results in an unstable protein with increased flexibility (ΔΔG: -2.400 kcal/mol). Transcriptome analysis revealed 1321 differentially expressed genes, with significant upregulation in interferon pathways, showing higher expression in patients compared to controls. CONCLUSION: This study describes the first reported cases in Brazil of two unrelated patients with the same ISG15 mutation c.83 T > A, exhibiting infectious features such as mycobacterial infections and systemic candidiasis, neurological findings, and skin lesions, without adverse reactions to the BCG vaccine. CLINICAL IMPLICATIONS: Reporting ISG15 gene mutations in Brazilian patients enhances understanding of genetic susceptibilities, guiding effective diagnostics and treatment. Identifying high-risk individuals aids clinical practices, genetic counseling, and influences public health policies. We have identified the first case in Brazil of the same ISG15 variant c.83 T > A that was identified in two unrelated patients with distinct clinical phenotypes, infectious and neurological.

Investigating Concomitant RAG-2 and LRBA Mutations in SCID and Autoimmunity.

Inborn errors of immunity (IEI) are a large heterogenous group of diseases characterized by immunodeficiency, immune dysregulation, allergy, auto-inflammation and predisposition for malignancies. Most are inherited in an autosomal recessive trait. We studied a patient with severe combined immunodeficiency (SCID) and immune dysregulation who harbored two distinct bi-allelic IEI-associated genetic mutations. Clinical, immunological and genetic data were collected. Genetic investigation included whole exome sequencing on DNA extracted from skin fibroblasts. Family segregation was performed by Sanger sequencing. Immunological evaluation included absolute and functional evaluation of lymphocytes and chimerism analysis post hematopoietic stem cell transplantation (HSCT). Treg subsets, LRBA and CTLA4 expression levels were measured by flow-cytometric analysis. A nineteen-year-old female patient from a consanguine background underwent unconditioned matched sibling related HSCT during infancy due to clinical presentation of SCID with an Omenn phenotype. At that time her underlying genetic defect was not defined. Years after HSCT, severe auto-immune phenomena were noted, including a systemic lupus erythematosus-like syndrome and ophthalmic manifestations. Genetic evaluation revealed bi-allelic homozygous mutations in RAG-2 (c.685C>T, p.Arg229Trp) and a previously undescribed mutation in LRBA (c.3325G>T, p.Asp1109Tyr). LRBA and CTLA4 expression levels were normal, suggesting that the LRBA variant identified in these kindred is unlikely to be pathogenic. Multiple genetic defects causing complex IEIs may be identified in the same individual in highly consanguineous populations. Functional immunological testing is essential for evaluation of novel genetic variants.

Successful Allogeneic Hematopoietic Cell Transplantation for Patients with IL10RA Deficiency in Japan.

BACKGROUND: IL10RA (IL10 receptor subunit alpha) deficiency is an autosomal recessive disease that causes inflammatory bowel disease during early infancy. Its clinical course is often fatal and the only curative treatment is allogeneic hematopoietic cell transplantation (HCT). In Japan, only case reports are available, and there are no comprehensive reports of treatment outcomes. METHODS: We retrospectively analyzed patients with IL10RA deficiency in Japan. RESULTS: Two newly identified and five previously reported patients were included in this study. Five patients underwent HCT; one untransplanted patient survived to age 14, and one died of influenza encephalopathy before transplantation. All five HCT recipients underwent HCT at the age before 2 years. They all were conditioned with fludarabine/busulfan- or fludarabine /melphalan-based regimens. The donor source was human leukocyte antigen haploidentical donor bone marrow (BM) for two patients and unrelated umbilical cord blood (CB) for two patients. One patient experienced graft failure with unrelated CB and required a second transplant with unrelated BM. All patients who underwent HCT survived and demonstrated an improved performance status. CONCLUSION: In cases of IL10RA deficiency, the need for transplantation should be promptly assessed, and early transplantation should be considered. (190/250).

Oral Diseases as a Manifestation of Inborn Errors of Immunity.

Oral findings such as inflammation, ulcerations, or lesions can indicate serious systemic diseases and should prompt suspicion of acquired chronic conditions or inborn errors of immunity (IEIs). Currently, there are approximately 500 disease entities classified as IEIs, with the list expanding annually. The awareness of the existence of such conditions is of paramount importance, as patients with these disorders frequently necessitate the utilization of enhanced diagnostic techniques. This is exemplified by patients with impaired antibody production, in whom conventional serological methods may prove to be undiagnostic. Patients with IEI may require distinct therapeutic approaches or antimicrobial prophylaxis throughout their lives. An accurate diagnosis and, more importantly, early identification of patients with immune deficiencies is crucial to ensure the quality and longevity of their lives. It is important to note that the failure to establish a proper diagnosis or to provide adequate treatment could also have legal implications for medical professionals. The article presents IEIs, which may manifest in the oral cavity, and their diagnosis alongside therapeutic procedures.

