Nationwide Seroprevalence of Scrub Typhus, Typhus, and Spotted Fever in Young Thai Men

Scrub typhus group (STG), typhus group (TG), and spotted fever group (SFG) rickettsiae are pathogens distributed worldwide and are important causes of febrile illnesses in southeast Asia. The levels of rickettsioses burden and distribution in Thai communities are still unclear. Nonspecific symptoms, limit diagnostic capacity and underdiagnoses contribute to the absence of clarity. The objective of this study was to determine the nationwide IgG seroprevalence of STG, TG, and SFG by ELISA in repository sera from the Royal Thai Army recruits collected during 2007-2008 and 2012 to estimate rickettsiae exposure in young Thai men to better understand rickettsiae exposure distribution in the Thai population. IgG seroprevalence of STG, Orientia tsutsugamushi; TG, Rickettsia typhi; and SFG, R. rickettsii was 12.4%, 6.8%, and 3.3% in 2007-2008 and 31.8%, 4.2%, and 4.5% in 2012, respectively. The STG had the highest seroprevalence of Rickettsia assessed, with the highest regional seroprevalence found in southern Thailand. The STG seroprevalence changed significantly from 2007 to 2008 (P value < 0.05), which corresponds with morbidity rate of scrub typhus from the last decade in Thailand. We were unable to determine the causality for seroprevalence changes between the two periods due to the limitation in sample numbers for intervening years and limited information available for archived specimens. Additional research would be required to determine agency. However, study results do confirm Rickettsia endemicity in Thailand lends weight to reports of increasing STG seroprevalence. It also corroborates the need to raise rickettsial disease awareness and educate the general public in prevention measures.

Human papillomavirus seroprevalence in young Thai men

Human papillomavirus (HPV) is one of the most common sexually transmitted infections in men and women. Most HPV studies have focused on vaccination toward women to prevent consequences of developing cervical cancer. However, persistent infections can cause penile, anal, and oropharyngeal cancers in men. Therefore, recent public health recommendations toward vaccination in men have been raised. There is limited HPV prevalence data among men in many countries, including Thailand. We conducted HPV sera IgG ELISA testing on a repository sera of Thai men (average age 21 years old) entering the Royal Thai Army as recruits in 2013 (n = 1000). HPV IgG antibodies against virus-like particles of HPV- type 6, 11, 16e, and 18 were evaluated using a commercial ELISA kit. Overall, the anti-HPV IgG was 47% (95% CI: 44%-50%). HPV seroprevalence was significantly associated with residence regions with the highest prevalence in South (64%), but not associated with educational level, marital status, or type of residence. This data suggested that almost half of the Thai men in this cohort were exposed to HPV by the age of 21. Thus, HPV vaccination provided to male adolescents should be considered for disease prevention and minimizing transmission to sexual partners.

Prevalence of HIV infection and related risk factors among young Thai men between 2010 and 2011

Introduction

Understanding the current epidemiology of human immunodeficiency virus (HIV) infection in Thailand will facilitate more effective national HIV prevention programs. This study aimed to determine the prevalence and risk factors for HIV infection among young Thai men.

Methods

A total survey was conducted of Royal Thai Army new conscripts, participating in the national HIV surveillance in November 2010 and May 2011. Behavioral risk factors for HIV infection were determined using a standardized survey questionnaire in the total study population and men who have sex with men (MSM) subgroup.

Results

A total of 301 (0.5%) HIV infected young Thai men were identified from the total study population (63,667). Independent risk factors associated with HIV infection among the total study population included being single (adjusted Odds Ratio [AOR] 1.6, 95% Confidence Interval [CI] 1.1–2.2), having no formal education (AOR 6.5, 95% CI 2.3–18.4) or a bachelor’s degree (AOR 1. 8, 95% CI 1.0–3.0), engaging in bisexual (AOR 3.7, 95% CI 2.4–5. 6) or exclusively homosexual activity (AOR 14.4, 95% CI 10.4–19.8), having a history of Sexually Transmitted Infection (STI) (AOR 2.3, 95% CI 1.6–3.3) and having sex in exchange for gifts/money (AOR 2.0, 95% CI 1. 5–2.8). A total of 4,594 (7.9%) MSM were identified, of which 121 (2.6%) were HIV infected. The prevalence of HIV infection among MSM in urban (2.8%) and rural (2.4%) areas were relatively comparable (p-value = 0.44). Of the identified MSM, 82.5% reported having sexual desire with females only. Risk factors associated with HIV infection in the MSM subgroup included living in the western region (AOR 3.5, 95% CI 1.2–10.4), having a bachelor’s degree (AOR 2.7, 95% CI 1.2–5.7), having a history of exclusive receptive (AOR 3.6, 95% CI 1.6–7.7) or versatile anal sex (AOR 4.7, 95% CI 3.0–7.5) and history of having sex in exchange for gifts/money (AOR 2.3, 95% CI 1.5–3.5).

Conclusion

The prevalence of HIV infection among young Thai men has continued to be below 0.5% in 2010 and 2011. High risk sexual activity, including MSM, played a major role in the HIV epidemic among this population. Effective HIV prevention programs should cover MSM who have heterosexual desire as well as having sex in exchange for gifts/money and be implemented in both urban and rural areas.

Common antibody dependent cell mediated cytotoxicity (ADCC) antibody epitopes of HIV-1 CRF01_AE Env and Gag in early HIV-1 infected individuals

BACKGROUND

There have been a few studies aimed at identifying epitopes of ADCC-inducing antibodies when compared to those of neutralizing antibodies and cytotoxic T lymphocytes against a variety of HIV-1 clades.

OBJECTIVE

To map the common ADCC epitopes of HIV-1 CRF01_AE.

METHODS

We screened 65 sera of confirmed early HIV-1 CRF01_AE infected individuals for ADCC antibody against gp120 utilizing an EGFP-CEM-NKr flow cytometric assay. Sera with high ADCC antibody were then examined against ADCC epitopes using the complete HIV-1 CRF01_AE gp160- and subtype A Gag-overlapping peptide sets which were divided into 7 pools:E1-E7 and 5 pools:G1-G5, respectively. Each positive peptide pool was further investigated for fine ADCC epitope mapping using matrix formats.

