Displaying publications 81 - 100 of 307 in total

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  1. Barathan M, Mohamed R, Saeidi A, Vadivelu J, Chang LY, Gopal K, et al.
    Eur J Clin Invest, 2015 May;45(5):466-74.
    PMID: 25721991 DOI: 10.1111/eci.12429
    Hepatitis C virus (HCV) causes persistent disease in ~85% of infected individuals, where the viral replication appears to be tightly controlled by HCV-specific CD8+ T cells. Accumulation of senescent T cells during infection results in considerable loss of functional HCV-specific immune responses.
  2. Azanan MS, Abdullah NK, Chua LL, Lum SH, Ghafar SS, Kamarulzaman A, et al.
    Eur J Immunol, 2016 Apr 30.
    PMID: 27129782 DOI: 10.1002/eji.201646356
    Many treatment complications which occur late in childhood cancer survivors resemble age-related co-morbidities observed in the elderly. An immune phenotype characterized by increased immune activation, systemic inflammation and accumulation of late-differentiated memory CD57(+) CD28(-) T cells has been associated with co-morbidities in the elderly. Here we explored if this phenotype was present in young adult leukemia survivors following an average of 19 years from chemotherapy and/or radiotherapy completion, and compared this with that in age-matched controls. We found that markers of systemic inflammation - IL-6 and human C-reactive protein (hCRP) and immune activation - CD38 and HLA-DR on T cells, sCD163 from monocytes and macrophages - were increased in survivors compared to controls. T-cell responses specific to cytomegalovirus (CMV) were also increased in survivors compared to controls while CMV IgG levels in survivors were comparable to levels measured in the elderly (>50years) and correlated with IL-6, hCRP, sCD163 and CD57(+) CD28(-) memory T cells. Immune activation and inflammation markers correlated poorly with prior chemotherapy and radiotherapy exposure. These data suggest that CMV infection/reactivation is strongly correlated with the immunological phenotype seen in young childhood leukemia survivors and these changes may be associated with the early onset of age-related co-morbidities in this group. This article is protected by copyright. All rights reserved.
  3. Ansari AW, Kamarulzaman A, Schmidt RE
    Front Immunol, 2013;4:312.
    PMID: 24109479 DOI: 10.3389/fimmu.2013.00312
    Active tuberculosis remains the leading cause of death among the HIV-1 seropositive individuals. Although significant success has been achieved in bringing down the number of HIV/AIDS-related mortality and morbidity following implementation of highly active anti-retroviral therapy (HAART). Yet, co-infection of Mycobacterium tuberculosis (Mtb) has posed severe clinical and preventive challenges in our efforts to eradicate the virus from the body. Both HIV-1 and Mtb commonly infect macrophages and trigger production of host inflammatory mediators that subsequently regulate the immune response and disease pathogenesis. These inflammatory mediators can impose beneficial or detrimental effects on each pathogen and eventually on host. Among these, inflammatory C-C chemokines play a central role in HIV-1 and Mtb pathogenesis. However, their role in lung-specific mechanisms of HIV-1 and Mtb interaction are poorly understood. In this review we highlight current view on the role of C-C chemokines, more precisely CCL2, on HIV-1: Mtb interaction, potential mechanisms of action and adverse clinical consequences in a setting HIV-1/Mtb co-infection. Targeting common chemokine regulators of HIV-1/Mtb pathogenesis can be an attractive and potential anti-inflammatory intervention in HIV/AIDS-related comorbidities.
  4. Ahmad F, Shankar EM, Yong YK, Tan HY, Ahrenstorf G, Jacobs R, et al.
    Front Immunol, 2017;8:338.
    PMID: 28396665 DOI: 10.3389/fimmu.2017.00338
    The CD1d-restricted invariant natural killer T (iNKT) cells are implicated in innate immune responses against human immunodeficiency virus (HIV). However, the determinants of cellular dysfunction across the iNKT cells subsets are seldom defined in HIV disease. Herein, we provide evidence for the involvement of the negative checkpoint regulator (NCR) 2B4 in iNKT cell alteration in a well-defined cohort of HIV-seropositive anti-retroviral therapy (ART) naïve, ART-treated, and elite controllers (ECs). We report on exaggerated 2B4 expression on iNKT cells of HIV-infected treatment-naïve individuals. In sharp contrast to CD4(-)iNKT cells, 2B4 expression was significantly higher on CD4(+) iNKT cell subset. Notably, an increased level of 2B4 on iNKT cells was strongly correlated with parameters associated with HIV disease progression. Further, iNKT cells from ART-naïve individuals were defective in their ability to produce intracellular IFN-γ. Together, our results suggest that the levels of 2B4 expression and the downstream co-inhibitory signaling events may contribute to impaired iNKT cell responses.
