Coordinated In Vitro Release of Granulysin, Perforin and IFN-γ in TB and HIV/TB Co-Infection Associated with Clinical Outcomes before and after Anti-TB Treatment.

Granule-associated killing molecules released from cytotoxic T lymphocytes participate as a crucial step in immunity against tuberculosis (TB), but the role of coordinated production remains controversial. Coordinated release of effector molecules in vitro after stimulating peripheral blood mononuclear cells (PBMCs) of active TB or HIV/TB coinfection patients with PPD, purified protein derivative of tuberculin and avirulent Mtb, H37Ra, an attenuated strain were investigated in association with clinical outcomes. Perforin, granzyme-B, granulysin and IFN-γ were measured using ELISA. Before anti-TB treatment, PBMCs of TB stimulated with PPD or H37Ra released higher perforin, granzyme-B, and granulysin levels than in HIV/TB and released significantly higher IFN-γ (p = 0.045, p = 0.022). Granulysin positively correlated with perforin in TB (p = 0.042, r = 0.385), HIV/TB coinfection (p = 0.003, r = 0.941) after PPD stimulation, and after H37Ra stimulation in TB (p = 0.005, r = 0.549), but negatively correlated with granzyme B in TB (p = 0.042, r = -0.386), HIV/TB coinfection (p = 0.042, r = 0.754) were noted. After anti-TB treatment, increased levels of perforin, granulysin and IFN-γ in TB or HIV/TB upon PPD or H37Ra stimulation, and decreased granzyme-B levels after PPD (p = 0.003) or H37Ra (p = 0.028) stimulation in TB were observed. These results suggest that granulysin may act synergistic with perforin and IFN-γ in TB, indicating its crucial function in host immunity to tuberculosis. Future studies with larger numbers of patients ought to be conducted in the future.

Cytokine Expression in Dengue Fever and Dengue Hemorrhagic Fever Patients with Bleeding and Severe Hepatitis.

Dengue is the most common mosquito-borne flaviviral infection in the world today. Several factors contribute and act synergistically to cause severe infection. One of these is dysregulated host immunological mediators that cause transient pathophysiology during infection. These mediators act on the endothelium to increase vascular permeability, which leads to plasma leakage compromising hemodynamics and coagulopathy. We conducted a prospective study to explore the expression of pro- and anti-inflammatory cytokines and how they relate to clinical dengue manifestations, by assessing their dynamics through acute dengue infection in adults admitted to the Hospital for Tropical Diseases, Bangkok, Thailand. We performed cytokine analysis at three phases of infection for 96 hospitalized adults together with serotyping of confirmed dengue infection during the outbreaks of 2015 and 2016. The serum concentrations of seven cytokines (interleukin [IL]-2, IL-4, IL-6, IL-8, IL-10, tumor necrosis factor alpha, and interferon gamma) were measured in duplicate using a commercial kit (Bio-Plex Human Cytokine Assay). In this study, the cytokine profile was suggestive of a T-helper 2 response. Most patients had secondary infection, and the levels of viremia were higher in patients with plasma leakage than those without plasma leakage. In addition, we observed that bleeding and hepatitis were associated with significantly higher levels of IL-8 during the early phases of infection. Furthermore, IL-6 levels in the early phase of infection were also elevated in bleeding patients with plasma leakage. These results suggest that IL-6 and IL-8 may act in synergy to cause bleeding in patients with plasma leakage.

Ethical issues of informed consent in malaria research proposals submitted to a research ethics committee in Thailand: a retrospective document review.

BACKGROUND: The informed-consent process should be one of meaningful information exchange between researchers and study participants. One of the responsibilities of research ethics committees is to oversee appropriate informed consent. The committee must consider various matters before deciding whether the process is appropriate, including the adequacy and completeness of the written information provided to study participants, and the process of obtaining informed consent. This study aimed to identify, quantitatively and qualitatively, consent-related issues in different types of malaria proposals submitted to the Faculty of Tropical Medicine, Ethics Committee. METHODS: This study reviewed proposal documentation submitted to two panels of the Ethics Committee of the Faculty of Tropical Medicine, Mahidol University, from 2011 to 2015. The documentation included proposals, notifications to researchers of review outcomes and ethical issues of concern to committee members. Each element of the informed-consent process was identified and analyzed by study classification, design, and specimen use, including whether the study involved a vulnerable population. Summative content analysis was used to analyze patterns of common issues raised in reviews. RESULTS: Of the 112 proposals reviewed, 63 required an informed consent process. All researchers proposed communicating with their study participants; however, about two-thirds needed to improve their explanations of study procedures (study activities and specimen/data-collection process) to participants. About 40% of the proposals attracted comments on informed-consent process elements--risk and discomfort, vulnerable status, and compensation. Studies that planned to collect or use new/linked specimens raised more issues around informed consent than studies using linked data/records. Studies that involved vulnerable populations raised more issues than those that did not. The committee usually asked researchers to clarify, elaborate, revise, or paraphrase the consent process elements that were considered to involve inadequate information exchange between researcher and study participant. CONCLUSIONS: This study aimed to describe lessons for malaria researchers about common informed-consent process issues in different types of malaria proposals. The information and analysis of informed-consent elements should assist the preparation of malaria-research proposals.