Delineating the Clinical and Immunologic Characteristics: A Comparative Study of Inborn Errors of Immunity in Adult versus Pediatric Diagnosed.

INTRODUCTION: Inborn errors of immunity (IEIs) are rare genetic disorders primarily identified in children due to their significant effects on immune system functionality. However, an increasing number of IEI cases are being diagnosed in adults, attributed to delayed presentation or advancements in diagnostic capabilities. This study explores the clinical and immunologic distinctions between IEIs diagnosed in adulthood versus childhood, shedding light on their differential presentations, the impact of diagnostic delays, and treatment outcomes. METHODS: This study focused on 122 adult patients with IEI above 17 years old, diagnosed in adulthood or childhood. We collected comprehensive data on demographics, clinical presentations, genetic mutations, and therapeutic interventions. RESULTS: The study revealed that 72.9% of participants were diagnosed in adulthood, facing a median diagnostic delay of 96 months. Diagnostic delays were longer in adults (132 months vs. 24 months) than in children. The most common clinical manifestations at onset were recurrent infections (46.7%) and autoimmunity (18%). Predominantly antibody deficiency was the most frequently diagnosed immunodeficiency (54.9%), followed by immunodysregulation at a rate of 26.2%. A higher incidence of immune thrombocytopenia or other complications, such as hepatomegaly and enteropathy, was observed in adult-diagnosed patients with IEI. Malignancies were more prevalent in patients with adult-onset IEI compared to those with childhood-onset (18.1% vs. 5.2%). Overall, 15 different malignancies were recorded in 13 patients (10.6%), including lymphomas and cancers of the stomach, thymus, skin, breast, and colon. CONCLUSIONS: The findings highlight a considerable diagnostic delay in recognizing IEI, especially in adults, and illustrate distinct differences in disease manifestation and progression between adult-onset and delayed-diagnosis groups.

Health Care Utilisation in a Cohort of Patients with Primary and Secondary Antibody Deficiency in the United Kingdom.

INTRODUCTION: This study investigates the frequency of hospital attendances, emergency care attendances and geographical influences on service interaction in cohorts of patients with primary and secondary antibody deficiency, to inform future service planning and delivery. METHODS: The COVID-19 in Antibody Deficiency (COV-AD) study was a United Kingdom study that enrolled 525 participants between April 2021 and September 2022. Data on health care utilisation was extracted from a screening cohort of participants at one participating site (Birmingham, UK). Hospital attendance (i.e. all outpatient and inpatient care episodes, including hospital-based IVIG treatment) and emergency care attendance patterns were analysed. Geographical differences in travel times to hospitals and associated costs were considered for all participants at all recruiting sites. RESULTS: Individuals with antibody deficiency had a median of 7 hospital attendances per year. A diagnosis of secondary antibody deficiency, and antibody deficiency severe enough to require treatment with immunoglobulin replacement were associated with an increased frequency of hospital attendance. 12.7% of the cohort attended the Emergency Department at least once in the preceding twelve months. Individuals with secondary antibody deficiency were at greater risk of requiring emergency care over the preceding one-year and five-year periods. Individuals receiving subcutaneous immunoglobulin lived further from their local immunology centre and were more likely to engage with the COV-AD research study remotely, via dried blood spots sampling. CONCLUSION: This study highlights the utilisation of emergency and secondary care usage amongst patient with immunodeficiency and may inform service adaptation and development to better accommodate patient needs and circumstances.

Insights into the genetic theory of infectious diseases.

Over the past century, classical approaches from microbiology and immunology have produced spectacular results in the control of infectious diseases. However, the recent SARS-COV-2 pandemic has highlighted our continued failure to control some infections. Other microorganisms still pose a threat to humanity such as HIV, Ebola, and influenza viruses. It seems that conventional approaches are not able to solve all the current problems caused by infectious diseases. Human genetics has shown that infections have a strong genetic determinism that can lead to a predisposition or resistance to infections. This explains much of the clinical variability observed in individuals infected with the same pathogen. The identification of the genetic etiology allows a better understanding of the pathogenesis of infectious diseases and, consequently, the consideration of appropriate preventive and therapeutic strategies. This review provides insights into the genetic theory and the concrete evidence to support it. We highlight the role of primary immunodeficiencies in the discovery of Mendelian and monogenic susceptibility to infections, then we show how genetic and phenotypic heterogeneity, redundancy, and resistance to infection manifest in the context of this genetic determinism. To effectively combat the constant threat of microbes, it is essential to integrate human genetics with microbiology to examine the interactions between pathogens and our immune system.

Class II Transactivator Gene (CIITA) Variants Associated with Bare Lymphocyte Syndrome II in a Female Sudanese Patient.

