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.

fSCIG 10% in pediatric primary immunodeficiency diseases: a European post-authorization safety study.

BACKGROUND: The safety, tolerability, and immunogenicity of hyaluronidase-facilitated subcutaneous immunoglobulin (fSCIG) 10% (dual-vial unit of human immunoglobulin 10% and recombinant human hyaluronidase [rHuPH20]) were assessed in children with primary immunodeficiency diseases (PIDs). METHODS: This phase 4, post-authorization, prospective, interventional, multicenter study (NCT03116347) conducted in the European Economic Area, enrolled patients aged 2 to < 18 years with a documented PID diagnosis who had received immunoglobulin therapy for ≥ 3 months before enrollment. New fSCIG 10% starters underwent fSCIG 10% dose ramp-up for ≤ 6 weeks (epoch 1) before receiving fSCIG 10% for ≤ 3 years (epoch 2); patients pretreated with fSCIG 10% entered epoch 2 directly. The primary outcome was the number and rate (per infusion) of all noninfectious treatment-related serious and severe adverse events (AEs). RESULTS: In total, 42 patients were enrolled and dosed (median [range] age: 11.5 [3-17] years; 81% male; 23 new starters; 19 pretreated). Overall, 49 related noninfectious, treatment-emergent AEs (TEAEs) were reported in 15 patients; most were mild in severity (87.8%). No treatment-related serious TEAEs were reported. Two TEAEs (infusion site pain and emotional distress) were reported as severe and treatment-related in a single new fSCIG 10% starter. The rate of local TEAEs was lower in pretreated patients (0.1 event/patient-year) versus new starters (1.3 events/patient-year). No patients tested positive for binding anti-rHuPH20 antibodies (titer of ≥ 1:160). CONCLUSIONS: No safety signals were identified, and the incidence of local AEs declined over the duration of fSCIG 10% treatment. This study supports fSCIG 10% long-term safety in children with PIDs. TRIAL REGISTRATION NUMBER (CLINICALTRIALS.GOV): NCT03116347.

Epstein-Barr virus-driven lymphoproliferation in inborn errors of immunity: a diagnostic and therapeutic challenge.

INTRODUCTION: Inborn errors of immunity (IEI) are a group of genetically heterogeneous disorders with a wide-ranging clinical phenotype, varying from increased predisposition to infections to dysregulation of the immune system, including autoimmune phenomena, autoinflammatory disorders, lymphoproliferation, and malignancy. Lymphoproliferative disorder (LPD) in IEI refers to the nodal or extra-nodal and persistent or recurrent clonal or non-clonal proliferation of lymphoid cells in the clinical context of an inherited immunodeficiency or immune dysregulation. The Epstein-Barr virus (EBV) plays a significant role in the etiopathogenesis of LPD in IEIs. In patients with specific IEIs, lack of immune surveillance can lead to an uninhibited proliferation of EBV-infected cells that may result in chronic active EBV infection, hemophagocytic lymphohistiocytosis, and LPD, particularly lymphomas. AREAS COVERED: We intend to discuss the pathogenesis, diagnosis, and treatment modalities directed toward EBV-associated LPD in patients with distinct IEIs. EXPERT OPINION: EBV-driven lymphoproliferation in IEIs presents a diagnostic and therapeutic problem that necessitates a comprehensive understanding of host-pathogen interactions, immune dysregulation, and personalized treatment approaches. A multidisciplinary approach involving immunologists, hematologists, infectious disease specialists, and geneticists is paramount to addressing the diagnostic and therapeutic challenges posed by this intriguing yet formidable clinical entity.

Ataxia-telangiectasia in Latin America: clinical features, immunodeficiency, and mortality in a multicenter study.

Ataxia-telangiectasia (AT) is a rare genetic disorder leading to neurological defects, telangiectasias, and immunodeficiency. We aimed to study the clinical and immunological features of Latin American patients with AT and analyze factors associated with mortality. Referral centers from 9 Latin American countries participated in this retrospective cohort study, and 218 patients were included. Median (IQR) ages at symptom onset and diagnosis were 1.0 (1.0-2.0)  and 5.0 (3.0-8.0) years, respectively. Most patients presented recurrent airway infections, which was significantly associated with IgA deficiency. IgA deficiency was observed in 60.8% of patients and IgG deficiency in 28.6%. T- and B-lymphopenias were also present in most cases. Mean survival was 24.2 years, and Kaplan-Meier 20-year-survival rate was 52.6%, with higher mortality associated with female gender and low IgG levels. These findings suggest that immunologic status should be investigated in all patients with AT.

