Displaying publications 21 - 31 of 31 in total

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  1. Human Immunodeficiency Virus-Human Pegivirus Coinfected Individuals Display Functional Mucosal-Associated Invariant T Cells and Follicular T Cells Irrespective of PD-1 Expression
    Vimali J, Yong YK, Murugesan A, Govindaraj S, Raju S, Balakrishnan P, et al.
    Viral Immunol, 2024 Jun;37(5):240-250.
    PMID: 38808464 DOI: 10.1089/vim.2024.0007
    Human pegivirus (HPgV) appears to alter the prognosis of HIV disease by modulating T cell homeostasis, chemokine/cytokine production, and T cell activation. In this study, we evaluated if HPgV had any 'favorable' impact on the quantity and quality of T cells in HIV-infected individuals. T cell subsets such as CD4lo, CD4hi, and CD8+ T cells, CD4+ MAIT cells, CD8+ MAIT cells, follicular helper T (TFH) cells, and follicular cytotoxic T (TFC) cells were characterized based on the expression of markers associated with immune activation (CD69, ICOS), proliferation (ki67), cytokine production (TNF-α, IFN-γ), and exhaustion (PD-1). HIV+HPgV+ individuals had lower transaminase SGOT (liver) and GGT (biliary) in the plasma than those who were HPgV-. HIV/HPgV coinfection was significantly associated with increased absolute CD4+ T cell counts. HIV+HPgV+ and HIV+HPgV- individuals had highly activated T cell subsets with high expression of CD69 and ICOS on bulk CD4+ and CD8+ T cells, CD4+ MAIT cells, CD8+ MAIT cells, and CXCR5+CD4+ T cells and CXCR5+CD8+ T cells compared with healthy controls. Irrespective of immune activation markers, these cells also displayed higher levels of PD-1 on CD4+ T and CD8+ T cells . Exploring effector functionality based on mitogen stimulation demonstrated increased cytokine production by CD4+ MAIT and CD8+ MAIT cells. Decrease in absolute CD4+ T cell counts correlated positively with intracellular IFN-γ levels by CD4lo T cells, whereas increase of the same correlated negatively with TNF-α in the CD4lo T cells of HIV+HPgV+ individuals. HIV/HPgV coinfected individuals display functional CD4+ and CD8+ MAIT, TFH, and TFC cells irrespective of PD-1 expression.
    Matched MeSH terms: T-Lymphocyte Subsets/immunology
  2. Fulltext Quantitation of T lymphocyte subsets helps to distinguish dengue hemorrhagic fever from classic dengue fever during the acute febrile stage
    Fadilah SA, Sahrir S, Raymond AA, Cheong SK, Aziz JA, Sivagengei K
    Southeast Asian J Trop Med Public Health, 1999 Dec;30(4):710-7.
    PMID: 10928365
    Activation of immunoregulatory T lymphocyte subsets has been observed in dengue viral infection, being more evident in dengue hemorrhagic fever (DHF) than in classical dengue fever (DF). There are, however, as yet no well-defined host markers to determine which patients with dengue viral infection will develop severe complications during the acute febrile stage of the disease. A study was performed to compare the cellular immune status in DHF, DF and non-dengue viral infections (NDF) in order to determine the value of these parameters in distinguishing DHF from classic DF and other viral infections during the acute febrile stage of the disease. This study involved 109 febrile patients admitted because of suspected DHF. Fifty patients were serologically confirmed cases of dengue infection, of which 25 had grade 1 or 2 DHF. There was a reduction in total T (CD3), CD4 and CD8 cells in DHF and demonstrated that a low level of CD3, CD4, CD8 and CD5 cells discriminated DHF from DF patients during the febrile stage of the illness. In contrast, B (CD19) cells and natural killer (NK) cells did not appear to be discriminatory in this study. Receiver operating characteristic (ROC) curve analysis showed that a combination of CD3 cell of < or = 45% and CD5 cell of < or = 55% was the best marker to identify DHF patients (sensitivity = 84% and specificity = 52% for CD3 cell of < or = 45%; sensitivity = 92% and specificity = 71% for CD5 cell of < or = 55%). CD4 cell of < or = 25% and CD8 cell < or = 30% were equally good in discriminating DHF from DF patients. On the other hand, the ROC curves indicated no clear difference between the immunoregulatory cell counts in DF from NDF Lymphopenia, atypical lymphocytosis and thrombocytopenia were significantly more evident in dengue compared to non-dengue infection but did not appear to be discriminatory among DHF and DF patients. The reduction in CD3, CD4, CD8, CD5 cells correlated with the degree of thrombocytopenia in DHF (p < 0.05) which suggests that these cells probably participate in a common pathogenetic mechanism.
