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.

The prevalence and persistence of human parvovirus B19 infection in thalassemic patients.

Human parvovirus B19 infection was studied in 60 thalassemic patients in Thailand. Seroprevalence, persistence of parvovirus B19 and their genotypes were identified in blood samples. Prevalence of anti-parvovirus B19 IgG and DNA found in thalassemic patients were 38% and 13%, respectively. Anti-parvovirus B19 IgM could be detected in 4% of these positive anti-parvovirus B19 IgG patients. The seroprevalence and parvovirus B19 DNA in patients with a history of blood transfusion were not significantly higher than those without such a history (44% vs. 34% and 20% vs. 9%, respectively). Phylogenetic analysis of NS1 nucleotide sequences of three parvovirus B19 samples revealed that they were parvovirus B19 genotype 1. They showed low genetic diversity from prototype (Au) strain. We concluded that acute and chronic persistent parvovirus B19 infection were found in the thalassemic Thai patients. Chronic persistence of parvovirus B19 infection might play important clinical role in thalassemic patients because of the high prevalence of parvovirus B19 DNA. Blood transfusion had no significant influence to increase the prevalence of parvovirus B19 infection in thalassemic patients.

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.

HIV-1 subtyping using gag/env heteroduplex mobility assay and peptide enzyme-linked immunosorbent assay.

Two HIV-1 subtypes have accounted for virtually all infections in Thailand: subtype B', found mainly in injection drug users (IDUs), and CRF01_AE (initially subtype E), found in over 90% of sexually infected persons and increasingly in IDUs in recent years. During 1997-1998, 227 blood samples were collected from HIV-1 infected individuals consisting of 92 mothers, 35 children and 100 IDUs. The blood samples were subtyped by heteroduplex mobility assay (HMA) and peptide enzyme-linked immunosorbent assay (PEIA). Using gag and env HMA, CRF01_AE and subtype B' accounted for 96-97% and 3-4% of both the mothers and the children, respectively. In the IDU group, 10% of the plasma samples could only be performed by gag HMA and gave the result as CRF01_AE. CRF01_AE and subtype B' using PEIA accounted for 67% and 33% of the IDUs. There was 100% concordance of the results between gag HMA and env HMA. Ninety-five percentages of concordant results were observed between HMA and PEIA. Of the 6/134 (5%) subjects with discordant results, nucleotide sequencing, used as a gold standard, confirmed the HMA result. In this study, HIV-1 was successfully genotyped by HMA and PEIA. However, a comparison of the subtyping results between HMA and PEIA revealed that HMA was slightly more accurate than PEIA.

The efficacy and effectiveness of influenza vaccination among Thai elderly persons living in the community.

OBJECTIVE: To determine the efficacy and cost-effectiveness of influenza vaccination in the Thai elderly living in an urban community. MATERIAL AND METHOD: The study design was a stratified, randomized, double blind, placebo-controlled trial. A total of 635 participants aged 60 years and older living in an urban community was randomized to receive an influenza vaccine or tetanus toxoid as a placebo injection. All participants were followed up 4-6 weeks in the community for influenza-like illness and treatment received, hospitalization and death for one year. A hemagglutination inhibition (HI) test for influenza virus antibody of all participants was done on the day of vaccination as well as 1 month, 5 months, and 12 months after the vaccination. Main outcome measures were immune response rate and protective titer, influenza-like illness, serological influenza, treatment received for influenza-like illness and their expenses, hospitalization and death during the study period. RESULTS: The immune response rate of vaccinations was 97.1% and protective titer for A (H1N1) and A (H3N2) strains were 96.4 and 98.6%, respectively. The incidence of influenza-like illness was 4.83% in the vaccine group compared with 10.88% in the placebo group. The relative risk reduction was 56% (95% CI = 14 to 77%). The survival analysis also showed that vaccinations significantly reduced the incidence of influenza (p = 0. 009). The number needed to prevent one episode was 17 persons (95% CI = 9 to 71 persons). The adverse reactions of vaccinations were mild and tolerable. However, the number of treatments received for influenza-like illness and their cost were not significantly different between the two groups. None of the subjects had pneumonia nor needed hospitalization during the study period. Seven participants died during the year of follow up, but not from influenza. CONCLUSION: In Thai elderly living in the community, influenza vaccination reduced the incidence of influenza-like illness by half, but not the number of treatments received for influenza-like illness, their cost, and its serious complications. In the year of the study, considering the cost of vaccines and the numbers needed to prevent one episode of infection from the provider's viewpoint, it may not be cost-effective to recommend that all Thai older persons living in the community should receive influenza vaccination annually. Vaccination recommendation for the elderly should be promptly implemented in expectation of a severe epidemic 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.

