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Clin Immunol. 2024 Oct 4:110375. doi: 10.1016/j.clim.2024.110375. Online ahead of print.

ABSTRACT

While next generation sequencing has expanded the scientific understanding of Inborn Errors of Immunity (IEI), the clinical use and re-use of exome sequencing is still emerging. We revisited clinical exome data from 1300 IEI patients using an updated in silico IEI gene panel. Variants were classified and curated through expert review. The molecular diagnostic yield after standard exome analysis was 11.8 %. Through systematic reanalysis, we identified variants of interest in 5.2 % of undiagnosed patients, with 76.7 % being (candidate) disease-causing, providing a (candidate) diagnosis in 15.2 % of our cohort. We find a 1.7 percentage point increase in conclusive molecular diagnoses. We find a high degree of actionability in patients with a genetic diagnosis (76.4 %). Despite the modest absolute diagnostic gain, these data support the benefit of iterative exome reanalysis in IEI patients, conveying the notion that our current understanding of genes and variants involved in IEI is by far not saturated.

PMID:39369972 | DOI:10.1016/j.clim.2024.110375

Pediatr Blood Cancer. 2024 Oct 4:e31363. doi: 10.1002/pbc.31363. Online ahead of print.

ABSTRACT

BACKGROUND: Thrombocytopenia is a common hematologic finding in children and adolescents. Immune thrombocytopenia (ITP) is the most common cause of this finding, but the differential diagnosis includes a growing list of genetic disorders. We aimed to report differences in phenotypes of patients with ITP, inherited platelet disorder (IPD)/primary immunodeficiency disorder (PID), and other causes, with a focus on differentiating ITP from inherited thrombocytopenia.

PROCEDURE: This retrospective, population-based observational cohort from 2006 to 2020 involved 506 Finnish children under 16 years of age presenting with isolated thrombocytopenia.

RESULTS: Of the 506 participants, 79.7% had ITP, 6.7% had IPD/PID, and 13.6% had other causes of thrombocytopenia. A platelet count of ≤12 × 10⁹/L best distinguished between ITP and other reasons with a sensitivity of 60% and a specificity of 80%. Among patients with the lowest platelet count of less than 10 × 10⁹/L, 95.9% had ITP, 3.3% had IPD/PID, and 0.8% had other causes. Severe bleeding events were reported in 20 patients (4.0%), but there were no cases of intracranial or fatal bleeding due to thrombocytopenia. Up to 50% of patients with a high suspicion of inherited thrombocytopenia remained without a specific diagnosis despite genetic testing.

CONCLUSIONS: ITP remains the most common cause of thrombocytopenia. A platelet count of ≤12 × 10⁹/L often leads to an ITP diagnosis. Genetic disorders are rare but should be suspected in patients with persisting thrombocytopenia, especially with platelet counts constantly above 12 × 10⁹/L, a positive family history, or atypical clinical features.

PMID:39367594 | DOI:10.1002/pbc.31363

Allergy Asthma Clin Immunol. 2024 Oct 4;20(1):52. doi: 10.1186/s13223-024-00914-7.

ABSTRACT

Primary immunodeficiency diseases (PIDs), also referred to as inborn errors of immunity, constitute a group of genetic conditions that affect the immune system. The current standard of care for patients with PIDs is lifelong immunoglobulin replacement therapy, delivered by intravenous (IVIG) or subcutaneous (SCIG) infusion. Immune globulin subcutaneous (human) 20% solution stabilized with glycine (Ig20Gly) is indicated as a replacement therapy for PIDs in adults and children of any age in Europe and in patients aged 2 years and above in the USA. Typically, Ig20Gly is administered using an infusion pump; however, delivery of Ig20Gly by manual administration has recently been approved in Europe. Practical recommendations on the use of Ig20Gly manual administration are lacking; this review therefore aims to provide guidance for use of this method of administration. Additionally, we summarize the infusion parameters, safety, patient-reported outcomes, and economic benefits associated with Ig20Gly manual administration. Manual administration of Ig20Gly was shown to permit faster rates of infusion than administration via infusion pump. Patients typically infused at two or fewer infusion sites with manual administration of Ig20Gly. Safety and tolerability profiles were similar for Ig20Gly manual administration and administration by infusion pump. Overall, there were comparable levels of patient satisfaction with manual administration and infusion pump, with patient preference deemed to be a key determinator of success for either method of administration. Economic studies identified cost savings for the healthcare system through manual administration compared with IVIG or SCIG infusion by infusion pump because of the reduced equipment costs and nurse support. For infusion of Ig20Gly by manual administration, a syringe and butterfly needle are used; patients are advised to start infusion at 1-2 mL/min to prevent discomfort. Overall, manual administration of Ig20Gly offers an effective and well-tolerated alternative to administration by infusion pump.

