The 2015 IUIS Phenotypic Classification for Primary Immunodeficiencies

Extended List of Warning Signs in Qualification to Diagnosis and Treatment of Inborn Errors of Immunity in Children and Young Adults

BACKGROUND AND OBJECTIVES

Inborn errors of immunity (IEI) refer to genetically determined disorders presenting with recurrent infections, autoimmunity, allergies, and malignancies. IEI is now commonly used, replacing the previously used term primary immunodeficiencies (PID). The 10 warning signs of IEI are widely used in the identification patients with IEI. The aim of the study was to determine and compare the utility of the 10 and 14 warning signs in IEI diagnosing.

METHODS

A retrospective analysis of 2851 patients was performed (98.17% were subjects under 18 years old and 1.83% were adults). All patients were questioned about the 10 warning signs and four additional signs: severe eczema, allergies, hemato-oncologic disorders and autoimmunity. Sensitivity, specificity, positive and negative predictive values, and odds ratio were calculated for the 10 and 14 warning signs.

RESULTS

IEI were diagnosed in a total of 896 (31.4%) patients and excluded in 1955 (68.6%). The strongest predictors of IEI were hemato-oncologic disorders (OR = 11.25; p < 0.001) and autoimmunity (OR = 7.74; p < 0.001). The strongest predictors of severe IEI were hemato-oncologic disorders (OR = 89.26; p < 0.001), positive family history (OR = 25.23; p < 0.001), and autoimmunity (OR = 16.89; p < 0.001). There were 20.4% and 14% of IEI patients without any signs from the 10 and 14 warnings signs, respectively (p < 0.001). 20.3% and 6.8% of patients with severe PIDs had no presence of any signs from 10 and 14 signs, respectively (p = 0.012).

CONCLUSIONS

The 10 warning signs have limited usefulness in identifying IEI. The modified list of 14 warning signs seems to represent an effective diagnostic method for the detection of IEI patients, especially those with severe PIDs.

Identification of novel NFKB1 and ICOS frameshift variants in patients with CVID

Common variable immunodeficiency (CVID) is a 'late-onset' primary immunodeficiency characterized by variable manifestations and genetic heterogeneity. A monogenic cause of CVID has been reported in 10% of patients. In this study, we identified two novel pathogenic variants implicated in monogenic CVID by whole exome sequencing (WES) analysis: a heterozygous nuclear factor κB subunit 1 (NFKB1) p.G686fs mutation and a homozygous inducible T-cell co-stimulator (ICOS) p.L96Sfs mutation. The predicted crystal models indicated premature truncation of the two mutated proteins. Both variants were demonstrated as loss-of-function mutations and were associated with overlapped manifestations of respiratory fungal infection and splenomegaly. We further performed a detailed assessment of immunologic phenotypes and impaired lymphocyte functions in patients. Moreover, we discovered an association between monoclonal T-large granular lymphocyte proliferation and ICOS-deficient CVID for the first time. These observations lead to a new perspective on the underlying genetic heterogeneity of CVID.

Impact of Genetic Diagnosis on the Outcome of Hematopoietic Stem Cell Transplant in Primary Immunodeficiency Disorders

To evaluate the relationship between knowledge of genetic diagnosis before HSCT and outcome, we reviewed all HSCTs for primary immune deficiencies (PID) performed at UCSF from 2007 through 2018. SCID, a distinct entity identified since 2010 in California by newborn screening and treated early, was considered separately. The underlying genetic condition was known at the time of HSCT in 85% of cases. Graft failure was less frequent in patients with a genetic diagnosis (19% with a genetic diagnosis versus 47% without, p = 0.020). Furthermore, event-free survival and overall survival (OS) at 5 years were better for those with a genetic diagnosis (78% with versus 44% without, p = 0.006; and 93% versus 60% without, p = 0.0002, respectively). OS at 5 years was superior for known-genotype patients with both SCID (p = 0.010) and non-SCID PID (p = 0.010). There was no difference in OS between HSCT done in 2007-2010 compared to more recently (p = 0.19). These data suggest that outcomes of HSCT for PID with known genotype may reflect specific experience and literature, or that a substantial proportion of patients with PID of undetermined genotype may have had underlying conditions for which HSCT may carry greater risk. The higher rate of graft failure in PID with unknown genotype may be in part explained by insufficient conditioning, which in turn could be dictated by compromised organ function in patients undergoing HSCT late in the course. Widespread availability of PID gene sequencing as standard care can provide genetic diagnoses for most patients with PID prior to HSCT, permitting optimization of transplant approach.

Early-Onset Diabetes in an Infant with a Novel Frameshift Mutation in LRBA

We describe early-onset diabetes in a 6-month-old patient carrying an LRBA gene mutation. Mutations in this gene cause primary immunodeficiency with autoimmune disorders in infancy. At admission, he was in diabetic ketoacidosis, and treatment with fluid infusion rehydration and then i.v. insulin was required. He was discharged with a hybrid closed-loop system for insulin infusion and prevention of hypoglycemia (Minimed Medtronic 670G). He underwent a next-generation sequencing analysis for monogenic diabetes genes, which showed that he was compound heterozygous for two mutations in the LRBA gene. In the following months, he developed arthritis of hands and feet, chronic diarrhea, and growth failure. He underwent bone marrow transplantation with remission of diarrhea and arthritis, but not of diabetes and growth failure. The blood glucose control has always been at target (last HbA1c 6%) without any severe hypoglycemia. LRBA gene mutations are a very rare cause of autoimmune diabetes. This report describes the clinical course in a very young patient. The hybrid closed-loop system was safe and efficient in the management of blood glucose. This report describes the clinical course of diabetes in a patient with a novel LRBA gene mutation.

Myelodysplastic Syndrome in a Patient With Common Variable Immunodeficiency: A Rare Occurrence

Common variable immunodeficiency (CVID) is a primary immunodeficiency disorder caused by impaired B-cell function and antibody production. It commonly presents with chronic sinopulmonary and gastrointestinal manifestations. It is also associated with transformation to acute myeloid leukemia. However, the association of CVID with myelodysplastic syndrome (MDS) is rare. This case report aims to present one such rare association in a 26-year-old patient presenting with severe thrombocytopenia. Bone marrow biopsy revealed hypercellular marrow with 80-90% cellularity along with an increase in CD34 blasts. Cytogenetics revealed loss of the Y chromosome. Diagnosis of MDS with excess blasts-2 was confirmed with a Revised International Prognostic Scoring System score of 4, placing the patient in the intermediate-risk category. The patient was started on azacitidine, a hypomethylating agent. A referral to a bone marrow transplant was also done for the consideration of an allogeneic stem cell transplant.

An ultra-rare case of immunoskeletal dysplasia with neurodevelopmental abnormalities in an Indian patient with homozygous c.953C > T variant in EXTL3 gene: a case report

Background

Immunoskeletal dysplasia with neurodevelopmental abnormalities (ISDNA) is an ultra-rare genetic condition that belongs to the group of spondyloepimetaphyseal dysplasias. It is caused due to presence of biallelic variants in the EXTL3 gene. The encoded exostosin like glycosyltransferase 3 (EXTL3) protein plays a key role in heparan sulfate synthesis. The skeletal and nervous systems are prominently affected in ISDNA with variability in immunological manifestations. Here, we report the 15^th case of ISDNA (third patient of an Indian ancestry) in the world, along with a review of literature.

Case presentation

A 15-month-old female child with clinical indications of global developmental delay, short stature, coarse facial features, and hypotonia was referred to our clinic. Spondyloepimetaphyseal dysplasias associated with extra-skeletal manifestations was suspected based on clinic-radiological correlation. Whole exome sequencing analysis revealed the presence of a homozygous known pathogenic variant c.953C > T (p. Pro318Leu) in exon 3 of the EXTL3 gene, thereby confirming diagnosis of ISDNA.

Conclusion

We present an ultra-rare case of ISDNA- third patient of Indian ancestry and only the 15^th reported case in the literature. On review of all cases in the literature, we find that the affected individuals show abnormalities primarily in three systems namely- skeletal, nervous and immune system. Notably, patients harbouring the same variant in EXTL3 gene show phenotypic variability especially with respect to presence or absence of immunological manifestations, suggesting a role of unknown modifiers. Hence, it is currently not possible to correlate the variant position in the EXTL3 gene with disease severity.

