Autoimmunity and Immune Dysregulation in Primary Immune Deficiency Disorders

Lung infections in immunocompromised children

Pulmonary infection is the leading cause of infectious morbidity and mortality in children with immune defects. We provide a comprehensive review of lung infections in immunocompromised children, with a focus on imaging findings and imaging-based management. We include an overview of the immune defences of the respiratory tract, the aetiologies of immune defects in children, the features of specific infections and important differential diagnoses and describe diagnostic strategies using imaging and non-imaging-based techniques.

Anti-Idiotypic mRNA Vaccine to Treat Autoimmune Disorders

The 80+ existing autoimmune disorders (ADs) affect billions with little prevention or treatment options, except for temporary symptomatic management, leading to enormous human suffering and a monumental financial burden. The autoantibodies formed in most ADs have been identified, allowing the development of novel anti-idiotypic antibodies to mute the autoantibodies using vaccines. Nucleoside vaccines have been successfully tested as antigen-specific immunotherapies (ASI), with mRNA technology offering multi-epitope targeting to mute multiple autoantibodies. This paper proposes using mRNA technology to produce anti-idiotypic antibodies with broad effectiveness in preventing and treating them. This paper delves into the state-of-the-art mRNA design strategies used to develop novel ASIs by selecting appropriate T cell and B cell epitopes to generate anti-idiotypic antibodies. The low cost and fast development of mRNA vaccines make this technology the most affordable for the global control of ADs.

The Autoimmune Manifestations in Patients with Genetic Defects in the B Cell Development and Differentiation Stages

PURPOSE

Primary B cell defects manifesting as predominantly antibody deficiencies result from variable inborn errors of the B cell lineage and their development, including impairments in early bone marrow development, class switch recombination (CSR), or terminal B cell differentiation. In this study, we aimed to investigate autoimmunity in monogenic patients with B cell development and differentiation defects.

METHODS

Patients with known genetic defects in the B cell development and differentiation were recruited from the Iranian inborn errors of immunity registry.

RESULTS

A total of 393 patients with a known genetic defect in the B cell development and differentiation (257 males; 65.4%) with a median age of 12 (6-20) years were enrolled in this study. After categorizing patients, 109 patients had intrinsic B cell defects. More than half of the patients had defects in one of the ATM (85 patients), BTK (76 patients), LRBA (34 patients), and DOCK8 (33 patients) genes. Fifteen patients (3.8%) showed autoimmune complications as their first manifestation. During the course of the disease, autoimmunity was reported in 81 (20.6%) patients at a median age of 4 (2-7) years, among which 65 patients had mixed intrinsic and extrinsic and 16 had intrinsic B cell defects. The comparison between patients with the mentioned four main gene defects showed that the patient group with LRBA defect had a significantly higher frequency of autoimmunity compared to those with other gene defects. Based on the B cell defect stage, 13% of patients with early B cell defect, 17% of patients with CSR defect, and 40% of patients who had terminal B cell defect presented at least one type of autoimmunity.

CONCLUSION

Our results demonstrated that gene mutations involved in human B cell terminal stage development mainly LRBA gene defect have the highest association with autoimmunity.

Genetic Causes, Clinical Features, and Survival of Underlying Inborn Errors of Immunity in Omani Patients: a Single-Center Study

PURPOSE

Early identification of inborn errors of immunity (IEIs) is crucial due to the significant risk of morbidity and mortality. This study aimed to describe the genetic causes, clinical features, and survival rate of IEIs in Omani patients.

METHODS

A prospective study of all Omani patients evaluated for immunodeficiency was conducted over a 17-year period. Clinical features and diagnostic immunological findings were recorded. Targeted gene testing was performed in cases of obvious immunodeficiency. For cases with less conclusive phenotypes, a gene panel was performed, followed by whole-exome sequencing if necessary.

