HLA class I serotypes and cytotoxic T-lymphocyte responses among human immunodeficiency virus-1-uninfected Thai volunteers immunized with ALVAC-HIV in combination with monomeric gp120 or oligomeric gp160 protein boosting.

Antigen-induced cellular immunogenicity may vary between populations due to differences in human leukocyte antigen (HLA) diversity and, hence, may play a critical role in the protection afforded by vaccines. In the setting of two, phase I/II human immunodeficiency virus-1 vaccine trials of a recombinant canarypox prime, and boosting with either recombinant monomeric gp120 or oligomeric gp160, we assessed the association between specific human leukocyte antigen (HLA) class I serotypes and the presence of cytotoxic T-lymphocyte response measured by 51Cr-release assay. HLA class I serotypes A11, A24, A33, B46, and B75 were the most common, present in 10% or more of 245 individuals studied. Forty of 187 (21.4%) Thai adults who received either ALVAC-HIV with gp120 or oligomeric gp160 or ALVAC alone had a precursor cytolytic CD8 T-cell response (pCTL). HLA-B44 was positively and significantly associated with a pCTL response (odds ratio 7.6, 95% CI: 2.7-21.2), whereas B46 was negatively associated but not robust when adjusted for multiple comparisons. Responses to Env proteins accounted for the majority (nine of 11) of pCTL activity among those persons with B44. This HLA class I serotype occurred in 9.4% of participants overall (including the placebo group), less commonly than what is reported from populations of European ancestry. These results strengthen the importance of assessing HLA class I distributions in conjunction with studies of vaccines designed to elicit cellular immunity in different populations.

Cytotoxic T lymphocyte responses to vaccinia virus antigens but not HIV-1 subtype E envelope protein seen in HIV-1 seronegative Thais.

The HIV-1 prime boost phase I/II vaccine trial using a recombinant canarypox vector, vCP1521, containing subtype E env (gp120), and subtype B env (gp41), gag and protease has started in Thailand. We have demonstrated that although 4 from 15 human immunodeficiency virus type 1 (HIV-1) seronegative Individuals showed cytotoxic T lymphocyte (CTL) responses to vaccinia virus antigens, none of them showed specific CTL responses to subtype E Env after in vitro stimulation. This preliminary study suggests that specific CTL responses to subtype E envelope detected in HIV-1 seronegative Individuals after vaccination should be considered as specific responses to the immunization.

Double annulus enlargement, Rastan-Manouguian's technique: a case report.

A 35-year old female patient underwent a double valve replacement. The operative findings revealed a small aortic annulus (about 17 mm in diameter). In order to implant the adequate-size prosthetic valve, the aortic and mitral annulus were enlarged using the technique described by Rastan and Manouguian. The annulus were enlarged with a patch of gel-sealed dacron graft. After the enlargement, the prosthetic valve No. 23A and 31M could be implanted in the aortic and mitral annulus, respectively. This is an effective technique to enlarge the aortic and mitral annulus in a double valve replacement procedure. The annular diameter could be increased approximately 30 per cent.

Progress and achievement of rabies control in Thailand.

The breakthrough in production of highly efficacious human and animal rabies vaccines has led to successful rabies control in developed countries, but rabies is still a major health problem in many developing countries. In Thailand, the new cell culture vaccines-purified chick embryo cell (PCEC), purified Vero cell (PVRV), purified duck embryo (PDEV) and human diploid cell (HDCV) are available, and since 1993 have completely replaced the nervous tissue vaccines. The impact of these cell culture vaccines has been considerable, with the number of human rabies deaths decreasing from 200-300 in the early 1980s to 74 in 1995. Rabies prevention has also focused on the vaccination of dogs, and since 1992, the year the Rabies Prevention Act was announced, every owned dog has to be vaccinated at 2-4 months of age annually thereafter. However, only about 20% of dogs have been vaccinated. In 1995, the Ministry of Agriculture and Cooperation collaborated with the Ministry of Public Health to set up a target of no human rabies deaths in 1996, and a rabies-free Thailand by the year 2000. An extensive educational campaign is underway.

Left ventricular outflow tract obstruction due to a left ventricular myxoma: a case report and review of the literature.

A 17-year-old-man who presented with syncope, had a left ventricular (LV) myxoma causing left ventricular outflow tract obstruction. The tumor was removed through left ventriculotomy using conventional cardiopulmonary bypass with good result. There have been 47 cases of LV myxoma reported in the world literature since 1957. Most of them are symptomatic (92.7%). Systemic embolism is the most common manifestation (50%) and often leads to death. The surgical removal should be performed urgently. Resection of the mass with limited normal tissue surrounding its pedicle is recommended. There are only three recurrences and five operative deaths.