Vulnerability to Meningococcal Disease in Immunodeficiency Due to a Novel Pathogenic Missense Variant in NFKB1

NF-κB1 deficiency is suggested to be the most common cause of common variable immunodeficiency (CVID). NFKB1 encodes for the p105 precursor protein of NF-κB1, which is converted into the active transcriptional subunit p50 through proteasomal processing of its C-terminal half upon stimulation and is implicated in the canonical NF-kB pathway. Rare monoallelic NFKB1 variants have been shown to cause (haplo) insufficiency. Our report describes a novel NFKB1 missense variant (c.691C>T, p.R230C; allele frequency 0.00004953) in a family vulnerable to meningitis, sepsis, and late-onset hypogammaglobulinemia. We investigated the pathogenic relevance of this variant by lymphocyte stimulation, immunophenotyping, overexpression study and immunoblotting. The ectopic expression of p50 for c.691 C>T restricted transcriptionally active p50 in the cytoplasm, and immunoblotting revealed reduced p105/50 expression. This study shows that the deleterious missense variant in NFKB1 adversely affects the transcriptional and translational activity of NFκB1, impairing its function. Patients immunological parameters show a progressive course of hypogammaglobulinemia, which may partially account for the incomplete disease penetrance and suggest the need for closer immunological monitoring of those mutation carriers.

Implementation of TREC/KREC detection protocol for newborn SCID screening in Bulgaria: a pilot study

Neonatal screening for inborn errors of immunity (IEI), based on quantification of T-cell-receptor- excision circles (TRECs) and kappa-deleting recombination-excision circles (KRECs) from dried blood spots (DBS), allows early diagnosis and improved outcomes for the affected children. Determination of TREC/KREC levels from prospectively collected newborns' Guthrie cards and from DBS samples of patients with confirmed IEI was done using a commercial kit. Retrospective assessment of flow cytometry evaluation of TREC/KREC correspondence with lymphocyte subpopulations and evaluation of the correlations between TREC and KREC with immune cells, based on the data from patients with suspected or confirmed immune disorders, were conducted. 2,228 Guthrie cards were tested, 1276 for TREC only and 952 for both TREC and KREC. Eight newborns (0.36%) were TREC positive and 10 (1.05%) had KREC below the cut-off. The re-testing rate was 1.88%. Retrospective analysis demonstrated that the TREC/KREC assay identifies 100% of severe combined immune deficiencies (SCID) cases when DBS were collected at birth. Correlation analysis showed moderate significant correlations between TREC and the absolute numbers of CD4 cells (r = 0.634, p < 0.01) and total T cells (r = 0.536, p < 0.01). The ability of KREC levels to predict abnormal absolute (AUC of 0.772) and relative (AUC 0.731) levels of B cells was demonstrated.

Functions of NK and iNKT cells in pediatric and adult CVID, ataxia telangiectasia and agammaglobulinemia patients

Primary immune deficiencies (PID) are known to be more than 400 genetic defects caused by the impairment in development and/or functions of the immune system. Common Variable Immunodeficiency (CVID), Ataxia Telangiectasia (AT) and Agammaglobulinemia (AG) are examples of the most common immunodeficiency syndrome. Natural killer (NK) cells are a component of innate immune system and play a major role in the host-rejection of both tumors and virally infected cells. iNKT cells have a role in autoimmune and infectious diseases and controlling of tumor rejection. In this study, NK and iNKT cells and their functions, and intracellular cytokine amount are aimed to determine in patients that suffer CVID, AT and AG. NKp30, NKp46, NKG2D, perforin and granzyme mRNA expression levels were analyzed using RT-PCR. Receptors, cytokine amount of NK cell subset and iNKT were analyzed by flow cytometry. Decreased CD3⁺ T and elevated NK cell subset in pediatric AT were found. Expression of NKp44 was decreased in adult AG, but not in pediatric patients. Low NKp44 expression in CD3^-CD16⁺CD56^dim NK cell subset was found in pediatric AT patients. High HLA-DR, perforin and granzyme expression were found in CD3^-CD16⁺CD56^dim NK cell subset of pediatric CVID and AT patients. Alteration of the number of NK subsets, NK receptor expression and cytokine production were observed in pediatric patients compared to healthy subjects.

Global systematic review of primary immunodeficiency registries

INTRODUCTION

During the last 4 decades, registration of patients with primary immunodeficiencies (PID) has played an essential role in different aspects of these diseases worldwide including epidemiological indexes, policymaking, quality controls of care/life, facilitation of genetic studies and clinical trials as well as improving our understanding about the natural history of the disease and the immune system function. However, due to the limitation of sustainable resources supporting these registries, inconsistency in diagnostic criteria and lack of molecular diagnosis as well as difficulties in the documentation and designing any universal platform, the global perspective of these diseases remains unclear.

AREAS COVERED

Published and unpublished studies from January 1981 to June 2020 were systematically reviewed on PubMed, Web of Science and Scopus. Additionally, the reference list of all studies was hand-searched for additional studies. This effort identified a total of 104614 registered patients and suggests identification of at least 10590 additional PID patients, mainly from countries located in Asia and Africa. Molecular defects in genes known to cause PID were identified and reported in 13852 (13.2% of all registered) patients.

EXPERT OPINION

Although these data suggest some progress in the identification and documentation of PID patients worldwide, achieving the basic requirement for the global PID burden estimation and registration of undiagnosed patients will require more reinforcement of the progress, involving both improved diagnostic facilities and neonatal screening.

[Immune dysregulation syndrome caused by STAT3 gene mutation: a complicated case study]

A boy, aged 4 years and 6 months, had disease onset of fever, cough, pale complexion, and weakness, with hepatosplenomegaly, lymphadenectasis, and pancytopenia. He had been having repeated respiratory and digestive tract infections. Gene detection showed a pathogenic heterozygous mutation, c.C2147 > T(p.T716M), in the STAT3 gene. The boy was thus diagnosed with immune dysregulation syndrome. Anti-infective therapy and irregular corticosteroid therapy had an unsatisfactory effect in the early stage, but the symptoms improved after regular corticosteroid therapy. This article reported the case of immune dysregulation syndrome caused by STAT3 gene mutation and summarized the epidemiology, clinical features, diagnosis, and treatment of this disease, which can provide a reference for early diagnosis, treatment, and future studies of this disease.

Dysregulatory processes of the cellular link of the immune system in the dynamics of common variable immunodeficiency

Common variable immunodeficiency (CVID) is a variant of primary immunodeficiency in which inhibition of antibody production is formed due to disorders of intercellular interaction affecting cellular elements of both innate and adaptive immune responses. A feature of CVID is the late start and variability of clinical minifestation. These arguments determine the purpose of the study: to identify the dynamics of changes in the cellular parameters of the adaptive and innate immune response depending on the duration and severity of the infectious manifestation of CVID. In this regard, a retrospective analysis of medical histories and dynamic observation of fifteen patients with CVID were carried out. Selection of specific parameters of cellular indices of factors of innate resistance and adaptive immunity was carried out on the basis of systemic-functional approach of immunodiagnostics. It is shown that in patients with CVID -mediated hypogammaglobulinemia and infectious phenotype of clinical manifestation, enhancement of quantitative and functional potentials of T-link effector cells of adaptive immunity is recorded against the background of reduction of number of regulatory T-helpers. With a more severe clinical course of the disease, the number of CD3+HLA DR + limphocytes is lower than with a more favorable version, there is a tendency to decrease the number of these cells, as well as the number of peripheral Treg with an increase in the length of the disease. Cellular components of innate immunity are characterized by a decrease in neutrophil activity, inhibition of antigen-presenting monocyte activity, the number and cytotoxicity of natural killers. At the same time, the tendency to decrease the cytolytic potential of NK with an increase in the length of illness and statistically significant differences depending on the severity of the manifestation of the infectious phenotype of CVID was recorded. The obtained results determine the importance of evaluating the cellular link of the immune system in patients with CVID, including as a prognostic criterion for the severity of the course.

