Initial presenting manifestations in 16,486 patients with inborn errors of immunity include infections and noninfectious manifestations

Inborn Errors of Immunity in Early Childhood: Essential Insights for the Neonatologist

BACKGROUND

Inborn errors of immunity (IEI), formerly referred to as primary immunodeficiencies, manifest with a wide range of symptoms such as increased susceptibility to infections, immune dysregulation, and autoinflammation. Although most cases manifest in childhood, onset during the neonatal period is rare but potentially critical.

SUMMARY

In this review, we discuss the diverse clinical presentations of IEI and the specific challenges they pose to neonatologists. Rather than detailing every molecular defect, we focus on common clinical scenarios in neonates and young infants, providing practical diagnostic strategies to ensure timely and effective therapeutic interventions.

KEY MESSAGES

Clinical presentations of IEI in neonates may include delayed separation of the umbilical cord, skin rashes such as eczema and erythroderma, and recurrent episodes of inflammation. We also highlight immunological emergencies that require urgent medical attention, such as hyperinflammatory activity mimicking acute neonatal liver failure, sometimes seen in hemophagocytic lymphohistiocytosis. We also discuss appropriate medical action in the case of a positive newborn screening for severe T-cell defects. Early medical intervention in such circumstances may significantly improve outcomes.

Association of paediatric autoimmune cytopenia and inflammatory bowel disease suggests a common genetic origin

The association of autoimmune cytopenia (AIC) and inflammatory bowel disease (IBD) has been reported in small series, but the incidence of and risk factors for IBD in children with AIC are not known. One thousand six hundred nine children with chronic immune thrombocytopenic purpura, autoimmune haemolytic anaemia or Evans syndrome from the prospective OBS'CEREVANCE cohort are included in this study. Overall, 15 children were diagnosed with IBD, including 14 who developed IBD after AIC diagnosis (median delay: 21 months). The only risk factor for IBD development is age at AIC over 10 years. Out of 10 children genetically tested, germline variants associated with autoimmune disorders were identified in three (CTLA4: two, DOCK11: one). In children and adolescents monitored for AIC or past history of AIC, especially children over 10 years, gastro-intestinal (GI) symptoms (recurrent abdominal pains, GI bleeding, chronic diarrhoea, weight loss) should suggest IBD and deserve specific work-up and genetic studies. Identification of a causal germline variant will allow targeted therapy.

IPINeT Ped-unPAD Study: Goals, Design, and Preliminary Results

Background: An unclassified primary antibody deficiency (unPAD) is a widely heterogeneous clinical entity, recently identified within the spectrum of Inborn Errors of Immunity (IEIs). Since unPAD has been traditionally considered as a mild condition, it has incorrectly received little attention, resulting in the paucity of extensive and comparable studies describing its natural history. To address the gaps in characterizing, understanding, and managing pediatric unPAD patients, the Italian Primary Immunodeficiency Network (IPINet) Ped-unPAD study has recently been launched. Methods: Seventeen IPINeT Centers have expressed interest to participate, and data collection is still on-going. Hereby, we anticipate preliminary key issues emerging from the first 110 enrolled patients, attending three IPINet Centers. Results: A proportion of unPAD patients have experienced a severe infectious phenotype, which required hospitalization in a quarter of patients and antibiotic prophylaxis or Immunoglobulin Replacement Therapy in approximately 10% of patients. In this partial cohort, a mean follow-up (FU) of 5 years confirmed unPAD diagnosis in fifty percent of cases, with the remaining being reclassified as the Transient Hypogammaglobulinemia of Infancy (25%) and other IEIs (25%), such as a Common Variable Immunodeficiency, Selective IgA deficiency, Selective IgM deficiency, and IgG3 subclass deficiency. Conclusions: Despite a phenotype overlap at diagnosis, clinicians should be aware that unPAD is a mutable condition that deserves comprehensive evaluation and long-term monitoring to dissect the final diagnosis for optimal treatment.

Primary immunodeficiency diseases of adults: a review of pulmonary complication imaging findings

Our objective in this review is to familiarize radiologists with the spectrum of initial and progressive CT manifestations of pulmonary complications observed in adult patients with primary immunodeficiency diseases, including primary antibody deficiency (PAD), hyper-IgE syndrome (HIES), and chronic granulomatous disease (CGD). In patients with PAD, recurrent pulmonary infections may lead to airway remodeling with bronchial wall-thickening, bronchiectasis, mucus-plugging, mosaic perfusion, and expiratory air-trapping. Interstitial lung disease associates pulmonary lymphoid hyperplasia, granulomatous inflammation, and organizing pneumonia and is called granulomatous-lymphocytic interstitial lung disease (GLILD). The CT features of GLILD are solid and semi-solid pulmonary nodules and areas of air space consolidation, reticular opacities, and lymphadenopathy. These features may overlap those of mucosa-associated lymphoid tissue (MALT) lymphoma, justifying biopsies. In patients with HIES, particularly the autosomal dominant type (Job syndrome), recurrent pyogenic infections lead to permanent lung damage. Secondary infections with aspergillus species develop in pre-existing pneumatocele and bronchiectasis areas, leading to chronic airway infection. The complete spectrum of CT pulmonary aspergillosis may be seen including aspergillomas, chronic cavitary pulmonary aspergillosis, allergic bronchopulmonary aspergillosis (ABPA)-like pattern, mixed pattern, and invasive. Patients with CGD present with recurrent bacterial and fungal infections leading to parenchymal scarring, traction bronchiectasis, cicatricial emphysema, airway remodeling, and mosaicism. Invasive aspergillosis, the major cause of mortality, manifests as single or multiple nodules, areas of airspace consolidation that may be complicated by abscess, empyema, or contiguous extension to the pleura or chest wall. CLINICAL RELEVANCE STATEMENT: Awareness of the imaging findings spectrum of pulmonary complications that can occur in adult patients with primary immunodeficiency diseases is important to minimize diagnostic delay and improve patient outcomes. KEY POINTS: • Unexplained bronchiectasis, associated or not with CT findings of obliterative bronchiolitis, should evoke a potential diagnosis of primary autoantibody deficiency. • The CT evidence of various patterns of aspergillosis developed in severe bronchiectasis or pneumatocele in a young adult characterizes the pulmonary complications of hyper-IgE syndrome. • In patients with chronic granulomatous disease, invasive aspergillosis is relatively frequent, often asymptomatic, and sometimes mimicking or associated with non-infectious inflammatory pulmonary lesions.

Inborn Errors of Immunity in Jordan: First Report from a Tertiary Referral Center

PURPOSE

Inborn errors of immunity (IEI) are a heterogeneous group of diseases with variable clinical phenotypes. This study was conducted to describe the epidemiology, clinical presentations, treatment, and outcome of IEI in Jordanian children.

METHODS

A retrospective data analysis was conducted for children under 15 years diagnosed with IEI from the pediatric Allergy, Immunology, and Rheumatology Division-based registry at Queen Rania Children's Hospital, Amman, Jordan, between 2010 and 2022.

RESULTS

A total of 467 patients, 263 (56.3%) males and 204 (43.7%) females, were diagnosed with IEI. The mean age at symptom onset was 18 months (1 week to 144 months), a positive family history of IEI was reported in 43.5%, and the consanguinity rate was 47.9%. The most common IEI category was immunodeficiencies affecting cellular and humoral immunity at 33.2%, followed by predominantly antibody deficiencies at 16.9%. The overall median diagnostic delay (range) was 6 (0-135) months; patients with a positive family history of IEI had a statistically significant shorter diagnostic delay. Pulmonary and gastrointestinal clinical features were the most common at 55.2% and 45.6%, respectively. The overall mortality was 33.2%; the highest rate was reported in severe combined immunodeficiency at 56.2%.

CONCLUSIONS

The high minimal estimated IEI prevalence at 16.2/100,000 Jordanian children compared to the regional and worldwide data, with the diversities in clinical presentation and distribution of IEI categories in our cohort point to unique features of IEI in Jordanian children, call for national registry establishment, regional and international collaborative networks.

