Lifelong Immune Modulation Versus Hematopoietic Cell Therapy for Inborn Errors of Immunity

Management of a Patient with Cardiovascular Disease Should Include Assessment of Primary and Secondary Immunodeficiencies: Part 1-Primary Immunodeficiencies

BACKGROUND

Cardiovascular diseases are some of the most prevalent chronic diseases that generate not only high social but also economic costs. It is becoming increasingly crucial to take into account inborn errors of immunity (IEIs, formerly known as primary immunodeficiencies (PIDs)) and secondary immunodeficiencies (SIDs) in the diagnostic and therapeutic management of cardiac patients. The number of diseases classified as IEIs is on the rise, with a current total of 485. It is essential to pay attention not only to already confirmed conditions but also to symptoms suggestive of immunodeficiencies.

OBJECTIVES

The aim of this article is to present IEIs with cardiovascular symptoms that may cause or exacerbate cardiovascular disease, as well as diagnostic and therapeutic procedures.

RESULTS

It is becoming increasingly evident that immunodeficiencies can be responsible for certain cardiovascular conditions, their hastened progression, and difficulties in their control.

CONCLUSIONS

Early detection of deficiencies improves not only the quality and longevity of patients, but also allows for better control of cardiovascular diseases and even prevention of their occurrence.

Restoring T and B cell generation in X-linked severe combined immunodeficiency mice through hematopoietic stem cells adenine base editing

Base editing of hematopoietic stem/progenitor cells (HSPCs) is an attractive strategy for treating immunohematologic diseases. However, the feasibility of using adenine-base-edited HSPCs for treating X-linked severe combined immunodeficiency (SCID-X1), the influence of dose-response relationships on immune cell generation, and the potential risks have not been demonstrated in vivo. Here, a humanized SCID-X1 mouse model was established, and 86.67% ± 2.52% (n = 3) of mouse hematopoietic stem cell (HSC) pathogenic mutations were corrected, with no single-guide-RNA (sgRNA)-dependent off-target effects detected. Analysis of peripheral blood over 16 weeks post-transplantation in mice with different immunodeficiency backgrounds revealed efficient immune cell generation following transplantation of different amounts of modified HSCs. Therefore, a large-scale infusion of gene-corrected HSCs within a safe range can achieve rapid, stable, and durable immune cell regeneration. Tissue-section staining further demonstrated the restoration of immune organ tissue structures, with no tumor formation in multiple organs. Collectively, these data suggest that base-edited HSCs are a potential therapeutic approach for SCID-X1 and that a threshold infusion dose of gene-corrected cells is required for immune cell regeneration. This study lays a theoretical foundation for the clinical application of base-edited HSCs in treating SCID-X1.

Hematopoietic stem cell transplantation for inborn errors of immunity: 30-year single-center experience

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) represents an effective treatment for a variety of inborn errors of immunity (IEI). We report the experience of children affected by IEI who received allo-HSCT over a period of 32 years at IRCCS Istituto Giannina Gaslini, Genoa, Italy. HSCTs were performed in 67 children with IEI. Kaplan-Meier estimates of overall survival (OS) rate at 5 years in the whole group of patients was 83.4% after a median follow-up of 4 years. Median age at transplant was 2.5 years. Eight allo-HSCTs were complicated by either primary or secondary graft failure (GF), the overall incidence of this complication being 10.9%. Incidence of grade 3-4 acute GvHD (aGvHD) was 18.7%, significantly lower in the haploidentical transplant cohort (p = 0.005). Year of transplant (≤2006 vs. >2006) was the main factor influencing the outcome. In fact, a significant improvement in 5-year OS was demonstrated (92.5% >2006 vs. 65% ≤2006, p = 0.049). Frequency of severe aGvHD was significantly reduced in recent years (≤2006 61.5%, vs. >2006 20%, p = 0.027). A significant progress has been the introduction of the TCR αβ/CD19-depleted haploidentical platform, which was associated with the absence of severe aGvHD. However, it was associated with 23.5% incidence of GF. All but one patient experiencing GF in the this specific cohort were successfully retransplanted. In summary, allo-HSCT is confirmed to be an effective treatment for children with IEI, even in the absence of an HLA-matched donor.

