Blog

J Clin Immunol. 2024 Jun 19;44(7):151. doi: 10.1007/s10875-024-01754-1.

ABSTRACT

A cell’s ability to survive and to evade cancer is contingent on its ability to retain genomic integrity, which can be seriously compromised when nucleic acid phosphodiester bonds are disrupted. DNA Ligase 1 (LIG1) plays a key role in genome maintenance by sealing single-stranded nicks that are produced during DNA replication and repair. Autosomal recessive mutations in a limited number of individuals have been previously described for this gene. Here we report a homozygous LIG1 mutation (p.A624T), affecting a universally conserved residue, in a patient presenting with leukopenia, neutropenia, lymphopenia, pan-hypogammaglobulinemia, and diminished in vitro response to mitogen stimulation. Patient fibroblasts expressed normal levels of LIG1 protein but exhibited impaired growth, poor viability, high baseline levels of gamma-H2AX foci, and an enhanced susceptibility to DNA-damaging agents. The mutation reduced LIG1 activity by lowering its affinity for magnesium 2.5-fold. Remarkably, it also increased LIG1 fidelity > 50-fold against 3′ end 8-Oxoguanine mismatches, exhibiting a marked reduction in its ability to process such nicks. This is expected to yield increased ss- and dsDNA breaks. Molecular dynamic simulations, and Residue Interaction Network studies, predicted an allosteric effect for this mutation on the protein loops associated with the LIG1 high-fidelity magnesium, as well as on DNA binding within the adenylation domain. These dual alterations of suppressed activity and enhanced fidelity, arising from a single mutation, underscore the mechanistic picture of how a LIG1 defect can lead to severe immunological disease.

PMID:38896336 | DOI:10.1007/s10875-024-01754-1

J Clin Immunol. 2024 Jun 19;44(7):152. doi: 10.1007/s10875-024-01753-2.

ABSTRACT

A boy with primary immunodeficiency, caused by a tyrosine kinase 2 (TYK2) mutation, presented with immune defects and a lifelong history of severe infections. Our aim was to determine whether allogeneic hematopoietic stem cell transplantation (HSCT) could restore the patient’s immune defenses and reduce susceptibility to infection. In the absence of a suitable HLA-matched blood relative to act as a donor, the patient received an allogeneic HSCT from unrelated donors. The patient’s clinical data were analyzed in the Children’s Hospital of Chongqing Medical University (Chongqing, China) before transplantation and during the 4-year follow-up period using a combination of western blotting (e.g., TYK2 and STAT levels), qRT-PCR (e.g., T cell receptor rearrangement excision circles, kappa deletion element recombination circles, and TYK2 transcript levels), and flow cytometry (e.g., lymphocyte subpopulations and CD107α secretion). We found that HSCT significantly reduced the incidence of severe infections, restored normal TKY2 levels, and reversed defects such as impaired JAK/STAT signaling in response to interferon-α or interleukin-10 treatment. Although the patient did not develop acute graft-versus-host disease (GVHD) after transplantation, he did experience chronic GVHD symptoms in a number of organs, which were effectively managed. Our findings suggest that HSCT is a feasible strategy for reconstituting the immune system in TYK2-deficient patients; however, the factors associated with GVHD and autoimmune thyroiditis development in TYK2-deficient patients undergoing HSCT warrant further investigation.

PMID:38896258 | DOI:10.1007/s10875-024-01753-2

J Clin Immunol. 2024 Jun 19;44(7):154. doi: 10.1007/s10875-024-01751-4.

ABSTRACT

Patients with chromosome 18q deletion syndrome generally experience hypogammaglobulinemia. Herein, we describe two patients with chromosome 18q deletion syndrome who presented with late-onset combined immune deficiency (LOCID), which has not been previously reported. Patient 1 was a 29-year-old male with 18q deletion syndrome, who was being managed for severe motor and intellectual disabilities at the Yamabiko Medical Welfare Center for 26 years. Although the patient had few infections, he developed Pneumocystis pneumonia at the age of 28. Patient 2, a 48-year-old female with intellectual disability and congenital malformations, was referred to Tokyo Medical and Dental University Hospital with abnormal bilateral lung shadows detected on her chest radiography. Computed tomography showed multiple lymphadenopathies and pneumonia. A lymph node biopsy of the inguinal region revealed granulomatous lymphadenitis, and a chromosomal examination revealed 18q deletion. Array-based genomic hybridization analysis revealed deletion at 18q21.32-q22.3 for patient 1 and at 18q21.33-qter for patient 2. Immune status work-up of the two patients revealed panhypogammaglobulinemia, decreased number of memory B cells and naïve CD4⁺ and/or CD8⁺ cells, reduced response on the carboxyfluorescein diacetate succinimidyl ester T-cell division test, and low levels of T-cell receptor recombination excision circles and Ig κ-deleting recombination excision circles. Consequently, both patients were diagnosed with LOCID. Although patients with 18q deletion syndrome generally experience humoral immunodeficiency, the disease can be further complicated by cell-mediated immunodeficiency, causing combined immunodeficiency. Therefore, patients with 18q deletion syndrome should be regularly tested for cellular/humoral immunocompetence.