A large deletion in a non-coding regulatory region leads to NFKB1 haploinsufficiency in two adult siblings

Mutations in NFkB pathway genes can cause inborn errors of immunity (IEI), with NFKB1 haploinsufficiency being a significant etiology for common variable immunodeficiency (CVID). Indeed, mutations in NFKB1 are found in 4 to 5% of in European and United States CVID cohorts, respectively; CVID representing almost ¼ of IEI patients in European countries registries. This case study presents a 49-year-old patient with respiratory infections, chronic diarrhea, immune thrombocytopenia, hypogammaglobulinemia, and secondary lymphoma. Comprehensive genetic analysis, including high-throughput sequencing of 300 IEI-related genes and copy number variation analysis, identified a critical 2.6-kb deletion spanning the first untranslated exon and its upstream region. The region's importance was confirmed through genetic markers indicative of enhancers and promoters. The deletion was also found in the patient's brother, who displayed similar but milder symptoms. Functional analysis supported haploinsufficiency with reduced mRNA and protein expression in both patients. This case underscores the significance of copy number variation (CNV) analysis and targeting noncoding exons within custom gene panels, emphasizing the broader genomic approaches needed in medical genetics.

Clinical updates in inborn errors of immunity: a focus on the noninfectious clinical manifestations

PURPOSE OF REVIEW

In the last 5 years, several new inborn errors of immunity (IEI) have been described, especially in the areas of immune dysregulation and autoinflammation. As a result, the clinical presentation of IEIs has broadened. We review the heterogeneous presentation of IEIs and detail several of the recently described IEIs with a focus on the noninfectious manifestations commonly seen.

RECENT FINDINGS

IEIs may present with early onset and/or multiple autoimmune manifestations, increased risk for malignancy, lymphoproliferation, severe atopy, autoinflammation and/or hyperinflammation. Because of this, patients can present to a wide array of providers ranging from primary care to various pediatric subspecialists. The International Union of Immunological Societies (IUIS) expert committee has created a phenotypic classification of IEIs in order to help clinicians narrow their evaluation based on the laboratory and clinical findings.

SUMMARY

Both primary care pediatricians and pediatric subspecialists need to be aware of the common clinical features associated with IEI and recognize when to refer to allergy-immunology for further evaluation. Early diagnosis can lead to earlier treatment initiation and improve clinical outcomes for our patients.

The autoimmune rheumatological presentation of Common Variable Immunodeficiency Disorders with an overview of genetic testing

Primary immunodeficiency Disorders (PIDS) are rare, mostly monogenetic conditions which can present to a number of specialties. Although infections predominate in most PIDs, some individuals can manifest autoimmune or inflammatory sequelae as their initial clinical presentation. Identifying patients with PIDs can be challenging, as some can present later in life. This is often seen in patients with Common Variable Immunodeficiency Disorders (CVID), where symptoms can begin in the sixth or even seventh decades of life. Some patients with PIDs including CVID can initially present to rheumatologists with autoimmune musculoskeletal manifestations. It is imperative for these patients to be identified promptly as immunosuppression could lead to life-threatening opportunistic infections in these immunocompromised individuals. These risks could be mitigated by prior treatment with subcutaneous or intravenous (SCIG/IVIG) immunoglobulin replacement or prophylactic antibiotics. Importantly, many of these disorders have an underlying genetic defect. Individualized treatments may be available for the specific mutation, which may obviate or mitigate the need for hazardous broad-spectrum immunosuppression. Identification of the genetic defect has profound implications not only for the patient but also for affected family members, who may be at risk of symptomatic disease following an environmental trigger such as a viral infection. Finally, there may be clinical clues to the underlying PID, such as recurrent infections, the early presentation of severe or multiple autoimmune disorders, as well as a relevant family history. Early referral to a clinical immunologist will facilitate appropriate diagnostic evaluation and institution of treatment such as SCIG/IVIG immunoglobulin replacement. This review comprises three sections; an overview of PIDs, focusing on CVID, secondly genetic testing of PIDs and finally the clinical presentation of these disorders to rheumatologists.

Inborn errors of immunity: A field without frontiers

The study of primary immunodeficiencies or inborn errors of immunity continues to drive our knowledge of the function of the human immune system. From the outset, the study of inborn errors has focused on unraveling genetic etiologies and molecular mechanisms. Aided by the continuous growth in genetic diagnostics, the field has moved from the study of an infection dominated phenotype to embrace and unravel diverse manifestations of autoinflammation, autoimmunity, malignancy, and severe allergy in all medical disciplines. It has now moved from the study of ultrarare presentations to producing meaningful impact in conditions as diverse as inflammatory bowel disease, neurological conditions, and hematology. Beyond offering immunogenetic diagnosis, the study of underlying inborn errors of immunity in these conditions points to targeted treatment which can be lifesaving.

Multilayer concept of autoimmune mechanisms and manifestations in inborn errors of immunity: Relevance for precision therapy

Autoimmunity in inborn errors of immunity (IEIs) has a multifactorial pathogenesis and develops subsequent to a genetic predisposition in conjunction with gene regulation, environmental modifiers, and infectious triggers. On the basis of incremental data availability owing to upfront application of omics technologies, a more granular and dynamic view of mechanisms and manifestations is warranted. Here, we present a comprehensive novel concept of autoimmunity in IEIs that considers multiple layers of interdependent elements and connects 101 causative genes or deletions according to the quality of the allelic variants with 47 molecular pathways and 22 immune effector mechanisms. Furthermore, we list 50 resulting manifestations together with the corresponding Human Phenotype Ontology terms and review the types and frequencies of the most relevant clinical presentations. When all of its elements are taken together, this concept (1) extends the historical anatomic view of central versus peripheral tolerance toward multiple interdependent mechanisms of immune tolerance, (2) delineates the mechanisms underlying the protean clinical manifestations, and thereby, (3) points toward the most suitable precision therapy for autoimmunity in IEIs. The multilayer concept of autoimmune mechanisms and manifestations in IEIs will facilitate research design and provide clinical guidance on the use of precision medicine irrespective of the data depth available in each health care scenario.

Enrichment of Immune Dysregulation Disorders in Adult Patients with Human Inborn Errors of Immunity

Human inborn errors of immunity (IEI) comprise a group of diseases resulting from molecular variants that compromise innate and adaptive immunity. Clinical features of IEI patients are dominated by susceptibility to a spectrum of infectious diseases, as well as autoimmune, autoinflammatory, allergic, and malignant phenotypes that usually appear in childhood, which is when the diagnosis is typically made. However, some IEI patients are identified in adulthood due to symptomatic delay of the disease or other reasons that prevent the request for a molecular study. The application of next-generation sequencing (NGS) as a diagnostic technique has given rise to an ever-increasing identification of IEI-monogenic causes, thus improving the diagnostic yield and facilitating the possibility of personalized treatment. This work was a retrospective study of 173 adults with IEI suspicion that were sequenced between 2005 and 2023. Sanger, targeted gene-panel, and whole exome sequencing were used for molecular diagnosis. Disease-causing variants were identified in 44 of 173 (25.43%) patients. The clinical phenotype of these 44 patients was mostly related to infection susceptibility (63.64%). An enrichment of immune dysregulation diseases was found when cohorts with molecular diagnosis were compared to those without. Immune dysregulation disorders, group 4 from the International Union of Immunological Societies Expert Committee (IUIS), were the most prevalent among these adult patients. Immune dysregulation as a new item in the Jeffrey Model Foundation warning signs for adults significantly increases the sensitivity for the identification of patients with an IEI-producing molecular defect.

Novel Genetic and Phenotypic Expansion in Ameliorated PUF60-Related Disorders

Heterozygous variants in the Poly(U) Binding Splicing Factor 60kDa gene (PUF60) have been associated with Verheij syndrome, which has the key features of coloboma, short stature, skeletal abnormalities, developmental delay, palatal abnormalities, and congenital heart and kidney defects. Here, we report five novel patients from unrelated families with PUF60-related disorders exhibiting novel genetic and clinical findings with three truncating variants, one splice-site variant with likely reduced protein expression, and one missense variant. Protein modeling of the patient's missense variant in the PUF60 AlphaFold structure revealed a loss of polar bonds to the surrounding residues. Neurodevelopmental disorders were present in all patients, with variability in speech, motor, cognitive, social-emotional and behavioral features. Novel phenotypic expansions included movement disorders as well as immunological findings with recurrent respiratory, urinary and ear infections, atopic diseases, and skin abnormalities. We discuss the role of PUF60 in immunity with and without infection based on recent organismic and cellular studies. As our five patients showed less-severe phenotypes than classical Verheij syndrome, particularly with the absence of key features such as coloboma or palatal abnormalities, we propose a reclassification as PUF60-related neurodevelopmental disorders with multi-system involvement. These findings will aid in the genetic counseling of patients and families.

