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.

Trends of HIV seropositivity at Siriraj Hospital: 13 year's observation from 1992-2004.

OBJECTIVE: The aim of the present report was to observe the trend of seroprevalence rates of HIV seropositivity for routine services at Siriraj Hospital for 13 years. MATERIAL AND METHOD: The prevalence rate of HIV seropositivity was analyzed in three groups of subjects: 1) patients who attended the hospital with HIV related diseases; 2) pregnant women at first visit to the antenatal care clinic; 3) emigrating workers who have applied for employment in foreign countries. RESULTS: Of the 13 year-observation, HIV seroprevalence rates in the groups of patients, pregnant women and emigrating workers was 10.6% (95%CI 8.9-12.3%), 2.0% (95%CI 1.8-2.2%) and 0.6% (95%CI 0.4-0.8%), respectively. CONCLUSION: The low prevalence of HIV seropositivity in the group of emigrating workers may be due to self selection, whereas the prevalence in pregnant women, which was rather consistent at about 2.0%, may represent the infection rate in the general population. The seroprevalence rate measured in the group of pregnant women demonstrates that Thailand should increase efforts to confine the spread of HIV infection in the community.

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.

Patterns of anti-HIV IgG3, IgA and p24Ag in perinatally HIV-1 infected infants.

The antibody patterns of HIV-1 IgG3, IgG and IgA and of HIV-1 p24 antigen were investigated in Thai infants born to mothers infected with HIV-1. In the 17 HIV-1 infected infants, anti-HIV antibodies were detected continuously over a period of 15-18 months and a high level of specific IgG3 subclass was observed. Anti-HIV IgA could be detected at 6 months of age whereas p24Ag was detected at 2 months. In 79 uninfected infants, maternal anti-HIV IgG gradually decreased over 9 months whilst specific IgG3 decayed rapidly during the first 6 months. Both p24Ag and anti-HIV IgA were not found in these uninfected infants. Thus, the disappearance of anti-IgG3 subclass antibodies within 6 months can predict whether infants are uninfected whereas the persistence of anti-HIV IgG and IgG3 subclass antibodies, the production of anti-HIV IgA antibody and the presence of p24Ag appear as an adjunct to the diagnosis of HIV vertical transmission. The necessary assays are relatively simple and could be performed individually.

Recombinant envelope protein of HIV-1 subtype E as antigen in HIV-1 antibody detection enzyme immunoassay.

In order to develop a reliable and inexpensive serodiagnostic method to be used for anti-HIV antibody detection in Thailand, recombinant envelope (TM or gp41 subunit) protein of HIV-1 subtype E was produced from prokaryotic cell (Escherichia coli) as the source of antigen in enzyme immunoassay (TE diagnostic EIA kit). HIV-1 gp41 subunit of subtype E was successfully expressed in E. coli in the form of polyhistidine-tagged proteins, comprising of rgp41A (601 bases N-terminal half of TM or 25kDa) and rgp41B (560 bases C-terminal half of TM or 24 kDa) by using an expression vector, pBAD/His C. The amount of protein, dilution of sera, and anti-human IgG labeled HRP used in the EIA test optimized by a checker board titration of the protein and seropositive or seronegative sera, were 5.0 microg/ml, 1:300, and 1:4,000, respectively. The blinded test evaluation of TE-diagnostic EIA in 500 seropositive and 500 seronegative sera which have been simultaneously tested by two available commercial kits and compared with our TE diagnostic EIA, gave 99.6% sensitivity and specificity. The other known genetic subtypes sera such as subtype A (n=5), B (n=9), C (n=4) and D (n=5) were also positive with this EIA. The estimated manufacturer cost per test of rgp41 based anti-HIV antibody detection EIA or TE-diagnostic EIA was about 15 baht. This recombinant envelope (gp41 or TM) protein from HIV-1, which can be produced in large quantities without any hazards from growing the virus and has lower cost to produce anti-HIV antibody serological diagnostic kit, should be considered as an HIV screening test in Thailand.

Detection of hepatitis C virus RNA by polymerase chain reaction: Design of amplification primers.

New sets of primers for amplification of hepatitis C virus (HCV) RNA were designed from the conserved regions of American and Japanese isolates of HCV. Primers set A amplified parts of the 5’-untranslated and core gene regions, whereas set B amplified parts of the core and envelope gene regions. PCR amplification were carried out from HCV RNA isolated from sera of 13 Thai patients with antibody to HCV, using these newly developed primers. HCV RNA was detectable in 8 patients (61.5%). Of those PCR positive samples, only 4 patients (50%) were positive with primer set A, whereas 7 patients (87.5%) were positive with primer set B. Interestingly, 4 patients were tested positive with only set B, 3 patients with both sets A and B, and just one patient with set A only. This result suggests that PCR assay as a diagnostic tool for HCV may need to be carried out with more than one primer set. The relatively low percentage of PCR positivity of the HCV from Thai patients using primer set A, which was previously identified as the most conserved region of the HCV genome, also indicates that the sequence of the Thai isolates of the virus may be different from those of the American and Japanese strains.

Reduced regimen of plasma derived hepatitis B vaccine.

The antibody response after vaccination by reduced regimen of plasma derived hepatitis B vaccine (Hevac B) was studied. The vaccines were 48 medical student, who were seronegative for HBV markers. The vaccination schedule was at 0, 1 and 6 months, whereas the recommended schedule for this vaccine is at 0, 1, 2, 12 months. Anti-HBs and anti-HBc were measured at 1, 2, 7 months after the first dose. The seroconversion rate of anti-HBs were 14.9, 62.2, 84.6% and GMT (geometric mean titer) were 24.3, 128.4, 8037.3 mlU/ml respectively. No serious side effect was recorded. Six vaccines, who were seronegative after the third dose of vaccination, received another additional dose at 1 year after first dose. Blood testing performed 1 month after such booster dose showed seroconversion in 5 of 6 vaccinees.

Antibody responses to two different yeast-derived hepatitis B vaccines.

Comparative study of antibody responses and adverse reactions after two different yeast derived hepatitis B vaccine administrations was performed. Subjects were 96 medical students who had seronegative for HBV markers. The first group of 47 students received H-B-Vax II® vaccine (MSD) 10 µg and the second group (49 students) received Engerix-B® vaccine (SKF-RIT) 20 µg. the vaccination schedule was two doses one month apart and a booster dose at sixth month. Antibody responses were measured at 1 month after each injection. The result showed that, seroconversion rate after booster dose was 100% in both groups. Anti-HBs titers after first and second doses showed no significant difference among two groups, but after booster dose the anti-HBs geometric mean titer was 3,070 mIU/ml in the first group and 6,634 mIU/ml in the second group, which showed statistical significance. Minor adverse reactions such as local pain, inflammation, itching, and malaise were found.