Clinical features and lymphocyte immunophenotyping analysis in primary immunodeficiency patients with non-transplant lymphoproliferative disorders.

Lymphoproliferative disorders (LPD) comprise a heterogeneous group and are originally classified into the "Disease of immune dysregulation" category. Of 96 Taiwanese patients during 2003-2022, 31 (median 66, range 0.03-675 months) developed LPD, mainly including palpable lymphadenopathy (in 10 patients), intestinal lymphadenopathy associated with refractory inflammatory bowel disease (IBD in 8) and hepatosplenomegaly (in 7) during long-term follow-up (median 144, range 3-252 months). They distributed in the categories of antibody deficiency (2 CVID, 2 TTC37, PIK3CD, PIK3R1 and AICDA each), phagocyte (4 CYBB, 1 STAT1 and 1 IFNRG1), immune dysregulation (2 FOXP3, 2 XIAP and 2 HLH), combined immunodeficiencies (2 IL2RG; CD40L, ZAP70 and unknown each), syndromic features (2 STAT3-LOF, 1 WAS and 1 ATM) and three with anti-IFN-γ autoantibodies. An increased senescent (CD8 + CD57+) and CD21-low, disturbed transitional B (CD38 + IgM++), plasmablast B (CD38++IgM-), memory B (CD19 + CD27+) and TEMRA (CD27-IgD-) components were often observed in cross-sectional immunophenotyping and trended to develop LPD.

[Immunophenotyping by spectral cytometry reveals a profile of lymphopenia associated with deregulation with an increase in effector memory lymphocytes in a patient with a mutation in the ITPR3 gene]. / Inmunofenotipo por citometría espectral, revela un perfil de linfopenia asociado a desregulación con aumento de linfocitos de memoria efectora en paciente con mutación en el gen ITPR3.

BACKGROUND: Variants in intracellular calcium transport genes have been associated with syndromic immunodeficiencies with a SCID phenotype. CASE REPORT: Seven-year-old girl of non-consanguineous parents, in Cartagena-Colombia. At two months of age, he presented hematochezia and was diagnosed with alimentary proctolitis without improvement with restriction to milk, wheat and eggs, and malnutrition developed. At eight months, a colon biopsy shows chronic lymphoid hyperplasia, presenting with anemia, eosinophilia, but total and specific IgE to normal foods. After four years, the Immunology Service found her asymptomatic, nutritionally recovered and without allergic sensitization, but eosinophilia and elevated calprotectin persisted, suggesting an early-onset inflammatory bowel disease. Immunoglobulins were normal, lymphocyte populations with CD3, CD4 and CD8 lymphopenia. At six years old, she presented atopic dermatitis, still had elevated calprotectin and was lymphopenic. Immunophenotyping by spectral cytometry using Cytek®cFluor®Immunoprofiling-Kit14 showed lymphopenia and CD4/CD8 inversion. Naïve CD4+ and CD8+ T lymphocytes were decreased, while T-CD8+CD45RA-CCR7- and T-CD8+CD45RA+CCR7- effector memory populations were expanded. Effector and central memory CD4+ T-lymphocytes were also increased1 (Image 1). The exome revealed a heterozygous variant in the ITPR3 gene (carrier father), c.7571G>A, p.(Arg2524His); predictors classify it as having a potential eliminating effect. CONCLUSIONS: The clinical features and immunophenotype of this candidate variant differ from others related to intracellular calcium transport. They are functional studies necessary to validate their causality. A patient with a potentially deleted variant presents an immunophenotype with CD3 lymphopenia and persistent lymphocyte activation.