Occurrence and protective level of influenza infections using serology in patients with COPD in vaccination study.

OBJECTIVE: To investigate the prevalence, occurrence and protective level of influenza infections using serology in patients with chronic obstructive pulmonary disease (COPD) during a one-year influenza vaccination study. MATERIAL AND METHOD: A total of 123 patients with COPD were enrolled during the period of 1997 to 1998. There were 61 patients in the vaccine group and 62 patients in the placebo group with a mean age +/- SD of 67.6 +/- 8.0 and 69.1 +/- 7.5, respectively. The vaccine was composed of influenza A/Texas/36/91 (H1N1), A/Nanchang/933/95 (H3N2) and B/Harbin/07/94 strains. Antibodies to influenza viruses were detected by hemagglutination inhibition (HI) test using antigens of vaccine strains. RESULTS: The incidence of influenza proven by serological examination was 22/123 (17.9%) cases. Among 17/62 (27.4%) influenza cases in the placebo group representing natural infections, 3 (17.6%) were diagnosed as A (H1N1), 8 (47.1%) as A (H3N2), 3 (17.6%) as type A, 1 (5.9%) as type B and 2 (11.8%) as untypeable viruses. The 8.2% of influenza cases found in the vaccine group was significantly lower than 27.4% of that in the placebo group (Chi-square test, p = 0.01). The protection rate of influenza vaccination was 71%. Among 23 acute blood samples from 22 influenza cases, the titers ranged from < 10 to 20 corresponding to its type/subtype. In the vaccine group, 5 influenza cases occurred at 7, 7, 10, 11 and 11 months after vaccination. The HI antibodies to influenza A (H1N1), A (H3N2) and B viruses at titers of > or = 10 vs > or = 40 were 50.4% vs 21.9%, 54.5% vs 28.5% and 17.9% vs 4.1%, respectively. CONCLUSION: The findings indicated that from 1997 to 1998, the occurrence of influenza as natural infection was 27.4%. Influenza A (H3N2) was more frequently prevalent than A (H1N1) and B viruses. The influenza vaccination in COPD patients was effective. The protective HI antibody titers were > or = 40. The patients without protective HI antibody to A (H1N1), A (H3N2) and B viruses were 78.1%, 71.5% and 95.9%, respectively. Such patients were considered to be at high-risk for influenza and recommended to have vaccination.

The prevalence of viral hepatitis among the Hmong people of northern Thailand.

Sera from 269 Hmong people (102 males and 167 females, with mean age 35.4 years, range 16-63 years) were examined in order to determine the seroprevalence of hepatitis virus infection. The seroprevalence rates for HAV (hepatitis A virus), HBV (hepatitis B virus), HCV (hepatitis C virus), HDV (hepatitis D virus), HEV (hepatitis E virus), HGV (hepatitis G virus) and TTV (TT virus) infection were 87.8% (n=140), 76.0% (n=150), 2.0% (n=150), 0.7% (n=150), 6.5% (n=139), 5.3% (n=94) and 25.6% (n=121) respectively. The rate for carriers of HBV (HBsAg) was 13.8% (20.5% in males and 9.6% females) with a peak prevalence in the 21-40 year age group. A high rate of HAV seropositivity was found among the younger subjects. The rate of HEV seroprevalence was low. The prevalence of TTV-DNA was high with no difference between the sexes. HGV-RNA prevalence was low and seen primarily in males. This study indicates that the Hmong people are endemically infected with HAV and HBV infection and should be considered for targeted vaccination. The role of TTV and HGV in producing illness and hepatic disease has yet to be determined in this population.