PMID:39367472 | PMC:PMC11453067 | DOI:10.1186/s13223-024-00914-7

J Clin Immunol. 2024 Oct 4;45(1):21. doi: 10.1007/s10875-024-01811-9.

ABSTRACT

BACKGROUND: ISG15 deficiency is a mixed syndrome of Mendelian susceptibility to mycobacterial infections (MSMD), a rare inherited condition characterized primarily by recurrent infections from low-virulence mycobacteria and monogenic type I interferonopathy.

OBJECTIVE: To characterize the laboratory and molecular features of two patients from different families affected by the same ISG15 variant.

METHODS: We began with clinical characterization and investigation, assessed IL-12/IFN-γ production, performed genetic characterization through WES and Sanger sequencing, conducted an in silico molecular analysis of the genetic ISG15 variant’s protein impact, and utilized RNAseq for transcriptome analysis to understand pathway impacts on ISG15-deficient subjects from unrelated families.

RESULTS: A mutation in the ISG15 gene was identified, affecting two patients treated in different hospitals and cities in Brazil (Fortaleza and Sao Paulo), who are also members of unrelated families. Both patients showed low IFN-γ production when stimulated with BCG or BCG + IL-12. ISG15 deficiency presented with two distinct clinical phenotypes: infectious and neurological. It was identified that both patients are homozygous for the variant (c.83 T > A). Furthermore, it was observed that the mutant protein p.L28Q results in an unstable protein with increased flexibility (ΔΔG: -2.400 kcal/mol). Transcriptome analysis revealed 1321 differentially expressed genes, with significant upregulation in interferon pathways, showing higher expression in patients compared to controls.

CONCLUSION: This study describes the first reported cases in Brazil of two unrelated patients with the same ISG15 mutation c.83 T > A, exhibiting infectious features such as mycobacterial infections and systemic candidiasis, neurological findings, and skin lesions, without adverse reactions to the BCG vaccine.

CLINICAL IMPLICATIONS: Reporting ISG15 gene mutations in Brazilian patients enhances understanding of genetic susceptibilities, guiding effective diagnostics and treatment. Identifying high-risk individuals aids clinical practices, genetic counseling, and influences public health policies. We have identified the first case in Brazil of the same ISG15 variant c.83 T > A that was identified in two unrelated patients with distinct clinical phenotypes, infectious and neurological.

PMID:39365299 | DOI:10.1007/s10875-024-01811-9

Crit Rev Clin Lab Sci. 2024 Oct 4:1-20. doi: 10.1080/10408363.2024.2404842. Online ahead of print.

ABSTRACT

Common variable immunodeficiency (CVID) is a heterogeneous primary immunodeficiency (PID) characterized by an impaired immunoglobulin production, in association with an increased susceptibility to infections and a diversity of clinical manifestations. This narrative review summarizes immunophenotypic abnormalities in CVID patients and their relevance for diagnosis and disease classification. A comprehensive search across four databases – PubMED, Web of Science, EMBASE and Google Scholar – yielded 170 relevant studies published between 1988 and April 31, 2023. Over the past decades, the role of immunophenotyping in CVID diagnosis has become evident by identifying “hallmark” immunophenotypic aberrancies in patient subsets, with some now integrated in the consensus diagnostic criteria. Furthermore, the role of immunophenotyping in subclassifying CVID in relation to clinical presentation and prognosis has been extensively studied. Certain immunophenotypic patterns consistently correlate with clinical manifestations and/or subsets of CVID, particularly those associated with noninfectious complications (i.e. low switched memory B cells, shifts in follicular helper T cell subsets, low naïve CD4⁺ T cells, low regulatory T cells, and expansion of CD21low B cells, often associated with autoimmunity and/or splenomegaly). Also, efforts to associate subset levels of innate immune cells, such as Natural Killer (NK) cells, invariant (i)NKT cells, innate lymphoid cells (ILCs), and dendritic cells (DCs) to CVID complications are evident albeit in a lesser degree. However, inconsistencies regarding the role of flow cytometry in classification and prognosis persist, reflecting the disease complexity, but probably also cohort variations and methodological differences between published studies. This underscores the need for collaborative efforts to integrate emerging concepts, such as standardized flow cytometry and computational tools, for a more precise CVID classification approach. Additionally, recent studies suggest a potential value of (epi)genetic-based molecular assays to this effort.