Skin manifestations in pediatric patients with primary immunodeficiency diseases (PIDs) in a tertiary care hospital in Colombia

Background

The current literature describes the characteristics of some skin manifestations in the context of primary immunodeficiency diseases (PIDs), also known as inborn errors of the immune system. However, there are hardly any data on the epidemiological trends of skin manifestations and PIDs in Latin America (LA). We aimed to describe the characteristics of patients with skin manifestations and the diagnosis of a PID treated at a tertiary hospital in Colombia.

Methods

This was a retrospective observational study. Data were taken from the institutional database of pediatric PIDs, which includes 306 patients under 18 years of age who attended a tertiary care center in Cali, Colombia for inpatient or outpatient services between December 2013 and December 2018. A trained third-year dermatology resident reviewed the electronic clinical records of all the patients in the database and double-checked patients who presented with cutaneous signs and symptoms.

Results

A total of 83 patients out of the original 306 patients (27.1%) presented with some type of cutaneous manifestation. Of these patients, 56.6% had atopic dermatitis, 56.6% reported at least one episode of skin infection, and some of the patients had both of these manifestations. Infections were more frequent in the PID group of combined immunodeficiency associated with well-defined syndromes and atopic dermatitis in the group of antibody deficiencies.

Conclusions

It is important to recognize dermatological clinical characteristics in patients with PIDs. More studies are necessary to establish recommendations regarding the approach of diagnosis and management of these patients.

Safety and tolerability of IgPro10 in Japanese primary immunodeficiency patients: a registrational study

Studies investigating the safety of IgPro10 (Privigen^®, CSL Behring, King of Prussia, PA, USA) in Japanese patients with primary immunodeficiency (PID) are lacking. This study evaluated safety and tolerability of IgPro10 in Japanese patients with PID. In this prospective, open-label, single-arm, registrational study for Japan, IgPro10 was administered intravenously at pre-study doses of 138-556 mg/kg body weight per 3-/4-weekly dosing cycle for up to 4 months. Frequency and intensity of adverse events (AEs), their relationship to IgPro10 and AE rate per infusion (AERI) were evaluated. Of 11 enrolled patients, 10 completed the study. The median (range) total duration of exposure was 16.14 (4.1-16.3) weeks. Eight patients reported 19 AEs, none severe (based on maximum severity), giving an AERI of 0.442. One AE was deemed related to IgPro10 treatment. Three patients experienced temporally associated AEs. No serious AEs or deaths were reported. Nine patients (90%) who completed the study tolerated flow rates of ≥ 8 mg/kg/min; 5 tolerated 12 mg/kg/min (7.2 mL/kg/h), translating into a threefold decrease in mean infusion time. IgPro10 was well tolerated at a flow rate of up to 12 mg/kg/min. Safety and tolerability findings were consistent with previously reported studies in non-Japanese patients with PID.

Tumor Necrosis Factor Receptor-Associated Periodic Syndrome (TRAPS) with a New Pathogenic Variant in TNFRSF1A Gene in a Family of the Adult Male with Renal AA Amyloidosis-Diagnostic and Therapeutic Challenge for Clinicians

Tumor necrosis factor receptor-associated periodic syndrome (TRAPS) belongs to systemic autoinflammatory diseases (AIDs). Many of these syndromes are genetically conditioned and can be inherited. Diagnosis relies on clinical symptoms and should be confirmed by genetic testing. One of the most serious complications is AA amyloidosis. We present the diagnostic route of a 33-year-old male with AA amyloidosis and his children, leading to diagnosis of monogenic autoinflammatory syndrome, confirmed by genetic analysis. A novel variant of the in-frame insertion type in one allele of TNFRSF1A gene was found by whole exome sequencing and confirmed by Sanger sequencing, which allowed a diagnosis of TRAPS. Three-dimensional modeling was used to assess the structural changes introduced into TNFR1 molecule by the insertion. The analysis of the 3D model revealed that accommodation of the 4AA insert induces misalignment of three cysteine bridges (especially the C70-C96 bridge) in the extracellular domain, leading to putatively misfolded and improperly functioning TNFR1. Three of the patient's daughters inherited the same variant of the TNFRSF1A gene and presented TRAPS symptoms. TRAPS is a very rare disease, but in the presence of suggestive symptoms the genetic diagnostic workout should be undertaken. Early diagnosis followed by appropriate clinical management can prevent irreversible complications.

Selective immunoglobulin M deficiency in a patient with celiac disease and recurrent pneumonia

SIgMD is a rare immune disorder that occurs in a primary or secondary condition. Patients with recurrent infectious, cancers, and autoimmune disorders should be investigated to determine SIgMD.

Immunologic evaluation and genetic defects of apoptosis in patients with autoimmune lymphoproliferative syndrome (ALPS)

Apoptosis plays an important role in controlling the adaptive immune response and general homeostasis of the immune cells, and impaired apoptosis in the immune system results in autoimmunity and immune dysregulation. In the last 25 years, inherited human diseases of the Fas-FasL pathway have been recognized. Autoimmune lymphoproliferative syndrome (ALPS) is an inborn error of immunity, characterized clinically by nonmalignant and noninfectious lymphoproliferation, autoimmunity, and increased risk of lymphoma due to a defect in lymphocyte apoptosis. The laboratory hallmarks of ALPS are an elevated percentage of T-cell receptor αβ double negative T cells (DNTs), elevated levels of vitamin B12, soluble FasL, IL-10, IL-18 and IgG, and defective in vitro Fas-mediated apoptosis. In order of frequency, the genetic defects associated with ALPS are germinal and somatic ALPS-FAS, ALPS-FASLG, ALPS-CASP10, ALPS-FADD, and ALPS-CASP8. Partial disease penetrance and severity suggest the combination of germline and somatic FAS mutations as well as other risk factor genes. In this report, we summarize human defects of apoptosis leading to ALPS and defects that are known as ALPS-like syndromes that can be clinically similar to, but are genetically distinct from, ALPS. An efficient genetic and immunological diagnostic approach to patients suspected of having ALPS or ALPS-like syndromes is essential because this enables the establishment of specific therapeutic strategies for improving the prognosis and quality of life of patients.

Diagnosis of primary immunodeficiencies in Peru

PURPOSE OF REVIEW

Primary immunodeficiencies (PIDs) are human inborn errors of immunity, leading to an increased susceptibility to infections, inflammatory manifestations, and malignancy. We estimate around 16 000 individuals with PIDs living in Peru who are still undiagnosed. The purpose of this review is to make a situational analysis of the diagnosis of PIDs in Peru.

RECENT FINDINGS

There is an evident underdiagnosis of PIDs in Peru. Insufficient awareness and lack of diagnostic tools can be solved partially by expanding the number and expertise of Clinical Immunologists and specialized medical centers. The availability of molecular testing at reasonable costs is mandatory to improve the diagnostic approach to patients with suspected PID. The development of didactic and innovative educational tools has been a critical strategy to improve PID awareness and diagnosis in Peru.

SUMMARY

Developing countries like Peru still have critical limitations to diagnose patients with PIDs such as insufficient awareness in physicians, lack of specialized reference centers, and unavailability of confirmatory genetic testing. Joint work between government, health professionals, patient organizations, and society is essential to overcome these limitations and provide a better future for patients with inborn errors of immunity.

Dynamic Transcriptome-Proteome Correlation Networks Reveal Human Myeloid Differentiation and Neutrophil-Specific Programming

Human neutrophilic granulocytes form the largest pool of innate immune cells for host defense against bacterial and fungal pathogens. The dynamic changes that accompany the metamorphosis from a proliferating myeloid progenitor cell in the bone marrow into a mature non-dividing polymorphonuclear blood cell have remained poorly defined. Using mass spectrometry-based quantitative proteomics combined with transcriptomic data, we report on the dynamic changes of five developmental stages in the bone marrow and blood. Integration of transcriptomes and proteome unveils highly dynamic and differential interactions between RNA and protein kinetics during human neutrophil development, which can be linked to functional maturation of typical end-stage blood neutrophil killing activities.