RESULTS

Twenty, 25 and 20 sera demonstrated the high-, medium- and low-ADCC antibody activities against gp120, respectively. Interestingly, 11 Env- and 6 Gag-peptides of pools E3, E4, E7 and pools G1, G2, G4 with high ADCC responses were also responded by at least 20%, 12% and 5%, 10% of medium- and low-ADCC antibody sera, respectively. These eleven common Env ADCC epitopes were localized at C2-V3-C3-V4 regions of gp120 and cytoplasmic tail of gp41 while six common Gag ADCC epitopes were localized at p17-p24-p2 regions.

CONCLUSIONS

Although the degree of ADCC antibody responses to the gp120 protein varied from high to low, there were certain consensus Env and Gag peptides that could induce the ADCC antibody responses of 21.54-58.46% and 23.08-41.54%, respectively of the early infected individuals. This epitope information should be useful as the new antibody-based vaccine immunogens.

Ellagic acid inhibits HIV-1 infection in vitro: Potential role as a novel microbicide

OBJECTIVE

To investigate the in vitro effects of ellagic acid on HIV-1 replication.

METHODS

Anti-HIV-1 activity of ellagic acid was determined in vitro using X4-tropic HIV-1_NPO3 and R5-tropic pBaL Env-recombinant virus. Anti-HIV-1_NPO3 activity of ellagic acid was investigated at a multiplicity of infection (MOI) of 0.01. Anti-HIV-1 integrase and protease activities of ellagic acid were tested using in vitro integration and proteolytic cleavage assays.

RESULTS

Ellagic acid, added either before or after HIV-1_NPO3 exposure, suppressed replication of the virus in C8166 cells up to 34%. Ellagic acid showed an anti-integrase IC₅₀ of 8.7 μM. No cytotoxicity of ellagic acid at concentrations ranging from 12.5 to 100 μM was observed.

CONCLUSION

We conclude that ellagic acid can inhibit HIV-1 infection without cytotoxicity. Thus, it may be a new effective agent that has potential to be developed as a novel microbicide against HIV-1.

Nationwide Seroprevalence of Leptospirosis among Young Thai Men, 2007-2008

Leptospirosis, a global neglected zoonotic disease, is an important public health problem in Thailand. Nonspecific symptoms, lack of laboratory confirmation, and underreporting contribute to its neglected disease status. To better understand the distribution of leptospirosis exposure in Thailand, a retrospective leptospirosis seroprevalence study was conducted on repository serum specimens obtained from young Thai men entering the Royal Thai Army during 2007–2008. The overall nationwide leptospirosis IgG seroprevalence among these young Thai men was 28% (95% confidence interval = 26–30%) and the range by province was 10–52% confirming leptospirosis as an endemic disease throughout Thailand. Seroprevalence was highest in individuals with the lowest education from rural areas, and higher seroprevalence was found in the north and south regions contrary to current morbidity reports. Improvement in reporting and surveillance as well as better access to leptospirosis diagnostics will increase leptospirosis awareness and detection and enable more effective public health interventions.

Measles susceptibility in young Thai men suggests need for young adult measles vaccination: a cross sectional study

Background

Measles remains a major public health concern in Thailand despite the introduction of vaccination since 1984. Similar to other countries, Thailand has experienced numerous measles outbreaks including adult communities such as university student dormitories, prisons, refugee camps, and military recruit camps. These outbreaks raise questions on the seroprotective antibody level in Thai adults.

Methods

To better understand measles susceptibility in young Thai adults, a retrospective measles seroprevalence study on repository serum specimens obtained with informed consent from young Thai men entering the Royal Thai Army (RTA) during 2007–2008 was conducted. A total of 7760 stratified randomized samples were chosen by residence province. Measles IgG titer was measured using a commercial IgG quantitative ELISA kit following the manufacturer’s instructions. An antibody level ≥ 250 International Units per Liter (IU/L) was interpreted as seropositive.

Results

The overall measles seroprevalence was 78.5 % (95 % Confidence Interval: 77.6–79.4 %) with geometric mean titer of 738 IU/L (95 % Confidence Interval: 716–760 IU/L). The measles seroprevalence by province ranged from 59.6 % to 93.1 %. A trend of decreasing seroprevalence in the younger cohorts despite increasing immunization coverage was found. Lower seroprevalence than vaccination coverage was observed in the youngest age group.

Conclusions

To achieve long term measles control and elimination, an integrated two doses vaccination strategy has been implemented in children in Thailand. This nationwide measles seroprevalence study in young adult RTA recruits found a measles seroprevalence lower than WHO’s recommendation for measles outbreak prevention and elimination. These results raise concerns for measles control in Thailand. Supplementary immunization in young adults is essential especially in high-risk and densely populated communities to establish herd immunity for outbreak prevention and elimination.

Neutralization breadth and potency of serum derived from recently human immunodeficiency virus type 1-infected Thai individuals

Neutralizing antibody responses play important roles in controlling several viral infections including human immunodeficiency virus type 1 (HIV-1). Potent and broad neutralizing antibody responses have been reported in some HIV-1-infected individuals; therefore, elucidating the mechanisms underlying neutralizing antibody responses will provide important information for the development of anti-HIV-1 vaccines. We herein performed a comparative study on the neutralization breadth and potency of serum samples collected from Thai individuals recently and chronically infected with HIV-1. Neutralization tests using a series of envelope glycoproteins (Env)-recombinant viruses revealed that although several serum samples derived from recently infected individuals did not show any HIV-1-specific neutralizing activity, the remaining serum samples exhibited neutralizing activity not only for recombinant viruses with CRF01_AE Env, but also for viruses with subtypes B and C Env. Furthermore, some serum samples derived from recently infected individuals showed the neutralization potency. Our results may provide a deeper insight into the characteristics of neutralizing antibody responses that develop during the course of HIV-1 infection among individuals in Thailand.