HIV-1 variants in South and South-East Asia.

HIV spread in South and South-East Asia is most alarming, and genetic variability of HIV-1 is an important consideration in vaccine development. In this study, we examined the third variable (V3) region of env gene of HIV-1 variants prevalent in Thailand, Malaysia, India, and the Philippines. By phylogenetic tree analyses, an HIV-1 variant from an injecting drug user (IDU) in Thailand belonged to subtype B, and HIV-1 variants from 2 IDUs in Malaysia were classified into 2 subtypes, B and E. One HIV-1 variant from a male homosexual in the Philippines belonged to subtype B. Out of 8 HIV-1 variants from sexually transmitted disease patients in India, 7 belonged to subtype C, and one to subtype A. Although the total number of individuals examined in this study was limited, 4 HIV-1 subtypes were found in South and South-East Asia and large international movements of HIV-1-infected individuals in this region could induce global dissemination of these HIV-1 variants.

Incidence of Mycoplasma pneumoniae, Chlamydia trachomatis, and viral infections in pneumonia cases under six months of age, Bangkok, Thailand.

The incidence of infections by Mycoplasma pneumoniae, Chlamydia trachomatis and respiratory viruses was investigated in 76 pneumonic patients aged under 6 months who attended Ramathibodi and Siriraj Hospitals in Bangkok during two study periods. M. pneumoniae infection was not found in any case from either hospital by serological diagnosis. By the isolation method, C. trachomatis infection was found in 7(16.7%) of 42 patients from Ramathibodi Hospital and 5(21.7%) of 23 patients from Siriraj Hospital with the average male:female ratio of 2.6:1; and 91.7% of the infected cases were under 3 months old. Laboratory diagnosis of respiratory virus infection was performed by indirect immunofluorescence (IIF), isolation, and by antibody detection. Data from Ramathibodi Hospital showed that 11 (24.4%), 4 (8.9%), 3 (6.7%) of the 45 patients were infected by respiratory syncytial virus (RSV), adenoviruses, parainfluenza virus type 3, and some other viruses, respectively; infection rates of 10 (32.3%), 4 (12.9%), 1 (3.2%) and 1 (3.2%) by those viruses respectively, were observed in the 31 patients from Siriraj Hospital.

Detection of human cytomegalovirus in urine of infants by polymerase chain reaction.

Polymerase chain reaction (PCR), viral isolation and serological methods were used to diagnose HCMV infection in infants. Specimens of urine and clotted blood were collected from suspected cases of congenital or HCMV infection who attended the Pediatric Clinic, Siriraj Hospital. Prevalence of HCMV infection was found in 3 per cent of infants aged under 14 days and increased to 48 per cent in infants aged over 14 days. PCR was the most sensitive technique, it could detect HCMV infection in 29 per cent of the study infants, whereas, detection rate by isolation was 17 per cent and by specific IgM ELISA was 15 per cent. Sensitivity and specificity of PCR compared with isolation and/or serology were 93 per cent and 96 per cent, respectively. Detection of HCMV in urine by PCR can be used as a sensitive and rapid test for diagnosis of HCMV infection in infants.

The abbreviated 2-1-1 schedule of purified chick embryo cell rabies vaccination for rabies postexposure treatment.

During August 1988 to January 1990, the immunogenicity and safety of purified chick embryo cell rabies vaccine (PCEC) given by the conventional and abbreviated regimens in 82 vaccinees moderately to severely exposed to laboratory proven rabid animals were studied. The 16 vaccinees received PCEC six doses as conventional schedule on days 0, 3, 7, 14, 28 and 90, the 11 vaccinees received six doses of PCEC plus human rabies immune globulin (HRIG) on day 0. The 29 vaccinees received an abbreviated schedule of PCEC as two doses on day 0, one dose each on days 7 and 21 and the 26 cases received PCEC abbreviated schedule plus HRIG on day 0. The kinetics of the neutralizing antibodies on days 0, 7, 14, 28, 56, 180 and 365 were studied for comparative purpose. All vaccinees had high antibody levels from day 14 which last longer than a year and were safe after one year follow up. The adverse reactions of the vaccine were mild and self-limited.

Prevalence of human herpesvirus 6 in Thai people and its correlation with human immunodeficiency virus type 1 infection.