    Matched MeSH terms: T-Lymphocyte Subsets/metabolism*
  3. Fulltext Human CD3+ T-Cells with the Anti-ERBB2 Chimeric Antigen Receptor Exhibit Efficient Targeting and Induce Apoptosis in ERBB2 Overexpressing Breast Cancer Cells
    Munisvaradass R, Kumar S, Govindasamy C, Alnumair KS, Mok PL
    Int J Mol Sci, 2017 Sep 08;18(9).
    PMID: 28885562 DOI: 10.3390/ijms18091797
    Breast cancer is a common malignancy among women. The innate and adaptive immune responses failed to be activated owing to immune modulation in the tumour microenvironment. Decades of scientific study links the overexpression of human epidermal growth factor receptor 2 (ERBB2) antigen with aggressive tumours. The Chimeric Antigen Receptor (CAR) coding for specific tumour-associated antigens could initiate intrinsic T-cell signalling, inducing T-cell activation, and cytotoxic activity without the need for major histocompatibility complex recognition. This renders CAR as a potentially universal immunotherapeutic option. Herein, we aimed to establish CAR in CD3+ T-cells, isolated from human peripheral blood mononucleated cells that could subsequently target and induce apoptosis in the ERBB2 overexpressing human breast cancer cell line, SKBR3. Constructed CAR was inserted into a lentiviral plasmid containing a green fluorescent protein tag and produced as lentiviral particles that were used to transduce activated T-cells. Transduced CAR-T cells were then primed with SKBR3 cells to evaluate their functionality. Results showed increased apoptosis in SKBR3 cells co-cultured with CAR-T cells compared to the control (non-transduced T-cells). This study demonstrates that CAR introduction helps overcome the innate limitations of native T-cells leading to cancer cell apoptosis. We recommend future studies should focus on in vivo cytotoxicity of CAR-T cells against ERBB2 expressing tumours.
    Matched MeSH terms: T-Lymphocyte Subsets/immunology*; T-Lymphocyte Subsets/metabolism*
  4. Keloids - the sebum hypothesis revisited
    Fong EP, Bay BH
    Med Hypotheses, 2002 Apr;58(4):264-9.
    PMID: 12027517
    The aetiology of the keloid scar has not been completely elucidated. Numerous hypotheses have been proposed in the past to explain the unusual characteristics of the keloid scar. While we do know that there is excessive and ongoing collagen-deposition, the exact triggering stimulus is a subject of conjecture. We present some of our photographic records of keloids and electron microscopic findings of keloid edges and reiterate the sebum hypothesis. We also attempt to explain the features of keloids in the light of the present knowledge of immunology and cell biology.
    Matched MeSH terms: T-Lymphocyte Subsets/immunology
  5. Chronic mucocutaneous candidiasis with deficient CD2 (E receptor) but normal CD3 mononuclear cells
    Noh LM, Hussein SH, Sukumaran KD, Rose I, Abdullah N
    J Clin Lab Immunol, 1991 Jun;35(2):89-93.
    PMID: 1688166
    A case of chronic mucocutaneous candidiasis in a Malaysian child who subsequently developed disseminated tuberculosis and toxoplasmosis is described. The phenotype of her peripheral blood mononuclear cells showed discordance for her T cell markers. The presence of a subpopulation of CD2-/CD3+ mononuclear cells leading to an immunodeficiency state is consistent with failure of activation of CD2-mediated alternative pathway resulting in immunodeficiency. Such abnormal CD2-/CD3+ subpopulations have been described in lepromatous leprosy and foetal abortuses.
    Matched MeSH terms: T-Lymphocyte Subsets/immunology*
  6. Fulltext Family History of Early Infant Death Correlates with Earlier Age at Diagnosis But Not Shorter Time to Diagnosis for Severe Combined Immunodeficiency
    Luk ADW, Lee PP, Mao H, Chan KW, Chen XY, Chen TX, et al.
    Front Immunol, 2017;8:808.
    PMID: 28747913 DOI: 10.3389/fimmu.2017.00808
    BACKGROUND: Severe combined immunodeficiency (SCID) is fatal unless treated with hematopoietic stem cell transplant. Delay in diagnosis is common without newborn screening. Family history of infant death due to infection or known SCID (FH) has been associated with earlier diagnosis.

    OBJECTIVE: The aim of this study was to identify the clinical features that affect age at diagnosis (AD) and time to the diagnosis of SCID.

    METHODS: From 2005 to 2016, 147 SCID patients were referred to the Asian Primary Immunodeficiency Network. Patients with genetic diagnosis, age at presentation (AP), and AD were selected for study.