HLA Class I Alleles Associated with Mortality in Thai Military Recruits with HIV-1 CRF01_AE Infection

In HIV-1-infected patients, variation at the HLA class I locus is associated with disease progression, but few studies have assessed the influence of HLA alleles on HIV-1 CRF01_AE infection, which is dominant in Thailand. We hypothesized that alleles predicted to confer more effective immune responses, such as HLA-B*46, would protect against disease progression. HLA typing was performed on HIV-1 incident cases surviving until 1998-1999 and HIV-1-negative matched controls from Thai army cohorts enrolled between 1991 and 1995. We assessed associations between class I alleles and disease progression subsequent to HLA typing. Ninety-nine HIV-1-incident cases were followed for a median of 3.7 years after HLA typing; during this time, 58 participants died. Two alleles were associated with mortality: HLA B*51 was protective (3-year survival B*51(pos) vs. B*51(neg): 75% vs. 52%; p = 0.034) whereas Cw*04 was deleterious (3-year survival Cw*04(pos) vs. Cw*04(neg): 39% vs. 60%; p = 0.027). HLA-B*46 was not associated with disease progression. Alleles present at different frequencies in HIV-1-incident compared with HIV-1-negative men included HLA-A*02:03, B*35, B*15, and C*08. 1. In conclusion in this Thai army cohort, HLA-B*51 was associated with lower mortality, confirming that this allele, which is protective in clade B HIV-1 infection, has a similar effect on HIV CRF01_AE infection. The deleterious effect of HLA-Cw*04 must be interpreted with caution because it may be in linkage disequilibrium with disease-susceptible HLA-B alleles. We did not find that HLA-B*46 was protective. These findings may inform vaccine development for areas of the world in which HIV-1 CRF01_AE infection is prevalent.

Risk Factors for HIV Infection among Young Thai Men during 2005-2009

Background

Thailand is one of several countries with a continuing generalized HIV epidemic. We evaluated the risk factors for HIV prevalence among 17–29 year old men conscripted by a random process into the Royal Thai Army (RTA) in 8 cohorts from 2005–2009.

Methods

A series of case-cohort studies were conducted among the male RTA conscripts who had been tested for HIV seroprevalence after they were inducted. Men who were HIV positive were compared with a systematic random sample (1 in 30–40) of men from the total population of new conscripts. Each subject completed a detailed risk factor questionnaire.

Results

A total of 240,039 young Thai men were conscripted into the RTA and were screened for HIV seroprevalence between November 2005 and May 2009. Of 1,208 (0.5%) HIV positive cases, 584 (48.3%) men were enrolled into the study. There were 7,396 men who were enrolled as a comparison group. Among conscripts who had an education lower than a college-level, the independent risk factors for HIV infection were age in years (AOR 1.38, 95% CI 1.28–1.48), a history of sex with another man (AOR 3.73, 95% CI 2.70–5.13), HCV infection (AOR 3.89, 95% CI 2.56–5.90), and a history of sex with a female sex worker (FSW) (AOR 1.35, 95% CI 1.10–1.66). Among conscripts who had a college degree, the independent risk factor for HIV infection was a history of sex with another man (AOR 23.04, 95% CI 10.23–51.90). Numbers of sexual partners increased and the age at first sex, as well as the use of condoms for sex with a FSW decreased in successive cohorts.

Conclusion

The HIV seroprevalence among cohorts of 17–29 years old men has remained at about 0.5% overall during 2005–2009. The most significant behavior associated with HIV prevalence was a history of sex with another man. Our data indicate continuing acquisition of HIV among young men in Thailand in recent years, especially among men with a history of same sex behavior.

Pork consumption and seroprevalence of hepatitis E virus,Thailand, 2007-2008

The nationwide seroprevalence of hepatitis E IgG was determined among young men in Thailand. Overall seroprevalence was 14% (95% CI 13%–15%); range by province was 3%–26%. Seroprevalence was lowest in the south, an area predominantly occupied by persons of the Islam religion, whose dietary laws proscribe pork.

Characterization of human immunodeficiency virus type 1 CRF01_AE env genes derived from recently infected Thai individuals

Transmitted/founder virus is responsible for the establishment of human immunodeficiency virus type 1 (HIV-1) infection and induces primary anti-HIV-1 immune responses; therefore, it is important to study the viral population to understand the early events of HIV-1 infection. We amplified HIV-1 env genes from sera derived from recently infected Thai individuals, and established envelope glycoproteins (Env)-recombinant viruses. Generated Env-recombinant viruses were tested for their neutralization susceptibility to neutralizing human monoclonal antibodies (NHMAbs) and entry inhibitors, as well as being subjected to genotypic analysis. Most recombinant viruses were susceptible to neutralization by NHMAbs to Env gp41, whereas approximately one-third of the recombinant viruses were susceptible to a NHMAb against the CD4 binding site of gp120. In addition, all env genes were classified into CRF01_AE genes and showed low genetic divergence. Taken together with our previous studies on CRF01_AE env genes derived from chronically infected Thai individuals, these results suggested that the immunological and genetic characteristics of CRF01_AE Env derived from recently infected Thai individuals were different from those derived from chronically infected individuals.

CTLA-4 and its ligands on the surface of T- and B-lymphocyte subsets in chronic hepatitis B virus infection

BACKGROUND

During chronic hepatitis B virus (CHB) infection, a number of co-stimulatory, co-inhibitory molecules and theirs ligands play a prominent role in the immune-regulation.

OBJECTIVE

To compare the number of peripheral-blood mononuclear cells expressing co-inhibitory marker, cytotoxic T lymphocyte associated antigen-4 (CTLA-4) and program cell death ligand-1 (PD-L1) between CHB infected patients and healthy controls.

