Ecthyma gangrenosum as the presenting clinical feature of X-linked agammaglobulinaemia: report of three cases and a review of literature

Background: Children with X-linked agammaglobulinaemia (XLA) usually present with pneumonia and otitis media caused by pyogenic bacteria. Rarely, ecthyma gangrenosum (EG), a known cutaneous manifestation of Pseudomonas septicaemia present in XLA as the first presenting features. We report three cases of EG caused by P. aeruginosa in previously healthy boys, leading to the diagnosis of XLA. In addition, we provide a brief literature review on those cases of EG where an underlying XLA was eventually diagnosed. Methods: Three paediatric cases admitted to the intensive care unit with P. aeruginosa septicaemia associated with ecthyma gangrenosum were reviewed retrospectively. Laboratory workup consisted of microbiological, haematological and immunological investigations were analysed. Results: The ages of the three patients were: one year and six months, three years and five months, and five years and six months. All patients had septic shock and required mechanical ventilation. P. aeruginosa was isolated in the blood and/or skin lesions of all patients. Underlying hypogammaglobulinaemia and neutropaenia were detected in all patients. Treatment consisted of combined antipseudomonal antimicrobial therapy and surgical debridement. All patients survived. Subsequent B-cell measurement and Brutonʼs tyrosine kinase (BTK) protein and genetic analysis confirmed the diagnosis of XLA. Twelve other similar reported cases were reviewed and analysed based on their clinical presentation, diagnosis and treatment. Conclusion: P. aeruginosa sepsis should be treated as early as possible. The most common risk factor for ecthyma gangrenosum in XLA patients is neutropaenia. In previously healthy children presenting with EG, immunological evaluation is important to rule out an underlying immunodeficiency

The establishment of in vitro human induced pluripotent stem cell-derived neurons

Induced pluripotent stem cells (iPSCs) have been generated using different reprogramming strategies. Lentiviruses remain a strategic method for cell reprogramming as it is highly efficient in gene transfer. The latest fourth-generation lentiviral packaging systems claimed to be efficient and safe. However, modifications made to enhance safety of lentiviral vectors have been shown to affect vector performance. In this study, we established that the fourth-generation lentiviral packaging system can produce high-titre lentiviruses with high-transduction efficiencies. Subsequently, the robustness and reproducibility of generating iPSCs from adult human dermal fibroblasts were tested using these lentiviruses. The use of fourth-generation lentiviruses consistently generates iPSCs with similar efficiency and quality in different primary cell lines. This study demonstrated that the human-derived iPSCs can be maintained using mitomycin-C inactivated feeder cells. The iPSCs clones highly expressed key pluripotency markers and can spontaneously differentiate into cells from the three embryonic germ layers. The iPSCs generated were able to differentiate into neural stem cell lineages, producing cells expressing Nestin and Sox2 as well as able to further differentiate into neurons with more than 70% efficiency. The data demonstrated that the use of the fourth-generation lentiviral packaging to produce lentiviruses for iPSCs generation is robust and reproducible as it can generate iPSCs from different adult dermal fibroblasts with the potential to differentiate into neural stem cells and neurons. The use of safer lentiviral packaging systems combined with established vector plasmids will help to expedite the generation of iPSCs for clinical applications

Clinical features and mutational analysis of X-linked agammaglobulinemia patients in Malaysia

BackgroundBruton’s tyrosine kinase (BTK) is a cytoplasmic protein involved in the B cell development. X-linked agammaglobulinemia (XLA) is caused by mutation in the BTK gene, which results in very low or absent B cells. Affected males have markedly reduced immunoglobulin levels, which render them susceptible to recurrent and severe bacterial infections. Methods: Patients suspected with X-linked agammaglobulinemia were enrolled during the period of 2010-2018. Clinical summary, and immunological profiles of these patients were recorded. Peripheral blood samples were collected for monocyte BTK protein expression detection and BTK genetic analysis. The medical records between January 2020 and June 2023 were reviewed to investigate COVID-19 in XLA.ResultsTwenty-two patients (from 16 unrelated families) were molecularly diagnosed as XLA. Genetic testing revealed fifteen distinct mutations, including four splicing mutations, four missense mutations, three nonsense mutations, three short deletions, and one large indel mutation. These mutations scattered throughout the BTK gene and mostly affected the kinase domain. All mutations including five novel mutations were predicted to be pathogenic or deleterious by in silico prediction tools. Genetic testing confirmed that eleven mothers and seven sisters were carriers for the disease, while three mutations were de novo. Flow cytometric analysis showed that thirteen patients had minimal BTK expression (0-15%) while eight patients had reduced BTK expression (16-64%). One patient was not tested for monocyte BTK expression due to insufficient sample. Pneumonia (n=13) was the most common manifestation, while Pseudomonas aeruginosa was the most frequently isolated pathogen from the patients (n=4). Mild or asymptomatic COVID-19 was reported in four patients.ConclusionThis report provides the first overview of demographic, clinical, immunological and genetic data of XLA in Malaysia. The combination of flow cytometric assessment and BTK genetic analysis provides a definitive diagnosis for XLA patients, especially with atypical clinical presentation. In addition, it may also allow carrier detection and assist in genetic counselling and prenatal diagnosis