Monogenic Primary Immunodeficiency Disorder Associated with Common Variable Immunodeficiency and Autoimmunity

BACKGROUND

Common variable immunodeficiency (CVID) is the most frequent primary immunodeficiency disorder mainly characterized by recurrent bacterial infections besides other immunological defects including loss of or dysfunction of B cells and decreased immunoglobulin levels. In this study, our aim is to evaluate clinical, immunological, and molecular data of patients with a primary clinical diagnosis of CVID and autoimmune phenotype with a confirmed genetic diagnosis.

METHODS

Among 297 patients with CVID, who were registered in the Iranian Primary Immunodeficiency Registry at Children's Medical Center Hospital in Iran, 83 patients have been genetically examined and 27 patients with autoimmunity and confirmed genetic mutations were selected for analysis. Whole-exome sequencing and confirmatory Sanger sequencing methods were used for the study population. A questionnaire was retrospectively filled for all patients to evaluate demographic, laboratory, clinical, and genetic data.

RESULTS

In the 27 studied patients, 11 different genetic defects were identified, and the most common mutated gene was LRBA, reported in 17 (63.0%) patients. Two patients (7.7%) showed autoimmune complications as the first presentation of immunodeficiency. Eleven patients (40.7%) developed one type of autoimmunity, and 16 patients (59.3%) progressed to poly-autoimmunity. Most of the patients with mono-autoimmunity (n = 9, 90.0%) primarily developed infectious complications, while in patients with poly-autoimmunity, the most common first presentation was enteropathy (n = 6, 37.6%). In 13 patients (61.9%), the diagnosis of autoimmune disorders preceded the diagnosis of primary immunodeficiency. The most frequent autoimmune manifestations were hematologic (40.7%), gastrointestinal (48.1%), rheumatologic (25.9%), and dermatologic (22.2%) disorders. Patients with poly-autoimmunity had lower regulatory T cells than patients with mono-autoimmunity.

CONCLUSION

In our cohort, the diagnosis of autoimmune disorders preceded the diagnosis of primary immunodeficiency in most patients. This association highlights the fact that patients referring with autoimmune manifestations should be evaluated for humoral immunity.

Whole-genome sequencing of a sporadic primary immunodeficiency cohort

Primary immunodeficiency (PID) is characterized by recurrent and often life-threatening infections, autoimmunity and cancer, and it poses major diagnostic and therapeutic challenges. Although the most severe forms of PID are identified in early childhood, most patients present in adulthood, typically with no apparent family history and a variable clinical phenotype of widespread immune dysregulation: about 25% of patients have autoimmune disease, allergy is prevalent and up to 10% develop lymphoid malignancies1-3. Consequently, in sporadic (or non-familial) PID genetic diagnosis is difficult and the role of genetics is not well defined. Here we address these challenges by performing whole-genome sequencing in a large PID cohort of 1,318 participants. An analysis of the coding regions of the genome in 886 index cases of PID found that disease-causing mutations in known genes that are implicated in monogenic PID occurred in 10.3% of these patients, and a Bayesian approach (BeviMed4) identified multiple new candidate PID-associated genes, including IVNS1ABP. We also examined the noncoding genome, and found deletions in regulatory regions that contribute to disease causation. In addition, we used a genome-wide association study to identify loci that are associated with PID, and found evidence for the colocalization of-and interplay between-novel high-penetrance monogenic variants and common variants (at the PTPN2 and SOCS1 loci). This begins to explain the contribution of common variants to the variable penetrance and phenotypic complexity that are observed in PID. Thus, using a cohort-based whole-genome-sequencing approach in the diagnosis of PID can increase diagnostic yield and further our understanding of the key pathways that influence immune responsiveness in humans.

Jeffrey's insights: Jeffrey Modell Foundation's global genetic sequencing pilot program to identify specific primary immunodeficiency defects to optimize disease management and treatment

Primary immunodeficiencies (PI) are genetic defects of the immune system that result in chronic and often life-threatening infections and/or life-threatening autoimmunity if not diagnosed and treated. Patients with a suspected PI, but without a genetic diagnosis, commonly undergo a diagnostic odyssey that is costly, time-consuming, and arduous. This delay in diagnosis prevents appropriate disease management and treatment, contributing to prolonged suffering and decreased quality of life. Although next generation sequencing (NGS) can provide these patients with relief from such a diagnostic odyssey, it is often unavailable, mainly due to cost and inaccessibility. In January 2019, the Jeffrey Modell Foundation (JMF) launched a free genetic sequencing pilot program for Jeffrey Modell Centers Network (JMCN) patients clinically diagnosed with an underlying PI. A total of 21 sites within the JMCN were invited to participate. JMF collaborated with Invitae, and testing was comprised of Invitae's Primary Immunodeficiency Panel, which currently includes 207 genes. A questionnaire was disseminated to each participating physician to evaluate barriers to access to genetic sequencing and changes in disease management and treatment after testing. One hundred fifty-eight patients and 29 family members were tested in this pilot study. Twenty-one percent of patients with a suspected monogenic disorder received a molecular diagnosis, and others received potentially useful diagnostic leads. Based on the results of genetic sequencing, clinical diagnosis was altered in 45% of patients, disease management was altered in 40%, treatment was altered in 36%, and genetic counseling was altered in 62%. The results of this pilot program demonstrate the utility, cost-efficiency, and critical importance of NGS for PI and make the case for broad scale sequence-based diagnostics for PI patients when requested by expert immunologists.

Patient experience with subcutaneous immunoglobulin 20%, Ig20Gly, for primary immunodeficiency diseases: a prespecified post hoc analysis of combined data from 2 pivotal trials

BACKGROUND

Often, patients with primary immunodeficiency diseases (PID), which are marked by the absence or loss of functional antibodies, require lifelong treatment with immunoglobulin (IG) replacement therapy administered either intravenously (intravenous immunoglobulin [IVIG]) or subcutaneously (subcutaneous immunoglobulin [SCIG]). In patients with PID, the 20% SCIG product, Ig20Gly, was shown to be efficacious and well tolerated in 2 phase 2/3 trials conducted in North America and Europe. This analysis evaluated patient satisfaction with Ig20Gly therapy and treatment preferences.

METHODS

This prespecified post hoc analysis showed combined data from 2 Ig20Gly pivotal trials. Treatment satisfaction was assessed in the pre-Ig20Gly period and after ≥11 months of Ig20Gly treatment using the Life Quality Index (LQI; both studies) and the Treatment Satisfaction Questionnaire for Medication-9 (TSQM-9; North American study only). Treatment preference was assessed using a survey at the end of the European study. Median within-patient differences in LQI and TSQM-9 scores between the pre-Ig20Gly period and the end of the Ig20Gly treatment period were assessed using the Wilcoxon signed-rank test.

RESULTS

A total of 113 patients (n = 68 [North American]; n = 45 [Europe]) with PID were included in the analysis. In the combined LQI analysis (n = 110), significant improvements were observed in the treatment interference (median ∆: + 2.8; P = 0.006) and therapy setting (median ∆: + 5.6; P < 0.0001) domains, and in the item-level scores for convenience (median ∆: + 1.0; P < 0.0001) and interference with work/school (median ∆: + 1.0; P = 0.0001) categories. In the subgroup analyses, significant improvements in the treatment interference and therapy setting domains and the convenience and interference with work/school items were observed for those who had previously received treatment outside the home, those who had previously received IVIG, and those in the North American study. Significant improvements were observed in the TSQM-9 treatment convenience domain (median ∆: + 11.1; P < 0.0001) and selected item-level scores in the North American study. In the European study, most (88.9%) patients preferred to continue Ig20Gly versus other IG treatments.

CONCLUSIONS

After ≥11 months of taking Ig20Gly, patients reported high levels of treatment satisfaction, convenience, and preference for Ig20Gly, with consistent results across studies and use of multiple patient-reported outcome measures.