Case report: Challenges in immune reconstitution following hematopoietic stem cell transplantation for CTLA-4 insufficiency-like primary immune regulatory disorders

Cytotoxic T-lymphocyte antigen-4 (CTLA-4) haploinsufficiency is a T-cell hyperactivation disorder that can manifest with both immunodeficiency and immune dysregulation. Approximately one-third of patients may present mild symptoms and remain stable under supportive care. The remaining patients may develop severe multiorgan autoimmunity requiring lifelong immunosuppressive treatment. Hematopoietic stem cell transplantation (HSCT) is potentially curable for patients with treatment-resistant immune dysregulation. Nevertheless, little experience is reported regarding the management of complications post-HSCT. We present case 1 (CTLA-4 haploinsufficiency) and case 2 (CTLA-4 insufficiency-like phenotype) manifesting with severe autoimmunity including cytopenia and involvement of the central nervous system (CNS), lung, and gut and variable impairment of humoral responses. Both patients underwent HSCT for which the main complications were persistent mixed chimerism, infections, and immune-mediated complications [graft-versus-host disease (GVHD) and nodular lung disease]. Detailed management and outcomes of therapeutic interventions post-HSCT are discussed. Concretely, post-HSCT abatacept and human leukocyte antigen (HLA)-matched sibling donor lymphocyte infusions may be used to increase T-cell donor chimerism with the aim of correcting the immune phenotype of CTLA-4 haploinsufficiency.

Immunosuppression in Patients With Primary Immunodeficiency-Walking the Line

Individuals with primary immunodeficiency (PIDD) experience not only infectious complications but also immune dysregulation leading to autoimmunity, inflammation, and lymphoproliferative manifestations. Management of these complications often requires treatment with additional immunosuppressive medications, which pose an additional risk of infectious complications. Immunosuppression in individuals with PIDD therefore requires careful assessment and consideration of risks and benefits. Medications should be closely monitored, and strategies for risk mitigation of adverse events considered, such as exposure reduction, appropriate vaccination, use of antibiotics/antivirals, and optimization of immunoglobulin replacement therapy. In a subset of individuals who are not tolerating immune modulation or experiencing disease progression despite appropriate interventions, hematopoietic stem-cell transplantation is a management option.

Sirolimus Restores Erythropoiesis and Controls Immune Dysregulation in a Child With Cartilage-Hair Hypoplasia: A Case Report

Cartilage-hair hypoplasia (CHH) is a syndromic immunodeficiency characterized by metaphyseal dysplasia, cancer predisposition, and varying degrees of anemia. It may present as severe combined immunodeficiency in infancy, or slowly progress until fully manifesting in late adolescence/adulthood. No targeted treatment is currently available, and patients are usually managed with supportive measures, or are offered a bone marrow transplant if the clinical phenotype is severe and a suitable donor is available. We report the case of a young girl presenting with transfusion-dependent erythropoietic failure and immunological features resembling autoimmune lymphoproliferative syndrome who responded well to empirical sirolimus. She later developed a marked growth delay, which was ultimately attributed to metaphyseal dysplasia. A diagnosis of CHH was reached through whole-genome sequencing (WGS), after a less sensitive genetic diagnostic strategy failed. The patient eventually underwent a haploidentical bone marrow transplant due to progressive combined immunodeficiency manifested as cryptococcal meningoencephalitis. This case illustrates the potential role of sirolimus in correcting anemia and partially controlling the immune aberrations associated with CHH, and serves as a reminder of the invaluable role of WGS in diagnosing patients with complex and atypical presentations.