ANTECEDENTES: Las variantes en genes del transporte de calcio intracelular han sido asociadas a inmunodeficiencias sindrómicas con un fenotipo IDCG. REPORTE DE CASO: Niña de siete años, de padres no consanguíneos, en Cartagena-Colombia. A los dos meses de vida, presenta hematoquecia y se diagnostica con proctolitis alimentaria sin mejoría con restricción a leche, trigo y huevo, desarrollando desnutrición. A los ocho meses, una biopsia de colon muestra hiperplasia linfoide crónica, cursa con anemia, eosinofilia, pero IgE total y específica a alimentos normales. A los cuatro años, el Servicio de Inmunología la encuentra asintomática, recuperada nutricionalmente y sin sensibilización alérgica, pero persiste eosinofilia y calprotectina elevada, sugiriendo una enfermedad inflamatoria intestinal de inicio temprano. Las inmunoglobulinas fueron normales, poblaciones linfocitarias con linfopenia CD3, CD4 y CD8. A los seis años, presenta dermatitis atópica, sigue con calprotectina elevada y linfopénica. El inmunofenotipo por citometría espectral mediante Cytek®cFluor®Immunoprofiling-Kit14, mostró linfopenia e inversión CD4/CD8. Los linfocitos T-vírgenes CD4+ y CD8+ estaban disminuidos, en cambio las poblaciones de memoria efectora T-CD8+CD45RA-CCR7- y T-CD8+CD45RA+CCR7­ estaban expandidas. Los linfocitos T-CD4+ de memoria efectora y central, también estaban aumentados1 (Imagen 1). El exoma reveló una variante heterocigótica en el gen ITPR3 (padre portador), c.7571G>A, p.(Arg2524His); los predictores la clasifican como de potencial efecto deletéreo. CONCLUSIONES: La clínica y el inmunofenotipo de esta variante candidata difiere de otras relacionadas con el transporte del calcio intracelular. Son necesarios estudios funcionales para validar su causalidad. Una paciente con una variante potencialmente deletérea, presenta un inmunofenotipo con linfopenia CD3 y activación persistente de los linfocitos.

Description of a Novel Pathogenic Variant in the ARPC1B and a Severe Allergy in Two Infants.

Actinrelated protein 2/3 complex subunit 1B (ARPC1B) deficiency is an inborn error of immunity (IEI) characterized by a combination of immunodeficiency and immune dysregulation and classified as an IEI with allergic manifestations. Here, we describe two patients with pathogenic variants in the ARPC1B gene. The first patient presented with eczema and bronchospasm at six months of age. The second patient presented with eczema and milk protein allergy at five months of age. The c.899_944 (p.Glu300Glyfs*7) pathogenic variant was previously described, whereas the c.863del (p.Pro288Leufs*9) variant was novel. ARPC1B deficiency should be considered because of the severe allergic manifestations at an early age.

STK4 deficiency and epidermodysplasia verruciformis-like lesions: A case report.

Serine/threonine kinase 4 deficiency (STK4 or MST1, OMIM:614868) is an autosomal recessive (AR) combined immunodeficiency that can present with skin lesions such as epidermodysplasia verruciformis-like lesions (EVLL). Herein, we describe a 17-year-old male patient born from consanguineous parents presenting with recurrent respiratory infections, verruciform plaques, poikiloderma, chronic benign lymphoproliferation, and Sjögren syndrome with suspected interstitial lymphocytic pneumonia.

Combined Treatment of Progressive Encephalitis in an X-linked Agammaglobulinemia Patient.

Most patients with X-linked agammaglobulinemia are susceptible to infections, while some cases also suffer from inflammatory or autoimmune complications. We describe a patient with progressive encephalitis who improved after the use of immunomodulatory treatment with corticosteroids, fluoxetine, and nitazoxanide. In most of the cases the evolution of the progressive encephalitis is complicated and catastrophic. Based on our experience and the review of the literature, we propose the use of this combined treatment to control this devastating complication.

Whole-exome sequencing to identify undiagnosed primary immunodeficiency disorders in children with community-acquired sepsis, admitted in the pediatric intensive care unit.

BACKGROUND: Whole-exome sequencing (WES) provides a powerful diagnostic tool for identifying primary immunodeficiency diseases (PIDs). This study explores the utility of this approach in uncovering previously undiagnosed PIDs in children with community-acquired sepsis (CAS), with a medical history of recurrent infections or a family history of PIDs. METHODS: We performed WES on DNA samples extracted from the blood of the 34 enrolled patients, followed by bioinformatic analysis for variant calling, annotation, and prioritization. We also performed a segregation analysis in available family members to confirm the inheritance patterns and assessed the potential impact of the identified variants on protein function. RESULTS: From 34 patients enrolled in the study, 29 patients (85%) with previously undiagnosed genetic diseases, including 28 patients with PIDs and one patient with interstitial lung and liver disease, were identified. We identified two patients with severe combined immunodeficiency (SCID), patients with combined immunodeficiency (CID), six patients with combined immunodeficiency with syndromic features (CID-SF), four patients with defects in intrinsic and innate immunity, four patients with congenital defects of phagocyte function (CPDF), and six patients with the disease of immune dysregulation. Autoinflammatory disorders and predominantly antibody deficiency were diagnosed in one patient each. CONCLUSION: Our findings demonstrate the potential of WES in identifying undiagnosed PIDs in children with CAS. Implementing WES in the clinical evaluation of CAS patients with a warning sign for PIDs can aid in their timely diagnosis and potentially lead to improved patient care.