ADA2 deficiency complicated by EBV-driven lymphoproliferative disease

A 29-year old male with recurrent respiratory and skin infections, anaemia and neutropaenia during childhood required immunoglobulin replacement for antibody deficiency from age 16. He remained relatively well until age 28 when he presented with a two-week history of fatigue, sore throat, fever and productive cough. He was found to have EBV viraemia and splenomegaly and a diagnosis of EBV-driven lymphoproliferative disease was made following bone marrow trephine. Family history was notable with three siblings: a healthy sister and two brothers with anaemia and neutropaenia; one who succumbed to septicaemia secondary to neutropaenic enterocolitis age 5 and another who developed intestinal vasculitis and antibody deficiency and had a successful haemopoetic stem cell transplant.

The proband's DNA underwent targeted sequencing of 279 genes associated with immunodeficiency (GRID panel). The best candidates were two ADA2 variants, p.Arg169Gln (R169Q) and p.Asn370Lys (N370K). Sanger sequencing and co-segregation of variants in the parents, unaffected sister and all three affected brothers was fully consistent with compound heterozygous inheritance. Subsequent whole genome sequencing of the proband identified no other potential causal variants. ADA2 activity was consistent with a diagnosis of ADA2 deficiency in affected family members.

This is the first description of EBV-driven lymphoproliferative disease in ADA2 deficiency. ADA2 deficiency may cause susceptibility to severe EBV-induced disease and we would recommend that EBV status and viral load is monitored in patients with this diagnosis and allogeneic SCT is considered at an early stage for patients whose ADA2 deficiency is associated with significant complications.

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We report a patient with ADA2 deficiency and EBV-driven lymphoproliferative disease.

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ADA2 deficiency may predispose to severe EBV-induced disease.

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We would recommend that EBV status and viral load is monitored in patients with ADA2 deficiency.

Rapid Low-Cost Microarray-Based Genotyping for Genetic Screening in Primary Immunodeficiency

Background: Genetic tests for primary immunodeficiency disorders (PIDs) are expensive, time-consuming, and not easily accessible in developing countries. Therefore, we studied the feasibility of a customized single nucleotide variant (SNV) microarray that we developed to detect disease-causing variants and copy number variation (CNV) in patients with PIDs for only 40 Euros. Methods: Probes were custom-designed to genotype 9,415 variants of 277 PID-related genes, and were added to the genome-wide Illumina Global Screening Array (GSA). Data analysis of GSA was performed using Illumina GenomeStudio 2.0, Biodiscovery Nexus 10.0, and R-3.4.4 software. Validation of genotype calling was performed by comparing the GSA with whole-genome sequencing (WGS) data of 56 non-PID controls. DNA samples of 95 clinically diagnosed PID patients, of which 60 patients (63%) had a genetically established diagnosis (by Next-Generation Sequencing (NGS) PID panels or Sanger sequencing), were analyzed to test the performance of the GSA. The additional SNVs detected by GSA were validated by Sanger sequencing. Results: Genotype calling of the customized array had an accuracy rate of 99.7%. The sensitivity for detecting rare PID variants was high (87%). The single sample replication in two runs was high (94.9%). The customized GSA was able to generate a genetic diagnosis in 37 out of 95 patients (39%). These 37 patients included 29 patients in whom the genetic variants were confirmed by conventional methods (26 patients by SNV and 3 by CNV analysis), while in 8 patients a new genetic diagnosis was established (6 patients by SNV and 2 patients suspected for leukemia by CNV analysis). Twenty-eight patients could not be detected due to the limited coverage of the custom probes. However, the diagnostic yield can potentially be increased when newly updated variants are added. Conclusion: Our robust customized GSA seems to be a promising first-line rapid screening tool for PIDs at an affordable price, which opens opportunities for low-cost genetic testing in developing countries. The technique is scalable, allows numerous new genetic variants to be added, and offers the potential for genetic testing not only in PIDs, but also in many other genetic diseases.

Pharmacometric Analysis of IgPro10 in Japanese and Non-Japanese Patients With Primary Immunodeficiency

PURPOSE

Immunoglobulin (Ig) G replacement therapy, administered intravenously (IVIG) or subcutaneously (SCIG), is the standard treatment in patients with primary immunodeficiencies (PID). We aimed to characterize the pharmacokinetic (PK) characteristics of serum IgG following administration of IgPro10 every 3 or 4 weeks in Japanese patients with PID, and compare with PK in non-Japanese patients. A previously developed population PK (PPK) model was validated, and predicted parameters were compared with the results from the clinical study.

METHODS

The previously developed PPK model, containing IgG concentration data from 5 non-Japanese studies, was supplemented with data from 3 Japanese studies of IgPro10 or IgPro20 to compare the IgG PK parameters between Japanese and non-Japanese patients. The model was externally validated by simulating IgG concentration-time profiles in Japanese patients to predict serum IgG PK characteristics and to compare them with observed Japanese PK data from Study IgPro10_3004.

FINDINGS

The analysis included 4502 serum IgG concentration values (from 34 Japanese and 168 non-Japanese patients). PPK estimates from the current analysis demonstrated a clearance (CL) of 0.139 L/d, central volume (V2) of 4.01 L, inter-compartmental clearance (Q) of 0.30 L/d, and peripheral volume of 3.51 L. These results were consistent with those from the previously published PPK model, with similar bootstrap means and 95% CIs. Goodness-of-fit criteria indicated that the final PPK model was consistent with observed data, with no systemic bias in model prediction. Prediction-corrected visual predictive checks confirmed a good description of data on both SCIG and IVIG. PK parameters were equivalent between Japanese and non-Japanese patients. Body weight was determined to be a significant covariate on both CL and V2. Simulated and observed AUC and maximum and minimum serum IgG concentrations were similar, with 90% CIs overlapping between simulated and observed IgG concentrations in Japanese patients.

IMPLICATIONS

PK parameter estimates of serum IgG were similar between Japanese and non-Japanese patients with PID. The PPK model, updated with Japanese data, was consistent with the previously published PPK model and could accurately predict both individual and population serum IgG concentration-time profiles following IgPro10 IV infusions every 3 or 4 weeks. EudraCT identifier: 2016-001631-12.

Genetic Basis of Myocarditis: Myth or Reality?

The genetic basis of myocarditis remains an intriguing concept, at least as long as the definition of myocarditis constitutes the definitive presence of myocardial inflammation sufficient to cause the observed ventricular dysfunction in the setting of cardiotropic infections. Autoimmune or immune-mediated myocardial inflammation constitutes a complex area of clinical interest, wherein numerous and not yet fully understood role of hereditary auto-inflammatory diseases can result in inflammation of the pericardium and myocardium. Finally, myocardial involvement in hereditary immunodeficiency diseases, cellular and humoral, is a possible trigger for infections which may complicate the diseases themselves. Whether the role of constitutional genetics can make the patient susceptible to myocardial inflammation remains yet to be explored.

Pharmacokinetic properties of Privigen® in Japanese patients with primary immunodeficiency

This prospective, Phase 3, open-label, study (EudraCT: 2016-001631-12) evaluated pharmacokinetic (PK) characteristics of 3-/4-weekly Privigen^® (IgPro10, CSL Behring, King of Prussia, PA, USA) in Japanese patients with PID. PK parameters including serum trough immunoglobulin (IgG) level before next infusion during the wash-in/wash-out phase (C_trough), area under the concentration-time curve from time point zero to the last time point with quantifiable concentration (AUC_0-last), dose-adjusted AUC_0-last (dAUC), lowest and highest observed IgG levels (C_min, C_max), time to reach C_max (T_max), and total clearance (CL) were analyzed for both regimens of Privigen^® (dose: 138-554 mg/kg body weight). Ten patients were included in this analysis (3-/4-weekly: n = 2/n = 8). C_trough levels achieved ranged 7.96-10.05 g/L. C_max was observed approximately 1 h after the start of the infusion in both regimens. Mean (SD [not applicable for 3-weekly data]) PK parameters: C_max, 16.60 and 14.20 (5.53) g/L; C_min, 10.60 and 8.53 (3.89) g/L; AUC_0-last, 5971 and 6591 (2633) g*h/L; dAUC, 0.41 and 0.46 (0.19) g*h/L/mg; CL, 2.53 and 2.53 (1.00) mL/h and median T_max was 1.19 and 1.14 h, for 3-/4-weekly dosing regimens, respectively. Privigen^® PK characteristics in Japanese patients were similar between dosing regimens and to previously-reported results in non-Japanese patients with PID.

