Targeted Therapy with Biologicals and Small Molecules in Primary Immunodeficiencies

Inborn errors of immunity in adulthood

Inborn errors of immunity (IEIs) are a group of conditions whereby parts of the immune system are missing or dysfunctional. Once thought to primarily be a pediatric disorder, it is now estimated that more than 50% of worldwide incident IEI cases are accounted for by adults. Delayed diagnosis, late symptom onset, and IEI phenocopies can all lead to adult-onset recognition of IEIs. Lack of awareness regarding the diversity of IEI manifestations in adults contributes to diagnostic and treatment delays. Prompt referral to immunology is critical so that patients can receive a precise molecular diagnosis and targeted therapy when available. This article serves as a primer on IEIs in adulthood, highlighting the pathophysiology, epidemiology and clinical features. We present clinical vignettes of three key IEIs to assist clinicians in building illness scripts on their presentations. We provide a framework for the laboratory evaluation of IEIs and their initial treatment, with the aim of improving recognition and management of these conditions.

The PID Odyssey 2030: outlooks, unmet needs, hurdles, and opportunities - proceedings from the IPOPI global multi-stakeholders' summit (June 2022)

IPOPI held its first Global Multi-Stakeholders' Summit on 23-24 June 2022 in Cascais, Portugal. This IPOPI initiative was designed to set the stage for a stimulating forward-thinking meeting and brainstorming discussion among stakeholders on the future priorities of the PID community. All participants were actively engaged in the entire Summit, bringing provocative questions to ensure a high level of discussion and engagement, and partnered in identifying the outlooks, unmet needs, hurdles and opportunities of PIDs for 2030. The topics that were covered include diagnosis (e.g., newborn screening [NBS], genomic sequencing- including ethical aspects on the application of genomics on NBS, the role of more accurate and timely diagnostics in impacting personalized management), treatment (e.g., the therapeutic evolution of immunoglobulins in a global environment, new therapies such as targeted therapies, new approaches in curative therapies), the interactions of Primary ID with Secondary ID, Autoinflammatory Diseases and other diseases as the field experiences an incessant evolution, and also the avenues for research in the field of humanities and human sciences such as Patient-Reported Outcome Measures (PROMs), Patient-Reported Experience Measures (PREMs), and Health-Related Quality Of Life (HRQoL). During this meeting, all participants contributed to the drafting of recommendations based on our common understanding of the future opportunities, challenges, and scenarios. As a collection of materials, perspectives and summaries, they are succinct and impactful and may help determine some of the next key steps for the PID community.

Precision medicine: The use of tailored therapy in primary immunodeficiencies

Primary immunodeficiencies (PID) are rare, complex diseases that can be characterised by a spectrum of phenotypes, from increased susceptibility to infections to autoimmunity, allergy, auto-inflammatory diseases and predisposition to malignancy. With the introduction of genetic testing in these patients and wider use of next-Generation sequencing techniques, a higher number of pathogenic genetic variants and conditions have been identified, allowing the development of new, targeted treatments in PID. The concept of precision medicine, that aims to tailor the medical interventions to each patient, allows to perform more precise diagnosis and more importantly the use of treatments directed to a specific defect, with the objective to cure or achieve long-term remission, minimising the number and type of side effects. This approach takes particular importance in PID, considering the nature of causative defects, disease severity, short- and long-term complications of disease but also of the available treatments, with impact in life-expectancy and quality of life. In this review we revisit how this approach can or is already being implemented in PID and provide a summary of the most relevant treatments applied to specific diseases.