Molecular and immunological analyses of confirmed Plasmodium vivax relapse episodes.

BACKGROUND: Relapse infections resulting from the activation hypnozoites produced by Plasmodium vivax and Plasmodium ovale represent an important obstacle to the successful control of these species. A single licensed drug, primaquine is available to eliminate these liver dormant forms. To date, investigations of vivax relapse infections have been few in number. RESULTS: Genotyping, based on polymorphic regions of two genes (Pvmsp1F3 and Pvcsp) and four microsatellite markers (MS3.27, MS3.502, MS6 and MS8), of 12 paired admission and relapse samples from P. vivax-infected patients were treated with primaquine, revealed that in eight of the parasite populations in the admission and relapse samples were homologous, and heterologous in the remaining four patients. The patients' CYP2D6 genotypes did not suggest that any were poor metabolisers of primaquine. Parasitaemia tended to be higher in the heterologous as compared to the homologous relapse episodes as was the IgG3 response. For the twelve pro- and anti-inflammatory cytokine levels measured for all samples, only those of IL-6 and IL-10 tended to be higher in patients with heterologous as compared to homologous relapses in both admission and relapse episodes. CONCLUSIONS: The data from this limited number of patients with confirmed relapse episodes mirror previous observations of a significant proportion of heterologous parasites in relapses of P. vivax infections in Thailand. Failure of the primaquine treatment that the patients received is unlikely to be due to poor drug metabolism, and could indicate the presence of P. vivax populations in Thailand with poor susceptibility to 8-aminoquinolines.

Acquisition of naturally acquired antibody response to Plasmodium falciparum erythrocyte membrane protein 1-DBLα and differential regulation of IgG subclasses in severe and uncomplicated malaria

Objectives:To explore whether individuals infected with Plasmodium falciparum (P.falciparum) develop antibodies directed against PfEMP1-DBLα,and to assess their IgG subclass distribution in severe and uncomplicated malaria.Methods:The anti-PfDBLα IgG and their IgG subclass distributions in plasma of severe (SM) and uncomplicated malaria (UCM) were assessed by enzyme-linked immunoabsorbent assay.The antibody profiles to P.falciparum blood stage antigens were evaluated.CD36 binding ability was determined by static receptor-binding assays.Rosette formation was performed by staining with acridine orange.Results:Significantly higher number of UCM (86.48％) than SM (57.78％) plasma contained total acquisition of specific IgG to P.falciparum antigens (P =0.000).Similar manners were seen in response to P.falciparum DBLα with significant difference (UCM,59.46％ vs SM,40.00％;P =0.014).Anti-PfDBLα-IgG1 and-IgG3 were the predominant subclasses.Similar percentage of UCM (31.82％) and SM (33.33％) plasma contained only IgG1,while 13.64％ of UCM and 27.78％ of SM plasma contained only IgG3.AntiPfTDBLα-IgG1 coexpressed with more than one subclass was noted (UCM,27.27％;SM,16.67％).Obviously,IgG1 coexpressed with IgG3 (9.09％) was observed in only UCM plasma.IgG1 was coexpressed with IgG2 in UCM (9.09％) and SM (11.11％) plasma,while IgG1 was coexpressed with IgG4 only in UCM plasma (4.55％).IgG subclasses to P.falciparum antigens were distributed in a similar manner.Only the levels of IgG1,but not IgG3 were significantly higher in UCM than in SM.Conclusions:These data suggest that individuals infected with P.falciparum can develop the anti-PfEMP1 antibodies with the major contribution of specific IgG subclasses.The balance and the levels of anti-PfDBLα IgG subclasses play a crucial role in antibody mediated protection against severe malaria.

Development of Rapid Enzyme-Linked Immunosorbent Assays for Detection of Antibodies to Burkholderia pseudomallei.