    RESULTS: A total of 88 different SCID gene mutations were identified in 94 patients, including 49 IL2RG mutations, 12 RAG1 mutations, 8 RAG2 mutations, 7 JAK3 mutations, 4 DCLRE1C mutations, 4 IL7R mutations, 2 RFXANK mutations, and 2 ADA mutations. A total of 29 mutations were previously unreported. Eighty-three of the 94 patients fulfilled the selection criteria. Their median AD was 4 months, and the time to diagnosis was 2 months. The commonest SCID was X-linked (n = 57). A total of 29 patients had a positive FH. Candidiasis (n = 27) and bacillus Calmette-Guérin (BCG) vaccine infection (n = 19) were the commonest infections. The median age for candidiasis and BCG infection documented were 3 months and 4 months, respectively. The median absolute lymphocyte count (ALC) was 1.05 × 10(9)/L with over 88% patients below 3 × 10(9)/L. Positive FH was associated with earlier AP by 1 month (p = 0.002) and diagnosis by 2 months (p = 0.008), but not shorter time to diagnosis (p = 0.494). Candidiasis was associated with later AD by 2 months (p = 0.008) and longer time to diagnosis by 0.55 months (p = 0.003). BCG infections were not associated with age or time to diagnosis.

    CONCLUSION: FH was useful to aid earlier diagnosis but was overlooked by clinicians and not by parents. Similarly, typical clinical features of SCID were not recognized by clinicians to shorten the time to diagnosis. We suggest that lymphocyte subset should be performed for any infant with one or more of the following four clinical features: FH, candidiasis, BCG infections, and ALC below 3 × 10(9)/L.

    Matched MeSH terms: Lymphocyte Subsets
  7. Fulltext Germline TET2 loss of function causes childhood immunodeficiency and lymphoma
    Stremenova Spegarova J, Lawless D, Mohamad SMB, Engelhardt KR, Doody G, Shrimpton J, et al.
    Blood, 2020 Aug 27;136(9):1055-1066.
    PMID: 32518946 DOI: 10.1182/blood.2020005844
    Molecular dissection of inborn errors of immunity can help to elucidate the nonredundant functions of individual genes. We studied 3 children with an immune dysregulation syndrome of susceptibility to infection, lymphadenopathy, hepatosplenomegaly, developmental delay, autoimmunity, and lymphoma of B-cell (n = 2) or T-cell (n = 1) origin. All 3 showed early autologous T-cell reconstitution following allogeneic hematopoietic stem cell transplantation. By whole-exome sequencing, we identified rare homozygous germline missense or nonsense variants in a known epigenetic regulator of gene expression: ten-eleven translocation methylcytosine dioxygenase 2 (TET2). Mutated TET2 protein was absent or enzymatically defective for 5-hydroxymethylating activity, resulting in whole-blood DNA hypermethylation. Circulating T cells showed an abnormal immunophenotype including expanded double-negative, but depleted follicular helper, T-cell compartments and impaired Fas-dependent apoptosis in 2 of 3 patients. Moreover, TET2-deficient B cells showed defective class-switch recombination. The hematopoietic potential of patient-derived induced pluripotent stem cells was skewed toward the myeloid lineage. These are the first reported cases of autosomal-recessive germline TET2 deficiency in humans, causing clinically significant immunodeficiency and an autoimmune lymphoproliferative syndrome with marked predisposition to lymphoma. This disease phenotype demonstrates the broad role of TET2 within the human immune system.
    Matched MeSH terms: B-Lymphocyte Subsets/pathology; T-Lymphocyte Subsets/pathology
  8. Fulltext CD4+CD25hiCD127low regulatory T cells are increased in oral squamous cell carcinoma patients
    Lim KP, Chun NA, Ismail SM, Abraham MT, Yusoff MN, Zain RB, et al.
    PLoS One, 2014;9(8):e103975.
    PMID: 25153698 DOI: 10.1371/journal.pone.0103975
    Regulatory T cells (Tregs), a subset of CD4+ T cells plays a pivotal role in regulating the immune system. An increase in Treg numbers enables cancer progression by dampening the immune system and allowing tumor cells to evade immune detection and destruction. An increase in Treg numbers and expression of inhibitory cytokines including TGF-β and IL-10 are mechanisms by which Tregs exert their immune suppressive function. However, the presence of Tregs and inhibitory cytokines in oral cancer patients is still unclear. In this study, the presence of circulating Tregs in 39 oral cancer patients and 24 healthy donors was examined by studying the presence of the CD4+CD25hiCD127low cell population in their peripheral blood mononuclear cells using flow cytometry. Serum levels of TGF-β and IL-10 were measured by ELISA. T cell subsets of OSCC patients were found to differ significantly from healthy donors where a decrease in CD8+ cytotoxic T cells and an increase in Tregs (CD4+CD25hiCD127low) were observed. Further, the ratio of CD8+ T cells/Tregs was also decreased in patients compared to healthy donors. The presence of Tregs was accompanied by a decrease in IL-10 but not TGF-β secretion in OSCC patients when compared to donors; in addition, the analysis also revealed that an increased presence of Tregs was accompanied by better patient survival. Amongst OSCC patients, smokers had significantly higher levels of TGF-β. It is apparent that the immune system is compromised in OSCC patients and the characterization of the Treg subpopulation could form a basis for improving our understanding of the perturbations in the immune system that occur during OSCC tumorigenesis.
