Biology subjects

Leong, J. Y.

Publications and source records attributed to Leong, J. Y..

3 recordsLinked to original sources

bioRxiv2024

CyNET- a network analysis framework for high dimensionality, system level analyses of the functional Immunome

The immune system is a complex "Network of Networks", in which various immune cell subsets interact and influence each others functions, ultimately determining immune competence and the control or onset of disease. The coordinated interactions between these cell subsets determine whether the outcome is a normal physiological state or a pathological condition. Established statistical procedures largely ignore the interactions between subsets and rely on statistically significant changes in the frequency of cell subsets. We developed CyNET (Cytometry Network)-- an analysis platform based on a network science approach to understand the immune system holistically. CyNET enables us to quantify the systems level and subsets level properties. We show that changes in the centrality of the nodes (immune subsets) reflect better biological functions than changes in frequency. We used CyNET to analyze the immune development along the chronological age gradient. Peripheral blood cells from healthy newborns (cord blood), adults (20 to 55 years), and elderly (70 years and above) human subjects were further used for validation using single-cell transcriptomics. We found that network edge density, degree centralization, and assortativity score reflect the maturation and development of the immune system along the age axis, thus enabling the characterisation of the functional architecture of the Immunome and the identification of key functional hubs within the immune networks.

immunology↗

bioRxiv2022

Compartmentalization and persistence of dominant (regulatory) T cell clones indicates antigen skewing in juvenile idiopathic arthritis

Autoimmune inflammation is characterized by tissue infiltration and expansion of antigen-specific T cells. Although this inflammation is often limited to specific target tissues, it remains yet to be explored whether distinct affected sites are infiltrated with the same, persistent T cell clones. Here we performed CyTOF analysis and T cell receptor (TCR) sequencing to study immune cell composition and (hyper-)expansion of circulating and joint-derived Tregs and non-Tregs in Juvenile Idiopathic Arthritis (JIA). We studied different joints affected at the same time, as well as over the course of relapsing-remitting disease. We found that the composition and functional characteristics of immune infiltrates are strikingly similar between joints within one patient, and observed a strong overlap between dominant T cell clones, especially Treg, of which some could also be detected in circulation and persisted over the course of relapsing remitting disease. Moreover, these T cell clones were characterized by a high degree of sequence similarity, indicating the presence of TCR clusters responding to the same antigens. These data suggest that in localized autoimmune disease there is auto-antigen driven expansion of both Teffector and Treg clones, that are highly persistent and are (re)circulating. These dominant clones might represent interesting therapeutic targets.

immunology↗

bioRxiv2019

An immunome perturbation is present in juvenile idiopathic arthritis patients who are in remission and will relapse upon anti-TNFα withdrawal

ObjectivesBiologics treatment with anti-TNF is efficacious in juvenile idiopathic arthritic (JIA) patients. Despite displaying clinical inactivity during treatment, many patients will flare upon cessation of therapy. The inability to definitively discriminate patients who will relapse or continue to remain in remission after therapy withdrawal is currently a major unmet medical need. CD4 T cells have been implicated in active disease, yet how they contribute to disease persistence despite treatment is unknown.\n\nMethodsWe interrogated the circulatory reservoir of CD4+ immune subsets at the single cell resolution with mass cytometry (CyToF) of JIA patients (n=20) who displayed continuous clinical inactivity for at least 6 months with anti-TNF, and were subsequently withdrawn from therapy for 8 months, and scored as relapse or remission. These patients were examined prior to therapy withdrawal for putative subsets that could discriminate relapse from remission. We verified on a separate JIA cohort (n=16), the continued dysregulation of these circulatory subsets 8 months into therapy withdrawal. The immunological transcriptomic signature of CD4 memory in relapse/remission patients was examined with Nanostring.\n\nResultsAn inflammatory memory subset of CD3+CD4+CD45RA-TNF+ T cells deficient in immune checkpoints (PD1-CD152-) was present in relapse patients prior to therapy withdrawal. Transcriptomic profiling reveals divergence between relapse and remission patients in disease centric pathways involving (a) TCR activation, (b) apoptosis, (c) TNF, (d) NF-kB and (e) MAPK signalling.\n\nConclusionsA unique discriminatory immunomic and transcriptomic signature is associated with relapse patients and may explain how relapse occurs.

immunology↗