Flexibility in the administration schedule of varicella vaccination in healthy adolescents and young adults.

A clinical trial to assess the immunogenicity and reactogenicity of two doses of varicella vaccine (live attenuated Oka-strain, GlaxoSmithKline Biologicals), when either given 8 or 4 weeks apart in healthy seronegative adolescents and young adults, was conducted in Khon Kaen and Bangkok, Thailand. Contrary to seroconversion rates generally reported for this age group, in our study all subjects were already seropositive after the first vaccine dose. After the first vaccine dose, geometric mean titers (GMTs) for anti-varicella antibodies were 78.4 (median 64) for the adolescent group and 136.5 (median 128) for the young adult group. Six weeks after administration of the second dose, anti-varicella GMTs reached 331.7 (median 256) and 636.9 (median 512) for the adolescent and young adult groups, respectively, with a 4.2-4.7-fold increase from pre-vaccination titers. The difference in GMTs between post-dose I and dose II was statistically significant for each group. The reactogenicity after the first and second doses of vaccination was low: no varicella rash was seen, in either the shorter or longer schedule. GlaxoSmithKline Biologicals varicella vaccine (Varilix) offered a high flexibility, administration possible at either 4 or 8 weeks interval, whilst eliciting good immunogenicity and good tolerability.

Rapid human immunodeficiency virus diagnostic test during the intrapartum period in pregnant women who did not receive antenatal care.

The main barrier to implementation of antiretroviral drugs in HIV-infected pregnant women is the lack of antenatal care (ANC). From April 1999 to December 2001, the prevalence of pregnant women not receiving ANC and coming for delivery in Siriraj Hospital was 7.3 per cent (2,152/29,484) and the prevalence of HIV infection among this group was 5.7 per cent, substantially higher than that of 27,332 pregnant women receiving ANC in Siriraj Hospital (2.2%). Besides developing interventions to increase use of ANC, the test for diagnosis of HIV infection during the intrapartum period should be rapid, inexpensive, highly sensitive and specific, easy to perform and results should be easy to interpret. The Determine Rapid Test for detection of HIV fulfills these criteria with 100 per cent sensitivity, 99.85 per cent specificity, 97.54 per cent positive predictive value, 100 per cent negative predictive value and 0.14 per cent false positive. To improve prevention of mother-to-child HIV transmission (PMTCT), the authors believe that this uncomplicated rapid HIV testing should be used during the intrapartum period to Thai-pregnant women who did not receive antenatal care and antiretroviral drugs might be offered as soon as possible for those testing HIV-positive and for their baby as chemoprophylaxis.

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.

Detection of anti-human papillomavirus antibodies in patients with cervical neoplasia and in normal population.

Because of the relative simplicity of specimen collection comparing to HPV-DNA detection from cervical specimens, HPV serology might have a role in screening and prediction of cervical cancer risk. Serprevalences to HPV proteins in Thai population has not been assessed. The prevelences of antibodies to HPV-16 E6,E7 oncoproteins-derived peptides in peptides in patients with cervical intraepithelial neoplasia (CIN) and invasive cervical cancer, and in control group with normal cervical cytology were studied. The selected peptides were previously shown to contain immunodominant epitopes. The seroprevalences of antibodies to the peptides in the control group were 4.7% - 11.5%. The antibody to an E6 peptide (E6 aa 1-23) was found in 75.5% of patients with invasive cervical cancer, associated with cervical neoplasia. Eighty-five percent of patients with invasive cervical cancer and 17% of the control group had antibodies to at least one of the three peptides.