RESULTS

A total of 185 patients were diagnosed with IEIs during the study period; of these, 60.5% were male. Mean ages at symptom onset and diagnosis were 30.0 and 50.5 months, respectively. Consanguinity and a family history of IEIs were present in 86.9% and 50.8%, respectively. Most patients presented with lower respiratory infections (65.9%), followed by growth and development manifestations (43.2%). Phagocytic defects were the most common cause of IEIs (31.9%), followed by combined immunodeficiency (21.1%). Overall, 109 of 132 patients (82.6%) who underwent genetic testing received a genetic diagnosis, while testing was inconclusive for the remaining 23 patients (17.4%). Among patients with established diagnoses, 37 genes and 44 variants were identified. Autosomal recessive inheritance was present in 81.7% of patients with gene defects. Several variants were novel. Intravenous immunoglobulin therapy was administered to 39.4% of patients and 21.6% received hematopoietic stem cell transplantation. The overall survival rate was 75.1%.

CONCLUSION

This study highlights the genetic causes of IEIs in Omani patients. This information may help in the early identification and management of the disease, thereby improving survival and quality of life.

Genetic diagnosis of immune dysregulation can lead to targeted therapy for interstitial lung disease: A case series and single center approach

In recent years, a growing number of monogenic disorders have been described that are characterized by immune dysregulation. A subset of these "primary immune regulatory disorders" can cause severe interstitial lung disease, often recognized in late childhood or adolescence. Patients presenting to pulmonary clinic may have long and complex medical histories, but lack a unifying genetic diagnosis. It is crucial for pulmonologists to recognize features suggestive of multisystem immune dysregulation and to initiate genetic workup, since targeted therapies based on underlying genetics may halt or even reverse pulmonary disease progression. Through such an approach, our center has been able to diagnose and treat a cohort of patients with interstitial lung disease from gene defects that affect immune regulation. Here we present representative cases related to pathogenic variants in three distinct pathways and summarize disease manifestations and treatment approaches. We conclude with a discussion of our perspective on the outstanding challenges for diagnosing and managing these complex life-threatening and chronic disorders.

Generation of Allogeneic CAR T Cells through Specific Degradation of the T Cell Antigen Receptor by E3 Ubiquitin Ligase Fusion Proteins

Receptor downregulation is instrumental for many therapeutic interventions. Receptor knockout through gene-editing technologies is efficient but can introduce off-target mutations and chromothripsis. Regulation of gene expression at the protein level is a promising alternative. Here, we present results showing the targeted T cell antigen receptor (TCR) degradation using chimeric E3 fusion proteins that we call Receptor Targeting Chimeras (ReceptorTAC). We show that TCR degradation is dependent on enzymatically active, membrane-anchored E3 ligase variants. TCR specificity was achieved by direct fusion of an E3 domain to the CD3ζ transmembrane sequence. Jurkat and primary T cells stably expressing the ReceptorTAC constructs showed significantly reduced responses to TCR stimulation. We also used our ReceptorTAC technology to generate TCR-deficient, claudin18.2-specific CAR T cells, where the activity of the CAR was unaffected by the expression of the ReceptorTAC. These data indicate that our ReceptorTAC molecule can be used to generate allogeneic CAR T cells.

Primary immune regulatory disorders: Undiagnosed needles in the haystack?

Primary Immune Regulatory Disorders (PIRD) describe a group of conditions characterized by loss of normal inflammatory control and immune tolerance mechanisms, with autoimmunity as a predominant clinical feature. PIRD can arise due to defects in the number or function of regulatory T-lymphocytes, defects in the immune mechanisms required to ‘turn off’ inflammation such as in perforin-dependent cytotoxicity or alterations in cytokine signalling pathways. Diagnosis of PIRD is a significant challenge to physicians due to their rarity, complexity, and diversity in clinical manifestations. Many of these individual conditions lack a genotype–phenotype correlation and display incomplete penetrance. However, establishing a diagnosis is integral in optimizing patient management, including the use of individualized treatment approaches. Increasing awareness among physicians is necessary as patients are likely to present to different subspecialties. Due to the rarity of these conditions, worldwide collaboration and data-sharing is essential to improve our knowledge of the clinical spectrum and disease course in PIRD, and to optimize therapeutic strategies including identification of which patients can benefit from hematopoietic stem cell transplant.