  5. Yong YK, Saeidi A, Tan HY, Rosmawati M, Enström PF, Batran RA, et al.
    Front Immunol, 2018;9:472.
    PMID: 29616020 DOI: 10.3389/fimmu.2018.00472
    Mucosal-associated invariant T (MAIT) cells, defined as CD161++TCR iVα7.2+ T cells, play an important role in the innate defense against bacterial infections, and their functionality is impaired in chronic viral infections. Here, we investigated the frequency and functional role of MAIT cells in chronic hepatitis B virus (HBV) infection. The peripheral CD3+CD161++TCR iVα7.2+ MAIT cells in chronic HBV-infected patients and healthy controls were phenotypically characterized based on CD57, PD-1, TIM-3, and CTLA-4, as well as HLA-DR and CD38 expression. The frequency of MAIT cells was significantly decreased among chronic HBV-infected individuals as compared to controls. Expression of CD57, PD-1, CTLA-4, as well as HLA-DR and CD38 on MAIT cells was significantly elevated in chronic HBV-infected individuals relative to controls. The percentage of T cell receptor (TCR) iVα7.2+ CD161+ MAIT cells did not correlate with HBV viral load but inversely with HLA-DR on CD4+ T cells and MAIT cells and with CD57 on CD8+ T cells suggesting that decrease of MAIT cells may not be attributed to direct infection by HBV but driven by HBV-induced chronic immune activation. The percentage and expression levels of PD-1 as well as CTLA-4 on MAIT cells inversely correlated with plasma HBV-DNA levels, which may suggest either a role for MAIT cells in the control of HBV infection or the effect of HBV replication in the liver on MAIT cell phenotype. We report that decrease of TCR iVα7.2+ MAIT cells in the peripheral blood and their functions were seemingly impaired in chronic HBV-infected patients likely because of the increased expression of PD-1.
  6. Kared H, Martelli S, Tan SW, Simoni Y, Chong ML, Yap SH, et al.
    Front Immunol, 2018;9:686.
    PMID: 29731749 DOI: 10.3389/fimmu.2018.00686
    Repetitive stimulation by persistent pathogens such as human cytomegalovirus (HCMV) or human immunodeficiency virus (HIV) induces the differentiation of natural killer (NK) cells. This maturation pathway is characterized by the acquisition of phenotypic markers, CD2, CD57, and NKG2C, and effector functions-a process regulated by Tim-3 and orchestrated by a complex network of transcriptional factors, involving T-bet, Eomes, Zeb2, promyelocytic leukemia zinc finger protein, and Foxo3. Here, we show that persistent immune activation during chronic viral co-infections (HCMV, hepatitis C virus, and HIV) interferes with the functional phenotype of NK cells by modulating the Tim-3 pathway; a decrease in Tim-3 expression combined with the acquisition of inhibitory receptors skewed NK cells toward an exhausted and cytotoxic phenotype in an inflammatory environment during chronic HIV infection. A better understanding of the mechanisms underlying NK cell differentiation could aid the identification of new immunological targets for checkpoint blockade therapies in a manner that is relevant to chronic infection and cancer.
  7. Han F, Gulam MY, Zheng Y, Zulhaimi NS, Sia WR, He D, et al.
    Front Immunol, 2022;13:985385.
    PMID: 36341446 DOI: 10.3389/fimmu.2022.985385
    MAIT cells are persistently depleted and functionally exhausted in HIV-1-infected patients despite long-term combination antiretroviral therapy (cART). IL-7 treatment supports MAIT cell reconstitution in vivo HIV-1-infected individuals and rescues their functionality in vitro. Single-nucleotide polymorphisms (SNPs) of the IL-7RA gene modulate the levels of soluble(s)IL-7Rα (sCD127) levels and influence bioavailability of circulating IL-7. Here we evaluate the potential influence of IL-7RA polymorphisms on MAIT cell numbers and function in healthy control (HC) subjects and HIV-1-infected individuals on long-term cART. Our findings indicate that IL-7RA haplotype 2 (H2*T), defined as T-allele carriers at the tagging SNP rs6897932, affects the size of the peripheral blood MAIT cell pool, as well as their production of cytokines and cytolytic effector proteins in response to bacterial stimulation. H2*T carriers had lower sIL-7Rα levels and higher MAIT cell frequency with enhanced functionality linked to higher expression of MAIT cell-associated transcription factors. Despite an average of 7 years on suppressive cART, MAIT cell levels and function in HIV-1-infected individuals were still significantly lower than those of HC. Notably, we observed a significant correlation between MAIT cell levels and cART duration only in HIV-1-infected individuals carrying IL-7RA haplotype 2. Interestingly, treatment with sIL-7Rα in vitro suppressed IL-7-dependent MAIT cell proliferation and function following cognate stimulations. These observations suggest that sIL-7Rα levels may influence MAIT cell numbers and function in vivo by limiting IL-7 bioavailability to MAIT cells. Collectively, these observations suggest that IL-7RA polymorphisms may play a significant role in MAIT cell biology and influence MAIT cells recovery in HIV-1 infection. The potential links between IL7RA polymorphisms, MAIT cell immunobiology, and HIV-1 infection warrant further studies going forward.