MATERIAL AND METHOD

Peripheral-blood mononuclear cells (PBMCs) from 19 CHB-infected patients and nine healthy controls were stained with specific combinations of the following monoclonal antibodies: CD3-PE/cy5, CD4-APC, CD8-APC, CD152-PE (CTLA-4), CD19PE/Cy5, CD80-FITC (B7-1), CD86-PE (B7-2) and CD274-FITC (B 7-H1) according to standard protocol.

RESULTS

The frequencies of B-lymphocyte expressing B7-1, B7-2 and B7-H1 of CHB-infected patients and healthy controls were not shown any statistical differences. The mean percentage of B-lymphocyte with B7-2 molecule was higher than those with B7-1 molecules in both infected- and non-infected groups. In contrast, the frequencies of T-lymphocyte subsets, CD3+, CD4+ and CD8+ expressing CTLA-4 molecules in CHB-infected patients were significantly higher than those in healthy controls with p = 0.04, 0.01 and 0.04 respectively.

CONCLUSION

An increase in percentage of circulating CD4+/CD152+ (T-cell) was observed in CHB-infected patients. A small but significant increase in percentage of CD8+/CD152+ T-cells raises the possibility that CTLA-4 are involved in the development of HBV-specific CD8+ T-cell exhaustion. Overall, CD4+ and CD8+ T-cells presenting CTLA-4 might contribute to the impaired immune response and likely to be a factor influencing in failure of immunological control of the persisting pathogens.

Cytokine profiles in HIV-1 subtype CRF01_AE infected individuals with different rates of diseases progression: a multiplex immunoassay

OBJECTIVE

Cytokines play an important role in controlling the homeostasis of the immune system and contribute to the pathogenesis of HIV infection. The measurement soluble cytokines in plasma of HIV-1 infected individuals with different rates of disease progression may provide additional information to complement prognostic markers and understand disease process. The aim of the present study was to determine the cytokine profiles in plasma of Thai HIV-1 CRFO1_AE infected individuals with different rates of disease progression by using a multiplex system for simultaneous detection of 7 cytokines.

MATERIAL AND METHOD

The authors used a multiplex immunoassay method to measure 7 cytokines (IL-2, IL-4, IL-6, IL-7, IL-10, IL-15 and IFN-gamma) in plasma of 23 progressors (PRs; symptomatic or AIDS within 5 years and CD4+ < 200/mm3), 23 slower progressors (SPs; asymptomatic more than 5 years and CD4+ > 350/mm3) and 23 normal healthy individuals.

RESULTS

Both PRs and SPs demonstrated significantly higher levels of IL-7, IL-10 and IFN-gamma than healthy controls (p < 0.05). No significant difference in IL-6 between SPs and healthy controls but significant difference between RPs and controls were found. Furthermore, PRs showed significantly higher levels of plasma IL-6 (p = 0.001), IL-7 (p = 0.016), IL-10 (p < 0.001) and IFN-gamma (p = 0.026) than SPs. No significant difference in IL-2, IL-4 and IL-15 was found among 3 groups (PRs, SPs and healthy control).

CONCLUSION

These results suggested that a Th1 to Th2 cytokine switch did not occur. However, the measurements of plasma levels of cytokines could be used for predicting disease progression.

Prevalence and risk factors for hepatitis C virus infection among young Thai men

Epidemiologic studies of hepatitis C virus (HCV) infection are unusual in developing countries, especially Thailand. We evaluated the prevalence and risk factors for HCV among military conscripts, including a sample of 5,246 men (1:30 sample), and human immunodeficiency virus (HIV)-1 positive men (N = 500) between 2005 and 2008. The HCV prevalence was 2.2% in the sampled group and 8.4% in HIV-1 sero-positives. Among the sampled group, HIV-1 infection, injection drug use (IDU) history, and unsafe injections were associated with HCV infection; adjusted prevalence rate ratios [RRs; 95% confidence intervals (CIs)] were 3.7 (1.04-12.77), 1.9 (1.04-3.54), and 1.8 (1.02-3.11), respectively. Among HIV-1 sero-positives, an IDU history and residence in southern Thailand were associated with HCV prevalence; adjusted RRs (95% CIs) were 3.5 (1.71-7.24) and 2.6 (1.18-5.61), respectively. Public health measures to prevent HCV in Thailand should focus on reducing injection drug use and other exposures to unsafe injections among young Thai men.

A whole blood lymphocyte proliferation assay in healthy Thais: comparison of heparinized blood and acid citrate dextrose blood

The lymphocyte proliferation assay (LPA) is a technique to determine T-lymphocyte functions in vitro. The standard LPA using peripheral blood mononuclear cells (PBMC) separated from heparinized blood requires a large blood sample, time consuming and expensive. It is more useful if acid citrate dextrose (ACD) blood could be used not only for LPA but also for other purposes. To determine whether whole blood composing between heparinized blood and ACD blood could be substituted for standard LPA using PBMC. Heparinized and ACD blood of 35 healthy Thai blood donors were studied herein. PBMC separated by density gradient centrifugation and diluted heparinized and ACD blood were used to test and compare for lymphoproliferative responses to phytohemagglutinin (PHA), pokeweed mitogen (PWM), and tetanus toxoid. A stimulation index (SI) for each mitogen or antigen was calculated. All Thai blood donors demonstrated positive proliferative responses to PHA and PWM by using PBMC and whole blood culture assays from both heparinized and ACD blood. However, the difference in the frequency of positive proliferative responses to tetanus toxoid by using PBMC and whole blood culture assays was significant. Nevertheless, no significant difference in frequency of positive responses to tetanus toxoid between heparinized and ACD blood was observed. This results suggested that no significant difference between using heparinized and ACD blood in standard LPA using PBMC. However, the whole blood LPA for measuring mitogen induced lymphoproliferation could be substituted for standard LPA from heparinized andACD blood. Whole blood LPA is easy, rapid, and more cost effective than PBMC culture assay. Thus, it would be applicable in a clinical laboratory as well as in research setting.