Aire-dependent production of XCL1 mediates medullary accumulation of thymic dendritic cells and contributes to regulatory T cell development

Aire regulates medullary epithelial cell production of XCL1, a chemoattractant for XCR1-expressing thymic DCs whose presence in the medulla contributes to the generation of T reg cells

Amino Acid Sequence and Structural Comparison of BACE1 and BACE2 Using Evolutionary Trace Method

Beta-amyloid precursor protein cleavage enzyme 1 (BACE1) and beta-amyloid precursor protein cleavage enzyme 2 (BACE2), members of aspartyl protease family, are close homologues and have high similarity in their protein crystal structures. However, their enzymatic properties differ leading to disparate clinical consequences. In order to identify the residues that are responsible for such differences, we used evolutionary trace (ET) method to compare the amino acid conservation patterns of BACE1 and BACE2 in several mammalian species. We found that, in BACE1 and BACE2 structures, most of the ligand binding sites are conserved which indicate their enzymatic property of aspartyl protease family members. The other conserved residues are more or less randomly localized in other parts of the structures. Four group-specific residues were identified at the ligand binding site of BACE1 and BACE2. We postulated that these residues would be essential for selectivity of BACE1 and BACE2 biological functions and could be sites of interest for the design of selective inhibitors targeting either BACE1 or BACE2

Study on histological properties of recellularized bioscaffolds from decellularized tissues for vessel regenerative application

The increasing number of arteries and organs needed for cardiovascular disease (CVD) patients with end-stage organ failure and bypass surgery has urge the need for future medical substituents. Transplantation provides an immediate treatment for the patients with end stage of organ failure by replacing tissues or organs with the normally function substitute. However, the need of immunosuppression and shortage of donors limit the impact of transplantation which then propel the evolution of tissue engineering. Recently, sonication decellularization technique is able to to prepare biological decellularized tissue efficiently. It has been established and proven by Azhim et al. and has successfully characterized some properties of the decellularized tissue scaffolds in the previous project (FRGS/1/2015/SG05/UIAM/02/6). However, its remaining research includes recellularized bioscaffolds properties evaluation and in-vitro cell infiltration and proliferation evaluations. It is hypothesized that recellularized bioscaffolds have fully seeded and infiltrated by autologous cells while producing new extracellular matrix (ECM) composition and providing sufficient biomechanical integrity of the ECM before implantation. In previous study, it has demonstrated that the decellularized tissues are able to prepare with lower toxicity level and significantly unchanged biomechanical strength. Henceforth, the objectives of this research are to investigate recellularization rate of the seeded cells onto/ into decellularized bioscaffolds which engineered by sonication decellularization system. The ECM integrity and cell removal of decellularized artery are confirmed by evaluation of histological HE staining, scanning electron microscopy and DNA quantitation. The recellularization of decellularized matrices are evaluated by measuring the coverage of the seeded endothelial cells on the matrices and their capability to infiltrate into the matrices using similar methods as described above. The outcome of this research could give an insight on the potential use of recellularized bioscaffolds in regenerative tissues/organs in future medicine

Enzymatic inhibitory activity of Ficus deltoidea leaf extract on matrix metalloproteinase-2, 8 and 9

Dysregulation of matrix metalloproteinases (MMPs) activity is known in many pathological conditions with which most of the conditions are related to elevate MMPs activities. Ficus deltoidea (FD) is a plant known for its therapeutic properties. In order to evaluate the therapeutic potential of FD leaf extract, we study the enzymatic inhibition properties of FD leaf extract and its major bioactive compounds (vitexin and isovitexin) on a panel of MMPs (MMP-2, MMP-8 and MMP-9) using experimental and computational approaches. FD leaf extract and its major bioactive compounds showed pronounced inhibition activity towards the MMPs tested. Computational docking analysis revealed that vitexin and isovitexin bind to the active site of the three tested MMPs. We also evaluated the cytotoxicity and cell migration inhibition activity of FD leaf extract in the endothelial EA.hy 926 cell line. Conclusively, this study provided additional information on the potential of FD leaf extract for therapeutical application. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group