  8. Vicknasingam B, Mohd Salleh NA, Chooi WT, Singh D, Mohd Zaharim N, Kamarulzaman A, et al.
    Front Psychiatry, 2021;12:630730.
    PMID: 33854449 DOI: 10.3389/fpsyt.2021.630730
    Background: Restrictive orders and temporary programmatic or ad hoc changes within healthcare and other supportive systems that were implemented in response to the COVID-19 epidemic in Malaysia may have created hindrances to accessing healthcare and/or receiving other supportive services for people who use drugs (PWUDs). Design: A primarily qualitative study has been conducted to evaluate how service providers and recipients were adapting and coping during the initial periods of the COVID-19 response. Settings: The study engaged several healthcare and non-governmental organizations (NGOs) in the peninsular states of Penang, Kelantan, Selangor, and Melaka. Participants: Medical personnel of methadone maintenance treatment (MMT) programs (n = 2) and HIV clinics (n = 3), staff of NGO services (n = 4), and MMT patients (n = 9) were interviewed using a semi-structured format. Results: Interviewed participants reported significant organizational, programmatic, and treatment protocols related changes implemented within the healthcare and support services in addition to nationally imposed Movement Control Orders (MCOs). Changes aimed to reduce patient flow and concentration at the on-site services locations, including less frequent in-person visits, increased use of telemedicine resources, and greater reliance on telecommunication methods to maintain contacts with patients and clients; changes in medication dispensing protocols, including increased take-home doses and relaxed rules for obtaining them, or delivery of medications to patients' homes or locations near their homes were reported by the majority of study participants. No significant rates of COVID-19 infections among PWUDs, including among those with HIV have been reported at the study sites. Conclusions: Although the reported changes presented new challenges for both services providers and recipients and resulted in some degree of initial disruption, generally, all participants reported successful implementation and high levels of compliance with the newly introduced restrictions, regulations, and protocols, resulting in relatively low rates of treatment disruption or discontinuation at the study sites.
  9. Pedersen CJ, Wickersham JA, Altice FL, Kamarulzaman A, Khoshnood K, Gibson BA, et al.
    Front Psychiatry, 2022;13:879479.
    PMID: 35774093 DOI: 10.3389/fpsyt.2022.879479
    The use of amphetamine-type stimulants (ATS) has been associated with increased sexual risk behaviors and HIV transmission, among other adverse health outcomes. However, ATS use among female sex workers (FSWs) in Malaysia has not yet been characterized. We examined the prevalence and correlates associated with ATS use among Malaysian FSW. Between February and December 2016, 492 FSWs, including cisgender (n = 299) and transgender (n = 193) women, were recruited using respondent-driven sampling in Greater Kuala Lumpur, Malaysia. A structured questionnaire was used to collect demographic characteristics, sexual behaviors, ATS and other substance use, behavioral health issues, involvement in criminal justice, and experience of physical and sexual trauma. Logistic regression analyses were conducted to determine factors associated with active ATS use, defined as ATS use in the last 30 days. Nearly one-third (32.3%) of participants reported active ATS use. In the multivariable model, ATS use was associated with drug use during sex work (aOR = 17.10; 8.32-35.15), having moderate to severe level of substance use disorder (aOR = 3.38; 1.48-7.70), and engaging in sex work with multiple clients per day (two clients: aOR = 3.39; 1.36-8.46; three clients: aOR = 5.06; 1.81-14.10). A high prevalence of ATS use was documented in our sample. The presence of moderate to severe substance use disorder, the use of drugs during sex work activity, and having multiple sex work clients per day were significantly associated with active ATS use. Given these findings, prevention and harm reduction strategies need to be tailored to address the increasing ATS use and the associated adverse health consequences among FSWs in Malaysia.
  10. Tan YM, Goh KL, Kamarulzaman A, Tan PS, Ranjeev P, Salem O, et al.
    Gastrointest Endosc, 2002 Feb;55(2):276-8.
    PMID: 11818941
  11. Chow WZ, Nizam S, Ong LY, Ng KT, Chan KG, Takebe Y, et al.