ZAP-70 positive cells in treated and untreated HIV-1 infected patients

ZAP-70 is a critical protein tyrosine kinase in T-cell activation and proliferation processes. Defective recruitment of ZAP-70 molecules results in termination of the T-cell receptor (TCR) signal transduction pathway. Impairment of this pathway is one of the early markers of disease progression in HIV-1 infected individuals. T-cell dysfunction in HIV infected patients may be connected to a defect in the proximal TCR signaling cascade. To evaluate this presumption, the numbers and mean fluorescence intensity (MFI) of ZAP-70 positive cells in patients with treated and untreated HIV-1 infection and healthy controls were analyzed by flow cytometry. A correlation between the MFI in ZAP 70 molecules and the viral load was evaluated. A total of 41 HIV-1 infected patients, 30 patients on HAART and 11 untreated patients, and 11 healthy controls were enrolled. The data show ZAP-70+/CD4+ cells in treated and untreated HIV-1 infected individuals had a greater MFI of ZAP-70 molecules than those from healthy controls (p < 0.001). The inverse correlation between the percentage of CD4+cells and the MFI of ZAP-70+/CD4+ T-cells was significant (r = -0.5; p < 0.01). A stronger correlation between the percentage of CD4+/CD25+ cells and the MFI of ZAP-70+/CD4+ cells was observed (r =-0.6; p < 0.01). However, no significant correlation was seen between the MFI of the ZAP-70+/CD4+cells and the viral load in patients with untreated HIV-1 infection (r = -0.4, p = 0.16). For HIV-1 treated patients, the viral loads were too low to detect so it was not possible to calculate the correlation. Elevated MFI levels of ZAP-70 molecules in CD4+ cells in HIV infected patients may be associated with an inability to further activate T-cells.

HIV-1 subtype B Tat gene activities and disease progression in HIV-1 CRF01_AE infection

HIV-1 tat gene function and immunogenicity of HIV-1 Tat protein from 3 low (PS01, PS40, PS58) and 3 high (PS19, PS65, LP22) viral load infected, untreated and asymptomatic individuals from Thailand were compared. Levels of Tat-dependent chloramphenicol acetyltransferase (CAT) induced in HL3T1 cells with tat1 gene from HIV-1 isolates of high viral load group was significantly higher than those from low viral load group. HIV-1 subtype determination using env (C2-V4) gene demonstrated that 2/3 (PS01 and PS40) and 1/3 (PS58) from low viral load group were CRF01_AE and subtype B, while all 3 HIV-1 isolates from high viral load group were CRF01_AE. However, all 3 HIV-1 tat nucleotide sequences from low viral load group, which contained env CRF01_AE sequence, belonged to subtype B whereas all those from high viral load group contained CRF01_AE sequence. HIV Tat recombinant proteins from these groups were tested for immunogenicity in mice. All recombinant Tat proteins (except from PS58) were immunogenic in a dose-dependent manner, but with significantly differences of the immunogenicity levels between high and low viral load groups. These results indicated that HIV-1 subtype B tat gene activities might be associated with reduced disease progression of HIV-1 CRF01_AE infected individuals.

HIV-1 incidence estimates among young Thai men using IgG-capture BED-enzyme immunoassay (BED-CEIA) during 2005-2006

BACKGROUND

Knowledge about the most recent HIV epidemic among young generation in Thailand is crucial for improving the prevention programs. It is important to distinguish between recent and long-term HIV-1 infections among the sero-surveillance populations to estimate the HIV-1 incidence.

OBJECTIVE

To obtain the HIV-1 incidence estimates in young Thai men from the HIV-1 sero-surveillance among the Royal Thai Army (RTA) conscripts inducted between November 2005 and November 2006.

MATERIAL AND METHOD

The confirmed HIV-1 positive serum samples obtained from the November 2005, May 2006, and November 2006 rounds of RTA conscripts induction were selected to be included in the study. The recent HIV-1 infections were detected among the confirmed HIV-1 positive serum samples using an HIV-1 BED incidence EIA Kit (Calypte HIV-1 BED Incidence EIA, Calypte Biomedical Corporation, Maryland, USA. The incidence estimates were obtained in each round of the induction using a consensus formula was agreed upon at the US Centers for Disease Controls and Preventions (CDC).

RESULTS

Eighty seven thousand one hundred seventy eight RTA conscripts were tested for HIV-1 infection between November 2005 and November 2006. The prevalence of HIV-1 infection was 0.51%, 0.60%, and 0.50% for the period of November 2005, May 2006, and November 2006, respectively. The HIV-1 incidence estimates were 0.14%/year (95% CI, 0.09-0.20), 0.20% year (95% CI, 0.13-0.28), and 0.17%/year (95% CI, 0.10-0.29) in November 2005, May 2006, and November 2006, respectively.

CONCLUSION

We reported the HIV-1 incidence estimates obtained from the IgG-capture BED-enzyme immunoassay (BED-CEIA) method in the RTA conscripts sero-surveillance population. The incidence estimates were ranging from 0.14% - 0.20%/year between November 2005 and November 2006. The estimates could serve as the recent baseline information for future HIV prevention interventions in Thailand.

Serum levels of MIP-1beta and RANTES in HIV-1 subtype CRF01_AE infected patients with different rates of disease progression

The beta-chemokines have been shown to inhibit HIV replication in vitro. To evaluate the role of serum beta-chemokines in disease progression and their anti-viral role in vivo, we determined serum levels of macrophage inflammatory protein-1beta (MIP-1beta) and regulated upon activation normal T-cell expressed and secreted (RANTES) of twenty HIV-1 subtype CRF01_AE infected patients: nine progressors (PRs, follow-up CD4+ cell count < 200/mm3 and progression to AIDS or death) and eleven slower progressors (SPs, asymptomatic and/or follow-up CD4+ cell counts > 350/mm3 at the end of follow-up) and determined their plasma viral loads. The subjects were followed for at least 36 months. All had initial CD4 values > 350 cells/mm3. In this longitudinal study, serum levels of MIP-1beta and RANTES in specimens obtained either early or later in the course of HIV infection did not differ significantly between progressors and slower progressors (p > 0.05). There were no significant changes in serum MIP-1beta and RANTES levels over time in either patient group (p > 0.05). No significant associations were observed between plasma viral loads and the measured beta-chemokines (r = -0.205, p = 0.21 for MIP-1beta and r = -0.12, p = 0.492 for RANTES). The results suggest these chemokines do not play a major systemic role in control of viremia or protection against the progression of HIV disease.