PMID:38896123 | DOI:10.1007/s10875-024-01751-4

Pediatr Transplant. 2024 Aug;28(5):e14810. doi: 10.1111/petr.14810.

ABSTRACT

BACKGROUND: Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE-mediated food allergy. In the last few years, after the publication of the consensus guidelines, with refined diagnostic criteria and improved awareness, FPIES is diagnosed with increased frequency. However, despite having a background of immune dysregulation, this complication has just been described once in the posttransplant setting, in an adult patient. To the best of our knowledge, there are no reports of pediatric patients developing FPIES after a hematopoietic stem cell transplant (HCT).

METHODS: Retrospective review of a pediatric patient who developed severe FPIEs after a HCT.

RESULTS: In this case report, the clinical presentation and diagnosis challenges of a pediatric patient who developed severe FPIES after HCT are described. The patient developed severe vomiting, diarrhea, lethargy, and shock and required admission to the pediatric intensive care unit in three occasions before the diagnosis was made.

CONCLUSIONS: To the best of our knowledge, this is the first report of severe FPIES post-HCT in a pediatric patient. Physicians who are looking after pediatric patients in the post-HCT setting need to be aware of this possibility and include this entity in the differential diagnosis in order to reduce its associated morbidity.

PMID:38894686 | DOI:10.1111/petr.14810

Immunotherapy. 2024 Jun 18:1-13. doi: 10.1080/1750743X.2024.2354091. Online ahead of print.

ABSTRACT

Aim: To assess the long-term safety of hyaluronidase-facilitated subcutaneous immunoglobulin (fSCIG) 10% in European routine clinical practice. Materials & methods: This prospective, noninterventional, open-label, post-authorization safety study (EUPAS5812) sourced data on adverse events, immunogenicity, treatment regimens and product administration for 106 adult patients prescribed fSCIG 10% across 17 sites in six European countries from July 2014 to February 2020. Results: In total, 1171 treatment-emergent adverse events were reported in 94 patients (88.7%); 25.5% of these events were considered related to fSCIG 10%. Positive binding antibody titers developed in three patients; no neutralizing antibodies to recombinant human hyaluronidase were detected. Conclusion: This real-world study of fSCIG 10% is the longest to date and confirms its long-term safety and tolerability in adults with antibody deficiency diseases.

PMID:38888495 | DOI:10.1080/1750743X.2024.2354091

J Med Virol. 2024 Jun;96(6):e29738. doi: 10.1002/jmv.29738.

ABSTRACT

Immunocompromised individuals are at significantly elevated risk for severe courses of coronavirus disease 2019 (COVID-19). In addition to vaccination, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing antibodies (nAbs) have been applied throughout the pandemic, with time of treatment onset and potency against the currently prevailing virus variant identified as relevant factors for medical benefit. Using data from the European Society for Immunodeficiencies (ESID) registry, the present study evaluated COVID-19 cases in three groups of patients with inborn errors of immunity (IEI; 981 agammaglobulinemia patients on immunoglobulin replacement therapy (IGRT); 8960 non-agammaglobulinemia patients on IGRT; 14 428 patients without IGRT), and the neutralizing capacity of 1100 immunoglobulin lots against SARS-CoV-2 (“Wuhan” and Omicron strains), throughout 3 years. From the first (2020/2021) to the second (2021/2022) cold season, i.e., during the virus drift to the more contagious Omicron variants, an increase in case numbers was recorded that was comparable (~2- to 3-fold) for all three study groups. During the same period, immunoglobulin lots showed a profound nAb increase against the archetypal SARS-CoV-2 strain, yet only low levels of Omicron nAbs. Notably, shortly before the third (2022/2023) cold season, Omicron-neutralizing capacity of released immunoglobulin lots had plateaued at high levels. From the second to the third cold season, COVID-19 cases dropped markedly. While a ~6-fold case reduction was recorded for the groups of non-agammaglobulinemia patients on IGRT and IEI patients not receiving IGRT, the decline was ~30-fold for the group of agammaglobulinemia patients on IGRT. These findings suggest a substantial COVID-19-protective effect of IGRT, at least for distinct groups of antibody-deficient patients.

PMID:38884390 | DOI:10.1002/jmv.29738

Front Neurol. 2024 May 31;15:1344018. doi: 10.3389/fneur.2024.1344018. eCollection 2024.