Burkholderia pseudomallei, the causative agent of melioidosis, is an environmental bacillus found in northeast Thailand. The mortality rate of melioidosis is ∼40%. An indirect hemagglutination assay (IHA) is used as a reference serodiagnostic test; however, it has low specificity in areas where the background seropositivity of healthy people is high. To improve assay specificity and reduce the time for diagnosis, four rapid enzyme-linked immunosorbent assays (ELISAs) were developed using two purified polysaccharide antigens (O-polysaccharide [OPS] and 6-deoxyheptan capsular polysaccharide [CPS]) and two crude antigens (whole-cell [WC] antigen and culture filtrate [CF] antigen) of B. pseudomallei The ELISAs were evaluated using serum samples from 141 culture-confirmed melioidosis patients from Thailand along with 188 healthy donors from Thailand and 90 healthy donors from the United States as controls. The areas under receiver operator characteristic curves (AUROCC) using Thai controls were high for the OPS-ELISA (0.91), CF-ELISA (0.91), and WC-ELISA (0.90), while those of CPS-ELISA (0.84) and IHA (0.72) were lower. AUROCC values using U.S. controls were comparable to those of the Thai controls for all ELISAs except IHA (0.93). Using a cutoff optical density (OD) of 0.87, the OPS-ELISA had a sensitivity of 71.6% and a specificity of 95.7% for Thai controls; for U.S. controls, specificity was 96.7%. An additional 120 serum samples from tuberculosis, scrub typhus, or leptospirosis patients were evaluated in all ELISAs and resulted in comparable or higher specificities than using Thai healthy donors. Our findings suggest that antigen-specific ELISAs, particularly the OPS-ELISA, may be useful for serodiagnosis of melioidosis in areas where it is endemic and nonendemic.

Genetic diversity among Plasmodium vivax isolates along the Thai-Myanmar border of Thailand.

BACKGROUND: Knowledge of the population genetics and transmission dynamics of Plasmodium vivax is crucial in predicting the emergence of drug resistance, relapse pattern and novel parasite phenotypes, all of which are relevant to the control of vivax infections. The aim of this study was to analyse changes in the genetic diversity of P. vivax genes from field isolates collected at different times along the Thai-Myanmar border. METHODS: Two hundred and fifty-four P. vivax isolates collected during two periods 10 years apart along the Thai-Myanmar border were analysed. The parasites were genotyped by nested-PCR and PCR-RFLP targeting selected polymorphic loci of Pvmsp1, Pvmsp3α and Pvcsp genes. RESULTS: The total number of distinguishable allelic variants observed for Pvcsp, Pvmsp1, and Pvmsp3α was 17, 7 and 3, respectively. High genetic diversity was observed for Pvcsp (H E = 0.846) and Pvmsp1 (H E = 0.709). Of the 254 isolates, 4.3 and 14.6 % harboured mixed Pvmsp1 and Pvcsp genotypes with a mean multiplicity of infection (MOI) of 1.06 and 1.15, respectively. The overall frequency of multiple genotypes was 16.9 %. When the frequencies of allelic variants of each gene during the two distinct periods were analysed, significant differences were noted for Pvmsp1 (P = 0.018) and the Pvcsp (P = 0.033) allelic variants. CONCLUSION: Despite the low malaria transmission levels in Thailand, P. vivax population exhibit a relatively high degree of genetic diversity along the Thai-Myanmar border of Thailand, in particular for Pvmsp1 and Pvcsp, with indication of geographic and temporal variation in frequencies for some variants. These results are of relevance to monitoring the emergence of drug resistance and to the elaboration of measures to control vivax malaria.

Ethical considerations in malaria research proposal review: empirical evidence from 114 proposals submitted to an Ethics Committee in Thailand.

BACKGROUND: Malaria research is typically conducted in developing countries in areas of endemic disease. This raises specific ethical issues, including those related to local cultural concepts of health and disease, the educational background of study subjects, and principles of justice at the community and country level. Research Ethics Committees (RECs) are responsible for regulating the ethical conduct of research, but questions have been raised whether RECs facilitate or impede research, and about the quality of REC review itself. This study examines the review process for malaria research proposals submitted to the Ethics Committee of the Faculty of Tropical Medicine at Mahidol University, Thailand. METHODS: Proposals for all studies submitted for review from January 2010 to December 2014 were included. Individual REC members' reviewing forms were evaluated. Ethical issues (e.g., scientific merit, risk-benefit, sample size, or informed-consent) raised in the forms were counted and analysed according to characteristics, including study classification/design, use of specimens, study site, and study population. RESULTS: All 114 proposals submitted during the study period were analysed, comprising biomedical studies (17 %), drug trials (13 %), laboratory studies (24 %) and epidemiological studies (46 %). They included multi-site (13 %) and international studies (4 %), and those involving minority populations (28 %), children (17 %) and pregnant women (7 %). Drug trials had the highest proportion of questions raised for most ethical issues, while issues concerning privacy and confidentiality tended to be highest for laboratory and epidemiology studies. Clarifications on ethical issues were requested by the ethics committee more for proposals involving new specimen collection. Studies involving stored data and specimens tended to attract more issues around privacy and confidentiality. Proposals involving minority populations were more likely to raise issues than those that did not. Those involving vulnerable populations were more likely to attract concerns related to study rationale and design. CONCLUSIONS: This study stratified ethical issues raised in a broad spectrum of research proposals. The Faculty of Tropical Medicine at Mahidol University is a significant contributor to global malaria research output. The findings shed light on the ethical review process that may be useful for stakeholders, including researchers, RECs and sponsors, conducting malaria research in other endemic settings.