SBT (Composed of Panax ginseng and Aconitum carmichaeli) and Stigmasterol Enhances Nitric Oxide Production and Exerts Curative Properties as a Potential Anti-Oxidant and Immunity-Enhancing Agent

Immune dysregulation is a risk factor for several diseases, including infectious diseases. Immunostimulatory agents have been used for the treatment of immune dysregulation, but deleterious adverse effects have been reported. The present study aims to establish the anti-oxidant and immunity-enhancing effects of Sambu-Tang (SBT), composed of Panax ginseng and Aconitum carmichaeli, and stigmasterol (Stig), an active compound of SBT. Immune-related factors were analyzed in RAW264.7 macrophage cells, mouse primary splenocytes, and the serum and spleen of cyclophosphamide-induced immunosuppressed mice. Results showed that the production levels of nitric oxide (NO) and expression levels of inducible NO synthase and heme oxygenase-1 were increased following SBT or Stig treatment in RAW264.7 cells. SBT or Stig increased the production levels of G-CSF, IFN-γ, IL-12, IL-2, IL-6, and TNF-α and induced the activation of NF-κB in RAW264.7 cells. SBT or Stig promoted splenic lymphocyte proliferation and increased splenic NK cell cytotoxic activity. In addition, SBT or Stig enhanced the levels of IFN-γ, IL-12, IL-2, IL-6, or TNF-α in the serum and spleen of the immunosuppressed mice. SBT or Stig increased the superoxide dismutase activity in the spleen. Collectively, SBT and Stig possess anti-oxidant and immunomodulatory activities, so they may be considered effective natural compounds for the treatment of various symptoms caused by immune dysregulation.

Autoimmunity in Primary Immunodeficiency Disorders: An Updated Review on Pathogenic and Clinical Implications

During the last years, studies investigating the intriguing association between immunodeficiency and autoimmunity led to the discovery of new monogenic disorders, the improvement in the knowledge of the pathogenesis of autoimmunity, and the introduction of targeted treatments. Autoimmunity is observed with particular frequency in patients with primary antibody deficiencies, such as common variable immunodeficiency (CVID) and selective IgA deficiency, but combined immunodeficiency disorders (CIDs) and disorders of innate immunity have also been associated with autoimmunity. Among CIDs, the highest incidence of autoimmunity is described in patients with autoimmune polyendocrine syndrome 1, LRBA, and CTLA-4 deficiency, and in patients with STAT-related disorders. The pathogenesis of autoimmunity in patients with immunodeficiency is far to be fully elucidated. However, altered germ center reactions, impaired central and peripheral lymphocyte negative selection, uncontrolled lymphocyte proliferation, ineffective cytoskeletal function, innate immune defects, and defective clearance of the infectious agents play an important role. In this paper, we review the main immunodeficiencies associated with autoimmunity, focusing on the pathogenic mechanisms responsible for autoimmunity in each condition and on the therapeutic strategies. Moreover, we provide a diagnostic algorithm for the diagnosis of PIDs in patients with autoimmunity.

Rituximab and Abatacept Are Effective in Differential Treatment of Interstitial Lymphocytic Lung Disease in Children With Primary Immunodeficiencies

Background

Interstitial lymphocytic lung disease (ILLD), a recently recognized complication of primary immunodeficiencies (PID), is caused by immune dysregulation, abnormal bronchus-associated lymphoid tissue (BALT) hyperplasia, with subsequent progressive loss of pulmonary function. Various modes of standard immunosuppressive therapy for ILLD have been shown as only partially effective.

Objectives

To retrospectively evaluate the safety and efficacy of abatacept or rituximab in treatment of ILLD in children with PID.

Methods

29 children (median age 11 years) with various forms of PID received one of the two therapy regimens predominantly based on the lesions’ immunohistopathology: children with prevalent B-cell lung infiltration received rituximab (n = 16), and those with predominantly T-cell infiltration received abatacept (n = 17). Clinical and radiological symptoms were assessed using a severity scale developed for the study.