Human herpesvirus 6 (HHV-6) is a human herpesvirus isolated from patients with various lymphoproliferative disorders and acquired immunodeficiency syndrome (AIDS). The prevalence of HHV-6 infection and its correlation as a cofactor in pathogenicity of HIV infection was investigated in serum samples from 365 healthy volunteers at various age groups, 50 persons at risk for HIV-1 infection, and 90 HIV-1 seropositive individuals. Sera were screened and titrated for antibodies against HHV-6 by a standard indirect immunofluorescence assay on an acetone fixed HHV-6 infected HSB2 cells. The data show high prevalence of HHV-6 in Thailand (71.7%) and the infection is acquired early in life. Prevalence of anti-HHV-6 IgG antibodies was not strikingly different among people at risk for HIV infection, asymptomatic HIV-1 infected cases, and aged-matched controls with low risk for HIV-1 infection. The AIDS cases showed high titers of anti-HHV-6 IgG antibody and high rates for presence of anti-HHV-6 IgM antibody (33.3%) which suggests higher prevalence of HHV-6 infection by either reactivation of an earlier HHV-6 infection or a new primary infection.

Detection of human immunodeficiency virus type 1 (HIV-1) proviral DNA in breast milk and colostrum of seropositive mothers.

There is increasing evidence of vertical transmission of HIV-1 to infants through breast feeding of milk from HIV-1 infected mothers. It has been postulated that transmission occurs mainly via ingestion of infected cells in breast milk and colostrum. In this study, detection of HIV-1 proviral DNA was used to prove that cells from colostrum and milk do contain HIV. DNA were extracted from these cells of colostrum and milk of 18 seropositive mothers and amplified by nested PCR for HIV-1 gag and pol and 44 per cent were positive mostly by two primers. All ten negative control samples from seronegative mothers were negative. This study demonstrated the infectivity of breast milk and colostrum. Nevertheless, recommendation against breast-feeding should be weighed against poor alternatives in low socioeconomic families.

PIP: In Thailand clinicians gathered breast milk and colostrum samples (1 ml) at 1-10 days postpartum from 18 HIV-1 seropositive mothers at Ramathibodi Hospital and Maharaj Hospital and from 10 HIV-1 seronegative mothers at the same hospitals. Researchers used polymerase chain reaction to detect HIV-1 proviral DNA in cells in the breast milk and colostrum. Breast milk and colostrum samples from 44% of the HIV-1 seropositive women tested positive for HIV-1 DNA. The pol primers were superior to the gag primers. All of the colostrum samples of the HIV-1 seronegative women tested negative. These results suggest that HIV-1 seropositive lactating mothers can transmit HIV-1 via breast feeding after childbirth. The Obstetrics and Gynaecology Department at Ramathibodi Hospital in Bangkok advises HIV-1 infected mothers to not breast feed if there is a suitable alternative available. Health professionals should weigh breast feeding against poor alternatives in impoverished families.

Immunoglobulin G antibody capture enzyme-linked immunosorbent assay: a versatile assay for detection of anti-human immunodeficiency virus type 1 and 2 antibodies in body fluids.

In tests on specimens of dried blood, saliva, and urine from 55 human immunodeficiency virus (HIV)-seropositive and 55 HIV-seronegative patients, an immunoglobulin G capture enzyme immunoassay for the detection of antibodies to HIV types 1 and 2, GACELISA, gave 109 of 110, 109 of 109, and 109 of 110 correct results, respectively. This performance, achieved in a laboratory previously unfamiliar with the assay, suggests that GACELISA is a useful new epidemiological tool for the study of HIV infection, equally applicable to all three kinds of specimen.

Epstein-Barr virus serological markers for nasopharyngeal carcinoma in Thailand.

The present study reports on the prevalence of specific IgA and IgG antibodies to EBV viral capsid antigen in nasopharyngeal carcinoma (NPC) patients with different histological types of carcinoma and their age-matched controls by the indirect immunofluorescence test, using the B-95-8 lymphoblastoid cell line as source of viral capsid antigen. EBV specific IgG was found in almost all the study cases, and antibody titers were significantly higher in the NPC patients than in non-cancer controls. GMT of anti-EBV IgG in NPC patients, patients with other malignant diseases, and those with non-malignant diseases were 371.5, 97.7 and 35.5, respectively. Anti-EBV specific IgA was more specific to NPC than was IgG, and was present in 86.5% (83 of 96) cases of NPC patients, 6.6% (2 of 30) of patients with other cancers, and 3.1% (3 of 97) cases of non-malignant diseases. A weak correlation between level of anti-EBV IgA in NPC patients was observed (r = 0.3). EBV IgA was found in all histological types of NPC, ie, WHO types 1, 2 and 3, but WHO type 1 was rare among NPC patients in Thailand. Use of anti-EBV IgA for monitoring cancer therapy is to be further investigated.

The epidemiology of HIV infection and AIDS in Thailand.