Genome-Wide Association Study of HIV-Related Lipoatrophy in Thai Patients: Association of a DLGAP1 Polymorphism with Fat Loss.

HIV-related lipoatrophy (LA) is a major adverse drug effect among HIV patients receiving the antiretroviral drug stavudine (d4T) in Southeast Asia. Although the development of LA could be observed in almost all HIV patients administered d4T for extended periods, there is considerable variation in the duration required to develop LA within this patient population. This study aimed to identify host genetic polymorphisms affecting the rate of LA onset in Thai HIV patients. We performed a genome-wide association study of HIV-related LA among patients at the Bamrasnaradura Infectious Diseases Institute, Thailand. Genotypes of HIV patients who developed LA within 2 years of treatment were compared with those of patients who did not develop LA after at least 4 years of treatment (non-LA patients). Genotypes of 49 LA and 92 non-LA patients at 578,525 single nucleotide polymorphisms (SNPs) were determined by Illumina bead arrays. The TaqMan real-time PCR method was used in a replication study. Five SNPs in the bead arrays, which showed the lowest p values in a comparison of LA with non-LA patients, were further tested in independent and sex-matched subpopulations consisting of 95 LA and 95 non-LA patients. This replication study revealed a significant association of LA with an SNP (rs12964965) in the gene encoding the Disks Large Homolog-Associated Protein 1 (DLGAP1), even after the correction for five multiple comparisons. These results strongly suggested involvement of the DLGAP1 gene product in the development of LA in Thai HIV patients.

Is your ethics committee efficient? Using "IRB Metrics" as a self-assessment tool for continuous improvement at the Faculty of Tropical Medicine, Mahidol University, Thailand.

Tensions between researchers and ethics committees have been reported in several institutions. Some reports suggest researchers lack confidence in the quality of institutional review board (IRB) reviews, and that emphasis on strict procedural compliance and ethical issues raised by the IRB might unintentionally lead to delays in correspondence between researchers and ethics committees, and/or even encourage prevarication/equivocation, if researchers perceive committee concerns and criticisms unjust. This study systematically analyzed the efficiency of different IRB functions, and the relationship between efficiency and perceived quality of the decision-making process. The major purposes of this study were thus (1) to use the IRB Metrics developed by the Faculty of Tropical Medicine, Mahidol University, Thailand (FTM-EC) to assess the operational efficiency and perceived effectiveness of its ethics committees, and (2) to determine ethical issues that may cause the duration of approval process to be above the target limit of 60 days. Based on a literature review of definitions and methods used and proposed for use, in assessing aspects of IRB quality, an "IRB Metrics" was developed to assess IRB processes using a structure-process-outcome measurement model. To observe trends in the indicators evaluated, data related to all protocols submitted to the two panels of the FTM-EC (clinical and non-clinical), between January 2010-September 2013, were extracted and analyzed. Quantitative information based on IRB Metrics structure-process-outcome illuminates different areas for internal-process improvement. Ethical issues raised with researchers by the IRB, which were associated with the duration of the approval process in protocol review, could be considered root causes of tensions between the parties. The assessment of IRB structure-process-outcome thus provides a valuable opportunity to strengthen relationships and reduce conflicts between IRBs and researchers, with positive outcomes for all parties involved in the conduct of human-subject research.

Low monocyte to neutrophil ratio in peripheral blood associated with disease complication in primary Plasmodium falciparum infection.