Results

The targeted therapy with abatacept (A) or rituximab (R) enabled long-term control of clinical (A 3.4 ± 1.3 vs. 0.6 ± 0.1; R 2.8 ± 1 vs. 0.7 ± 0.05, p < 0.01) and radiological (A 18.4 ± 3.1 vs. 6.0 ± 2.0; R 30 ± 7.1 vs. 10 ± 1.7, p < 0.01) symptoms of ILLD in both groups and significantly improved patients’ quality of life, as measured by the total scale (TS) score of 57 ± 2.1 in treatment recipients vs. 31.2 ± 1.9 before therapy (p < 0.01).

Conclusions

ILLD histopathology should be considered when selecting treatment. Abatacept and rituximab are effective and safe in differential treatment of ILLD in children.

Dysregulated immunity in PID patients with low GARP expression on Tregs due to mutations in LRRC32

Immune dysregulation diseases are characterized by heterogeneous clinical manifestations and may have severe disease courses. The identification of the genetic causes of these diseases therefore has critical clinical implications. We performed whole-exome sequencing of patients with immune dysregulation disorders and identified two patients with previously undescribed mutations in LRRC32, which encodes glycoprotein A repetitions predominant (GARP). These patients were characterized by markedly reduced numbers and frequencies of regulatory T cells (Tregs). Tregs with mutated LRRC32 exhibited strongly diminished cell-surface GARP expression and reduced suppressor function. In a model of conditional Garp deficiency in mice, we confirmed increased susceptibility to inflammatory diseases once GARP expression on Tregs was decreased. Garp deficiency led to an unstable Treg phenotype due to diminished Foxp3 protein acetylation and stability. Our study reinforces the understanding of the immunological mechanisms of immune dysregulation and expands the knowledge on the immunological function of GARP as an important regulator of Treg stability.

Ssu72 Dual-Specific Protein Phosphatase: From Gene to Diseases

More than 70% of eukaryotic proteins are regulated by phosphorylation. However, the mechanism of dephosphorylation that counteracts phosphorylation is less studied. Phosphatases are classified into 104 distinct groups based on substrate-specific features and the sequence homologies in their catalytic domains. Among them, dual-specificity phosphatases (DUSPs) that dephosphorylate both phosphoserine/threonine and phosphotyrosine are important for cellular homeostasis. Ssu72 is a newly studied phosphatase with dual specificity that can dephosphorylate both phosphoserine/threonine and phosphotyrosine. It is important for cell-growth signaling, metabolism, and immune activation. Ssu72 was initially identified as a phosphatase for the Ser5 and Ser7 residues of the C-terminal domain of RNA polymerase II. It prefers the cis configuration of the serine-proline motif within its substrate and regulates Pin1, different from other phosphatases. It has recently been reported that Ssu72 can regulate sister chromatid cohesion and the separation of duplicated chromosomes during the cell cycle. Furthermore, Ssu72 appears to be involved in the regulation of T cell receptor signaling, telomere regulation, and even hepatocyte homeostasis in response to a variety of stress and damage signals. In this review, we aim to summarize various functions of the Ssu72 phosphatase, their implications in diseases, and potential therapeutic indications.

Phenotypical T Cell Differentiation Analysis: A Diagnostic and Predictive Tool in the Study of Primary Immunodeficiencies

Multiparametric flow cytometry (MFC) represents a rapid, highly reproducible, and sensitive diagnostic technology for primary immunodeficiencies (PIDs), which are characterized by a wide range of T cell perturbations and a broad clinical and genetic heterogeneity. MFC data from CD4+ and CD8+ T cell subsets were examined in 100 patients referred for Primary Immunodeficiencies to our center. Naïve, central memory, effector memory, and terminal effector memory cell differentiation stages were defined by the combined expression CD45RA/CD27 for CD4 and CD45RA/CCR7 for CD8. Principal component analysis (PCA), a non-hypothesis driven statistical analysis, was applied to analyze MFC data in order to distinguish the diverse PIDs. Among severe lymphopenic patients, those affected by severe combined and combined immunodeficiency (SCID and CID) segregated in a specific area, reflecting a homogenous, and a more severe T cell impairment, compared to other lymphopenic PID, such as thymectomized and partial DiGeorge syndrome patients. PID patients with predominantly antibody defects were distributed in a heterogeneous pattern, but unexpectedly PCA was able to cluster some patients' resembling CID, hence warning for additional and more extensive diagnostic tests and a diverse clinical management. In conclusion, PCA applied to T cell MFC data might help the physician to estimate the severity of specific PID and to diversify the clinical and diagnostic approach of the patients.