Future of Therapy for Inborn Errors of Immunity

Over the past 20 years, the rapid evolution in the diagnosis and treatment of primary immunodeficiencies (PI) and the recognition of immune dysregulation as a feature in some have prompted the use of "inborn errors of immunity" (IEI) as a more encompassing term used to describe these disorders [1, 2] . This article aims to review the future of therapy of PI/IEI (referred to IEI throughout this paper). Historically, immune deficiencies have been characterized as monogenic disorders resulting in immune deficiencies affecting T cells, B cells, combination of T and B cells, or innate immune disorders. More recently, immunologists are also recognizing a variety of phenotypes associated with one genotype or similar phenotypes across genotypes and a role for incomplete penetrance or variable expressivity of some genes causing inborn errors of immunity [3]. The IUIS classification of immune deficiencies (IEIs) has evolved over time to include 10 categories, with disorders of immune dysregulation accounting for a new subset, some treatable with small molecule inhibitors or biologics. [1] Until recently, management options were limited to prompt treatment of infections, gammaglobulin replacement, and possibly bone marrow transplant depending on the defect. Available therapies have expanded to include small molecule inhibitors, biologics, gene therapy, and the use of adoptive transfer of virus-specific T cells to fight viral infections in immunocompromised patients. Several significant contributions to the field of clinical immunology have fueled the rapid advancement of therapies over the past two decades. Among these are educational efforts to recruit young immunologists to the field resulting in the growth of a world-wide community of clinicians and investigators interested in rare diseases, efforts to increase awareness of IEI globally contributing to international collaborations, along with advancements in diagnostic genetic testing, newborn screening, molecular biology techniques, gene correction, use of immune modulators, and ex vivo expansion of engineered T cells for therapeutic use. The development and widespread use of newborn screening have helped to identify severe combined immune deficiency (SCID) earlier resulting in better outcomes [4]. Continual improvements and accessibility of genetic sequencing have helped to identify new IEI diseases at an accelerated pace [5]. Advances in gene therapy and bone marrow transplant have made treatments possible in otherwise fatal diseases. Furthermore, the increased awareness of IEI across the world has driven networks of immunologists working together to improve the diagnosis and treatment of these rare diseases. These improvements in the diagnosis and treatment of IEI noted over the past 20 years bring hope for a better future for the IEI community. This paper will review future directions in a few of the newer therapies emerging for IEI. For easy reference, most of the diseases discussed in this paper are briefly described in a summary table, in the order mentioned within the paper (Appendix).

Mitochondrial Nucleic Acid as a Driver of Pathogenic Type I Interferon Induction in Mendelian Disease

The immune response to viral infection involves the recognition of pathogen-derived nucleic acids by intracellular sensors, leading to type I interferon (IFN), and downstream IFN-stimulated gene, induction. Ineffective discrimination of self from non-self nucleic acid can lead to autoinflammation, a phenomenon implicated in an increasing number of disease states, and well highlighted by the group of rare genetic disorders referred to as the type I interferonopathies. To understand the pathogenesis of these monogenic disorders, and polyfactorial diseases associated with pathogenic IFN upregulation, such as systemic lupus erythematosus and dermatomyositis, it is important to define the self-derived nucleic acid species responsible for such abnormal IFN induction. Recently, attention has focused on mitochondria as a novel source of immunogenic self nucleic acid. Best appreciated for their function in oxidative phosphorylation, metabolism and apoptosis, mitochondria are double membrane-bound organelles that represent vestigial bacteria in the cytosol of eukaryotic cells, containing their own DNA and RNA enclosed within the inner mitochondrial membrane. There is increasing recognition that a loss of mitochondrial integrity and compartmentalization can allow the release of mitochondrial nucleic acid into the cytosol, leading to IFN induction. Here, we provide recent insights into the potential of mitochondrial-derived DNA and RNA to drive IFN production in Mendelian disease. Specifically, we summarize current understanding of how nucleic acids are detected as foreign when released into the cytosol, and then consider the findings implicating mitochondrial nucleic acid in type I interferonopathy disease states. Finally, we discuss the potential for IFN-driven pathology in primary mitochondrial disorders.