    Genome Announc, 2014;2(2).
    PMID: 24675847 DOI: 10.1128/genomeA.00139-14
    A complex HIV-1 unique recombinant form involving subtypes CRF01_AE, B, and B' was recently identified from an injecting drug user in Malaysia. A total of 13 recombination breakpoints were mapped across the near-full-length genome of isolate 10MYPR226, indicating the increasingly diverse molecular epidemiology and frequent linkage among various high-risk groups.
  12. Ng KT, Lee YM, Al-Darraji HA, Xia X, Takebe Y, Chan KG, et al.
    Genome Announc, 2013 Jan;1(1).
    PMID: 23409272 DOI: 10.1128/genomeA.00168-12
    We report the full genome sequence of hepatitis C virus (HCV) subtype 6n from Kuala Lumpur, Malaysia. Phylogenetic analysis of the isolate 10MYKJ032 suggests that Southeast Asia might be the origin for the HCV subtype 6n and highlights the possible spread of this lineage from Southeast Asia to other regions.
  13. Cheong HT, Ng KT, Ong LY, Takebe Y, Chan KG, Koh C, et al.
    Genome Announc, 2015;3(6).
    PMID: 26543107 DOI: 10.1128/genomeA.01220-15
    Three strains of HIV-1 unique recombinant forms (URFs) descended from subtypes B, B', and CRF01_AE were identified among people who inject drugs in Kuala Lumpur, Malaysia. These three URFs shared a common recombination breakpoint in the reverse transcriptase region, indicating frequent linkage within the drug-injecting networks in Malaysia.
  14. Chan KG, Ng KT, Pang YK, Chong TM, Kamarulzaman A, Yin WF, et al.
    Genome Announc, 2015;3(3).
    PMID: 26021924 DOI: 10.1128/genomeA.00541-15
    Streptococcus parasanguinis causes invasive diseases. However, the mechanism by which it causes disease remains unclear. Here, we describe the complete genome sequence of S. parasanguinis C1A, isolated from a patient diagnosed with an acute exacerbation of chronic obstructive pulmonary disease. Several genes that might be associated with pathogenesis are also described.
  15. Tee KK, Bon AH, Chow WZ, Ng KT, Chan KG, Kamarulzaman A, et al.
    Genome Announc, 2017 Jun 29;5(26).
    PMID: 28663289 DOI: 10.1128/genomeA.00459-17
    We report here the first HIV-1 circulating recombinant form (CRF) complex identified among the blood donors in Malaysia. The CRF77_cpx mosaic genome consists of parental subtypes B', C, and CRF01_AE and is structurally related to CRF07_BC. The identification of CRF77_cpx underlines the genetic complexity and mobility of HIV-1 among the blood donors.
  16. Gibson BA, Brown SE, Rutledge R, Wickersham JA, Kamarulzaman A, Altice FL
    Glob Public Health, 2016 Aug-Sep;11(7-8):1010-25.
    PMID: 26824463 DOI: 10.1080/17441692.2015.1134614
    Transgender women (TGW) face compounded levels of stigma and discrimination, resulting in multiple health risks and poor health outcomes. TGW identities are erased by forcing them into binary sex categories in society or treating them as men who have sex with men (MSM). In Malaysia, where both civil and religious law criminalise them for their identities, many TGW turn to sex work with inconsistent prevention methods, which increases their health risks. This qualitative study aims to understand how the identities of TGW sex workers shapes their healthcare utilisation patterns and harm reduction behaviours. In-depth, semi-structured interviews were conducted with 21 male-to-female transgender (mak nyah) sex workers in Malaysia. Interviews were transcribed, translated into English, and analysed using thematic coding. Results suggest that TGW identity is shaped at an early age followed by incorporation into the mak nyah community where TGW were assisted in gender transition and introduced to sex work. While healthcare was accessible, it failed to address the multiple healthcare needs of TGW. Pressure for gender-affirming health procedures and fear of HIV and sexually transmitted infection screening led to potentially hazardous health behaviours. These findings have implications for developing holistic, culturally sensitive prevention and healthcare services for TGW.
  17. Tan DB, Yong YK, Tan HY, Kamarulzaman A, Tan LH, Lim A, et al.
    HIV Med, 2008 May;9(5):307-16.
    PMID: 18400078 DOI: 10.1111/j.1468-1293.2008.00565.x
    A proportion of HIV patients beginning antiretroviral therapy (ART) develop immune restoration disease (IRD). Immunological characteristics of IRD were investigated in a cohort of HIV patients beginning therapy in Kuala Lumpur, Malaysia.
  18. Bijker R, Jiamsakul A, Uy E, Kumarasamy N, Ditango R, Chaiwarith R, et al.
    HIV Med, 2019 03;20(3):183-191.
    PMID: 30620108 DOI: 10.1111/hiv.12687
    OBJECTIVES: With aging of the HIV-positive population, cardiovascular disease (CVD) increasingly contributes to morbidity and mortality. We investigated CVD-related and other causes of death (CODs) and factors associated with CVD in a multi-country Asian HIV-positive cohort.