Immunity to malaria can be acquired but only after repeat exposures to polymorphic Plasmodium. However, the development of clinical outcomes during P. falciparum infection is not clearly understood. This study elucidated whether monocytes, neutrophils and pro/anti-inflammatory cytokines were associated with clinical outcomes in single infection and prior repeated malaria infections. Two hundred and seventy-nine patients with complicated and uncomplicated malaria were investigated. Peripheral blood IFN-gamma, TNF-alpha and IL-10 levels were measured by ELISA, and monocytes and neutrophils by an automated cell counter. On admission, in patients with uncomplicated malaria prior repeated infections, absolute neutrophil counts were positively and monocyte to neutrophil ratio negatively correlated significantly with parasitemia (r = 0.358, p = 0.000; r = -0.356, p = 0.000, respectively), while those with single infection absolute monocyte counts and monocyte to neutrophil ratio were significantly correlated negatively with IFN-gamma (r = -0.381, p = 0.001; r = -0.393, p = 0.000, respectively), and positively with TNF-alpha levels (r = 0.310, p = 0.007; r = 0.227, p = 0.017, respectively). In sharp contrast, in complicated malaria with single infection extremely high IFN-gamma and IL-10 levels but significantly low percent monocyte counts and monocyte to neutrophil ratio were seen. After 7 days of treatment, absolute monocyte counts and monocyte to neutrophil ratio were significantly increased, while absolute neutrophil counts significantly decreased (p = 0.000, 0.000, and 0.001, respectively), similarly after 28 days of treatment (p = 0.008, 0.000 and 0.000, respectively). These results suggest different functions of monocytes, neutrophils and pro/anti-inflammatory cytokines in complicated and uncomplicated malaria with single P. falciparum infection or prior repeated infections in the context of disease severity. Low monocyte to neutrophil ratio may be regarded as a risk factor in developing complication in primary malaria infection.

Ethical issues in research involving minority populations: the process and outcomes of protocol review by the Ethics Committee of the Faculty of Tropical Medicine, Mahidol University, Thailand.

BACKGROUND: Recruiting minorities into research studies requires special attention, particularly when studies involve "extra-vulnerable" participants with multiple vulnerabilities, e.g., pregnant women, the fetuses/neonates of ethnic minorities, children in refugee camps, or cross-border migrants. This study retrospectively analyzed submissions to the Ethics Committee of the Faculty of Tropical Medicine (FTM-EC) in Thailand. Issues related to the process and outcomes of proposal review, and the main issues for which clarification/revision were requested on studies, are discussed extensively. METHODS: The study data were extracted from proposals and amendments submitted to the FTM-EC during the period October 2009 - September 2012, and then analyzed qualitatively and quantitatively. The main issues for clarification/revision were analyzed by thematic content analysis. RESULTS: 373 proposals were submitted; 44 studies involved minority groups with 21 extra-vulnerable minorities. All clinical and 2/3 of non-clinical studies submitted for initial review underwent full-board review. For combined clinical and non-clinical study submissions, 92.1% were referred back to the investigators and approved after clarification/revision, while 2.7% were deferred due to major/critical changes, and 2.1% not approved due to substantial violations of ethical principles. The main issues needing clarification/revision differed between all studies and those involving minorities: participant information sheet (62.2% vs. 86.4%), informed consent/assent form (51.2% vs. 86.4%), and research methodology (80.7% vs. 84.1%), respectively. The main ethical issues arising during the meetings, regarding studies involving minorities, included ensuring no exploitation, coercion, or pressure on the minority to participate; methodology not affecting their legal status; considering ethnicity and cultural structure; and providing appropriate compensation. CONCLUSION: Delays in the approval or non-approval of studies involving minorities were mainly due to major or minor deviations from acceptable ethical standards and/or unclear research methodology. The FTM-EC has employed several mechanisms in its operations, including transparency in the review process, building good relationships via open communication with investigators, requesting investigators to consider closely the necessity to enroll minority groups and the risk-benefits for individuals and their communities, and the inclusion of minority-community engagement when developing the proposal. Other effective activities include annual study-site inspections, and offering refresher courses to raise awareness of minority and vulnerability issues among researchers.

Potential function of granulysin, other related effector molecules and lymphocyte subsets in patients with TB and HIV/TB coinfection.