Novel SLC5A6 mutations lead to B lymphocyte maturation defects with metabolic abnormality rescuable by biotin replenishment.

We characterized a family diagnosed with immunodeficiency disease presenting with low immunoglobulin levels and skin dyskeratosis. Exome sequencing revealed compound heterozygous missense variants in SLC5A6, the gene encoding a cellular sodium-dependent multivitamin transporter (SMVT) responsible for transporting vitamins, including biotin (vitamin B7). We showed that the biotin deficiency was caused by the SLC5A6 variants resulting in defective B cell differentiation and antibody deficiency. Altered cellular metabolic profiles, including aberrant mitochondrial respiration and reliance on glycolysis, may underlie the failure in plasma cell maturation. Replenishment of biotin improved plasma cell maturation and recovered the antibody producing activity in the patient and in a CRISPR-Cas9 gene-edited mouse model bearing a patient-specific SLC5A6 variant. Our results demonstrate the critical role of metabolic reprogramming in the maturation of plasma cells and nominate SLC5A6 as a causative gene for immunodeficiency that may be treated by biotin replenishment.

Respiratory Comorbidities Associated with Bronchiectasis in Patients with Common Variable Immunodeficiency in the USIDNET Registry.

BACKGROUND: Bronchiectasis is a major respiratory complication in patients with common variable immunodeficiency (CVID) and is associated with recurrent pulmonary infections. However, it is unclear whether other infections or non-infectious respiratory conditions are related to its development. OBJECTIVE: To identify respiratory comorbidities associated with bronchiectasis in patients with CVID. METHODS: A total of 1470 CVID patients enrolled in the USIDNET registry were included in a cross-sectional analysis. The primary outcome of our study was to determine the clinical characteristics and other respiratory conditions associated with respiratory comorbidities and physician-reported bronchiectasis. RESULTS: One hundred ninety-seven CVID patients were noted to have bronchiectasis (13.4%). Affected patients were significantly older than patients without bronchiectasis (median age 54 years vs. 49 years, p = 0.0004). These patients also had lower serum IgA (13 mg/dL IQR 60 mg/dL vs. 28.4 mg/dL IQR 66 mg/dL, p = 0.000). Notably, chronic rhinosinusitis (OR = 1.69 95%CI 1.05-2.75), sinusitis (OR = 2.06 95%CI 1.38-3.09), pneumonia (OR = 2.70 95%CI 1.88-3.88), COPD (OR = 2.66 95%CI 1.51-4.67), and interstitial lung disease (OR = 2.34 95%CI 1.41-3.91) were independently associated with the development of bronchiectasis in this population. CONCLUSION: These data suggest that lower and upper respiratory infections, chronic lower airway disease, and interstitial lung diseases are independently associated with bronchiectasis in CVID patients. Further study into predisposing conditions related to the development of bronchiectasis in CVID patients may allow prediction and early intervention strategies to prevent the development of this complication.

The first case report of complement component 7 deficiency in Qatar and a 10-year follow-up.

Introduction: Neisseria meningitidis is a significant cause of bacterial meningitis and septicemia worldwide. Recurrent Neisseria meningitidis is frequently associated with terminal complement protein deficiency, including Complement component 7. This report discusses the first case of C7 deficiency in Qatar. Case report: A 30-year-old Qatari man presented with a meningococcal infection, which was verified by a blood culture. He experienced two episodes of meningitis caused by an undetermined organism. His blood tests revealed low levels of CH50 and C7. His C7 gene testing revealed a homozygous mutation in exon 10 (c.1135G>C p.Gly379Arg), a mutation that has not been previously documented in Qatar. However, it has been observed in 1% of Moroccan-origin Israeli Jews who also exhibit C7 deficiency. Regular prophylactic quadrivalent vaccinations against types A, C, Y, and W-135 with azithromycin tabs were administered. Over the last 10 years of follow-up, he remained in good health, with no further meningitis episodes. Conclusion: To our knowledge, this is the first confirmed case of C7 deficiency reported in the Arabian Gulf countries. Such rare diseases should be a public health priority. Awareness among medical practitioners and the community should help with early detection of C7 deficiency and the prevention of its consequences.