Expression of monocyte markers in HIV-1 infected individuals with or without HIV associated dementia and normal controls in Bangkok Thailand

HIV Associated Dementia (HAD) is a complication of HIV infection in developed countries and is still poorly defined in resource-limited settings. In this study we investigated the expression of the monocyte phenotype CD14CD16HLADR and the inflammatory profiles in monocytes supernatants by surface-enhanced laser desorption/ionization-time of flight (SELDI-TOF) mass spectrometry in a cohort of HAD and non-HAD Thai volunteers prior to the initiation of ARV. The CD14CD16HLADR phenotype was significantly increased in monocytes from HAD and non-HAD versus negative controls, but there was no difference in phenotype and in the secretion protein profiles between the two seropositive groups. In addition, monocytes supernatants from HAD and non-HAD did not induced apoptosis or cell death in brain aggregate culture. In conclusion it appears that HAD in Thai individuals has a different immunological profile then in North America cohorts.

Description of the first reported human case of spotted fever group rickettsiosis in urban Bangkok

Described herein is the clinical presentation of a patient from Bangkok, with fever, petechial rash, history of a tick bite, and a diagnosis of spotted fever rickettsiosis.

Surveillance of subtype and genetic variation of the circulating strains of HIV-1 in Thailand

Two HIV-1 strains, CRF01_AE and subtype B', were reported in Thailand during the early years of the epidemic. Recently, an intersubtype recombination of HIV-1 strain was found in Thailand. Eight-hundred and twenty-eight samples collected during years 1995-2004 from high-risk groups in Bangkok, northern, northeastern, and southern region of Thailand were studied. HIV-1 env nucleotide sequences were used for phylogenetic analysis of the circulating HIV-1 strain. By single HIV-1 region (env) genotyping, CRFO1_AE was found in 97.3% and HIV-1 subtype B was found in 2.7%. A predominance of CRF01_AE was found in all geographic regions. Parallel analysis of the HIV-1 gag and env genes demonstrated that 2.1% and 4.0% of recombinant HIV-1 strains were found using p17 and p24 region sequences, respectively. The recombinant gag gene was also found in one southern isolate. Phylogenetic analysis of HIV-1 isolated from 20 provinces in 2002 suggested the northern and northeastern isolates were more related than the southern isolates which had the lowest genetic diversity of 0.13. The GPGQ V3 loop tip was also present in isolates from all regions. The molecular epidemiological data from this study may be useful for surveillance design as well as targeting prevention efforts. It also provides information regarding new antigenic regions of circulating strains responsible for the HIV-1 epidemic in Thailand.

Neuropsychological abnormalities in patients with dementia in CRF 01_AE HIV-1 infection

HIV-associated dementia (HAD) is not firmly established in patients with circulating recombinant form (CRF) 01_AE HIV-1. In this study, we compared neuropsychological performance among 15 Thai individuals with HAD, 15 Thai individuals without HAD, and 30 HIV-negative control subjects. HIV-1 participants were highly active anti-retroviral therapy naive and matched by age, education, and CD4 count. Neuropsychological testing abnormalities were identified in most cognitive domains among HAD vs HIV-negative participants, confirming the presence of HAD in CRF01_AE.

Cytokine production in NK and NKT cells from Mycobacterium tuberculosis infected patients

Tuberculosis, a major health problem in developing countries, has re-emerged in recent years in many countries. While it is accepted that various lymphocyte subsets are important responses to mycobacterial infection, the roles of NK and NKT cells in producing cytokines are still unclear. Thus we have evaluated, in Mycobacterium tuberculosis infection, the frequency of cytokine producing cells by flow cytometry. Of 30 individuals examined, 17 had clinical evidence of pulmonary tuberculosis while the rest showed no evidence of infection. Patients had a significantly higher number of IFN-gamma and IL-4-producing T cells compared to control subjects, but the ratio of IFN-gamma to IL-4-producing T cells was similar in both groups. There were no differences between cytokine profiles of NK cells in patients and control subjects. A significant increase in the number of NKT cells was observed in patients. A striking finding was the higher frequency of IL-4-producing NKT cells compared to IFN-gamma-producing cells. Moreover, individual NKT cell produced both IFN-gamma and IL-4. The preferential type of Thl or Th2 cells is due to mycobacterial strain, type of antigen presenting cells and stage of disease, all of which can lead to different patterns of cytokine production by variety of lymphocyte subsets.

HIV DNA and dementia in treatment-naïve HIV-1-infected individuals in Bangkok, Thailand

High HIV-1 DNA (HIV DNA) levels in peripheral blood mononuclear cells (PBMC) correlate with HIV-1-associated dementia (HAD) in patients on highly active antiretroviral therapy (HAART). If this relationship also exists among HAART-naïve patients, then HIV DNA may be implicated in the pathogenesis of HAD. In this study, we evaluated the relationship between HIV DNA and cognition in subjects naïve to HAART in a neuro AIDS cohort in Bangkok, Thailand. Subjects with and without HAD were recruited and matched for age, gender, education, and CD4 cell count. PBMC and cellular subsets were analyzed for HIV DNA using real-time PCR. The median log(10) HIV DNA copies per 10(6) PBMC for subjects with HAD (n=15) was 4.27, which was higher than that found in subjects without dementia (ND; n=15), 2.28, p<0.001. This finding was unchanged in a multivariate model adjusting for plasma HIV-1 RNA levels. From a small subset of individuals, in which adequate number of cells were available, more HIV DNA was in monocytes/macrophages from those with HAD compared to those with ND. These results are consistent with a previous report among HAART-experienced subjects, thus further implicating HIV DNA in the pathogenesis of HAD.

