Paediatrics (RCH) - Research Publications

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    Benchmarking single-cell hashtag oligo demultiplexing methods
    Howitt, G ; Feng, Y ; Tobar, L ; Vassiliadis, D ; Hickey, P ; Dawson, MA ; Ranganathan, S ; Shanthikumar, S ; Neeland, M ; Maksimovic, J ; Oshlack, A (OXFORD UNIV PRESS, 2023-10-11)
    Sample multiplexing is often used to reduce cost and limit batch effects in single-cell RNA sequencing (scRNA-seq) experiments. A commonly used multiplexing technique involves tagging cells prior to pooling with a hashtag oligo (HTO) that can be sequenced along with the cells' RNA to determine their sample of origin. Several tools have been developed to demultiplex HTO sequencing data and assign cells to samples. In this study, we critically assess the performance of seven HTO demultiplexing tools: hashedDrops, HTODemux, GMM-Demux, demuxmix, deMULTIplex, BFF (bimodal flexible fitting) and HashSolo. The comparison uses data sets where each sample has also been demultiplexed using genetic variants from the RNA, enabling comparison of HTO demultiplexing techniques against complementary data from the genetic 'ground truth'. We find that all methods perform similarly where HTO labelling is of high quality, but methods that assume a bimodal count distribution perform poorly on lower quality data. We also suggest heuristic approaches for assessing the quality of HTO counts in an scRNA-seq experiment.
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    DNA Methylation Profiles of Purified Cell Types in Bronchoalveolar Lavage: Applications for Mixed Cell Paediatric Pulmonary Studies
    Shanthikumar, S ; Neeland, MR ; Saffery, R ; Ranganathan, SC ; Oshlack, A ; Maksimovic, J (FRONTIERS MEDIA SA, 2021-12-22)
    In epigenome-wide association studies analysing DNA methylation from samples containing multiple cell types, it is essential to adjust the analysis for cell type composition. One well established strategy for achieving this is reference-based cell type deconvolution, which relies on knowledge of the DNA methylation profiles of purified constituent cell types. These are then used to estimate the cell type proportions of each sample, which can then be incorporated to adjust the association analysis. Bronchoalveolar lavage is commonly used to sample the lung in clinical practice and contains a mixture of different cell types that can vary in proportion across samples, affecting the overall methylation profile. A current barrier to the use of bronchoalveolar lavage in DNA methylation-based research is the lack of reference DNA methylation profiles for each of the constituent cell types, thus making reference-based cell composition estimation difficult. Herein, we use bronchoalveolar lavage samples collected from children with cystic fibrosis to define DNA methylation profiles for the four most common and clinically relevant cell types: alveolar macrophages, granulocytes, lymphocytes and alveolar epithelial cells. We then demonstrate the use of these methylation profiles in conjunction with an established reference-based methylation deconvolution method to estimate the cell type composition of two different tissue types; a publicly available dataset derived from artificial blood-based cell mixtures and further bronchoalveolar lavage samples. The reference DNA methylation profiles developed in this work can be used for future reference-based cell type composition estimation of bronchoalveolar lavage. This will facilitate the use of this tissue in studies examining the role of DNA methylation in lung health and disease.
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    Patient and family perspectives regarding the use of telehealth for cystic fibrosis care
    Shanthikumar, S ; Moore, E ; Corda, J ; Reardon, N ; Louey, S ; Frayman, K ; Harrison, J ; Ranganathan, S (WILEY, 2021-05)
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    Optimism with Caution: Elexacaftor-Tezacaftor-Ivacaftor in Patients with Advanced Pulmonary Disease
    Kuek, SL ; Ranganathan, SC ; Harrison, J ; Robinson, PJ ; Shanthikumar, S (AMER THORACIC SOC, 2021-08-01)
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    Mapping Pulmonary and Systemic Inflammation in Preschool Aged Children With Cystic Fibrosis
    Shanthikumar, S ; Ranganathan, SC ; Saffery, R ; Neeland, MR (FRONTIERS MEDIA SA, 2021-10-15)
    The immune landscape of the paediatric respiratory system remains largely uncharacterised and as a result, the mechanisms of globally important childhood respiratory diseases remain poorly understood. In this work, we used high parameter flow cytometry and inflammatory cytokine profiling to map the local [bronchoalveolar lavage (BAL)] and systemic (whole blood) immune response in preschool aged children with cystic fibrosis (CF) and aged-matched healthy controls. We demonstrate that children with CF show pulmonary infiltration of CD66b+ granulocytes and increased levels of MIP-1α, MIG, MCP-1, IL-8, and IL-6 in BAL relative to healthy control children. Proportions of systemic neutrophils positively correlated with age in children with CF, whilst systemic CD4 T cells and B cells were inversely associated with age. Inflammatory cells in the BAL from both CF and healthy children expressed higher levels of activation and migration markers relative to their systemic counterparts. This work highlights the utility of multiplex immune profiling and advanced analytical pipelines to understand mechanisms of lung disease in childhood.