Diagnostic evaluation of paediatric autoimmune lymphoproliferative immunodeficiencies (ALPID): a prospective cohort study

BACKGROUND

Lymphoproliferation and autoimmune cytopenias characterise autoimmune lymphoproliferative syndrome. Other conditions sharing these manifestations have been termed autoimmune lymphoproliferative syndrome-like diseases, although they are frequently more severe. The aim of this study was to define the genetic, clinical, and immunological features of these disorders to improve their diagnostic classification.

METHODS

In this prospective cohort study, patients were referred to the Center for Chronic Immunodeficiency in Freiburg, Germany, between Jan 1, 2008 and March 5, 2022. We enrolled patients younger than 18 years with lymphoproliferation and autoimmune cytopenia, lymphoproliferation and at least one additional sign of an inborn error of immunity (SoIEI), bilineage autoimmune cytopenia, or autoimmune cytopenia and at least one additional SoIEI. Autoimmune lymphoproliferative syndrome biomarkers were determined in all patients. Sanger sequencing followed by in-depth genetic studies were recommended for patients with biomarkers indicative of autoimmune lymphoproliferative syndrome, while IEI panels, exome sequencing, or genome sequencing were recommended for patients without such biomarkers. Genetic analyses were done as decided by the treating physician. The study was registered on the German Clinical Trials Register, DRKS00011383, and is ongoing.

FINDINGS

We recruited 431 children referred for autoimmune lymphoproliferative syndrome evaluation, of whom 236 (55%) were included on the basis of lymphoproliferation and autoimmune cytopenia, 148 (34%) on the basis of lymphoproliferation and another SoIEI, 33 (8%) on the basis of autoimmune bicytopenia, and 14 (3%) on the basis of autoimmune cytopenia and another SoIEI. Median age at diagnostic evaluation was 9·8 years (IQR 5·5-13·8), and the cohort comprised 279 (65%) boys and 152 (35%) girls. After biomarker and genetic assessments, autoimmune lymphoproliferative syndrome was diagnosed in 71 (16%) patients. Among the remaining 360 patients, 54 (15%) had mostly autosomal-dominant autoimmune lymphoproliferative immunodeficiencies (AD-ALPID), most commonly affecting JAK-STAT (26 patients), CTLA4-LRBA (14), PI3K (six), RAS (five), or NFκB (three) signalling. 19 (5%) patients had other IEIs, 17 (5%) had non-IEI diagnoses, 79 (22%) were unresolved despite extended genetics (ALPID-U), and 191 (53%) had insufficient genetic workup for diagnosis. 16 (10%) of 161 patients with a final diagnosis had somatic mutations. Alternative classification of patients fulfilling common variable immunodeficiency or Evans syndrome criteria did not increase the proportion of genetic diagnoses.

INTERPRETATION

The ALPID phenotype defined in this study is enriched for patients with genetic diseases treatable with targeted therapies. The term ALPID might be useful to focus diagnostic and therapeutic efforts by triggering extended genetic analysis and consideration of targeted therapies, including in some children currently classified as having common variable immunodeficiency or Evans syndrome.

FUNDING

Deutsche Forschungsgemeinschaft under Germany's Excellence Strategy.

TRANSLATION

For the German translation of the abstract see Supplementary Materials section.

Predicting valuable missense variants with AlphaMissense in a multiple pulmonary infection patient

AlphaMissense is proficient in predicting the clinical classification of missense variants. we utilized AlphaMissense to find disease-relevant variants within a polymicrobial pulmonary infection case. Exome sequencing was performed in this patient, and AlphaMissense and Phenolyzer were combined to investigate disease-relevant variants screening from exome sequencing results.

New primary immunodeficiencies 2023 update

PURPOSE OF REVIEW

Primary immunodeficiency diseases (PIDs), also called inborn errors of immunity (IEI), are genetic disorders characterized by increased susceptibility to infection and/or aberrant regulation of immunological pathways. This review summarizes and highlights the new IEI disorders in the International Union of Immunological Societies (IUIS) 2022 report and current trends among new PIDs.

RECENT FINDINGS

Since the 2019 IUIS report and the 2021 IUIS interim update, the IUIS IEI classification now includes 485 validated IEIs. Increasing utilization of genetic testing and advances in the strategic evaluation of genetic variants has continued to drive the identification of, not only novel IEI disorders, but additional genetic etiologies for known IEI disorders and phenotypes.

SUMMARY

The recognition of new IEIs continues to advance at a rapid pace, which is due in part to increased performance and application of genetic modalities as well as expansion of the underlying science that is applied to convincingly establish causality. These disorders, as a whole, continue to emphasize the specificity of immunity, complexity of immune mechanisms, and the fine balance that defines immune homeostasis.

Inborn Errors of Immunity Contribute to the Burden of Skin Disease and Create Opportunities for Improving the Practice of Dermatology

Opportunities to improve the clinical management of skin disease are being created by advances in genomic medicine. Large-scale sequencing increasingly challenges notions about single-gene disorders. It is now apparent that monogenic etiologies make appreciable contributions to the population burden of disease and that they are underrecognized in clinical practice. A genetic diagnosis informs on molecular pathology and may direct targeted treatments and tailored prevention strategies for patients and family members. It also generates knowledge about disease pathogenesis and management that is relevant to patients without rare pathogenic variants. Inborn errors of immunity are a large class of monogenic etiologies that have been well-studied and contribute to the population burden of inflammatory diseases. To further delineate the contributions of inborn errors of immunity to the pathogenesis of skin disease, we performed a set of analyses that identified 316 inborn errors of immunity associated with skin pathologies, including common skin diseases. These data suggest that clinical sequencing is underutilized in dermatology. We next use these data to derive a network that illuminates the molecular relationships of these disorders and suggests an underlying etiological organization to immune-mediated skin disease. Our results motivate the further development of a molecularly derived and data-driven reorganization of clinical diagnoses of skin disease.

Clinical and Treatment History of Patients with Partial DiGeorge Syndrome and Autoimmune Cytopenia at Multiple Centers

BACKGROUND

Patients with partial DiGeorge syndrome (pDGS) can present with immune dysregulation, the most common being autoimmune cytopenia (AIC). There is a lack of consensus on the approach to type, combination, and timing of therapies for AIC in pDGS. Recognition of immune dysregulation early in pDGS clinical course may help individualize treatment and prevent adverse outcomes from chronic immune dysregulation.

OBJECTIVES

Objectives of this study were to characterize the natural history, immune phenotype, and biomarkers in pDGS with AIC.

METHODS

Data on clinical presentation, disease severity, immunological phenotype, treatment selection, and response for patients with pDGS with AIC were collected via retrospective chart review. Flow cytometric analysis was done to assess T and B cell subsets, including biomarkers of immune dysregulation.

RESULTS

Twenty-nine patients with the diagnosis of pDGS and AIC were identified from 5 international institutions. Nineteen (62%) patients developed Evan's syndrome (ES) during their clinical course and twenty (69%) had antibody deficiency syndrome. These patients demonstrated expansion in T follicular helper cells, CD19hiCD21lo B cells, and double negative cells and reduction in CD4 naïve T cells and regulatory T cells. First-line treatment for 17/29 (59%) included corticosteroids and/or high-dose immunoglobulin replacement therapy. Other overlapping therapies included eltrombopag, rituximab, and T cell immunomodulators.

CONCLUSIONS

AIC in pDGS is often refractory to conventional AIC treatment paradigms. Biomarkers may have utility for correlation with disease state and potentially even response to therapy. Immunomodulating therapies could be initiated early based on early immune phenotyping and biomarkers before the disease develops or significantly worsens.

The Inborn Errors of Immunity-Virtual Consultation System Platform in Service for the Italian Primary Immunodeficiency Network: Results from the Validation Phase

PURPOSE

Inborn errors of immunity (IEI) represent a heterogeneous group of rare genetically determined diseases. In some cases, patients present with complex or atypical phenotypes, not fulfilling the accepted diagnostic criteria for IEI and, thus, at high risk of misdiagnosis or diagnostic delay. This study aimed to validate a platform that, through the opinion of immunologist experts, improves the diagnostic process and the level of care of patients with atypical/complex IEI.

METHODS

Here, we describe the functioning of the IEI-Virtual Consultation System (VCS), an innovative platform created by the Italian Immunodeficiency Network (IPINet).