Primary immunodeficiency and autoimmunity: A comprehensive review

The primary immunodeficiency diseases (PIDs) include many genetic disorders that affect different components of the innate and adaptive responses. The number of distinct genetic PIDs has increased exponentially with improved methods of detection and advanced laboratory methodology. Patients with PIDs have an increased susceptibility to infectious diseases and non-infectious complications including allergies, malignancies and autoimmune diseases (ADs), the latter being the first manifestation of PIDs in several cases. There are two types of PIDS. Monogenic immunodeficiencies due to mutations in genes involved in immunological tolerance that increase the predisposition to develop autoimmunity including polyautoimmunity, and polygenic immunodeficiencies characterized by a heterogeneous clinical presentation that can be explained by a complex pathophysiology and which may have a multifactorial etiology. The high prevalence of ADs in PIDs demonstrates the intricate relationships between the mechanisms of these two conditions. Defects in central and peripheral tolerance, including mutations in AIRE and T regulatory cells respectively, are thought to be crucial in the development of ADs in these patients. In fact, pathology that leads to PID often also impacts the Treg/Th17 balance that may ease the appearance of a proinflammatory environment, increasing the odds for the development of autoimmunity. Furthermore, the influence of chronic and recurrent infections through molecular mimicry, bystander activation and super antigens activation are supposed to be pivotal for the development of autoimmunity. These multiple mechanisms are associated with diverse clinical subphenotypes that hinders an accurate diagnosis in clinical settings, and in some cases, may delay the selection of suitable pharmacological therapies. Herein, a comprehensively appraisal of the common mechanisms among these conditions, together with clinical pearls for treatment and diagnosis is presented.

Primary immunodeficiency

Primary immunodeficiency disorder (PID) refers to a large heterogeneous group of disorders that result from defects in immune system development and/or function. PIDs are broadly classified as disorders of adaptive immunity (i.e., T cell, B-cell or combined immunodeficiencies) or of innate immunity (e.g., phagocyte and complement disorders). Although the clinical manifestations of PIDs are highly variable, many disorders involve an increased susceptibility to infection. Early consultation with a clinical immunologist is essential, as timely diagnosis and treatment are imperative for preventing significant disease-associated morbidity. PIDs should be suspected in patients with: recurrent sinus or ear infections or pneumonias within a 1 year period; failure to thrive; poor response to prolonged use of antibiotics; persistent thrush or skin abscesses; or a family history of PID. Patients with multiple autoimmune diseases should also be evaluated. Diagnostic testing often involves lymphocyte proliferation assays, flow cytometry, measurement of serum immunoglobulin (Ig) levels, assessment of serum specific antibody titers in response to vaccine antigens, neutrophil function assays, stimulation assays for cytokine responses, and complement studies. The treatment of PIDs is complex and generally requires both supportive and definitive strategies. Ig replacement therapy is the mainstay of therapy for B-cell disorders, and is also an important supportive treatment for many patients with combined immunodeficiency disorders. The disorders affecting the activity of the T-cell arm of the adaptive system, such as severe combined immunodeficiency, require immune reconstitution as soon as possible. The treatment of innate immunodeficiency disorders varies depending on the type of defect, but may involve antifungal and antibiotic prophylaxis, cytokine replacement, vaccinations and bone marrow transplantation. This article provides an overview of the major categories of PIDs and strategies for the appropriate diagnosis and management of these rare disorders.

Approach to the Management of Autoimmunity in Primary Immunodeficiency

Primary immunodeficiency diseases (PIDs) consist of a genetically heterogeneous group of immune disorders that affect distinct elements of the immune system. PID patients are more prone to infections and non-infectious complications, particularly autoimmunity. The concomitance of immunodeficiency and autoimmunity appears to be paradoxical and leads to difficulty in the management of autoimmune complications in PID patients. Therefore, management of autoimmunity in patients with PID requires special considerations because dysregulations and dysfunctions of the immune system along with persistent inflammation impair the process of diagnosis and treatment.