Human Infection with Rickettsia honei, Thailand

Human spotted fever rickettsiosis was detected molecularly by 2 real-time polymerase chain reaction (PCR) assays performed on DNA extracted from a Thai patient's serum sample. Sequences of PCR amplicons from 5 rickettsial genes used for multilocus sequence typing were 100% identical with those deposited with GenBank for Rickettsia honei TT-118.

The development of HIV research laboratories in the Royal Thai Army Medical Department

The development of HIV research laboratories at the Armed Forces Research Institute of Medical Sciences (AFRIMS), Royal Thai Army Medical Department in supporting of HIV-1 vaccine trials in Thailand was implemented in 1991. The collaboration between AFRIMS, Royal Thai Army Medical Department, and the US Military HIV Research Program with the ultimate goal to conduct the HIV-1 vaccine trial phase III. The HIV serology lab was set up for surveillance program in military recruits. Then, there was a need to strengthen more on the existing laboratories by training personnel to cope with the confidentiality of the lab results, specimen processing and data management which are critical. Later on, the necessary laboratory for measuring of vaccine immunogenicity was developed, such as lymphoproliferation assay. Additionally, a molecular biology lab was also developed. The HIV research laboratory management must include an ability to deal with some problems, such as late specimen receiving, fluctuating of power supply, technical staffs maintained. Good laboratory practices and safety must be strictly implemented. Communication network among facilities also played an important role in HIV laboratory strengthening at AFRIMS.

Distribution of CD38 molecules on CD3+ and CD8+ T- lymphocyte in adulthood HIV-1-uninfected Thais

The expression of CD38 on CD8+ T-lymphocyte is a significant predictive value in disease progression of HIV infected individuals and in monitoring a response to therapy. CD38 molecules expressing on CD3+ and CD8+ T-cells were measured quantitatively by flow cytometry in 30 healthy Thai adults. In each experiment, the known amount of fluorochrome in CD38 antibodies bound per cell of QuantiBRITE PE beads was plotted, and set a regression line. With this line, the amount of CD38 molecules bound to CD3 and CD8 target cells was estimated. The aim of this study was to determine the reference value of CD38 molecules on CD8+ T-lymphocyte, which is the baseline in comparison to the CD38 molecule expressing on CD8+ T-lymphocyte in HIV-infected individuals. The present results showed that the amount of CD38 expressions on CD8+ T-lymphocyte in HIV negative Thai adults was about 2 times higher than those from Caucasian's lymphocyte. The reference range of CD38 molecules in the present study would best be used as baseline in prognosis and drug monitoring of HIV-1 infection in Thailand.

Binding antibody to neutralizing epitope gp41 in HIV-1 subtype CRF 01_AE infection related to stage of disease

The responsiveness of gp41 antibody against epitope ELDKWA in HIV-1 infected subjects is of importance in neutralizing viral infectivity and for being related to disease progression. In this study, antibody titers to this neutralizing epitope from HIV-1 infected subjects at asymptomatic and AIDS stages in Thailand were investigated by peptide ELISA. The results showed that the frequency of antibody production against this neutralizing epitope was low (15-35%). Moreover, antibody titers to this epitope in sera from AIDS patients were significantly lower than those in sera from asymptomatic subjects which were collected in the same year (p=0.001). Comparison between the past (1992-1994) and present (2002) sera from asymptomatic infected individuals revealed that the earlier panel contained lower antibody titers than the later panel did (p = 0.05). In addition, random sera for HIV-1 infected subjects who were infected by diverse genetic subtypes, (A through G) including CRF 01_AE, had low titers of antibody to this region as well. It is assumed that antibody production to this epitope is low and related to the stage of HIV-1 infection.

Specific antibody responses to vaccination with bivalent CM235/SF2 gp120: detection of homologous and heterologous neutralizing antibody to subtype E (CRF01.AE) HIV type 1

HIV-1 CRF.AE-01 (formerly subtype E) infection is highly prevalent in Southeast Asia. Despite success with public health measures, the development of an effective CRF01.AE vaccine is critical to the control of this epidemic. Sera from the open-label arms of the first clinical trial of a bivalent HIV gp120 SF2/CM235 (subtypes B and CRF.AE-01, respectively) vaccine were evaluated for the presence of gp120-specific binding (BAb) and neutralizing antibody (NAb). Twelve pre- and postvaccination sera pairs were tested for CM235 BAb; anti-gp120 CM235 BAb was found in all postvaccination samples. The 12 pre- and postvaccination (1 month after third vaccination) serum pairs were evaluated in several neutralization formats: heterologous T cell line adapted (TCLA) NP03/H9, homologous CM235/PBMC, CM235/dendritic cell, and CM235M4-C4.6/A3R5. A3R5 is a CCR5+ T cell line, and CM235M4-C4.6 is the homologous CM235 virus adapted to growth in A3R5 cells. All volunteers developed BAb, but meaningful NAb was not demonstrable against primary isolate CM235. Using the TCLA CRF01.AE virus NP03 in H9 cells, 9 of 12 persons had NAb with a geometric mean titer (GMT) of 46. The CM235M4-C4.6 virus in A3R5 cells also detected NAb in 9 of 12 persons, with a GMT of 41. CM235M4-C4.6/A3R5 detected NAb in two persons with negligible NAb to NP03/H9 and vice versa. Whether the NAb detected by the CM235M4-C4.6/A3R5 system is qualitatively different from those in more traditional NP03/H9 assays will require further study.