RESULTS

In the validation phase, from January 2020 to June 2021, 68 cases were entered on the IEI-VCS platform. A final diagnosis was achieved in 35/68 cases (51%, 95% CI 38.7 to 64.2). In 22 out of 35 solved cases, the diagnosis was confirmed by genetic analysis. In 3/35 cases, a diagnosis of secondary immunodeficiency was made. In the remaining 10 cases, an unequivocal clinical and immunological diagnosis was obtained, even though not substantiated by genetic analysis.

CONCLUSION

From our preliminary study, the VCS represents an innovative and useful system to improve the diagnostic process of patients with complex unsolved IEI disorders, with benefits both in terms of reduction of time of diagnosis and access to the required therapies. These results may help the functioning of other international platforms for the management of complex cases.

Distinct Immunophenotypic Features in Patients Affected by 22q11.2 Deletion Syndrome with Immune Dysregulation and Infectious Phenotype

The clinical expression of 22q11.2 deletion syndrome (22q11.2 DS) is extremely variable, as patients can present with recurrent or severe infections, immune dysregulation, atopic diseases, or extra-immunological manifestations. The immunological background underlying the different disease manifestations is not completely elucidated. The aim of this study was to identify the immunophenotypic peculiarities of 22q11.2 DS patients presenting with different disease expressions. This study included 34 patients with 22q11.2 DS, divided into three groups according to the clinical phenotype: isolated extra-immunological manifestations (G1), infectious phenotype with increased/severe infections (G2), and immune dysregulation (G3). The patients underwent extended immunophenotyping of the T and B lymphocytes and analysis of the circulating dendritic cells (DCs). In patients with an infectious phenotype, a significant reduction in CD3+ and CD4+ cells and an expansion of CD8 naïve cells was evidenced. On the other hand, the immunophenotype of the patients with immune dysregulation showed a skewing toward memory T cell populations, and reduced levels of recent thymic emigrants (RTEs), while the highest levels of RTEs were detected in the patients with isolated extra-immunological manifestations. This study integrates the current literature, contributing to elucidating the variability in the immune status of patients with 22q11.2DS with different phenotypic expressions, particularly in those with infectious phenotype and immune dysregulation.

Cluster analysis of flowcytometric immunophenotyping with extended T cell subsets in suspected immunodeficiency

BACKGROUND

Patients with immunodeficiencies commonly experience diagnostic delays resulting in morbidity. There is an unmet need to identify patients earlier, especially those with high risk for complications. Compared to immunoglobulin quantification and flowcytometric B cell subset analysis, expanded T cell subset analysis is rarely performed in the initial evaluation of patients with suspected immunodeficiency. The simultaneous interpretation of multiple immune variables, including lymphocyte subsets, is challenging.

OBJECTIVE

To evaluate the diagnostic value of cluster analyses of immune variables in patients with suspected immunodeficiency.

METHODS

Retrospective analysis of 38 immune system variables, including seven B cell and sixteen T cell subpopulations, in 107 adult patients (73 with immunodeficiency, 34 without) evaluated at a tertiary outpatient immunology clinic. Correlation analyses of individual variables, k-means cluster analysis with evaluation of the classification into "no immunodeficiency" versus "immunodeficiency" and visual analyses of hierarchical heatmaps were performed.

RESULTS

Binary classification of patients into groups with and without immunodeficiency was correct in 54% of cases with the full data set and increased to 69% and 75% of cases, respectively, when only 16 variables with moderate (p < .05) or 7 variables with strong evidence (p < .01) for a difference between groups were included. In a cluster heatmap with all patients but only moderately differing variables and a heatmap with only immunodeficient patients restricted to T cell variables alone, segregation of most patients with common variable immunodeficiency and combined immunodeficiency was observed.

CONCLUSION

Cluster analyses of immune variables, including detailed lymphocyte flowcytometry with T cell subpopulations, may support clinical decision making for suspected immunodeficiency in daily practice.

Screening for Antibody Deficiencies in Adults by Serum Electrophoresis and Calculated Globin

PURPOSE

This study aimed to investigate the correlation between calculated globulin (CG, total protein level minus albumin level) and the gamma globulin fraction (Gamma), obtained from serum protein electrophoresis with serum IgG levels in adults (≥ 18 years).

METHODS

Using linear regression models, analyses of CG and Gamma levels correlation with IgG levels in adults were performed. Receiver-operator curves were created to determine cutoff values and the respective sensitivity and specificity measures.

RESULTS

A total of 886 samples were analyzed. CG and Gamma were positively and statistically correlated with IgG levels (r2 = 0.4628 for CG, and = 0.7941 for Gamma, p < 0.0001 for both analyses). For the detection of hypogammaglobulinemia, i.e., IgG level below the reference value (6 g/L), a CG cutoff value of 24 g/L showed a sensitivity of 86.2% (95% CI 69.4-94.5) and a specificity of 92% (90.0-93.6). A Gamma cutoff value of 7.15 g/L yielded a sensitivity of 100% (88.3-100) and a specificity of 96.8 (95.3-97.8).

CONCLUSION

Both CG and Gamma levels determined by protein electrophoresis analysis may be used to screen for antibody deficiencies in adults, enabling earlier diagnosis of antibody deficiencies in a routine clinical setting.

Mycophenolate mofetil for autoimmune cytopenias in children: high rates of response in inborn errors of immunity

Second-line treatments of autoimmune cytopenias (AC) are not well-defined in children. Mycophenolate mofetil (MMF) is an immunosuppressant agent that has been demonstrated to be safe and effective in this setting. A retrospective observational study was conducted in 18 children with prolonged AC who received MMF, in order to describe clinical and biological markers of response. The overall response rate of MMF at 20-30 mg/kg per day was 73.3%. All patients with Evans syndrome (n = 9) achieved complete response. Among the patients with monolineage AC (n = 9), those with an underlying inborn errors of immunity (IEI), tended to respond better to MMF. No biological markers related to treatment response were found. Rather, lymphocyte subpopulations proved useful for patient selection as a marker suggestive of IEI along with immunoglobulin-level determination.

Decline of gastric cancer mortality in common variable immunodeficiency in the years 2018-2022

Introduction

In patients with Common Variable Immunodeficiency, malignancy has been reported as the leading cause of death in adults, with a high risk of B-cell lymphomas and gastric cancer.

Methods

We conducted a five-year prospective study aiming to update the incidence and mortality of gastric cancer and the incidence of gastric precancerous lesions in 512 CVID patients who underwent a total of 400 upper gastrointestinal endoscopies.

Results

In the pre-pandemic period, 0.58 endoscopies were performed per patient/year and in the COVID-19 period, 0.39 endoscopies were performed per patient/year. Histology revealed areas with precancerous lesions in about a third of patients. Patients who had more than one gastroscopy during the study period were more likely to have precancerous lesions. Two patients received a diagnosis of gastric cancer in the absence of Helicobacter pylori infection. The overall prevalence of Helicobacter pylori infection in biopsy specimens was 19.8% and related only to active gastritis. Among patients who had repeated gastroscopies, about 20% progressed to precancerous lesions, mostly independent of Helicobacter pylori.

Discussion

While gastric cancer accounted for one in five deaths from CVID in our previous survey, no gastric cancer deaths were recorded in the past five years, likely consistent with the decline in stomach cancer mortality observed in the general population. However, during the COVID-19 pandemic, cancer screening has been delayed. Whether such a delay or true decline could be the reason for the lack of gastric cancer detection seen in CVID may become clear in the coming years. Due to the high incidence of precancerous lesions, we cannot rely on observed and predicted trends in gastric cancer mortality and strongly recommend tailored surveillance programs.

Activated phosphoinositide 3-kinase δ syndrome: Update from the ESID Registry and comparison with other autoimmune-lymphoproliferative inborn errors of immunity

BACKGROUND

Activated phosphoinositide-3-kinase δ syndrome (APDS) is an inborn error of immunity (IEI) with infection susceptibility and immune dysregulation, clinically overlapping with other conditions. Management depends on disease evolution, but predictors of severe disease are lacking.

OBJECTIVES

This study sought to report the extended spectrum of disease manifestations in APDS1 versus APDS2; compare these to CTLA4 deficiency, NFKB1 deficiency, and STAT3 gain-of-function (GOF) disease; and identify predictors of severity in APDS.