Introduction: Inborn errors of immunity (IEI) are disorders that present a health issue, especially in developing countries where there is a high rate of consanguineous marriages and an increasing rate of diagnosis. One of these disorders is Bare Lymphocyte Syndrome II (BLS II) which is a rare and genetically complex disease that has high morbidity and mortality. The exact genotypic and phenotypic characteristics are still poorly characterized especially in developing countries. Case Presentation: Here, we report the first case of BLS II in a seven-month-old Sudanese female with recurrent chest infections, dermatitis, persistent diarrhea, and failure to thrive. The patient's all four sisters and three paternal uncles died in early infancy. Laboratory investigations revealed low CD3+, CD4+, and CD8+ lymphocytes, along with normal CD19+ and CD16+ lymphocytes, and low serum IgM and IgA levels. Genetic analysis revealed two CIITA variants; c.2296C >G p. (Pro766Ala) and c.439+1G >A. Conclusion: Further bioinformatics, immunological and clinical workups supported a pathogenic effect of both mutations affecting the function of CIITA protein, and suggesting a compound heterozygote mutation. The patient was started on prophylactic antibiotics and regular intravenous immunoglobulin replacement therapy. The prognosis of this disease is poor in most of the cases, with only a few reported cases surviving until adulthood.

The lung in inborn errors of immunity.

The lungs are integral to immune defense, and inborn errors of immunity (IEI) often manifest as lung disease. Lung complications of IEI can involve the airways, alveolar spaces, interstitium, vasculature, and pleura. Accurate identification of these lung disease patterns requires a thorough clinical history, physical examination, and high-resolution computed tomography (HRCT), as lung imaging patterns guide further respiratory and immunological evaluations. Respiratory assessment may also include pulmonary function tests, bronchoscopy with bronchoalveolar lavage, and, in some cases, lung biopsy. Additionally, molecular diagnosis of underlying immune defects, typically through comprehensive clinical phenotyping, functional immune studies, and genetic testing, is crucial for informing patient management and guiding targeted therapies. Importantly, given the complexity of IEI, a multidisciplinary approach is necessary. Furthermore, ongoing research is required to refine therapies and improve outcomes for lung complications.

Case report: Deep sequencing and long-read genome sequencing refine prior genetic analyses in families with apparent gonadal mosaicism in PIK3CD-related activated PI3K delta syndrome.

Gonadal and gonosomal mosaicism describe phenomena in which a seemingly healthy individual carries a genetic variant in a subset of their gonadal tissue or gonadal and somatic tissue(s), respectively, with risk of transmitting the variant to their offspring. In families with one or more affected offspring, occurrence of the same apparently de novo variants can be an indicator of mosaicism in either parent. Panel-based deep sequencing has the capacity to detect low-level mosaic variants with coverage exceeding the typical limit of detection provided by current, readily available sequencing techniques. In this study, we report three families with more than one affected offspring with either confirmed or apparent parental gonosomal or gonadal mosaicism for PIK3CD pathogenic variants. Data from targeted deep sequencing was suggestive of low-level maternal gonosomal mosaicism in Family 1. Through this approach we did not detect pathogenic variants in PIK3CD from parental samples in Family 2 and Family 3. We conclude that mosaicism was likely confined to the maternal gonads in Family 2. Subsequent long-read genome sequencing in Family 3 showed that the paternal chromosome harbored the pathogenic variant in PIK3CD in both affected children, consistent with paternal gonadal mosaicism. Detection of parental mosaic variants enables accurate risk assessment, informs reproductive decision-making, and provides helpful context to inform clinical management in families with PIK3CD pathogenic variants.

Case report on activated PI3K-delta syndrome.

BACKGROUND: Activated phosphoinositide 3-kinase delta syndrome (APDS) [OMIM 615513] is an inborn error of immunity with autosomal dominant inheritance caused by a pathogenic variant in the PIK3CD gene. The prevalence ratio of APDS is < 1: 1,000,000 newborns. The main clinical features of APDS are sinopulmonary infections, benign lymphoproliferation, autoinflammatory disease, and a major risk of lymphoid neoplasms. CLINICAL CASE: A 17-year-old female with a history of pneumonia at 9 months of age subsequently developed recurrent respiratory tract infections, bronchiectasis, perforated otitis media, unilateral tonsillar lymphoid hyperplasia, pansinusitis, recurrent oral candidiasis, and chronic rhinitis. Laboratory studies reported persistent leukopenia and lymphopenia, low CD4 lymphocyte subpopulation, and persistently elevated immunoglobulin M immunoglobulin studies with values up to 692 mg/dL. An inborn error of immunity next-generation sequencing and multiplex ligation-dependent probe amplification analysis detected a heterozygous pathogenic variant in the PIK3CD gene, compatible with APDS. Treatment with monthly injectable gamma globulin and prophylactic antibiotics was started, allowing better control of the infectious processes. CONCLUSION: This is the second case of APDS reported in Mexico in the literature. It is important to be aware of this condition to make a timely diagnosis, which requires a high clinical suspicion and immunological and genetic studies to provide adequate treatment and prevent complications.