Current Issues in the Management of IgG Subclass Deficiencies in Adults With Chronic Respiratory Diseases.

Primary immunodeficiency diseases (PIDs) are uncommon in adults; however, immunoglobulin G subclass deficiency (IGGSCD) is often found in a subset of adult patients with chronic respiratory diseases. As quantitative laboratory tests are used to diagnose IGGSCD, the clinical significance of IGGSCD remains controversial. However, respiratory infection is a common presenting feature of IGGSCD, and respiratory complications are responsible for subsequent morbidities, such as severe asthma, bronchiectasis, chronic obstructive airway diseases, and mortality. This review summarizes the current epidemiological data for PIDs, focusing on IGGSCD in the adult population. In addition, the investigation, treatment, and management strategies are detailed, including distinct issues faced by patients with chronic airway disease and their physicians in the proper diagnosis and treatment of IGGSCD.

Patient-reported outcomes in patients with primary immunodeficiency diseases in Japan: baseline results from a prospective observational study.

Introduction: Primary immunodeficiency diseases (PIDs) are rare inherited diseases resulting in impaired immunity. People with PID experience lower health-related quality of life (HR-QOL) and disease-related burdens in daily activities. This ongoing, prospective observational study aims to evaluate disease activity, treatment status, treatment-related burden, daily activities, and HR-QOL in patients with PID in Japan over a 1-year period. In this interim report (database lock: July 29, 2022), we present baseline results. Methods: Participants were enrolled between November 2021 and May 2022; data were collected four times/year per participant until May 2023 using an online electronic patient-reported outcomes system. Patients with PID and healthy volunteers aged ≥12 years, residing in Japan, and with access to a smartphone were eligible. HR-QOL (primary endpoint) was assessed by the EuroQol-5 Dimensions-5 Levels (EQ-5D-5L) and the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36). Work productivity was assessed by the Work Productivity and Activity Impairment (WPAI) Questionnaire. Other aspects of PID and burden were assessed with a new questionnaire developed in-house. The study is registered at the University hospital Medical Information Network clinical trials registry (UMIN000045622). Results: The full interim analysis set comprised 71 patients with PID and 47 healthy volunteers. The most common International Union of Immunological Societies PID category was primary antibody deficiency (56.3% of patients). Complications were common, especially recurrent respiratory tract infections (63.4%). Most patients with PID were treated with immunoglobulin replacement therapy (73.2%); 22.4% of these patients had serum immunoglobulin levels <700 mg/dL. Among patients who did not undergo hematopoietic cell transplantation, EQ-5D-5L (n=67) and SF-36 (n=59) Physical and Mental Component Summary scores were significantly lower than in healthy volunteers (p < 0.001). WPAI absenteeism, work productivity loss, and activity impairment scores were significantly lower in 42 working patients with PID than in 37 working healthy volunteers (p < 0.05). Other results indicated that patients with PID experience substantial burdens related to medical visits, expenses, work, and daily activities. Discussion: This interim analysis confirms that patients with PID in Japan have lower HR-QOL and work productivity compared with healthy individuals and experience substantial limitations and burdens in their daily lives.

A Nationwide Study of GATA2 Deficiency in Italy Reveals Novel Symptoms and Genotype-phenotype Association.