METHODS

Data was collected from the ESID (European Society for Immunodeficiencies)-APDS registry and was compared with published cohorts of the other IEIs.

RESULTS

The analysis of 170 patients with APDS outlines high penetrance and early onset of APDS compared to the other IEIs. The large clinical heterogeneity even in individuals with the same PIK3CD variant E1021K illustrates how poorly the genotype predicts the disease phenotype and course. The high clinical overlap between APDS and the other investigated IEIs suggests relevant pathophysiological convergence of the affected pathways. Preferentially affected organ systems indicate specific pathophysiology: bronchiectasis is typical of APDS1; interstitial lung disease and enteropathy are more common in STAT3 GOF and CTLA4 deficiency. Endocrinopathies are most frequent in STAT3 GOF, but growth impairment is also common, particularly in APDS2. Early clinical presentation is a risk factor for severe disease in APDS.

CONCLUSIONS

APDS illustrates how a single genetic variant can result in a diverse autoimmune-lymphoproliferative phenotype. Overlap with other IEIs is substantial. Some specific features distinguish APDS1 from APDS2. Early onset is a risk factor for severe disease course calling for specific treatment studies in younger patients.

Paediatric-onset Evans syndrome: Breaking away from refractory immune thrombocytopenia

Since its first description by Evans in 1951, this syndrome has been linked to chronic immune thrombocytopenia with the concurrent or delayed onset of autoimmune haemolytic anaemia or neutropenia. For decades, the evolution of Evans syndrome (ES) has carried a poor prognosis and often resulted in chronic steroid exposure, multiple immune suppressing medications directed against T or B lymphocytes, and splenectomy. This paper presents a new view of ES based on recent advances in genomics which begin to classify patients based on their underlying molecular variants in previously described primary immune disorders. This has opened up new avenues of targeted therapy or bone marrow transplant at rather than broad long-term immune suppression or splenectomy. Importantly, recent studies of the full lifespan of ES suggest that at least 80% of those paediatric patients will progress to various clinical or biological immunopathological manifestations with age despite the resolution of their cytopenias. Those patients merit long-term follow-up and monitoring in dedicated transition programs to improve outcome at the adult age.

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.

Inborn Errors of Immunity in Hidradenitis Suppurativa Pathogenesis and Disease Burden

Hidradenitis suppurativa (HS), also known as Verneuil's disease and acne inversa, is a prevalent, debilitating, and understudied inflammatory skin disease. It is marked by repeated bouts of pathological inflammation causing pain, hyperplasia, aberrant healing, and fibrosis. HS is difficult to manage and has many unmet medical needs. There is clinical and pharmacological evidence for extensive etiological heterogeneity with HS, suggesting that this clinical diagnosis is capturing a spectrum of disease entities. Human genetic studies provide robust insight into disease pathogenesis. They also can be used to resolve etiological heterogeneity and to identify drug targets. However, HS has not been extensively investigated with well-powered genetic studies. Here, we review what is known about its genetic architecture. We identify overlap in molecular, cellular, and clinical features between HS and inborn errors of immunity (IEI). This evidence indicates that HS may be an underrecognized component of IEI and suggests that undiagnosed IEI are present in HS cohorts. Inborn errors of immunity represent a salient opportunity for rapidly resolving the immunological landscape of HS pathogenesis, for prioritizing drug repurposing studies, and for improving the clinical management of HS.

The Multifaceted Syndromic Primary Immunodeficiencies in Children

BACKGROUND

Disorders of immunity are poorly recognised in some rare multisystem genetic conditions. We aim to describe syndromic features and immunological defects in children with syndromic primary immunodeficiencies (sPIDs).

METHODS

This is a retrospective descriptive study of children aged 0-18 years with sPIDs under the care of the paediatric immunology service at the Bristol Royal Hospital for Children, United Kingdom, from January 2006 to September 2021.

RESULTS

sPIDs were identified in 36 patients. Genetic diagnoses which are not commonly associated with PIDs and not included in the International Union of Immunological Societies classification were present in 7/36 (19%): Trisomy 22, Arboleda-Tham syndrome, 2p16.3 deletion syndrome, supernumerary ring chromosome 20 syndrome, Myhre syndrome, Noonan syndrome, and trichothiodystrophy/Cockayne syndrome complex. Recurrent and/or severe infections were the most common clinical features (n = 33, 92%). Approximately half had combined immunodeficiency or antibody deficiency. The most common extra-immunological manifestations include dysmorphism (72%), disorders of nervous (78%), musculoskeletal (69%), haematology/lymphatic (58%), and gastrointestinal, hepatic/pancreatic (58%) systems.

CONCLUSIONS

Patients with sPIDs often have multiorgan involvement and some are non-immunologically mediated. There should be a low threshold to clinically assess and investigate for disorders of immunity in any patients with syndromic features especially when they present with recurrent/severe/opportunistic infections, features of immune dysregulation, autoinflammation or lymphoproliferation.

The Evolutionary Scenario of Pediatric Unclassified Primary Antibody Deficiency to Adulthood

BACKGROUND

Unclassified primary antibody deficiency (unPAD) is a relatively novel inborn error of immunity (IEI) condition that can vary with time to more defined entities. Since long-term follow-up (FU) studies are scarce, we aimed to provide insight into the evolutionary clinical and immunological scenario of unPAD children to adulthood and identification of biomarkers of primary immune deficiency (PID) persistence.

METHODS

A total of 23 pediatric unPAD patients underwent clinical and immunological FU for a mean time of 14 years (range 3-32 years, median 16 years).

RESULTS

UnPAD diagnosis may change over time. At the last FU, 10/23 (44%) children matched the diagnosis of transient hypogammaglobulinemia of infancy and 13/23 (56%) suffered from a persistent PID. In detail, an unPAD condition was confirmed in 7/23 (30%) patients, whereas 3/23 (13%), 2/23 (9%), and 1/23 (4%) were reclassified as common variable immunodeficiency, selective IgA deficiency, and isolated IgM deficiency, respectively. Low IgA, low specific antibody response to pneumococcus, and lower respiratory tract infections at diagnosis were independently associated with IEI persistence.

CONCLUSIONS

Long-term monitoring of unPAD patients is required to define their outcome and possible evolution towards a definitive IEI diagnosis.

Case Report: A novel IRF2BP2 mutation in an IEI patient with recurrent infections and autoimmune disorders

Introduction

Inborn errors of immunity (IEI) are a heterogeneous group of disorders characterized by increased risk of infections, autoimmunity, autoinflammatory diseases, malignancy and allergy. Next-generation sequencing has revolutionized the identification of genetic background of these patients and assists in diagnosis and treatment. In this study, we identified a probable unique monogenic cause of IEI, and evaluated the immunological methods and pathogenic detections.

Methods

A family with a member with a clinical diagnosis of IEI was screened by whole genomic sequencing (WGS). Demographic data, clinical manifestations, medical history, physical examination, laboratory findings and imaging features of the patient were extracted from medical records. Comprehensive immune monitoring methods include a complete blood count with differential, serum levels of cytokines and autoantibodies, T-cell and B-cell subsets analysis and measurement of serum immunoglobulins. In addition, metagenomic sequencing (mNGS) of blood, cerebrospinal fluid and biopsy from small intestine were used to detect potential pathogens.

Results

The patient manifested with recurrent infections and autoimmune disorders, who was eventually diagnosed with IEI. Repetitive mNGS tests of blood, cerebrospinal fluid and biopsy from small intestine didn't detect pathogenic microorganism. Immunological tests showed a slightly decreased level of IgG than normal, elevated levels of tumor necrosis factor and interleukin-6. Lymphocyte flow cytometry showed elevated total B cells and natural killer cells, decreased total T cells and B-cell plasmablasts. WGS of the patient identified a novel heterozygous mutation in IRF2BP2 (c.439_450dup p. Thr147_Pro150dup), which was also confirmed in his father. The mutation was classified as variant of uncertain significance (VUS) according to the American College of Medical Genetics and Genomics guidelines.

Conclusion

We identified a novel IRF2BP2 mutation in a family with a member diagnosed with IEI. Immune monitoring and WGS as auxiliary tests are helpful in identifying genetic defects and assisting diagnosis in patients with clinically highly suspected immune abnormalities and deficiencies in inflammation regulation. In addition, mNGS techniques allow a more comprehensive assessment of the pathogenic characteristics of these patients. This report further validates the association of IRF2BP2 deficiency and IEI, and expands IEI phenotypes.