The plethora, clinical manifestations and treatment options of autoimmunity in patients with primary immunodeficiency

AIM

Although the association between primary immunodeficiency and autoimmunity is already well-known, it has once again become a topic of debate with the discovery of newly-defined immunodeficiencies. Thus, investigation of the mechanisms of development of autoimmunity in primary immunodefficiency and new target-specific therapeutic options has come to the fore. In this study, we aimed to examine the clinical findings of autoimmunity, autoimmunity varieties, and treatment responses in patients who were genetically diagnosed as having primary immunodeficiency.

MATERIAL AND METHODS

The files of patients with primary immunodeficiency who had clinical findings of autoimmunity, who were diagnosed genetically, and followed up in our clinic were investigated. The demographic and clinical features of the patients and their medical treatments were evaluated.

RESULTS

Findings of autoimmunity were found in 30 patients whose genetic mutations were identified. The mean age at the time of the first symptoms was 8.96±14.64 months, and the mean age of receiving a genetic diagnosis was 82.55±84.71 months. The most common diseases showing findings of autoimmunity included immune dysregulation, polyendocrinopathy, enteropathy X-linked syndrome (16.7%); autoimmune lymphoproliferative syndrome (10%); lipopolysaccharide-responsive beige-like anchor protein deficiency (10%); and DiGeorge syndrome (10%). Twelve (40%) patients showed findings of autoimmunity at the time of first presentation. The most common findings of autoimmunity included inflammatory bowel disease, inflammatory bowel disease-like findings (n=14, 46.7%), immune thrombocytopenic purpura (n=11, 36.7%), and autoimmune hemolytic anemia (n=9, 30.0%). A response to immunosupressive agents was observed in 15 (50%) patients. Ten patients underwent hematopoietic stem cell transplantation. Six patients were lost to follow-up due to a variety of complications.

CONCLUSION

Autoimmunity is frequently observed in patients with primary immunodeficiency. The possibility of primary immunodeficiency should be considered in patients with early-onset manifestations of autoimmunity, and these patients should be carefully monitored in terms of immunodeficiency development. Early diagnosis of primary immunodeficiency may provide favorable outcomes in terms of survival.

Unbalanced Immune System: Immunodeficiencies and Autoimmunity

Increased risk of developing autoimmune manifestations has been identified in different primary immunodeficiencies (PIDs). In such conditions, autoimmunity and immune deficiency represent intertwined phenomena that reflect inadequate immune function. Autoimmunity in PIDs may be caused by different mechanisms, including defects of tolerance to self-antigens and persistent stimulation as a result of the inability to eradicate antigens. This general immune dysregulation leads to compensatory and exaggerated chronic inflammatory responses that lead to tissue damage and autoimmunity. Each PID may be characterized by distinct, peculiar autoimmune manifestations. Moreover, different pathogenetic mechanisms may underlie autoimmunity in PID. In this review, the main autoimmune manifestations observed in different PID, including humoral immunodeficiencies, combined immunodeficiencies, and syndromes with immunodeficiencies, are summarized. When possible, the pathogenetic mechanism underlying autoimmunity in a specific PID has been explained.

The Incidence and Prevalence of Common Variable Immunodeficiency Disease in Taiwan, A Population-Based Study

Common variable immunodeficiency (CVID) is one of the primary immunodeficiency diseases that occur in both children and adults. We present here a nationwide, population-based epidemiological study of CVID across all ages in Taiwan during 2002–2011. Using the International Classification of Diseases, Ninth Revision code 279.06, cases of CVID were identified from Taiwan's National Health Insurance Research Database from January 2002 to December 2011. Age- and sex-specific incidence and prevalence rates were calculated. A total of 47 new cases of CVID during 2002–2011 were identified. Total prevalence rose from 0.13 per 100,000 in 2002 to 0.28 per 100,000 in 2011. The annual incidence rate during 2002–2011 was 0.019 per 100,000. Cases were equally distributed between males and females and males mostly occurred in younger patients. This nationwide population-based study showed that the incidence and prevalence of CVID in Taiwan were lower than that in Western countries.