Pathogenesis of Autoimmune Cytopenias in Inborn Errors of Immunity Revealing Novel Therapeutic Targets

Autoimmune diseases are usually associated with environmental triggers and genetic predisposition. However, a few number of autoimmune diseases has a monogenic cause, mostly in children. These diseases may be the expression, isolated or associated with other symptoms, of an underlying inborn error of immunity (IEI). Autoimmune cytopenias (AICs), including immune thrombocytopenic purpura (ITP), autoimmune hemolytic anemia (AIHA), autoimmune neutropenia (AN), and Evans’ syndrome (ES) are common presentations of immunological diseases in the pediatric age, with at least 65% of cases of ES genetically determined. Autoimmune cytopenias in IEI have often a more severe, chronic, and relapsing course. Treatment refractoriness also characterizes autoimmune cytopenia with a monogenic cause, such as IEI. The mechanisms underlying autoimmune cytopenias in IEI include cellular or humoral autoimmunity, immune dysregulation in cases of hemophagocytosis or lymphoproliferation with or without splenic sequestration, bone marrow failure, myelodysplasia, or secondary myelosuppression. Genetic characterization of autoimmune cytopenias is of fundamental importance as an early diagnosis improves the outcome and allows the setting up of a targeted therapy, such as CTLA-4 IgG fusion protein (Abatacept), small molecule inhibitors (JAK-inhibitors), or gene therapy. Currently, gene therapy represents one of the most attractive targeted therapeutic approaches to treat selected inborn errors of immunity. Even in the absence of specific targeted therapies, however, whole exome genetic testing (WES) for children with chronic multilineage cytopenias should be considered as an early diagnostic tool for disease diagnosis and genetic counseling.

Molecular diagnosis of childhood immune dysregulation, polyendocrinopathy, and enteropathy, and implications for clinical management

BACKGROUND

Most patients with childhood-onset immune dysregulation, polyendocrinopathy, and enteropathy have no genetic diagnosis for their illness. These patients may undergo empirical immunosuppressive treatment with highly variable outcomes.

OBJECTIVE

We sought to determine the genetic basis of disease in patients referred with Immune dysregulation, polyendocrinopathy, enteropathy, X-linked-like (IPEX-like) disease, but with no mutation in FOXP3; then to assess consequences of genetic diagnoses for clinical management.

METHODS

Genomic DNA was sequenced using a panel of 462 genes implicated in inborn errors of immunity. Candidate mutations were characterized by genomic, transcriptional, and (for some) protein analysis.

RESULTS

Of 123 patients with FOXP3-negative IPEX-like disease, 48 (39%) carried damaging germline mutations in 1 of the following 27 genes: AIRE, BACH2, BCL11B, CARD11, CARD14, CTLA4, IRF2BP2, ITCH, JAK1, KMT2D, LRBA, MYO5B, NFKB1, NLRC4, POLA1, POMP, RAG1, SH2D1A, SKIV2L, STAT1, STAT3, TNFAIP3, TNFRSF6/FAS, TNRSF13B/TACI, TOM1, TTC37, and XIAP. Many of these genes had not been previously associated with an IPEX-like diagnosis. For 42 of the 48 patients with genetic diagnoses, knowing the critical gene could have altered therapeutic management, including recommendations for targeted treatments and for or against hematopoietic cell transplantation.

CONCLUSIONS

Many childhood disorders now bundled as "IPEX-like" disease are caused by individually rare, severe mutations in immune regulation genes. Most genetic diagnoses of these conditions yield clinically actionable findings. Barriers are lack of testing or lack of repeat testing if older technologies failed to provide a diagnosis.

An Update on Pediatric Immune Thrombocytopenia (ITP): Differentiating Primary ITP, IPD, and PID

Immune thrombocytopenia (ITP) is the most common acquired thrombocytopenia in children and is caused by both immune-mediated decreased platelet production and increased platelet destruction. In the absence of a diagnostic test, ITP must be differentiated from other thrombocytopenic disorders, including inherited platelet disorders (IPD). In addition, a diagnosis of secondary ITP due to a primary immune deficiency (PID) with immune dysregulation may not be apparent at diagnosis but can alter management and should be considered in an expanding number of clinical scenarios. The diagnostic evaluation of children with thrombocytopenia will vary based on the clinical history and laboratory features. Access to genotyping has broadened the ability to specify the etiology of thrombocytopenia, while increasing access to immunophenotyping, functional immunologic and platelet assays, and biochemical markers has allowed for more in-depth evaluation of patients. With this greater availability of testing, diagnostic algorithms in patients with thrombocytopenia have become complex. In this article, we highlight the diagnostic evaluation of thrombocytopenia in children with a focus on ITP, including consideration of underlying genetic and immune disorders, and utilize hypothetical patient cases to describe disease manifestations and strategies for treatment of pediatric ITP.