BACKGROUND: Host effector mechanism against Mycobacterium tuberculosis (Mtb) infection is dependent on innate immune response by macrophages and neutrophils and the alterations in balanced adaptive immunity. Coordinated release of cytolytic effector molecules from NK cells and effector T cells and the subsequent granule-associated killing of infected cells have been documented; however, their role in clinical tuberculosis (TB) is still controversy. OBJECTIVE: To investigate whether circulating granulysin and other effector molecules are associated with the number of NK cells, iNKT cells, Vγ9(+)Vδ2(+) T cells, CD4(+) T cells and CD8(+) T cells, and such association influences the clinical outcome of the disease in patients with pulmonary TB and HIV/TB coinfection. METHODS: Circulating granulysin, perforin, granzyme-B and IFN-γ levels were determined by ELISA. The isoforms of granulysin were analyzed by Western blot analysis. The effector cells were analyzed by flow cytometry. RESULTS: Circulating granulysin and perforin levels in TB patients were lower than healthy controls, whereas the granulysin levels in HIV/TB coinfection were much higher than in any other groups, TB and HIV with or without receiving HAART, which corresponded to the number of CD8(+) T cells which kept high, but not with NK cells and other possible cellular sources of granulysin. In addition, the 17kDa, 15kDa and 9kDa isoforms of granulysin were recognized in plasma of HIV/TB coinfection. Increased granulysin and decreased IFN-γ levels in HIV/TB coinfection and TB after completion of anti-TB therapy were observed. CONCLUSION: The results suggested that the alteration of circulating granulysin has potential function in host immune response against TB and HIV/TB coinfection. This is the first demonstration so far of granulysin in HIV/TB coinfection.

Drug resistance and IS6110-RFLP patterns of Mycobacterium tuberculosis in patients with recurrent tuberculosis in northern Thailand.

The emergence of drug resistant Mycobacterium tuberculosis has become a global threat to tuberculosis (TB) prevention and control efforts. This study aimed to determine the drug resistance profiles and DNA fingerprints of M. tuberculosis strains isolated from patients with relapsed or retreatment pulmonary TB in Chiang Rai province in northern Thailand. Significant differences in multidrug resistance (MDR) (P = 0.025) and resistance to isoniazid (P = 0.025) and rifampin (P = 0.046) between first and second registrations of patients with retreatment TB were found. However, there were no significant differences in resistance to any drugs in patients with relapsed TB. The rate of MDR-TB strains was 12.2% among new patients at first registration, 22.5% among patients with recurrence who had previously undergone treatment at second registration and 12.5% at third registration. Two retreatment patients whose initial treatment had failed had developed MDR-TB with resistance to all TB drugs tested, including rifampin, isoniazid, streptomycin and ethambutol. IS6110-RFLP analysis revealed that 66.7% (10/15 isolates) of MDR-TB belonged to the Beijing family. In most cases, IS6110-RFLP patterns of isolates from the same patients were identical in relapse and retreatment groups. However, some pairs of isolates from retreatment patients after treatment failure had non-identical IS6110-RFLP patterns. These results suggest that, after failure and default treatment, patients with retreatment tuberculosis have a significantly greater risk of MDR-TB, isoniazid and rifampin resistance than do other patients.

Influence of ABCB-1 C3435T polymorphisms on plasma nevirapine and efavirenz levels and their effects on virologic and immunological outcomes in HIV/TB co-infected Thai adults under anti-retroviral therapy.

ATP-binding cassette, sub-family B (encoded by ABCB-1 or MDR-1) has an important role in cellular export of antiretroviral agents. A previous study showed that ABCB-1 C3435T polymorphism affects plasma efavirenz and nelfinavir concentrations and rate of CD4+ T cell recovery after starting antiretroviral treatment (ART). The present study examined the influence of ABCB-1 polymorphisms on plasma nevirapine and efavirenz levels when co-administered with rifampicin in 124 HIV/TB patients who received nevirapine- (400 mg/day) (n = 59) and efavirenz- (600 mg/day) (n = 65) based ART. ABCB-1 C3435T polymorphisms were genotyped using real-time PCR. CD4 T cell counts and HIV-1 viral RNA were evaluated in response to ART. The frequencies of CC, CT and TT genotypes of ABCB-1 C3435T polymorphism were 34% (n = 42), 55% (n = 68) and 12% (n = 14), respectively. Contrary to the previous report, no association was found among these genotypes and plasma drug concentrations at weeks 6 and 12 of ART and after rifampicin discontinuation. We also observed no differences in CD4+ T cell recovery rate among different ABCB-1 C3435T genotypes. In nevirapine group, however, all the patients with CT genotype achieved HIV-1 RNA levels of < 50 copies/ml, while 67% of those with TT and 95% with CC genotypes achieved < 50 copies/ml (p = 0.040). These data suggested that ABCB-1 C3435T polymorphisms do not affect plasma nevirapine and efavirenz concentrations in HIV/TB co-infected Thai patients or their immunological outcome, but had an effect on virologic outcome in the nevirapine-treated group.

Decreased plasma granulysin and increased interferon-gamma concentrations in patients with newly diagnosed and relapsed tuberculosis.