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    Telehealth and virtual health monitoring in cystic fibrosis
    Vagg, T ; Shanthikumar, S ; Morrissy, D ; Chapman, WW ; Plant, BJ ; Ranganathan, S (LIPPINCOTT WILLIAMS & WILKINS, 2021-11)
    PURPOSE OF REVIEW: At many institutions, the Covid-19 pandemic made it necessary to rapidly change the way services are provided to patients, including those with cystic fibrosis (CF). The purpose of this review is to explore the past, present and future of telehealth and virtual monitoring in CF and to highlight certain challenges/considerations in developing such services. RECENT FINDINGS: The Covid-19 pandemic has proven that telehealth and virtual monitoring are a feasible means for safely providing services to CF patients when traditional care is not possible. However, both telehealth and virtual monitoring can also provide further support in the future in a post-covid era through a hybrid-model incorporating traditional care, remote data collection and sophisticated platforms to manage and share data with CF teams. SUMMARY: We provide a detailed overview of telehealth and virtual monitoring including examples of how paediatric and adult CF services adapted to the need for rapid change. Such services have proven popular with people with CF meaning that co-design with stakeholders will likely improve systems further. In the future, telehealth and virtual monitoring will become more sophisticated by harnessing increasingly powerful technologies such as artificial intelligence, connected monitoring devices and wearables. In this review, we harmonise definitions and terminologies before highlighting considerations and limitations for the future of telehealth and virtual monitoring in CF.
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    Interventional bronchoscopy in children: Planning the path ahead
    Shanthikumar, S ; Steinfort, DP ; Ranganathan, S (WILEY, 2020-02)
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    Gene modifiers of cystic fibrosis lung disease: A systematic review
    Shanthikumar, S ; Neeland, MN ; Saffery, R ; Ranganathan, S (WILEY, 2019-09)
    BACKGROUND: Lung disease is the major source of morbidity and mortality in cystic fibrosis (CF), with large variability in severity between patients. Although accurate prediction of lung disease severity would be extremely useful, no robust methods exist. Twin and sibling studies have highlighted the importance of non-cystic fibrosis transmembrane conductance regulator (CFTR) genes in determining lung disease severity but how these impact on the severity in CF remains unclear. METHODS: A systematic review was undertaken to answer the question "In patients with CF which non-CFTR genes modify the severity of lung disease?" The method for this systematic review was based upon the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)" statement, with a narrative synthesis of results planned. RESULTS: A total of 1168 articles were screened for inclusion, with 275 articles undergoing detailed assessment for inclusion. One hundred and forty articles were included. Early studies focused on candidate genes, whereas more recent studies utilized genome-wide approaches and also examined epigenetic mechanisms, gene expression, and therapeutic response. DISCUSSION: A large body of evidence regarding non-CFTR gene modifiers of lung disease severity has been generated, examining a wide array of genes. Limitations to existing studies include heterogeneity in outcome measures used, limited replication, and relative lack of clinical impact. Future work examining non-CFTR gene modifiers will have to overcome these limitations if gene modifiers are to have a meaningful role in the care of patients with CF.
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    Pulmonary Mycobacterium abscessus complex in children with cystic fibrosis: A practical management guideline
    Andrew, EC ; Connell, T ; Robinson, P ; Curtis, N ; Massie, J ; Robertson, C ; Harrison, J ; Shanthikumar, S ; Bryant, PA ; Starr, M ; Steer, A ; Ranganathan, S ; Gwee, A (WILEY, 2019-05)
    The treatment of Mycobacterium abscessus complex (MABSC) pulmonary infections is an emerging challenge in patients with cystic fibrosis (CF). Multidrug therapy for prolonged durations is required and carries the significant burden of drug-related toxicity, cost and selective pressure for multiresistant bacteria. International guidelines acknowledge that clinical and in vitro data to support treatment regimens are limited, particularly in children. As part of a collaboration between the infectious diseases and respiratory units at our institution, we have developed a modified treatment guideline that aims to balance the aims of MABSC eradication and slowing disease progression with minimising drug toxicity and resistance. The outcomes of this treatment approach will be monitored and reported. In this manuscript, we discuss the available evidence for treatment choices and present our treatment guideline for paediatric patients with CF and MABSC infection.