Update in Primary Immunodeficiencies

Primary immunodeficiencies (PIDs) are inherited disorders classically characterized by increased susceptibility to infections. Nevertheless, in the last two decades, genomic analysis (such as NGS) coupled with biochemical and cellular studies led to a more accurate definition for a growing number of novel genetic disorders associated with PIDs. This revealed new aspects of the immune system and its function and regulation within these diseases. In particular, it has been clarified that the clinical features of PIDs are much broader that originally thought and extend beyond an increased susceptibility to infections. More specifi- cally, immune dysregulation is very often described in novel characterized PIDs and can lead to multiple autoimmune diseases, lymphoproliferation and malignancies. If not promptly diagnosed, these could negatively impact patient's prognosis. The aim of this review is to increase the awareness of recently discovered PIDs, characterized predominantly by immune dysregulation phenotypes. Findings highlighted in this review  suggest screening for immunodeficiency in patients with lymphoproliferation or early onset/multiple autoimmune diseases. Prompt diagnosis would potentially allow most successful treatment and clinical outcome for patients with PIDs.

Frequency and Manifestations of Autoimmunity Among Children Registered in the Kuwait National Primary Immunodeficiency Registry

Objectives: To present a prospective report on the characteristics of autoimmune manifestations in patients with primary immunodeficient children registered in the Kuwait National PIDs Registry (KNPIDR).

Methods: The data were obtained from the Kuwait National Primary Immunodeficiency Disorders Registry during the period of January 2004 to December 2019.

Results: A total of 286 PID children were registered in KNPIDR during the study period with a predominance of immunodeficiencies affecting cellular and humoral immunity followed by combined immunodeficiencies with associated syndromic features and diseases of immune dysregulation. Fifty-seven (19.9%) patients presented with a total of 107 autoimmune manifestations. There was no significant statistical association between autoimmune manifestations and gender. Patients with autoimmune manifestations were older at onset of PID symptoms compared to those with no such manifestations, but this did not reach level of significance. The diagnosis delay was longer in patients with autoimmune manifestations compared to those with no such manifestations (p = 0.038). Forty-seven percent of these manifestations were among the presenting symptoms while 53% were documented later during the course of the disease. Fifty-seven percent of the patients developed 1 autoimmune manifestation, 30% developed 2 such manifestations, and 16% had ≥3 autoimmune manifestations. The most common autoimmune manifestation was cytopenia, followed by gastrointestinal manifestations and manifestations of the skin, hair, and nails. Autoimmune cytopenia were more common in patients with immune dysregulation syndromes, while gastrointestinal and skin manifestations predominate in patients with immunodeficiencies affecting cellular and humoral immunity and endocrine manifestations were more common in immune dysregulation syndromes. There were significant statistical associations between developing autoimmune manifestations and death as well as PID categories, being more common in patients with immune dysregulation. The frequency of autoimmunity was high among patients with RAG, WAS, STAT5b, NF-κB2, Fas, FasL, LRBA, APECED, IL-10, and C4 deficiencies.

Conclusions: Autoimmunity is frequent in patients with PIDs in Kuwait. This should prompt the suspicion of a PID in patients who present initially with autoimmunity, especially autoimmune cytopenia. Such patients should be managed with extra care since they are at a higher risk of death.

Recent advances in primary immunodeficiency: from molecular diagnosis to treatment

The technological advances in diagnostics and therapy of primary immunodeficiency are progressing at a fast pace. This review examines recent developments in the field of inborn errors of immunity, from their definition to their treatment. We will summarize the challenges posed by the growth of next-generation sequencing in the clinical setting, touch briefly on the expansion of the concept of inborn errors of immunity beyond the classic immune system realm, and finally review current developments in targeted therapies, stem cell transplantation, and gene therapy.