Granulysin and interferon-gamma (IFN-γ) have broad antimicrobial activity which controls Mycobacterium tuberculosis (M. tuberculosis) infection. Circulating granulysin and IFN-γ concentrations were measured and correlated with clinical disease in Thai patients with newly diagnosed, relapsed and chronic tuberculosis (TB). Compared to controls, patients with newly diagnosed, relapsed and chronic TB had lower circulating granulysin concentrations, these differences being significant only in newly diagnosed and relapsed TB (P < 0.001 and 0.004, respectively). Granulysin concentrations in patients with newly diagnosed and relapsed TB were significantly lower than in those with chronic TB (P= 0.003 and P= 0.022, respectively). In contrast, significantly higher circulating IFN-γ concentrations were found in patients with newly diagnosed and relapsed TB compared to controls (P < 0.001). The IFN-γ concentrations in newly diagnosed and relapsed patients were not significantly different from those of patients with chronic TB. However, in vitro stimulation of peripheral blood mononuclear cells (PBMCs) from patients with newly diagnosed, relapsed and chronic TB with purified protein derivative (PPD) or heat killed M. tuberculosis (H37Ra) enhanced production of granulysin by PBMCs. In vitro, stimulation of PBMCs of newly diagnosed TB patients with PPD produced greater amounts of IFN-γ than did controls, while those stimulated with H37Ra did not. The results demonstrate that patients with active pulmonary TB have low circulating granulysin but high IFN-γ concentrations, suggesting possible roles in host defense against M. tuberculosis for these agents.

Association between circulating full-length osteopontin and IFN-gamma with disease status of tuberculosis and response to successful treatment.

The T helper type 1 (Th1) immune response plays an important role in protective immunity, pathophysiology and development of tuberculosis (TB). To investigate whether osteopontin (OPN) and other Th1 response-related molecules are associated withTB disease status, including co-infection with HIV, and response to anti-TB treatment, circulating levels of full-length OPN (F-OPN), thrombin-cleaved N-terminal fragment of OPN (N-half OPN), IFN-gamma, IP-10, IL-18, IL-12/ IL-23 (p40), IL-10, IL-15 and C-reactive protein (CRP) were measured before and after anti-TB treatment. Patients with newly active pulmonary TB had significantly higher plasma levels of F-OPN, IFN-gamma and CRP than healthy controls (HC). F-OPN, N-half OPN, IFN-gamma, IP-10, IL-18 and IL-10 levels were higher in patients with extensive TB/HIV co-infection than in patients with a single disease of TB or HIV. Plasma levels of F-OPN correlated well with those of IP-10, IL-18 and N-half OPN among patients with active TB. The F-OPN, IFN-gamma, IP-10 and CRP levels decreased significantly after effective anti-TB treatment. These data suggest that circulating OPN and Th1 response-related molecules, including IFN-gamma, may be regulated in response to expansion of active TB and could serve as markers of disease activity before and during treatment.

Detection of Salmonella invA gene in shrimp enrichment culture by polymerase chain reaction.

Contamination of seafood with salmonellae is a major public health concern. Detection of Salmonella by standard culture methods is time consuming. In this study, an enrichment culture step prior to polymerase chain reaction (PCR) was applied to detect 284 bp fragment of Salmonella invA in comparison with the conventional culture method in 100 shrimp samples collected from four different shrimp farms and fresh food markets around Bangkok. Samples were pre-enriched in non-selective lactose broth (LB) and selective tetrathionate broth (TTB). PCR detection limit was 10 pg and 10(4) cfu/ml of viable salmonellae with 100% specificity. PCR assay detected 19 different Salmonella serovars belonging to 8 serogroups (B, C1, C2-C3, D1, E1, E4 and K) commonly found in clinical and environmental samples in Thailand. The detection rate of PCR following TTB enrichment (24%) was higher than conventional culture method (19%). PCR following TTB, but not in LB enrichment allowed salmonella detection with 84% sensitivity, 90% specificity and 89% accuracy. Shrimp samples collected from fresh food markets had higher levels of contaminated salmonellae than those from shrimp farms. The results indicated that incorporation of an enrichment step prior to PCR has the potential to be applied for detection of naturally contaminated salmonellae in food, environment and clinical samples.

Haplotypes of IL12B promoter polymorphisms condition susceptibility to severe malaria and functional changes in cytokine levels in Thai adults.