GATA2 deficiency is a rare disorder encompassing a broadly variable phenotype and its clinical picture is continuously evolving. Since it was first described in 2011, up to 500 patients have been reported. Here, we describe a cohort of 31 Italian patients (26 families) with molecular diagnosis of GATA2 deficiency. Patients were recruited contacting all the Italian Association of Pediatric Hematology and Oncology (AIEOP) centers, the Hematology Department in their institution and Italian societies involved in the field of vascular anomalies, otorhinolaryngology, dermatology, infectious and respiratory diseases. Median age at the time of first manifestation, molecular diagnosis and last follow-up visit was 12.5 (age-range, 2-52 years), 18 (age-range, 7-64 years) and 22 years (age-range, 3-64), respectively. Infections (39%), hematological malignancies (23%) and undefined cytopenia (16%) were the most frequent symptoms at the onset of the disease. The majority of patients (55%) underwent hematopoietic stem cell transplantation. During the follow-up rarer manifestations emerged. The clinical penetrance was highly variable, with the coexistence of severely affected pediatric patients and asymptomatic adults in the same pedigree. Two individuals remained asymptomatic at the last follow-up visit. Our study highlights new (pilonidal cyst/sacrococcygeal fistula, cholangiocarcinoma and gastric adenocarcinoma) phenotypes and show that lymphedema may be associated with null/regulatory mutations. Countrywide studies providing long prospective follow-up are essential to unveil the exact burden of rarer manifestations and the natural history in GATA2 deficiency.

ORAI1 defect in a patient with disseminated CMV infection and severe hypotonia.

BACKGROUND: A clinical presentation similar to severe combined immunodeficiency (SCID) with defective T cell activation but normal lymphocyte development occurs due to certain molecule defects including ORAI1- and STIM1. CASE: A four-month-old girl sufferd from fever, restlessness, diarrhea, and poor weight gain following the neonatal period. There was consanguinity and a positive family history. She had hypotonia and spontaneous opisthotonic posture. Refractory and extensive CMV infections were detected; immunological investigations revealed normal quantitative immunoglobulins and low numbers of CD3+, CD4+, and CD8+ cells. The next generation sequencing analysis revealed a mutation in the ORAI1 gene. CONCLUSIONS: The present patient`s history of refractory and widespread CMV infections shows a clinically substantial reduction in resistance against opportunistic microorganisms. This case emphasizes the importance of considering STIM1 and ORAI1 defects in patients with SCID phenotype and neurologic involvement, such as hypotonia.

Effects of Body Mass and Age on the Pharmacokinetics of Subcutaneous or Hyaluronidase-facilitated Subcutaneous Immunoglobulin G in Primary Immunodeficiency Diseases.

PURPOSE: To assess the pharmacokinetics (PK) of subcutaneous immunoglobulin (SCIG) and hyaluronidase-facilitated SCIG (fSCIG) therapy across body mass index (BMI) and age categories in patients with primary immunodeficiency diseases (PIDD) previously treated with intravenous immunoglobulin (IVIG). METHODS: Using our previously published integrated population PK model based on data from eight clinical trials, simulations were conducted to examine the effects of BMI and age on serum immunoglobulin G (IgG) PK after administration of SCIG 0.15 g/kg weekly or fSCIG 0.6 g/kg every 4 weeks in patients switching from stable IVIG. Patients were assumed to have baseline IgG trough concentrations of 7 g/L (hypothetical protective threshold). RESULTS: Mean steady-state serum IgG trough values (Cmin,ss or trough) increased with BMI and age. Mean Cmin,ss was 18% (SCIG) and 16% (fSCIG) higher in the obese than the healthy BMI group. Pediatric patients aged < 18 years had 8-22% (SCIG) and 4-20% (fSCIG) lower mean Cmin,ss values than adults, with the youngest group (2- < 6 years) having the lowest Cmin,ss. All patients across populations maintained Cmin,ss IgG concentrations of ≥ 7 g/L after switching to SCIG or fSCIG. CONCLUSION: Both SCIG and fSCIG successfully maintained trough values at or above the hypothetical protective threshold after switching from stable IVIG, irrespective of BMI or age. Differences in trough values between BMI groups and age groups (≤ 22%) may not warrant SCIG or fSCIG dose adjustments based on BMI or age alone; instead, the dosing paradigm should be guided by prior IVIG dose, individual IgG monitoring, and clinical findings.

Real-World Use, Safety, and Patient Experience of 20% Subcutaneous Immunoglobulin for Primary Immunodeficiency Diseases.