PMID:39364936 | DOI:10.1080/10408363.2024.2404842

J Clin Invest. 2024 Oct 1;134(19):e180251. doi: 10.1172/JCI180251.

ABSTRACT

Infants with biallelic IL7R loss-of-function variants have severe combined immune deficiency (SCID) characterized by the absence of autologous T lymphocytes, but normal counts of circulating B and NK cells (T-B+NK+ SCID). We report 6 adults (aged 22 to 59 years) from 4 kindreds and 3 ancestries (Colombian, Israeli Arab, Japanese) carrying homozygous IL7 loss-of-function variants resulting in combined immunodeficiency (CID). Deep immunophenotyping revealed relatively normal counts and/or proportions of myeloid, B, NK, and innate lymphoid cells. By contrast, the patients had profound T cell lymphopenia, with low proportions of innate-like adaptive mucosal-associated invariant T and invariant NK T cells. They also had low blood counts of T cell receptor (TCR) excision circles, recent thymic emigrant T cells and naive CD4+ T cells, and low overall TCR repertoire diversity, collectively indicating impaired thymic output. The proportions of effector memory CD4+ and CD8+ T cells were high, indicating IL-7-independent homeostatic T cell proliferation in the periphery. Intriguingly, the proportions of other T cell subsets, including TCRγδ+ T cells and some TCRαβ+ T cell subsets (including Th1, Tfh, and Treg) were little affected. Peripheral CD4+ T cells displayed poor proliferation, but normal cytokine production upon stimulation with mitogens in vitro. Thus, inherited IL-7 deficiency impairs T cell development less severely and in a more subset-specific manner than IL-7R deficiency. These findings suggest that another IL-7R-binding cytokine, possibly thymic stromal lymphopoietin, governs an IL-7-independent pathway of human T cell development.

PMID:39352394 | PMC:PMC11444196 | DOI:10.1172/JCI180251

Nat Commun. 2024 Sep 30;15(1):8439. doi: 10.1038/s41467-024-52388-1.

ABSTRACT

Chimeric antigen receptor (CAR)-modified natural killer (NK) cells show antileukemic activity against acute myeloid leukemia (AML) in vivo. However, NK cell-mediated tumor killing is often impaired by the interaction between human leukocyte antigen (HLA)-E and the inhibitory receptor, NKG2A. Here, we describe a strategy that overcomes CAR-NK cell inhibition mediated by the HLA-E-NKG2A immune checkpoint. We generate CD33-specific, AML-targeted CAR-NK cells (CAR33) combined with CRISPR/Cas9-based gene disruption of the NKG2A-encoding KLRC1 gene. Using single-cell multi-omics analyses, we identified transcriptional features of activation and maturation in CAR33-KLRC1^ko-NK cells, which are preserved following exposure to AML cells. Moreover, CAR33-KLRC1^ko-NK cells demonstrate potent antileukemic killing activity against AML cell lines and primary blasts in vitro and in vivo. We thus conclude that NKG2A-deficient CAR-NK cells have the potential to bypass immune suppression in AML.

PMID:39349459 | PMC:PMC11442982 | DOI:10.1038/s41467-024-52388-1

Appl Clin Genet. 2024 Sep 23;17:133-141. doi: 10.2147/TACG.S472788. eCollection 2024.

ABSTRACT

INTRODUCTION: Inborn errors of immunity (IEI) are disorders that present a health issue, especially in developing countries where there is a high rate of consanguineous marriages and an increasing rate of diagnosis. One of these disorders is Bare Lymphocyte Syndrome II (BLS II) which is a rare and genetically complex disease that has high morbidity and mortality. The exact genotypic and phenotypic characteristics are still poorly characterized especially in developing countries.

CASE PRESENTATION: Here, we report the first case of BLS II in a seven-month-old Sudanese female with recurrent chest infections, dermatitis, persistent diarrhea, and failure to thrive. The patient’s all four sisters and three paternal uncles died in early infancy. Laboratory investigations revealed low CD3+, CD4+, and CD8+ lymphocytes, along with normal CD19+ and CD16+ lymphocytes, and low serum IgM and IgA levels. Genetic analysis revealed two CIITA variants; c.2296C >G p. (Pro766Ala) and c.439+1G >A.