Polymorphic variability in immune response genes, such as IL12B, encoding the IL-12p40 subunit is associated with susceptibility to severe malaria in African populations. Since the role of genetic variation in conditioning severe malaria in Thai adults is largely unexplored, the functional association between IL12B polymorphisms [i.e. IL12Bpro (rs17860508) and IL12B 3' UTR T/G (rs3212227)], severe malaria and cytokine production was examined in patients with Plasmodium falciparum infections (n = 355) recruited from malaria endemic areas along the Thai-Myanmar border in northwest Thailand. Circulating IL-12p40 (p = 0.049) and IFN-gamma (p = 0.051) were elevated in patients with severe malaria, while only IL-12p40 was significantly higher in severe malaria patients with hyperparasitaemia (p = 0.046). Carriage of the IL12Bpro1.1 genotype was associated with enhanced severity of malaria (OR, 2.34; 95% CI, 0.94-5.81; p = 0.066) and hyperparasitaemia (OR, 3.42; 95% CI, 1.17-9.87; p = 0.025) relative to the IL12Bpro2.2 genotype (wild type). Individuals with the IL12Bpro1.1 genotype also had the lowest IL-12p40 (p = 0.002) and the highest IFN-gamma (p = 0.004) levels. Construction of haplotypes revealed that carriage of the IL12Bpro-2/3' UTR-T haplotype was associated with protection against severe malaria (OR, 0.51; 95% CI, 0.29-0.90; p = 0.020) and reduced circulating IFN-gamma (p = 0.06). Thus, genotypic and haplotypic variation at IL12Bpro and IL12B 3' UTR in this population influences susceptibility to severe malaria and functional changes in circulating IL-12p40 and IFN-gamma levels. Results presented here suggest that protection against severe malaria in Thai adults is associated with genotypic variants that condition enhanced IL-12p40 and reduced IFN-gamma levels.

Effects of CYP2B6 G516T polymorphisms on plasma efavirenz and nevirapine levels when co-administered with rifampicin in HIV/TB co-infected Thai adults.

BACKGROUND: Cytochrome P450 2B6 (CYP2B6) metabolizes efavirenz and nevirapine, the major core antiretroviral drugs for HIV in Thailand. Rifampicin, a critical component of tuberculosis (TB) therapy is a potent inducer of CYP enzyme activity. Polymorphisms of CYP2B6 and CYP3A4 are associated with altered activity of hepatic enzyme in the liver and pharmacokinetics resulting in treatment efficacy. This study aimed to investigate whether CYP2B6 or CYP3A4 polymorphisms had effects on plasma efavirenz and nevirapine concentrations when co-administered with rifampicin in HIV/TB co-infected Thai adults. RESULTS: We studied 124 rifampicin recipients with concurrent HIV-1/TB coinfection, receiving efavirenz (600 mg/day) (n = 65) or nevirapine (400 mg/day) (n = 59) based antiretroviral therapy (ART). The frequencies of GG, GT and TT genotypes of CYP2B6-G516T were 38.46%, 47.69% and 13.85% in efavirenz group and 44.07%, 52.54% and 3.39% in nevirapine group, respectively. The mean 12-hour post-dose plasma efavirenz concentration in patients with TT genotype at weeks 6 and 12 of ART and 1 month after rifampicin discontinuation (10.97 +/- 2.32, 13.62 +/- 4.21 and 8.48 +/- 1.30 mg/L, respectively) were significantly higher than those with GT (3.43 +/- 0.29, 3.35 +/- 0.27 and 3.21 +/- 0.22 mg/L, respectively) (p < 0.0001) or GG genotypes (2.88 +/- 0.33, 2.45 +/- 0.26 and 2.08 +/- 0.16 mg/L, respectively) (p < 0.0001). Likewise, the mean 12-hour post-dose plasma nevirapine concentration in patients carrying TT genotype at weeks 6 and 12 of ART and 1 month after rifampicin discontinuation (14.09 +/- 9.49, 7.94 +/- 2.76 and 9.44 +/- 0.17 mg/L, respectively) tended to be higher than those carrying GT (5.65 +/- 0.54, 5.58 +/- 0.48 and 7.03 +/- 0.64 mg/L, respectively) or GG genotypes (5.42 +/- 0.48, 5.34 +/- 0.50 and 6.43 +/- 0.64 mg/L, respectively) (p = 0.003, p = 0.409 and p = 0.448, respectively). Compared with the effects of CYP2B6-516TT genotype, we could observe only small effects of rifampicin on plasma efavirenz and nevirapine levels. After 12 weeks of both drug regimens, there was a trend towards higher percentage of patients with CYP2B6-TT genotype who achieved HIV-1 RNA levels <50 copies/mL compared to those with GT or GG genotypes. This is the first report to demonstrate the effects of CYP2B6 G516T polymorphisms on plasma efavirenz and nevirapine concentrations when co-administered with rifampicin in HIV/TB co-infected Thai adults. CONCLUSIONS: CYP2B6-TT genotype had impact on plasma efavirenz and nevirapine concentrations, while rifampicin co-administration had only small effects.