    METHODS: Patient data from 2003-2017 were obtained from the Therapeutics, Research, Education and AIDS Training in Asia (TREAT Asia) HIV Observational Database (TAHOD). We included patients on antiretroviral therapy (ART) with > 1 day of follow-up. Cumulative incidences were plotted for CVD-related, AIDS-related, non-AIDS-related, and unknown CODs, and any CVD (i.e. fatal and nonfatal). Competing risk regression was used to assess risk factors of any CVD.

    RESULTS: Of 8069 patients with a median follow-up of 7.3 years [interquartile range (IQR) 4.4-10.7 years], 378 patients died [incidence rate (IR) 6.2 per 1000 person-years (PY)], and this total included 22 CVD-related deaths (IR 0.36 per 1000 PY). Factors significantly associated with any CVD event (IR 2.2 per 1000 PY) were older age [sub-hazard ratio (sHR) 2.21; 95% confidence interval (CI) 1.36-3.58 for age 41-50 years; sHR 5.52; 95% CI 3.43-8.91 for ≥ 51 years, compared with < 40 years], high blood pressure (sHR 1.62; 95% CI 1.04-2.52), high total cholesterol (sHR 1.89; 95% CI 1.27-2.82), high triglycerides (sHR 1.55; 95% CI 1.02-2.37) and high body mass index (BMI) (sHR 1.66; 95% CI 1.12-2.46). CVD crude IRs were lower in the later ART initiation period and in lower middle- and upper middle-income countries.