CONCLUSION: Further bioinformatics, immunological and clinical workups supported a pathogenic effect of both mutations affecting the function of CIITA protein, and suggesting a compound heterozygote mutation. The patient was started on prophylactic antibiotics and regular intravenous immunoglobulin replacement therapy. The prognosis of this disease is poor in most of the cases, with only a few reported cases surviving until adulthood.

PMID:39347515 | PMC:PMC11430264 | DOI:10.2147/TACG.S472788

Front Pharmacol. 2024 Sep 13;15:1426826. doi: 10.3389/fphar.2024.1426826. eCollection 2024.

ABSTRACT

BACKGROUND: In the context of the cytokine storm the takes place in severe COVID-19 patients, the Interleukin 6 (IL6) pathway emerges as one of the key pathways involved in the pathogenesis of this hyperinflammatory state. The strategy of blocking the inflammatory storm by targeting the IL6 is a promising therapy to mitigate mortality. The use of Tocilizumab was recommended by the World Health Organization (WHO) to treat severe COVID-19 patients. However, the efficacy of Tocilizumab is variable. We hypothesize that the genetic background could be behind the efficacy of Tocilizumab in terms of mortality.

METHODS: We performed a targeted-next generation sequencing of 287 genes, of which 264 belong to a community panel of ThermoFisher for the study of genetic causes of primary immunodeficiency disorders, and 23 additional genes mostly related to inflammation, not included in the original community panel. This panel was sequenced in an initial cohort of 425 COVID-19 patients, of which 232 were treated with Tocilizumab and standard therapy, and 193 with standard therapy only. Selected genetic variants were genotyped by single base extension in additional 245 patients (95 treated with Tocilizumab and 150 non-treated with Tocilizumab). Appropriate statistical analyses and internal validation, including logistic regression models, with the interaction between Tocilizumab and genetic variants, were applied to assess the impact of these genetic variants in the efficacy of Tocilizumab in terms of mortality.

RESULTS: Age (p < 0.001) and cardiovascular disease (p < 0.001) are risk factors for mortality in COVID-19 patients. The presence of GG and TT genotypes at IL10Rβ (rs2834167) and IL1β (rs1143633) genes significantly associates with a reduced risk of mortality in patients treated with Tocilizumab (OR = 0.111; 95%CI = 0.015-0.829; p = 0.010 and OR = 0.378; 95%CI = 0.154-0.924; p = 0.028 respectively). The presence of CC genotype at IL1RN (rs2234679) significantly associates with an increased risk of mortality, but only in patients not treated with Tocilizumab (OR = 3.200; 95%CI = 1.512-6.771; p = 0.002). Exhaustive internal validation using a bootstrap method (B = 500 replicates) validated the accuracy of the predictive models.

CONCLUSION: We developed a series of predictive models based on three genotypes in genes with a strong implication in the etiopathogenesis of COVID-19 disease capable of predicting the risk of mortality in patients treated with Tocilizumab.

PMID:39346556 | PMC:PMC11428153 | DOI:10.3389/fphar.2024.1426826

Curr Opin Pediatr. 2024 Sep 27. doi: 10.1097/MOP.0000000000001401. Online ahead of print.

ABSTRACT

PURPOSE OF REVIEW: Primary immune regulatory disorders (PIRDs) are an increasing indication for hematopoietic stem cell transplant (HCT) in pediatric patients. Here, we provide an updated overview of HCT for PIRDs, and discuss future avenues for improvement in outcomes.

RECENT FINDINGS: There are now more than 50 described monogenic PIRDs, which impact all aspects of immune tolerance, regulation, and suppression. Disease characteristics are highly variable, and HCT remains the only option for cure. We review advances in targeted therapies for individual PIRDs, which have significantly improved outcomes and the ability to safely bridge to transplant. Additionally, advances in GVHD prevention, graft manipulation, personalized conditioning regimens, and supportive care have all increased survival after HCT. The high inflammatory state increases the risk of nonengraftment, rejection, and autologous reconstitution. Therapy to reduce the inflammatory state may further improve outcomes. In addition, although younger patients with fewer comorbidities have better outcomes, the clinical courses of these diseases may be extremely variable thereby complicating the decision to proceed to HCT.

SUMMARY: HCT for PIRDs is a growing consideration in cell therapy. Yet, there remain significant gaps in our understanding of which patients this curative therapy could benefit the most. Here, we review the current data supporting HCT for PIRDs as well as areas for future improvement.

PMID:39345097 | DOI:10.1097/MOP.0000000000001401