INTRODUCTION: The CORE study aimed to provide a detailed understanding of real-world immune globulin subcutaneous (human) 20% solution (Ig20Gly) utilization in patients with primary immunodeficiency diseases (PIDs) in Germany and Switzerland. METHODS: Patients with PIDs receiving a stable dose of any subcutaneous immunoglobulin for ≥ 3 months before enrollment were eligible for this multicenter (n = 5), phase 4, non-interventional, prospective, longitudinal cohort study. Besides baseline demographics and clinical characteristics, Ig20Gly utilization and safety data, and patient-reported outcomes (Life Quality Index/Treatment Satisfaction Questionnaire for Medication) were collected at baseline, 6 and 12 months. Statistical analysis was descriptive. RESULTS: Overall, 36 patients provided data at baseline [69.4% female; mean age: 41.6 years (7-78 years)]. Totals of 23 and 26 patients attended 6- and 12-month visits, respectively; 16 attended all three visits. One patient withdrew consent before 6-month follow-up. Median maximum infusion rates of Ig20Gly at baseline, 6 months, and 12 months were 26.7, 24.5, and 40.0 mL/h, respectively (10-60 mL/h). Infusion and dosing parameters remained consistent across time points: patients used a median of two infusion sites, primarily the abdomen, and all patients used an infusion pump; all but one infused at home and most self-administered Ig20Gly (80.8-83.3%) at once-weekly intervals (69.2-73.9%). During follow-up, 10 adverse events were reported: none were rated serious, while 2 were considered probably related to Ig20Gly. Total patient-reported outcome scores remained high throughout the study. CONCLUSION: The CORE study provides real-world evidence of the flexibility, feasibility, safety, and tolerability of Ig20Gly infusions, at mostly weekly intervals, over 1 year in patients with PIDs. TRIAL REGISTRATION: German Clinical Trials Register, DRKS00014562. Registered April 9, 2018, https://drks.de/search/en/trial/DRKS00014562.

Primary immunodeficiency diseases are rare diseases that make patients more likely to develop infections than the general population. Many patients with primary immunodeficiency diseases do not produce enough antibodies, which are an important part of the immune system that fight infection. Replacing antibodies is the main way to treat primary immunodeficiency diseases and reduce the risk of infection. Ig20Gly is a type of medication used to replace antibodies and treat primary immunodeficiency diseases. Patients receive Ig20Gly through a needle inserted under the skin and can learn to do this themselves at home. Ig20Gly can be delivered more quickly than other antibody treatments that are less concentrated. CORE was a study of 36 patients (children and adults) taking Ig20Gly for primary immunodeficiency diseases for 1 year in Germany and Switzerland. The aim of the study was to understand how patients use and experience Ig20Gly as part of their normal treatment. In this study, nearly all patients received Ig20Gly treatment at home, and most patients gave Ig20Gly to themselves once a week. A few patients developed serious bacterial infections while being treated with Ig20Gly, and patients were generally satisfied with the treatment. Overall, the CORE study describes how patients with primary immunodeficiency diseases use Ig20Gly in their daily lives, and shows that Ig20Gly treatment can be tailored to suit each patient's needs. Information from this study will help doctors to support patients in making decisions about their treatment.

Subcutaneous immunoglobulin 20% (Ig20Gly) treatment regimens in pediatric patients with primary immunodeficiencies - real-world data from the IG TATRY study.

BACKGROUND: Subcutaneous administration of immunoglobulins is associated with fewer systemic adverse events and easier infusion compared to intravenous administration. Ig20Gly is a 20% immunoglobulin formulation effective and safe in patients with primary immune deficiency diseases (PIDDs). Real-world data are scarce, therefore our study aimed to examine the real-life treatment regimen and clinical outcomes of Ig20Gly in Polish children with PIDDs. RESEARCHDESIGN: We retrospectively analyzed the medical documentation of 75 pediatric patients aged 0-17 years (mean 9.9) who received Ig20Gly (Cuvitru®; Baxalta US, Inc.; part of Takeda, MA, U.S.A.). RESULTS: The median exposure to treatment of the study population was 22.3 months. At the end of the study, 59 (78.7%) were still on Ig20Gly. The median monthly dose was 0.40 g/kg. The median treatment interval was 7.7 days. Most patients (96%) used one infusion site. The median infusion rate increased with patient age. The median IgG level in the study population, 8.0 g/L, was stable. There was one case of serious bacterial infection. CONCLUSION: This is the largest, long-term real-world study to date on the treatment patterns of Ig20Gly in pediatric patients with PIDDs. The results of this study support the feasibility and tolerability of Ig20Gly usage in PIDD patients across the pediatric age spectrum. TRIAL REGISTRATION: The trial is registered at ClinicalTrials.gov (NCT04636502).