    Matched MeSH terms: T-Lymphocyte Subsets/immunology
  9. Proportions of circulating T cells with a regulatory cell phenotype increase with HIV-associated immune activation and remain high on antiretroviral therapy
    Lim A, Tan D, Price P, Kamarulzaman A, Tan HY, James I, et al.
    AIDS, 2007 Jul 31;21(12):1525-34.
    PMID: 17630546
    To examine the relationships between blood CD4 natural regulatory T (Treg) cells, plasma HIV RNA level, CD4 T-cell count and immune activation in untreated HIV-infected patients and immunodeficient patients beginning antiretroviral therapy (ART), using a novel phenotype to define Treg cells (CD25CD127CD4). Data were compared with established Treg cell markers (FoxP3, CTLA-4 and GITR).
    Matched MeSH terms: T-Lymphocyte Subsets/immunology
  10. A comparison of the pattern of liver involvement in dengue hemorrhagic fever with classic dengue fever
    Wahid SF, Sanusi S, Zawawi MM, Ali RA
    Southeast Asian J Trop Med Public Health, 2000 Jun;31(2):259-63.
    PMID: 11127322
    The impact of dengue on liver function was studied on fifty serologically confirmed dengue cases admitted to Hospital Universiti Kebangsaan Malaysia (HUKM). Twenty-five of these patients had classic dengue fever (DF) and 25 had grade 1 or 2 dengue hemorrhagic fever (DHF). There were more (60%) DHF patients with hepatomegaly compared to DF (40%) but the difference was not statistically significant. Analysis of the liver profile showed that liver dysfunction was commoner in DHF compared to DF, indicating that the degree of liver impairment may be related to the severity of DHF. Hyperbilirubinemia was noted in 3 (12%) DHF and 2 (8%) DF patients. The mean (range) serum bilirubin was higher in DHF [14.2(5-50) micromol/l] compared to DF [10.9(5-30) micromol/l)] (p > 0.05). Elevated levels of serum alanine aminotransferase (ALT) and alkaline phosphatase (ALP) were observed more frequently in DHF (20 and 12 patients respectively) compared to DF (16 and 8 patients respectively). Nine (36%) DHF and 6 (24%) DF patients had concomitant elevation of ALT and ALP levels. The mean (range) serum ALT levels were 109.3(23-325) U/l in DHF and 90.8(13-352) U/l in DF (p > 0.05). The mean (range) serum ALP levels were 102.2(15-319) U/l in DHF and 93.3(34-258) U/l in DF (p > 0.05). The ALT and ALP levels were significantly higher in DHF patients with spontaneous bleeding than those without bleeding (p < 0.05) None of the patients developed fulminant hepatitis. The immunoregulatory cells, which include the T (CD3), B (CD 19), CD4, CD8, CD5 and natural killer (NK) cells were significantly lower in DHF compared to DF patients (p < 0.05). However, the reduction in these cell counts did not correlate with the liver dysfunction seen in DHF patients. In conclusion, hepatomegaly and liver dysfunction were commoner in DHF compared to DF.
    Matched MeSH terms: Lymphocyte Subsets
  11. Fulltext Co-administration of avian influenza virus H5 plasmid DNA with chicken IL-15 and IL-18 enhanced chickens immune responses
    Lim KL, Jazayeri SD, Yeap SK, Alitheen NB, Bejo MH, Ideris A, et al.
    BMC Vet Res, 2012;8:132.
    PMID: 22866758 DOI: 10.1186/1746-6148-8-132
    DNA vaccines offer several advantages over conventional vaccines in the development of effective vaccines against avian influenza virus (AIV). However, one of the limitations of the DNA vaccine in poultry is that it induces poor immune responses. In this study, chicken interleukin (IL) -15 and IL-18 were used as genetic adjuvants to improve the immune responses induced from the H5 DNA vaccination in chickens. The immunogenicity of the recombinant plasmid DNA was analyzed based on the antibody production, T cell responses and cytokine production, following inoculation in 1-day-old (Trial 1) and 14-day-old (Trial 2) specific-pathogen-free chickens. Hence, the purpose of the present study was to explore the role of chicken IL-15 and IL-18 as adjuvants following the vaccination of chickens with the H5 DNA vaccine.
    Matched MeSH terms: T-Lymphocyte Subsets
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