ABSTRACT

Ataxia-telangiectasia (A-T) is an autosomal recessive primary immunodeficiency disorder (PID) caused by biallelic mutations occurring in the serine/threonine protein kinase (ATM) gene. The major role of nuclear ATM is the coordination of cell signaling pathways in response to DNA double-strand breaks, oxidative stress, and cell cycle checkpoints. Defects in ATM functions lead to A-T syndrome with phenotypic heterogeneity. Our study reports the case of a Tunisian girl with A-T syndrome carrying a compound heterozygous mutation c.[3894dupT]; p.(Ala1299Cysfs3;rs587781823), with a splice acceptor variant: c.[5763-2A>C;rs876659489] in the ATM gene that was identified by next-generation sequencing (NGS). Further genetic analysis of the family showed that the mother carried the c.[5763-2A>C] splice acceptor variant, while the father harbored the c.[3894dupT] variant in the heterozygous state. Molecular analysis provides the opportunity for accurate diagnosis and timely management in A-T patients with chronic progressive disease, especially infections and the risk of malignancies. This study characterizes for the first time the identification of compound heterozygous ATM pathogenic variants by NGS in a Tunisian A-T patient. Our study outlines the importance of molecular genetic testing for A-T patients, which is required for earlier detection and reducing the burden of disease in the future, using the patients’ families.

PMID:38882696 | PMC:PMC11178103 | DOI:10.3389/fneur.2024.1344018

Front Immunol. 2024 May 30;15:1371118. doi: 10.3389/fimmu.2024.1371118. eCollection 2024.

ABSTRACT

BACKGROUND: The respiratory tract microbiome is essential for human health and well-being and is determined by genetic, lifestyle, and environmental factors. Patients with Common Variable Immunodeficiency (CVID) suffer from respiratory and intestinal tract infections, leading to chronic diseases and increased mortality rates. While CVID patients’ gut microbiota have been analyzed, data on the respiratory microbiome ecosystem are limited.

OBJECTIVE: This study aims to analyze the bacterial composition of the oropharynx of adults with CVID and its link with clinical and immunological features and risk for respiratory acute infections.

METHODS: Oropharyngeal samples from 72 CVID adults and 26 controls were collected in a 12-month prospective study. The samples were analyzed by metagenomic bacterial 16S ribosomal RNA sequencing and processed using the Quantitative Insights Into Microbial Ecology (QIME) pipeline. Differentially abundant species were identified and used to build a dysbiosis index. A machine learning model trained on microbial abundance data was used to test the power of microbiome alterations to distinguish between healthy individuals and CVID patients.

RESULTS: Compared to controls, the oropharyngeal microbiome of CVID patients showed lower alpha- and beta-diversity, with a relatively increased abundance of the order Lactobacillales, including the family Streptococcaceae. Intra-CVID analysis identified age >45 years, COPD, lack of IgA, and low residual IgM as associated with a reduced alpha diversity. Expansion of Haemophilus and Streptococcus genera was observed in patients with undetectable IgA and COPD, independent from recent antibiotic use. Patients receiving azithromycin as antibiotic prophylaxis had a higher dysbiosis score. Expansion of Haemophilus and Anoxybacillus was associated with acute respiratory infections within six months.

CONCLUSIONS: CVID patients showed a perturbed oropharynx microbiota enriched with potentially pathogenic bacteria and decreased protective species. Low residual levels of IgA/IgM, chronic lung damage, anti antibiotic prophylaxis contributed to respiratory dysbiosis.

PMID:38873612 | PMC:PMC11169596 | DOI:10.3389/fimmu.2024.1371118

Front Immunol. 2024 May 29;15:1430313. doi: 10.3389/fimmu.2024.1430313. eCollection 2024.

ABSTRACT

[This corrects the article DOI: 10.3389/fimmu.2022.1075527.].

PMID:38873596 | PMC:PMC11175654 | DOI:10.3389/fimmu.2024.1430313

iScience. 2024 May 18;27(6):109984. doi: 10.1016/j.isci.2024.109984. eCollection 2024 Jun 21.

ABSTRACT

The Tousled-like kinases 1 and 2 (TLK1/TLK2) regulate DNA replication, repair and chromatin maintenance. TLK2 variants underlie the neurodevelopmental disorder (NDD) ‘Intellectual Disability, Autosomal Dominant 57’ (MRD57), characterized by intellectual disability and microcephaly. Several TLK1 variants have been reported in NDDs but their functional significance is unknown. A male patient presenting with ID, seizures, global developmental delay, hypothyroidism, and primary immunodeficiency was determined to have a heterozygous TLK1 variant (c.1435C>G, p.Q479E), as well as a mutation in MDM1 (c.1197dupT, p.K400∗). Cells expressing TLK1 p.Q479E exhibited reduced cytokine responses and elevated DNA damage, but not increased radiation sensitivity or DNA repair defects. The TLK1 p.Q479E variant impaired kinase activity but not proximal protein interactions. Our study provides the first functional characterization of NDD-associated TLK1 variants and suggests that, such as TLK2, TLK1 variants may impact development in multiple tissues and should be considered in the diagnosis of rare NDDs.

PMID:38868186 | PMC:PMC11166698 | DOI:10.1016/j.isci.2024.109984