Improving Access to Therapy for Patients With Inborn Errors of Immunity: A Call to Action

Breakthroughs in sequencing technology, targeted immunotherapy, and immune reconstituting treatment have increased the pool of patients with inborn errors of immunity, requiring expertise from clinical immunologists. A growing category of immunodeficiency, presenting as primary immune regulatory disorder and secondary immunodeficiency due to targeted immune therapy for cancer and autoimmunity, has added to the growing burden of patients needing access to immune-supportive therapy. The confluence of a growing population of patients needing a clinical immunologist, complex payer structures, and inadequate health care representation will exacerbate current problems with access to therapy. Patients, health care providers, researchers, public and private payers, and industry must come together to find solutions to improve access to therapy. In this article, we reviewed the major topics regarding access to therapy for patients with immunodeficiency.

ANCA vasculitis expands the spectrum of autoimmune manifestations of activated PI3 kinase δ syndrome

Activated phosphoinositide 3-kinase δ syndrome (APDS) is a combined immunodeficiency with a broad clinical phenotype, including not only an increased propensity for sinopulmonary and herpesviruses infections but also immune dysregulation, such as benign lymphoproliferation, autoimmunity, and malignancy. Autoimmune complications are increasingly recognized as initial presenting features of immune dysregulation in inborn errors of immunity (IEIs), including APDS, so awareness of the spectrum of autoimmune features inherit within these disorders is critical. We present here a patient vignette to highlight cutaneous antineutrophil cytoplasmic antibody (ANCA) vasculitis as an underrecognized autoimmune manifestation of APDS. The genetic defects underlying APDS result in increased PI3Kδ signaling with aberrant downstream signaling pathways and loss of B- and/or T-cell immunologic tolerance mechanisms, which promote the development of autoimmunity. An understanding of the molecular pathways and mechanisms that lead to immune dysregulation in APDS has allowed for significant advancements in the development of precision-medicine therapeutics, such as leniolisib, to reduce the morbidity and mortality for these patients. Overall, this case and review highlight the need to maintain a high index of suspicion for IEIs, such as APDS, in those presenting with autoimmunity in combination with a dysregulated immune phenotype for prompt diagnosis and targeted intervention.

Long-term follow-up in common variable immunodeficiency: the pediatric-onset and adult-onset landscape

Introduction

The primary aim of this study is to investigate the evolution of the clinical and laboratory characteristics during the time in a longitudinal cohort of pediatric-onset and adult-onset Common Variable Immunodeficiency (CVID) patients in order to identify early predictive features of the disease and immune dysregulation complications.

Methods

This is a retrospective-prospective monocentric longitudinal study spanning from 1984 to the end of 2021. The data of pediatric-onset vs. adult-onset patients have been compared for immunological features and for infectious and non-infectious complications assessed at diagnosis and follow-up.

Results

Seventy-three CVID patients have been enrolled, with a mean of 10.0 years (SD ± 8.17) of prospective follow-up. At diagnosis, infections were observed in 89.0% of patients and immune dysregulation in 42.5% of patients. At diagnosis, 38.6% of pediatric-onset and 20.7% of adult-onset patients presented with only infections. Polyclonal lymphoid proliferation (62.1%) and autoimmunity (51.7%) were more prevalent in the adult-onset than in the pediatric-onset group (polyclonal lymphoid proliferation 52.3% and autoimmunity 31.8%, respectively). Enteropathy was present in 9.1% of pediatric-onset and 17.2% of adult-onset patients. The prevalence of polyclonal lymphoid proliferation increased during follow-up more in pediatric-onset patients (diagnosis 52.3%-follow-up 72.7%) than in adult-onset patients (diagnosis 62.1%-follow-up 72.7%). The cumulative risk to develop immune dysregulation increases according to the time of disease and the time of diagnostic delay. At the same age, pediatric-onset patients have roughly double the risk of having a complication due to immune dysregulation than adult-onset patients, and it increases with diagnostic delay. The analysis of lymphocyte subsets in the pediatric-onset group showed that CD21 low B cells at diagnosis may be a reliable prognostic marker for the development of immune dysregulation during follow-up, as the ROC curve analysis showed (AUC = 0.796). In the adult-onset group, the percentage of transitional B cells measured at diagnosis showed a significant accuracy (ROC AUC = 0.625) in identifying patients at risk of developing immune dysregulation.

Discussion

The longitudinal evaluation of lymphocyte subsets combined with clinical phenotype can improve the prediction of lymphoid proliferation and allow experts to achieve early detection and better management of such complex disorder.

Impact of SARS-CoV-2 infection and COVID-19 on patients with inborn errors of immunity

Since the arrival of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in December 2019, its characterization as a novel human pathogen, and the resulting coronavirus disease 2019 (COVID-19) pandemic, over 6.5 million people have died worldwide-a stark and sobering reminder of the fundamental and nonredundant roles of the innate and adaptive immune systems in host defense against emerging pathogens. Inborn errors of immunity (IEI) are caused by germline variants, typically in single genes. IEI are characterized by defects in development and/or function of cells involved in immunity and host defense, rendering individuals highly susceptible to severe, recurrent, and sometimes fatal infections, as well as immune dysregulatory conditions such as autoinflammation, autoimmunity, and allergy. The study of IEI has revealed key insights into the molecular and cellular requirements for immune-mediated protection against infectious diseases. Indeed, this has been exemplified by assessing the impact of SARS-CoV-2 infection in individuals with previously diagnosed IEI, as well as analyzing rare cases of severe COVID-19 in otherwise healthy individuals. This approach has defined fundamental aspects of mechanisms of disease pathogenesis, immunopathology in the context of infection with a novel pathogen, and therapeutic options to mitigate severe disease. This review summarizes these findings and illustrates how the study of these rare experiments of nature can inform key features of human immunology, which can then be leveraged to improve therapies for treating emerging and established infectious diseases.

The link between rheumatic disorders and inborn errors of immunity

Inborn errors of immunity (IEIs) are immunological disorders characterized by variable susceptibility to infections, immune dysregulation and/or malignancies, as a consequence of damaging germline variants in single genes. Though initially identified among patients with unusual, severe or recurrent infections, non-infectious manifestations and especially immune dysregulation in the form of autoimmunity or autoinflammation can be the first or dominant phenotypic aspect of IEIs. An increasing number of IEIs causing autoimmunity or autoinflammation, including rheumatic disease have been reported over the last decade. Despite their rarity, identification of those disorders provided insight into the pathomechanisms of immune dysregulation, which may be relevant for understanding the pathogenesis of systemic rheumatic disorders. In this review, we present novel IEIs primarily causing autoimmunity or autoinflammation along with their pathogenic mechanisms. In addition, we explore the likely pathophysiological and clinical relevance of IEIs in systemic rheumatic disorders.

Clinical and Immunologic Characteristics of Non-Hematologic Cancers in Patients with Inborn Errors of Immunity

Inborn errors of immunity (IEI) are a heterogeneous group of inherited disorders, and almost 500 genes associated with these disorders have been identified. Defects in IEI genes lead to diverse clinical manifestations including increased susceptibility to recurrent or prolonged infections, immune dysregulation phenotypes (such as severe atopy, allergy, autoimmunity, and uncontrolled inflammation, lymphoproliferation), as well as predisposition to malignancies. Although the majority of IEI patients present hematologic cancers, the characteristics of other types of cancers are not well described in these groups of patients. By investigating 5384 IEI patients registered in the Iranian national registry the clinical and immunologic phenotypes of patients with non-hematologic cancers were compared with other malignant and non-malignant patients. Solid tumors were reported <20% of malignant IEI patients (n = 27/144 patients) and appeared to be very heterogeneous by type and localization as well as molecular defects (mainly due to DNA repair defect resulted from ATM deficiency). The correlation between the type of malignancy and survival status was remarkable as patients with non-hematologic cancers survive higher than IEI patients with hematologic cancers. Our findings showed that different types of malignancy could be associated with specific entities of IEI. Therefore, the education of physicians about the risk of malignancies in IEI is required for personalized treatment and appropriate management of patients.