Human immunodeficiency virus type 1 primary isolate neutralization resistance is associated with the syncytium-inducing phenotype and lower CD4 cell counts in subtype CRF01_AE-infected patients

A number of human immunodeficiency virus type 1 (HIV-1) non-B-subtype products have been developed for present or future vaccine trials; in Thailand, several studies using subtype B and/or CRF01_AE vaccines have been conducted. To better characterize the biologic properties of these subtypes, 70 HIV-1 subtype B and E isolates were phenotyped as syncytium-inducing (SI) or non-syncytium-inducing (NSI) isolates and assessed for sensitivity to neutralizing antibody (NAb). A significantly higher number of NSI subtype E viruses were neutralization sensitive than SI subtype E viruses (P = 0.009), while no association between viral phenotype and sensitivity to NAb was observed for subtype B (P = 0.856), suggesting a difference in the neutralization patterns of subtypes B and E. Strikingly, concurrent CD4 T-cell numbers were significantly lower for subtype E-infected patients whose isolates were more resistant to NAb, both for the overall study group (P < 0.001) as well as for the 22 patients with NSI isolates (P = 0.013). Characterization of the evolution of biologic properties of both B and non-B HIV-1 subtypes will provide a clearer understanding of the repertoire of antibodies that must be elicited for a vaccine to be effective against all phenotypes and subtypes.

Safety and immunogenicity of combinations of recombinant subtype E and B human immunodeficiency virus type 1 envelope glycoprotein 120 vaccines in healthy Thai adults

Safety and immunogenicity of 2 recombinant human immunodeficiency virus (HIV) type 1 envelope glycoprotein (gp) 120 vaccines derived from SF2 (subtype B) and CM235 (CRF01_AE, Thai E) were evaluated in 370 Thai adults at low risk of HIV infection. Various doses of CM235 (25, 50, or 100 microg) and SF2 (0, 25, or 50 microg) gp120 were used. Eighty volunteers received placebo. There were no serious adverse events related to vaccination. Binding antibody developed in all vaccine recipients. There was no dose response to CM235 gp120, but a dose response to gp120 SF2 was present. Neutralizing antibodies to subtype E HIV-1 NPO3 and subtype B HIV-1 SF2 developed in 84% and 82% of vaccine recipients, respectively. Lymphoproliferative responses were detected in >95% of vaccine recipients. There was no evidence of antigenic interference in HIV-specific humoral or cellular responses. The gp120 Thai E and SF2 vaccines were safe and immunogenic in combination and could be advanced into phase 3 testing.

Longitudinal study of humoral immune responses in HIV type 1 subtype CRF01_AE (E)-infected Thai patients with different rates of disease progression

Identification of immune correlates associated with disease progression will provide information for HIV-1 vaccine design in countries such as Thailand, where the prevalent subtypes (B and CRF01_AE [E]) are characterized. In this study, plasma viral load and humoral immune responses were measured in 20 HIV-1 subtype E-infected Thai patients with different rates of disease progression, based on CD4(+) T cell decline and clinical symptoms. Nine progressors (PRs) and 11 slower progressors (SPs) were evaluated. CD4(+) T cell counts were inversely correlated with viral load (p = 0.004) and positively correlated with p24 Ab (p = 0.022). In progressors, p24 Ab showed a significant decrease (p < 0.001) over time. V3 and gp41 Ab did not change significantly in either group. Both CD4-binding site (CD4/gp120BS) and gp120 titers correlated positively with neutralizing antibody (NAb) against both a subtype E cell line-adapted virus (NP03) and a primary isolate (TH023). However, V3 Ab correlated only with NAb against NP03 (p < 0.001). Increased NAb over time was observed more frequently in SPs as compared with PRs, against both the TH023 (p = 0.004) and NPO3 (p = 0.004) viruses. Cross-clade antibody-dependent cellular cytotoxicity was demonstrated in both groups. These data suggest that in HIV-1 subtype E infection, declining p24 Ab titer is a predictive marker of disease progression, as described for subtype B. Furthermore, in subtype E-infected patients, slower progressors retain the immune competence to develop new antibody responses to Env over time; these evolving responses may contribute to prolonged survival during HIV-1 disease progression.

Flow cytometric detection of intracellular cytokines in peripheral blood of HIV-1 infected Thai children

The objective of this study was to determine changes in Th1/Th2 cytokine production at the cellular level which occur during the progression of HIV-1 subtype E infection in Thai children born to HIV-1 subtype E infected mothers. Mitogen stimulated whole blood cultures from 12 uninfected and 27 HIV-1 subtype E infected Thai children were stained intracellularly with fluorescein labelled monoclonal antibodies against Interleukin (IL)-2 and IFN-gamma (Th1 cytokines) and IL-4 (Th2 cytokine). Additionally, co-staining of CD4+ and CD8+ T cells was performed. Results were analyzed by two and three color flow cytometry. The percentage of IFN-gamma expressing cells in CD4+ T cells was increased in HIV-1 subtype E infected Thai children with mild and moderate immunosuppression (Immunological categories 1 + 2, Centers for Diseases Control and Prevention (CDC) staging system, 1994). The percentages of IFN-gamma expression was continuously enhanced accompanied by remaining preserved in the proportion of IL-2 producing T cells in HIV-1 subtype E infected Thai children with severe immunosuppression (Immunological category 3, CDC staging system, 1994). The percentages of IFN-gamma expression was continuously augmented whereas the proportion of IL-2 producing T cells remained unchanged in HIV-1 subtype E infected Thai Children with severe immunosuppression (immunological category 3, CDC staging system, 1994). The percentage of Th2 cytokine producing cells within the CD4+ ad CD8+ T cells increased in HIV-1 subtype E infected individuals and showed a significant difference in HIV-1 subtype E infected Thai children with AIDS compared with uninfected infants. These results suggest that in vertically acquired HIV-1 infection with severe immunosuppression, the percentages of IL-2 producing CD4+ T cell was consistent but the percentages of IL-4 and IFN-gamma producing cell were increased. Similar results were found for CD8+ T cells in which IL-4 producing cells were increased in conjunction with a remaining in the number of IL-2 producing cells in HIV-1 subtype E infected Thai children. Thus, changes in the Th1 and Th2 cytokine pattern during HIV-1 infection may contribute to the prognosis of HIV disease in children.