INTRODUCCIÓN: El síndrome de la Fosfoinositida 3-cinasa delta activado (Activated Phosphoinositide 3-kinase δ síndrome, APDS) [OMIM 615513] es un error innato de la inmunidad con patrón de herencia autosómica dominante causada por una variante patogénica heterocigota del gen PIK3CD. Su prevalencia es < 1: 1,000,000 nacidos vivos. Las principales manifestaciones clínicas son infecciones sinopulmonares, linfoproliferación benigna, autoinmunidad y aumento del riesgo de malignización linfoide. CASO CLÍNICO: Femenino de 17 años de vida con antecedentes de neumonía a los 9 meses de edad, posteriormente infecciones de vías respiratorias recurrentes, bronquiectasias, otitis media perforada, hiperplasia linfoide de amigdala unilateral, pansinusitis, candidiasis oral recurrente y rinitis crónica. Los estudios de laboratorio reportaron leuco linfopenia persistente, subpoblación linfocitaria con CD4 baja y estudios de inmunoglobulinas con IgM persistentemente elevada con valor de hasta 692 mg/dl. Se realizó estudio molecular de secuenciación de siguiente generación (NGS por sus siglas en inglés Next-Generation Sequencing) y amplificación de sondas dependientes de ligandos múltiples (MLPA por sus siglas en inglés Multiplex Ligation-dependent Probe Amplification) dirigido a errores innatos de la inmunidad que detectó una variante patogénica en estado heterocigoto en el gen PIK3CD, compatible con APDS. Se inició tratamiento con gammaglobulina intravenosa mensual y antibiótico profiláctico, permitiendo mejor control de los procesos infecciosos. CONCLUSIONES: Este es el segundo caso reportado en la literatura de APDS en México, por lo que es importante su conocimiento para poder realizar un diagnóstico oportuno, para el cual se requiere una alta sospecha clínica, además de estudios inmunológicos y genéticos, con la finalidad de otorgar el tratamiento adecuado y prevenir complicaciones.

Transitions of Care in Patients With Inborn Errors of Immunity.

Inborn errors of immunity (IEI) are a group of inherited conditions caused by damaged monogenic variants that result in impairment and/or dysregulation within the immune system. IEI are typically diagnosed in infancy or early childhood, with clinical presentations that include increased susceptibility to infections, immune dysregulation, autoinflammation, bone marrow failure, and/or malignancy. Historically, transitions of care experienced by patients with IEI have not been well described in the literature. However, with treatment advances extending the long-term survival of patients, this has become a primary area of research. It is crucial to establish guidelines and recommendations specific to the transition of patients with IEI. Transitions may include patients who naturally progress from pediatric to adult care, from inpatient to outpatient settings, or from their established health care team to a new team (ie, moving from one geographic area to another). This narrative review summarizes the current data on transitions of care and describes the health care challenges and patient-related barriers impacting transitions of care. Frameworks with practical guidance on how health care practitioners can better manage care transitions faced by patients with IEI are presented.

Reduction in mucosal-associated invariant T cells (MAIT) in APECED patients is associated with elevated serum IFN-γ concentration.

Mucosal-associated invariant T cells (MAIT) are innate-like lymphocytes enriched in mucosal organs where they contribute to antimicrobial defense. APECED is an inborn error of immunity characterized by immune dysregulation and chronic mucocutaneous candidiasis. Reduction in the frequency of circulating MAITs has been reported in many inborn errors of immunity, but only in a few of them, the functional competence of MAITs has been assessed. Here, we show in a cohort of 24 patients with APECED, that the proportion of circulating MAITs was reduced compared with healthy age and sex-matched controls (1.1% vs. 2.6% of CD3+ T cells; p < 0.001) and the MAIT cell immunophenotype was more activated. Functionally the IFN-γ secretion of patient MAITs after stimulation was comparable to healthy controls. We observed in the patients elevated serum IFN-γ (46.0 vs. 21.1 pg/mL; p = 0.01) and IL-18 (42.6 vs. 13.7 pg/mL; p < 0.001) concentrations. Lower MAIT proportion did not associate with the levels of neutralizing anti-IL-22 or anti-IL-12/23 antibodies but had a clear negative correlation with serum concentrations of IFN-γ, IL-18, and protein C-reactive protein. Our data suggest that reduction of circulating MAITs in patients with APECED correlates with chronic type 1 inflammation but the remaining MAITs are functionally competent.