    CONCLUSIONS: The development of fatal and nonfatal CVD events in our cohort was associated with older age, and treatable risk factors such as high blood pressure, triglycerides, total cholesterol and BMI. Lower CVD event rates in middle-income countries may indicate under-diagnosis of CVD in Asian-Pacific resource-limited settings.

  19. Jiamsakul A, Kiertiburanakul S, Ng OT, Chaiwarith R, Wong W, Ditangco R, et al.
    HIV Med, 2019 08;20(7):439-449.
    PMID: 30980495 DOI: 10.1111/hiv.12734
    OBJECTIVES: With earlier antiretroviral therapy (ART) initiation, time spent in HIV care is expected to increase. We aimed to investigate loss to follow-up (LTFU) in Asian patients who remained in care 5 years after ART initiation.

    METHODS: Long-term LTFU was defined as LTFU occurring after 5 years on ART. LTFU was defined as (1) patients not seen in the previous 12 months; and (2) patients not seen in the previous 6 months. Factors associated with LTFU were analysed using competing risk regression.

    RESULTS: Under the 12-month definition, the LTFU rate was 2.0 per 100 person-years (PY) [95% confidence interval (CI) 1.8-2.2 among 4889 patients included in the study. LTFU was associated with age > 50 years [sub-hazard ratio (SHR) 1.64; 95% CI 1.17-2.31] compared with 31-40 years, viral load ≥ 1000 copies/mL (SHR 1.86; 95% CI 1.16-2.97) compared with viral load < 1000 copies/mL, and hepatitis C coinfection (SHR 1.48; 95% CI 1.06-2.05). LTFU was less likely to occur in females, in individuals with higher CD4 counts, in those with self-reported adherence ≥ 95%, and in those living in high-income countries. The 6-month LTFU definition produced an incidence rate of 3.2 per 100 PY (95% CI 2.9-3.4 and had similar associations but with greater risks of LTFU for ART initiation in later years (2006-2009: SHR 2.38; 95% CI 1.93-2.94; and 2010-2011: SHR 4.26; 95% CI 3.17-5.73) compared with 2003-2005.

    CONCLUSIONS: The long-term LTFU rate in our cohort was low, with older age being associated with LTFU. The increased risk of LTFU with later years of ART initiation in the 6-month analysis, but not the 12-month analysis, implies that there was a possible move towards longer HIV clinic scheduling in Asia.

  20. Rupasinghe D, Kiertiburanakul S, Kamarulzaman A, Zhang F, Kumarasamy N, Chaiwarith R, et al.
    HIV Med, 2020 07;21(6):397-402.
    PMID: 31852025 DOI: 10.1111/hiv.12836
    OBJECTIVES: Early mortality among those still initiating antiretroviral therapy (ART) with advanced stages of HIV infection in resource-limited settings remains high despite recommendations for universal HIV treatment. We investigated risk factors associated with early mortality in people living with HIV (PLHIV) starting ART at low CD4 levels in the Asia-Pacific.

    METHODS: PLHIV enrolled in the Therapeutics, Research, Education and AIDS Training in Asia (TREAT Asia) HIV Observational Database (TAHOD) who initiated ART with a CD4 count  1 year were censored at 12 months. Competing risk regression was used to analyse risk factors with loss to follow-up as a competing risk.

    RESULTS: A total of 1813 PLHIV were included in the study, of whom 74% were male. With 73 (4%) deaths, the overall first-year mortality rate was 4.27 per 100 person-years (PY). Thirty-eight deaths (52%) were AIDS-related, 10 (14%) were immune reconstituted inflammatory syndrome (IRIS)-related, 13 (18%) were non-AIDS-related and 12 (16%) had an unknown cause. Risk factors included having a body mass index (BMI)  100 cells/μL: SHR 0.12; 95% CI 0.05-0.26) was associated with reduced hazard for mortality compared to CD4 count ≤ 25 cells/μL.

    CONCLUSIONS: Fifty-two per cent of early deaths were AIDS-related. Efforts to initiate ART at CD4 counts > 50 cell/μL are associated with improved short-term survival rates, even in those with late stages of HIV disease.

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