[Recurrent infections of the upper aerodigestive tract in patients with primary immunodeficiency]

BACKGROUND

Primary immunodeficiency is a rare disease of humoral and cellular immune defense, which can lead to severe and recurrent infections of different organs. The diagnosis of this disease is often difficult, and its early identification is necessary for adequate treatment and control.

OBJECTIVE

This study aimed to analyze ear, nose, and throat (ENT) infections in adults and children with a primary immunodeficiency. We attempted to characterize possible warning signs that should trigger an immunologic diagnostic workup.

MATERIALS AND METHODS

The current study comprised a retrospective case series of patients with primary immunodeficiencies. The type of immunodeficiency and the number of ENT infections were recorded.

RESULTS

A total of 85 Patients were included in the study. 56 patients (66%) had an acute exacerbation of chronic rhinosinusitis (n = 28), cervical lymphadenitis (n = 16), acute tonsillitis (n = 14), and acute otitis media (n = 6). Reporting detailed information about the frequencies and dates of infections was not possible, due to the retrospective nature of the analysis.

CONCLUSION

The prevalence of ENT infections in patients with a primary immunodeficiency is increased compared to the normal population. For the ENT specialist, these findings underline the necessity of including primary immunodeficiency in the differential diagnosis and initiating targeted diagnostic methods where indicated. Interdisciplinary collaboration with rheumatologists and immunologists is highly recommended, particularly for pediatric patients.

Recurrent microdeletions at chromosome 2p11.2 are associated with thymic hypoplasia and features resembling DiGeorge syndrome

BACKGROUND

Thymic hypoplasia/aplasia occurs as a part of DiGeorge syndrome, which has several known genetic causes, and with loss-of-function mutations in forkhead box N1 (FOXN1).

OBJECTIVE

We sought to determine the cause of selective T-cell lymphopenia with inverted kappa/lambda ratio in several kindreds.

METHODS

Patients were identified through newborn screening for severe combined immunodeficiency using the T-cell receptor excision circle assay. Those found to have selective T-cell lymphopenia underwent testing with chromosomal microarray analysis. Three-week-old mice heterozygous for a loss-of-function mutation in forkhead box I3 (FOXI3), a candidate gene within the common deleted region found in patients, were compared with wild-type littermates. Assessments included body and organ weights, flow cytometric analysis of thymocytes and splenocytes, and histologic/transcriptomic analyses of thymic tissue.

RESULTS

Five kindreds with similar immunophenotypes that included selective T-cell lymphopenia had overlapping microdeletions at chromosome 2p11.2 that spanned FOXI3 and, in most cases, the immunoglobulin kappa light chain locus. Studies in a mouse knockout strain for FOXI3 revealed smaller body weights and relatively lower thymus weights in heterozygous compared with wild-type animals. Histology and flow cytometry on spleens and thymi from 3-week-old pups for T- and B-cell subsets and epithelial cells did not show any significant qualitative or quantitative differences. Transcriptomic analysis of thymic RNA revealed divergence in global transcriptomic signatures, and Ingenuity Pathway Analysis revealed predicted dysfunction in epithelial adherens junctions.

CONCLUSIONS

Microdeletions at chromosome 2p11.2 are associated with T-cell lymphopenia and probable thymic hypoplasia in human subjects, and haploinsufficiency for FOXI3, a candidate gene within the deleted region, is the likely underlying cause.

Primary Immunodeficiency Disorders Among North Indian Children

OBJECTIVES

To report the distribution pattern of various categories of primary immunodeficiency disorders (PIDs) in children from North India, frequency of warning signs and critical parameters for evaluation.

METHODS

In this retrospective study, 528 children below 18 y of age after clinical assessment and presentation suggestive of PID were further screened by immunophenotyping for immune cell markers by flow cytometry.

RESULTS

A total of 120 (23%) children were diagnosed with PID with median age at diagnosis being 2.5 y in males and 3.5 y in females and an average delay in diagnosis from onset of symptoms being approximately 5 y. Chronic lower respiratory tract infections, gastrointestinal symptoms like persistent diarrhea and failure to thrive were amongst the most common warning signs in these patients. PIDs were classified according to the International Union of Immunological Societies' (IUIS) criteria. The diagnosis of index study subjects included combined humoral and cellular immunodeficiency (29%), phagocytic defects (29%), followed by predominantly antibody deficiency (18%), innate immunity and dysregulation (17%) and other well-defined syndromes (7%). A family history of PID (23%), consanguineous marriage (8%) and previous sibling death (23%) were observed as major clinical predictors/clues for underlying PID. All children received prophylactic antibiotics and/or antifungals in addition to specific therapy for underlying immune deficiency.

CONCLUSIONS

The field of PIDs in India remains largely unexplored and we are faced with various challenges in the diagnosis of PIDs due to lack of awareness as well as absence of equipped immunological laboratory support. The authors propose a methodical step-wise laboratory diagnostic approach that can facilitate early diagnosis and timely intervention of these mis/underdiagnosed disorders.

Endocrine Disorders Are Prominent Clinical Features in Patients With Primary Antibody Deficiencies

Background: Primary antibody deficiencies (PADs) and anterior pituitary dysfunction are both rare conditions. However, recent studies have remarkably reported the occurrence of anterior pituitary dysfunction in PAD patients. Methods: In this cross-sectional, single-center study we evaluated the prevalence of endocrine disorders in adult PAD patients. Our study focused on common variable immunodeficiency (CVID), immunoglobulin G (IgG) subclass deficiency (IgGSD), and specific anti-polysaccharide antibody deficiency (SPAD). We assessed hormone levels, performed provocative tests and genetic testing in a subset of patients by direct sequencing of the nuclear factor kappa beta subunit 2 (NFKB2) gene and primary immunodeficiency (PID) gene panel testing by whole exome sequencing (WES). Results: Our results demonstrated that one out of 24 IgGSD/SPAD patients had secondary hypothyroidism and three out of 9 men with IgGSD/SPAD had secondary hypogonadism. Premature ovarian failure was observed in four out of 9 women with CVID and primary testicular failure in one out of 15 men with CVID. In two out of 26 CVID patients we found partial adrenal insufficiency (AI) and in one out of 18 patients with IgGSD/SPAD secondary AI was found. Moreover, in one out of 23 patients with CVID and in two out of 17 patients with IgGSD/SPAD severe growth hormone deficiency (GHD) was found, while one patient with IgGSD/SPAD showed mild GHD. Combined endocrine disorders were detected in two women with CVID (either partial secondary AI or autoimmune thyroiditis with primary hypogonadism) and in three men with IgGSD/SPAD (two with either mild GHD or secondary hypothyroidism combined with secondary hypogonadism, and one man with secondary AI and severe GHD). Genetic testing in a subset of patients did not reveal pathogenic variants in NFKB2 or other known PID-associated genes. Conclusion: This is the first study to describe a high prevalence of both anterior pituitary and end-organ endocrine dysfunction in adult PAD patients. As these endocrine disorders may cause considerable health burden, assessment of endocrine axes should be considered in PAD patients.

RAS-associated Autoimmune Leukoproliferative disease (RALD) manifested with early-onset SLE-like syndrome: a case series of RALD in Chinese children

BACKGROUND

Primary immunodeficiency diseases (PIDs) patients may show systemic lupus erythematosus (SLE)-like autoimmunity disorders, such as cytopenias, as well as polyarthritis, which leads to concerns of misdiagnosis. We diagnosed three RALD cases between 2015 and 2018, who were suspected as SLE and summarized clinical characteristics.

METHODS

We collected and analyzed the clinical data of the 3 cases. DNA was extracted from the patients' and their parents' peripheral blood as well as oral mucosa cells, hair follicles, and nails. Genes were detected with the application of gene trapping high-throughput sequencing using PIDs panel and suspicious gene or mutation was further verified by Sanger sequencing.

RESULTS

1.