Initial manifestations in Patients with Inborn Errors of Immunity Based on Onset Age: a Study from a Nationwide Survey in Japan

PURPOSE

Patients with inborn errors of immunity (IEI) manifest various initial symptoms; however, those that are critical for the early diagnosis of IEI have not been identified. Also, the significance of the ten warning signs of primary immunodeficiency (PID) among infants has not been established. This study aimed to conduct a nationwide survey of IEI in Japan and investigated the initial manifestations based on onset age.

METHODS

Among 1298 patients, data regarding the initial manifestation were available from 505 patients. Patients with autoinflammatory diseases, complement deficiency, and phenocopies of IEI were excluded.

RESULTS

The ten warning signs were positive in 67.3% of the cases. The positivity rate was low (20.5%) in patients with immune dysregulation. Although the positivity rate was low (36.6%) in patients aged less than 3 months, they were highly positive for family history of IEI (26.8%). Infectious symptoms were the most commonly observed in all age groups and in all disease categories. Symptoms of "immune dysregulation" were present in approximately 15% of the patients. Regarding the anatomical category, almost all initial symptoms were "systemic" infections in patients with X-linked severe combined immunodeficiency. Moreover, "respiratory" symptoms were the most common in patients with IEI aged ≥ 1 year and accounted for more than 50% in all age groups in patients with common variable immunodeficiency.

CONCLUSION

These results highlight the significance of the 10 warning signs and may serve as clinical indicators for early diagnosis, considering the initial presentation of IEI.

Recurrent or unusual infections in children - when to worry about inborn errors of immunity

Recurrent infections are a common presenting feature in paediatrics and, while most times considered part of normal growing up, they are also a classical hallmark of inborn errors of immunity (IEI). We aimed to outline the value of currently used signs for IEI and the influence of the changing epidemiology of infectious diseases due to implementation of new vaccines and the effect of the COVID-19 pandemic on the assessment of children with recurrent infections. Warning signs for IEI have been developed, but the supporting evidence for their effectiveness is limited, and immune dysregulation is more commonly recognised as a feature for IEI, making reliable identification of children who should be screened for IEI on clinical grounds difficult. In addition, the epidemiology of infectious diseases is changing due to restrictions related to Covid-19 as well as immunisations, which may change the threshold to screen children for IEI. Treatments for IEI are evolving and are often more effective and less complicated when started early. Screening for IEI can be initiated by the non-immunologist and should be considered early to ensure optimal treatment outcomes.

Advances and Challenges of the Decade: The Ever-Changing Clinical and Genetic Landscape of Immunodeficiency

In the past 10 years, we have witnessed major advances in clinical immunology. Newborn screening for severe combined immunodeficiency has become universal in the United States and screening programs are being extended to severe combined immunodeficiency and other inborn errors of immunity globally. Early genetic testing is becoming the norm for many of our patients and allows for informed selection of targeted therapies including biologics repurposed from other specialties. During the COVID-19 pandemic, our understanding of essential immune responses expanded and the discovery of immune gene defects continued. Immunoglobulin products, the backbone of protection for antibody deficiency syndromes, came into use to minimize side effects. New polyclonal and monoclonal antibody products emerged with increasing options to manage respiratory viral agents such as SARS-CoV-2 and respiratory syncytial virus. Against these advances, we still face major challenges. Atypical is becoming typical as phenotypes of distinct genetic disease overlap whereas the clinical spectrum of the same genetic defect widens. Therefore, clinical judgment needs to be paired with repeated deep immune phenotyping and upfront genetic testing, as technologies rapidly evolve, and clinical disease often progresses with age. Managing patients with organ damage resulting from immune dysregulation poses a special major clinical challenge and management often lacks standardization, from autoimmune cytopenias, granulomatous interstitial lung disease, enteropathy, and liver disease to endocrine, rheumatologic, and neurologic complications. Clinical, translational, and basic science networks will continue to advance the field; however, cross-talk and education with practicing allergists/immunologists are essential to keep up with the ever-changing clinical and genetic landscape of inborn errors of immunity.

The Middle East and North Africa Diagnosis and Management Guidelines for Inborn Errors of Immunity

Human inborn errors of immunity (IEI) are a group of 485 distinct genetic disorders affecting children and adults. Signs and symptoms of IEI are heterogeneous, and accurate diagnosis can be challenging and depends on the available human expertise and laboratory resources. The Middle East and North Africa (MENA) region has an increased prevalence of IEI because of the high rate of consanguinity with a predominance of autosomal recessive disorders. This area also exhibits more severe disease phenotypes compared with other regions, probably due to the delay in diagnosis. The MENA-IEI registry network has designed protocols and guidelines for the diagnosis and treatment of IEI, taking into consideration the variable regional expertise and resources. These guidelines are primarily meant to improve the care of patients within the region, but can also be followed in other regions with similar patient populations.

Immune dysregulation

The understanding of immune dysregulation in many different diseases continues to grow. There is increasing evidence that altered microbiome and gut barrier dysfunction contribute to systemic inflammation in patients with primary immunodeficiency and in patients with rheumatic disease. Recent research provides insight into the process of induction and maturation of pathogenic age-associated B cells and highlights the role of age-associated B cells in creating tissue inflammation. T follicular regulatory cells are shown to help maintain B-cell tolerance, and therapeutic approaches to increase or promote T follicular regulatory cells may help prevent or decrease immune dysregulation. Meanwhile, novel studies of systemic-onset juvenile idiopathic arthritis reveal a strong HLA association with interstitial lung disease and identify key aspects of the pathogenesis of macrophage activation syndrome. Studies of hyperinflammatory syndromes, including the recently described multisystem inflammatory syndrome of children, characterize similarities and differences in cytokine profiles and T-cell activation. This review focuses on recent advances in the understanding of immune dysregulation and describes potential key factors that may function as biomarkers for disease or targets for therapeutic interventions. Future trials are necessary to address the many remaining questions with regards to pathogenesis, diagnosis, and treatment of autoimmune, inflammatory, and immunodeficiency syndromes.

Disease Progression of WHIM Syndrome in an International Cohort of 66 Pediatric and Adult Patients

Warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome (WS) is a combined immunodeficiency caused by gain-of-function mutations in the C-X-C chemokine receptor type 4 (CXCR4) gene. We characterize a unique international cohort of 66 patients, including 57 (86%) cases previously unreported, with variable clinical phenotypes. Of 17 distinct CXCR4 genetic variants within our cohort, 11 were novel pathogenic variants affecting 15 individuals (23%). All variants affect the same CXCR4 region and impair CXCR4 internalization resulting in hyperactive signaling. The median age of diagnosis in our cohort (5.5 years) indicates WHIM syndrome can commonly present in childhood, although some patients are not diagnosed until adulthood. The prevalence and mean age of recognition and/or onset of clinical manifestations within our cohort were infections 88%/1.6 years, neutropenia 98%/3.8 years, lymphopenia 88%/5.0 years, and warts 40%/12.1 years. However, we report greater prevalence and variety of autoimmune complications of WHIM syndrome (21.2%) than reported previously. Patients with versus without family history of WHIM syndrome were diagnosed earlier (22%, average age 1.3 years versus 78%, average age 5 years, respectively). Patients with a family history of WHIM syndrome also received earlier treatment, experienced less hospitalization, and had less end-organ damage. This observation reinforces previous reports that early treatment for WHIM syndrome improves outcomes. Only one patient died; death was attributed to complications of hematopoietic stem cell transplantation. The variable expressivity of WHIM syndrome in pediatric patients delays their diagnosis and therapy. Early-onset bacterial infections with severe neutropenia and/or lymphopenia should prompt genetic testing for WHIM syndrome, even in the absence of warts.

Clinical, immunological, molecular and therapeutic findings in monogenic immune dysregulation diseases: Middle East and North Africa registry

Monogenic immune dysregulation diseases (MIDD) are caused by defective immunotolerance. This study was designed to increase knowledge on the prevalence and spectrum of MIDDs, genetic patterns, and outcomes in Middle East and North Africa (MENA). MIDD patients from 11 MENA countries (Iran, Turkey, Kuwait, Oman, Algeria, Egypt, United Arab Emirates, Tunisia, Jordan, Qatar, and Azerbaijan) were retrospectively evaluated. 343 MIDD patients (58% males and 42% female) at a median (IQR) age of 101 (42-192) months were enrolled. The most common defective genes were LRBA (23.9%), LYST (8.2%), and RAB27A (7.9%). The most prevalent initial and overall manifestations were infections (32.2% and 75.1%), autoimmunity (18.6% and 41%), and organomegaly (13.3% and 53.8%), respectively. Treatments included immunoglobulin replacement therapy (53%), hematopoietic stem cell transplantation (HSCT) (14.3%), immunosuppressives (36.7%), and surgery (3.5%). Twenty-nine (59.2%) patients survived HSCT. Along with infectious complications, autoimmunity and organomegaly may be the initial or predominant manifestations of MIDD.