CLINICAL FEATURES

On the one hand, the patients presented with severe thrombocytopenia, facial erythema, arthritis, positive autoantibodies and other manifestations, supporting the diagnosis of SLE. On the other hand, symptoms including early onset ages, recurrent infections, lymphadenopathy, hepatosplenomegaly, monocytosis and hypergammaglobulinemia, were common observed in PIDs. 2. Gene analysis: NRAS mutations (c.38G > A, p.G13D or c.37G > T, p.G13C) were found in the blood of the patients. Besides, the same set of mutations was detected in buccal mucosa of patient 1 and nails of patient 3 while the frequency was much lower. However, no mutation was found in other tissues or in their parents' blood. Consequently, they were NRAS somatic mutated RALD.

CONCLUSIONS

For those early-onset SLE-like patients with predominant hematologic disorders, monocytosis, recurrent infectious history, accompanied with hepatosplenomegaly and lymphadenopathy, a genetic screening of PIDs might be required.

Natural Clearance of Prolonged VDPV Infection in a Child With Primary Immunodeficiency Disorder

The emergence of immunodeficiency-associated vaccine-derived polioviruses (iVDPV) from children with primary immunodeficiency disorders poses a threat to the eradication program. Herein, we report a patient with severe combined immunodeficiency (SCID), identified as a prolonged serotype 3 iVDPV (iVDPV3) excreter with 13 VDPV3 isolates and a maximum of 10.33% nucleotide divergence, who abruptly cleared infection after a period of 2 years. Occurrence of an episode of norovirus diarrhea associated with increased activated oligoclonal cytotoxic T cells, inverse CD4:CD8 ratio, significantly elevated pro-inflammatory cytokines, and subsequent clearance of the poliovirus suggests a possible link between inflammatory diarrheal illness and clearance of iVDPV. Our findings suggest that in the absence of B cells and sufficiently activated T/NK cells, macrophages and other T cells may produce auto-inflammatory conditions by TLR/RLR ligands expressed by previous/ongoing bacterial or viral infections to clear VDPV infection. The study highlights the need to screen all the patients with combined immunodeficiency for poliovirus excretion and intermittent follow-up of their immune parameters if found positive, in order to manage the risk of iVDPV excretion in the polio eradication endgame strategy.

ICOS deficiency hampers the homeostasis, development and function of NK cells

Signaling through the inducible costimulator ICOS is required for the homeostasis and function of various immune cell populations, with an outstanding role in the generation and maintenance of germinal centers. Very recently, it has been suggested that the clinical phenotype of ICOS-deficient patients is much broader than initially anticipated and the innate immune response might be also affected. However, the role of the ICOS/ICOS-Ligand axis in the homeostasis and development of innate NK cells is not known, and reports on its participation in NK cell activation are scarce. NK cells may express low levels of ICOS that are markedly enhanced upon activation. We show here that ICOS-deficient (ICOS-KO) mice present low NK cell numbers and defects in the homeostasis of these cells, with delayed maturation and altered expression of the developmental NK cell markers CD122, NK1.1, CD11b or CD27. Our experiments in mixed bone marrow chimera mice indicate that, both, cell-intrinsic defects of ICOS-KO NK and deficiencies in the milieu of these mice contribute to the altered phenotype. ICOS-deficient NK cells show impaired production of IFN-γ and cytotoxicity, and a final outcome of defects in NK cell-mediated effector function during the response to poly(I:C) or vaccinia virus infection in vivo. Interestingly, we show that murine innate cells like IL-2-cultured NK and bone marrow-derived dendritic cells can simultaneously express ICOS and ICOS-Ligand; both molecules are functional in NK intracellular signaling, enhancing early phosphorylation of Akt and Erk, or IFN-γ secretion in IL-2-activated NK cells. Our study shows the functional importance of the ICOS/ICOS-L pair in NK cell homeostasis, differentiation and activity and suggests novel therapeutic targets for NK manipulation.

Global report on primary immunodeficiencies: 2018 update from the Jeffrey Modell Centers Network on disease classification, regional trends, treatment modalities, and physician reported outcomes

Primary immunodeficiencies (PI) are genetic defects of the immune system that result in chronic, serious, and often life-threatening infections, if not diagnosed and treated. Many patients with PI are undiagnosed, underdiagnosed, or misdiagnosed. In fact, recent studies have shown that PI may be more common than previously estimated and that as many as 1% of the population may be affected with a PI when all types and varieties are considered. In order to raise awareness of PI with the overall goal of reducing associated morbidity and mortality, the Jeffrey Modell Foundation (JMF) established a network of specialized centers that could better identify, diagnose, treat, and follow patients with PI disorders. Over the past decade, the Jeffrey Modell Centers Network (JMCN) has provided the infrastructure to accept referrals, provide diagnosis, and offer treatments. Currently, the network consists of 792 Expert Physicians at 358 institutions, in 277 cities, and 86 countries spanning 6 continents. JMF developed an annual survey for physician experts within the JMCN, using the categories and gene defects identified by the International Union of Immunological Societies Expert Committee for the Classification of PI, to report on the number of patients identified with PI; treatment modalities, including immunoglobulins, transplantation, and gene therapy; and data on gender and age. Center Directors also provided physician-reported outcomes and differentials pre- and post-diagnosis. The current physician-reported data reflect an increase in diagnosed patients, as well as those receiving treatment. Suspected patients are being identified and referred so that they can receive early and appropriate diagnosis and treatment. The significant increase in patients identified with a PI is due, in part, to expanding education and awareness initiatives, newborn screening, and the expansion of molecular diagnosis and sequencing. To our knowledge, this is the most extensive single physician report on patients with PI around the world.

Common Variable Immune Deficiency and Associated Complications

Common variable immunodeficiency disorders refer to a relatively common primary immune deficiency group of diseases that present with infectious and inflammatory complications secondary to defects in antibody production and sometimes in cellular immunity. The disorder often presents in middle age or later with recurrent sinopulmonary infections, bronchiectasis, or a plethora of noninfectious complications such as autoimmune disorders, granulomatous interstitial lung disease, GI diseases, malignancies (including lymphoma), and multisystem granulomatous disease resembling sarcoidosis. Infusion of immunoglobulin by IV or subcutaneous is the mainstay of therapy. Management of complications is often difficult as immune suppression may be necessary in these conditions and entails the use of medications and biologicals which may further increase the risk for infections. Specifically, bronchiectasis, granulomatous lymphocytic interstitial lung disease, repeated sinopulmonary infections, and malignancies are sequelae of antibody deficiency that may present to the pulmonologist. This review will provide an updated understanding of the molecular aspects, differential diagnosis, presentations, and the management of common variable immunodeficiency disorders.

Family-Based Next-Generation Sequencing Study Identifies an IL2RG Variant in an Infant with Primary Immunodeficiency

Primary immunodeficiencies (PIDs) are a rare and heterogeneous group of inherited genetic disorders that are characterized by an absent or impaired immune system. In this report, we describe the use of next-generation sequencing to investigate a male infant with clinical and immunological manifestations suggestive of a PID. Whole-exome sequencing of the infant along with his parents revealed a novel nucleotide variant (cytosine to adenine substitution at nucleotide position 252) in the coding region of the interleukin 2 receptor subunit gamma (IL2RG) gene. The mother was found to be a carrier. These findings are consistent with a diagnosis of X-linked severe combined immunodeficiency and represent the first such reported mutation in an Indian family. This mutation leads to an asparagine to lysine substitution (p.Asn84Lys) located in the extracellular domain of IL2RG, which is predicted to be pathogenic. Our study demonstrates the power of next-generation sequencing in identifying potential causative mutations to enable accurate clinical diagnosis, prenatal screening, and carrier female detection in PID patients. We believe that this approach, which is not a current routine in clinical practice, will become a mainstream component of individualized medicine in the near future.

Next-Generation Sequencing Reveals A JAGN1 Mutation in a Syndromic Child With Intermittent Neutropenia

BACKGROUND

Jagunal homolog 1 (JAGN1) gene was identified as a novel responsible for severe congenital neutropenia. The protein encoded by this gene is required for neutrophil differentiation, survival and function in microbial activity. JAGN1-deficient human neutrophils are characterized by alterations in trafficking within the endoplasmic reticulum and golgi compartments because of ultrastructural defects in endoplasmic reticulum and susceptibility to apoptosis.

OBSERVATIONS

We report a patient exhibiting an intermittent neutropenia, for which a next-generation sequencing revealed a homozygous mutation in the JAGN1 gene.

CONCLUSIONS

The patient extends the clinical variability associated to JAGN1 mutations, and this case highlights the importance of genetic investigations in patients with suspected neutropenia.

Pathogenic NFKB2 variant in the ankyrin repeat domain (R635X) causes a variable antibody deficiency

Genetic studies are identifying an increasing number of monogenic causes of Common Variable Immunodeficiency (CVID). Pathogenic variants in the C-terminus of NFKB2 have been identified in the subset of CVID patients whose immunodeficiency is associated with ectodermal dysplasia and central adrenal insufficiency. We describe 2 unrelated CVID pedigrees with 4 cases of pathogenic stop gain variants (c.1903C > T) in the ankyrin repeat domain (ARD) of NF-κB2, leading to a premature truncation of the protein at p.Arg635Term (R635X). By immunophenotyping and functional ex vivo B- and T-cell experiments we characterized the variant by reduced class-switched memory B-cell counts and immature plasmablasts, unable to produce IgG and IgA. Features of a poor proliferative T-cell response and reduced expansion of CD4⁺CXCR5⁺ T cells was only observed in the two clinically affected index cases without any clear clinical correlate. In conclusion, pathogenic stop variants in the ARD of NFKB2 can cause 'infection-only' CVID with an abnormal B-cell phenotype and a variable clinical penetrance.

Health-Related Quality of Life in Children and Adults with Primary Immunodeficiencies: A Systematic Review and Meta-Analysis

BACKGROUND

Primary immunodeficiency diseases (PIDs) are a group of diseases that have been found to have an adverse impact on quality of life and health-related quality of life (HRQOL).

OBJECTIVE

To systematically assess available evidence on the HRQOL of patients with PID.

METHODS

We performed a literature search of all studies reporting HRQOL assessments in patients with PID published in English from inception to April 11, 2017, using MEDLINE and EMBASE.

RESULTS

Of 1699 articles, 37 met the inclusion criteria. HRQOL was assessed by using various generic instruments. Child Health Questionnaire - Parent Form 50 and short-form 36 were the most frequently used (for children and adults, respectively). No PID-specific HRQOL instruments were used for children. HRQOL is significantly lower in adults with PID (mean score difference, -24.46; 95% CI, -34.57 to -14.34) and children (-10.06; 95% CI, -12.95 to -7.17) compared with the reference population and lower than in patients with other chronic conditions. There is a general agreement between child- and parent-reported data, although parents report child school-related HRQOL as more impaired than do children (6.19; 95% CI, 0.38 to 11.99). Most studies were of low to moderate quality and had methodological limitations.

CONCLUSIONS

Available evidence suggests that patients with PID have a lower HRQOL than do healthy individuals and patients with other chronic conditions, including diabetes mellitus and juvenile idiopathic arthritis. No disease-specific instruments are available for children, and few options are available for adults. This finding highlights the need for developing PID-specific instruments that would allow for a more sensitive evaluation of PID impact on patient health and psychological well-being, school/work, and social activities.

Missense variants in NOX1 and p22phox in a case of very-early-onset inflammatory bowel disease are functionally linked to NOD2

Whole-genome and whole-exome sequencing of individual patients allow the study of rare and potentially causative genetic variation. In this study, we sequenced DNA of a trio comprising a boy with very-early-onset inflammatory bowel disease (veoIBD) and his unaffected parents. We identified a rare, X-linked missense variant in the NAPDH oxidase NOX1 gene (c.C721T, p.R241C) in heterozygous state in the mother and in hemizygous state in the patient. We discovered that, in addition, the patient was homozygous for a common missense variant in the CYBA gene (c.T214C, p.Y72H). CYBA encodes the p22phox protein, a cofactor for NOX1. Functional assays revealed reduced cellular ROS generation and antibacterial capacity of NOX1 and p22phox variants in intestinal epithelial cells. Moreover, the identified NADPH oxidase complex variants affected NOD2-mediated immune responses, and p22phox was identified as a novel NOD2 interactor. In conclusion, we detected missense variants in a veoIBD patient that disrupt the host response to bacterial challenges and reduce protective innate immune signaling via NOD2. We assume that the patient's individual genetic makeup favored disturbed intestinal mucosal barrier function.

TREC and KREC Levels as a Predictors of Lymphocyte Subpopulations Measured by Flow Cytometry

Primary immunodeficiency diseases (PID) is a heterogeneous group of disorders caused by genetic defects of the immune system, which manifests clinically as recurrent infections, autoimmune diseases, or malignancies. Early detection of other PID remains a challenge, particularly in older children due to milder and less specific symptoms, a low level of clinician PID awareness and poor provision of hospital laboratories with appropriate devices. T-cell recombination excision circles (TREC) and kappa-deleting element recombination circle (KREC) in a dried blood spot and in peripheral blood using real-time polymerase chain reaction (PCR) are used as a tool for severe combined immune deficiency but not in PID. They represent an attractive and cheap target for a more extensive use in clinical practice. This study aimed to assess TREC/KREC correspondence with lymphocyte subpopulations, measured by flow cytometry and evaluate correlations between TREC/KREC, lymphocyte subpopulations and immunoglobulins. We carried out analysis of data from children assessed by clinical immunologists at Speransky Children's Hospital, Moscow, Russia with suspected immunodeficiencies between May 2013 and August 2016. Peripheral blood samples were sent for TREC/KREC, flow cytometry (CD3, CD4, CD8, and CD19), IgA, IgM, and IgG analysis. A total of 839 samples were analyzed for using TREC assay and flow cytometry and 931 KREC/flow cytometry. TREC demonstrated an AUC of 0.73 (95% CI 0.70-0.76) for CD3, 0.74 (95% CI 0.71-0.77) for CD4 and 0.67 (95% CI 0.63-0.70) for CD8, respectively, while KREC demonstrated an AUC of 0.72 (95% CI 0.69-0.76) for CD19. Moderate correlation was found between the levels of TREC and CD4 (r = 0.55, p < 0.01) and KREC with CD19 (r = 0.56, p < 0.01). In this study, promising prediction models were tested. We found that TREC and KREC are able to moderately detect abnormal levels of individual lymphocyte subpopulations. Future research should assess associations between TREC/KREC and other lymphocyte subpopulations and approach TREC/KREC use in PID diagnosis.

T-cell defects in patients with ARPC1B germline mutations account for combined immunodeficiency

ARPC1B is a key factor for the assembly and maintenance of the ARP2/3 complex that is involved in actin branching from an existing filament. Germline biallelic mutations in ARPC1B have been recently described in 6 patients with clinical features of combined immunodeficiency (CID), whose neutrophils and platelets but not T lymphocytes were studied. We hypothesized that ARPC1B deficiency may also lead to cytoskeleton and functional defects in T cells. We have identified biallelic mutations in ARPC1B in 6 unrelated patients with early onset disease characterized by severe infections, autoimmune manifestations, and thrombocytopenia. Immunological features included T-cell lymphopenia, low numbers of naïve T cells, and hyper-immunoglobulin E. Alteration in ARPC1B protein structure led to absent/low expression by flow cytometry and confocal microscopy. This molecular defect was associated with the inability of patient-derived T cells to extend an actin-rich lamellipodia upon T-cell receptor (TCR) stimulation and to assemble an immunological synapse. ARPC1B-deficient T cells additionally displayed impaired TCR-mediated proliferation and SDF1-α-directed migration. Gene transfer of ARPC1B in patients' T cells using a lentiviral vector restored both ARPC1B expression and T-cell proliferation in vitro. In 2 of the patients, in vivo somatic reversion restored ARPC1B expression in a fraction of lymphocytes and was associated with a skewed TCR repertoire. In 1 revertant patient, memory CD8⁺ T cells expressing normal levels of ARPC1B displayed improved T-cell migration. Inherited ARPC1B deficiency therefore alters T-cell cytoskeletal dynamics and functions, contributing to the clinical features of CID.