Eosinophilic gastrointestinal disorders in patients with inborn errors of immunity: Data from the USIDNET registry

Rationale

Eosinophilic gastrointestinal disorders (EGID), including eosinophilic esophagitis (EoE), are inflammatory disorders of the gastrointestinal mucosa mediated by complex immune mechanisms. Although there have been initial reports of EGID in patients with inborn errors of immunity (IEI), little is known about the presentation of EGID in immunodeficient individuals.

Methods

We queried the U.S. Immunodeficiency Network (USIDNET) for patient records including the terms eosinophilic esophagitis, gastritis, enteritis, or colitis. We analyzed 74 patient records from the database, including diagnoses, demographics, infectious history, laboratory findings, genetic studies, therapeutic interventions, and clinical outcomes.

Results

We examined 74 patient records. A total of 61 patients had isolated EoE, and 13 had distal gastrointestinal involvement consistent with EGID. The most common IEI were common variable immunodeficiency (43.2%), some form of combined immunodeficiency (21.6%), chronic granulomatous disease (8.1%), hyper-IgE syndrome (6.8%), and autoimmune lymphoproliferative syndrome (6.8%). The median age at presentation with IEI was 0.5 years (IQR 1.725, max 39 years) and 56.76% were male. Approximately 20% of the patients in the cohort received a hematopoietic stem cell transplantation for treatment of IEI, but the timing of the HSCT in relationship to the EGID diagnosis was unknown.

Conclusions

Here, we report EGID in a diverse cohort of IEI patients, suggesting that both non-EoE EGID and EoE can be seen as comorbid conditions with a variety of IEI. Our data suggests that EGID may be more common in patients with IEI than would be expected based on estimates of EGID in the general population.

Autoantibodies in immunodeficiency syndromes: The Janus faces of immune dysregulation

Immunodeficiency syndromes represent a diverse group of inherited and acquired disorders, characterized by a spectrum of clinical manifestations, including recurrent infections, autoimmunity, lymphoproliferation and malignancy. Autoantibodies against various self-antigens reflect the immune dysregulation underlying these disorders, and could contribute to certain clinical findings, such as susceptibility to opportunistic infections, cytopenia of different hematopoietic lineages, and organ-specific autoimmune diseases. The mechanism of autoantibody production in the context of immunodeficiency remains largely unknown but is likely shaped by both intrinsic genetic aberrations and extrinsic exposures to possible infectious agents. These autoantibodies if harbor neutralizing activities and reach certain levels in the circulation, could disrupt the biological functions of their targets, resulting in specific clinical manifestations. Herein, we reviewed the prevalence of autoantibodies against cytokines, hematopoietic cells and organ-specific antigens in immunodeficiency syndromes and examined their associations with certain clinical findings. Moreover, the potential mechanism of autoantibody production was also discussed. These may shed light on the development of mechanism-based therapies to reset the dysregulated immune system in immunodeficient patients.

Secondary Immune Deficiency and Primary Immune Deficiency Crossovers: Hematological Malignancies and Autoimmune Diseases

Primary immunodeficiencies (PIDs), a heterogenous group of inborn errors of immunity, are predetermined at birth but may evolve with age, leading to a variable clinical and laboratory presentation. In contrast, secondary immunodeficiencies (SIDs) are acquired declines of immune cell counts and or/function. The most common type of SID is a decreased antibody level occurring as a consequence of extrinsic influences, such as an underlying condition or a side effect of some medications used to treat hematological malignancies and autoimmune disorders. Paradoxically, immune deficiencies initially attributed to secondary causes may partly be due to an underlying PID. Therefore, in the era of immune-modulating biologicals, distinguishing between primary and secondary antibody deficiencies is of great importance. It can be difficult to unravel the relationship between PID, SID and hematological malignancy or autoimmunity in the clinical setting. This review explores SID and PID crossovers and discusses challenges to diagnosis and treatment strategies. The case of an immunodeficient patient with follicular lymphoma treated with rituximab illustrates how SID in the setting of hematological cancer can mask an underlying PID, and highlights the importance of screening such patients. The risk of hematological cancer is increased in PID: for example, lymphomas in PID may be driven by infections such as Epstein-Barr virus, and germline mutations associated with PID are enriched among patients with diffuse large B-cell lymphoma. Clues suggesting an increased risk of hematological malignancy in patients with common variable immune deficiency (CVID) are provided, as well as pointers for distinguishing PID versus SID in lymphoma patients. Two cases of patients with autoimmune disorders illustrate how an apparent rituximab-induced antibody deficiency can be connected to an underlying PID. We highlight that PID is increasingly recognized among patients with autoimmune cytopenias, and provide guidance on how to identify PID and distinguish it from SID in such patients. Overall, healthcare professionals encountering patients with malignancy and/or autoimmunity who have post-treatment complications of antibody deficiencies or other immune abnormalities need to be aware of the possibility of PID or SID and how to differentiate them.

Peripheral‐blood cytopenia, an early indicator of inborn errors of immunity

Inborn errors of immunity (IEI) are inherited monogenic disorders resulting in defective immune response. Non‐infectious presentations are increasingly more apparent. Widely available, cost‐effective early indicators are needed. Peripheral‐blood cytopenia may be a presenting laboratory feature or an observed secondary phenomenon. This retrospective review of the South African Primary Immunodeficiency Registry (SAPIDR) aimed to assess the haematological indices at presentation and their association with the International Union of Immunological Societies (IUIS) 2019 IEI classification and mortality. Of 396 patients on the SAPIDR, 66% (n = 257) had available haematological results. Sixty percent were males and 85% under 18 years. A majority (53%) had predominantly antibody deficiency. At presentation, infection was prominent (86%) followed by cytopenia (62%). Neutropenia was associated with IUIS III [odds ratio (OR) 3.65, confidence interval (CI) 1.44–9.25], thrombocytopenia with IUIS II (OR 14.39, CI 2.89–71.57), lymphopenia with IUIS I (OR 12.16, CI 2.75–53.73) and pancytopenia with IUSI I (OR 12.24, CI 3.82–39.05) and IUIS II (OR 5.99, CI 2.80–12.76). Cytopenia showed shorter overall survival (OR 2.81, CI 1.288–4.16). Cytopenias that are severe, persistent, unusual and/or recurrent should prompt further investigation for IEI. The full blood count and leucocyte differential may facilitate earlier identification and serve as an adjunct to definitive molecular classification.

Copy Number Analysis in a Large Cohort Suggestive of Inborn Errors of Immunity Indicates a Wide Spectrum of Relevant Chromosomal Losses and Gains

Inborn errors of immunity (IEI) are genetically driven disorders. With the advancement of sequencing technologies, a rapidly increasing number of gene defects has been identified, thereby mirroring the high heterogeneity in immunological and clinical presentations observed in patients. However, for a large majority of patients, no causative single nucleotide variant (SNV) or small indel can be identified using next-generation sequencing. First studies have shown that also copy number variants (CNVs) can cause IEI. Unfortunately, CNVs are not well examined in many routine diagnostic settings and the aim of this study was to assess the number of clinically relevant chromosomal losses and gains in a large cohort. We identified a total of 20 CNVs using whole exome sequencing data of a cohort of 191 patients with a suspected IEI. A definite molecular diagnosis could be made in five patients (2.6%), including pathogenic deletions affecting ICOS, TNFAIP3, and 22q11.2. CNVs of uncertain significance were observed in fifteen patients (7.9%), including deletions of 11q22.1q22.3 and 16p11.2 but also duplications affecting entire or parts of genes previously associated with IEI. Importantly, five patients carrying a CNV of uncertain significance also carried pathogenic or likely pathogenic SNVs (PIK3R1, NFKB1, NLRC4, DOCK2), or SNVs of unknown significance (NFKB2). This cooccurrence of SNVs and CNVs suggests modifying effects in some patients, and functional follow-up is warranted now in order to better understand phenotypic heterogeneity. In summary, the diagnostic yield of IEI can be increased substantially by evaluating CNVs, which allows an improved therapeutic management in those patients.