PIP: There were very few AIDS cases reported in Thailand as of 1988, where HIV was introduced relatively late in the course of the AIDS pandemic. Thailand was therefore classified as an epidemiologic pattern III country with regard to the HIV/AIDS pandemic. Also in 1988, however, Thailand experienced a major and rapid increase in HIV prevalence among IV drug users (IVDU). The Thai experience with HIV after the rapid spread first among IVDUs has been successive waves of HIV transmission to female prostitutes, then to their non-IVDU male clients, and then into the non-prostitute wives and girlfriends of these latter men in the general population. Three years after being declared a pattern III country, 300,000 people in Thailand were estimated to be infected out of a population of 55 million. Reasons for this unprecedented rapid spread of HIV infection may eventually come from research on sexual behavior and related diseases given the lack of evidence for human host genetic factors or particularly virulent etiologic agent factors to explain the phenomenon. The reason and dynamics behind the timing and rapidity of the 1988 epidemic among IVDUs for now remains unknown. The authors note that the scenario of HIV transmission observed in Thailand also seems to be unfolding in neighboring countries. HIV infection among female prostitutes and heterosexual men is consistently highest in the northern Thai provinces adjacent to Myanmar and Laos. This paper reviews the epidemiology and prevention of HIV infection and AIDS in Thailand, updating previous reports and commentary, and including previously unpublished or not widely available data.^ieng

A hospital-based study of acute viral infections of the respiratory tract in Thai children, with emphasis on laboratory diagnosis.

The hospital-based study described here examined the viruses found in 738 children less than 5 years old who presented at Ramathibodi Hospital, Bangkok, Thailand, from January 1986 to December 1987 with acute respiratory tract infections. Three methods for detection of viral infection are compared: direct examination of epithelial cells of the respiratory tract with the use of fluorescent antibody staining, isolation of virus, and measurement of antibody in acute- and convalescent-phase sera. Viral infections were found in 44.7% of the study population. Diagnosis by the examination of epithelial cells with the fluorescent antibody staining procedure was found to have several deficiencies; however, this technique was the most sensitive for diagnosis of infection due to respiratory syncytial virus. Isolation of virus was the best method for identification of adenoviruses, parainfluenza 1 and 3 viruses, and influenza B virus. Problems associated with serodiagnosis included failure to obtain specimens of convalescent-phase blood in 24.5% of cases and insensitivity of serodiagnosis for young children except for the identification of antibody to influenza A virus. The combination of all three tests yielded the best rate of detection of virus.

Rabies and post-exposure prophylaxis in Thai children.

Thailand is an endemic area for rabies, with approximately 300 human deaths reported annually. More than half of the rabies patients are children under 14 years of age. This paper reports clinical data of paediatric rabies cases occurring from 1980 to 1986, and the protective efficacies of human diploid cell rabies vaccine (HDCV) and purified Vero cell rabies vaccine (PVRV) in children exposed to rabid animals. The analysis of 120 medical records revealed that rabies in children had incubation periods which ranged from less than fifteen days to more than three months, but generally between one to three months. The most frequent symptoms observed in the patients were hydrophobia, restlessness, fever, vomiting and aerophobia. Most of the rabid children admitted to hospital died within 24 hours. HDCV was administered to 50 children exposed to rabies with the cumulative dosages of 327 ml. All patients survived without serious adverse effects during a-two year follow-up. Mild reactions were seen in 1.5 percent (5/327 doses). Unfortunately, levels of rabies antibody in these vaccinees were not determined. Among another series of children exposed to rabid animals, comprising 27 individuals who received a total of 168 doses of PVRV, only mild local reactions were seen in 6 subjects. No rabies deaths were reported in 2 years of follow-up. The children who received PVRV either with or without human rabies immune globulin developed similar levels of rabies neutralizing (NT) antibody, which reached the high titers on day 30. At one year after the first dose of vaccination, all vaccinees still had NT antibody at titers higher than 0.5 IU/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

High prevalence of delta virus infection in Thai intravenous drug abusers.

The prevalence of antibodies to delta virus (anti-delta) in the selected groups of hepatitis B surface antigenemia population was investigated. The subjects were 84 intravenous drug abusers; 20 chronic hepatitis, 12 cirrhosis, 6 primary hepatocellular carcinoma and 46 asymptomatic healthy carriers. Anti-delta was detected in 65.48% of intravenous drug abusers, 11.11% of chronic active hepatitis and 8.33% of cirrhosis cases. None of asymptomatic carriers had anti-delta. In addition, 51 acute icteric hepatitis B patients who were positive for HBs Ag and 20 IV drug abusers positive for anti-HBc only (HBsAg and anti-HBs negative) were negative for anti-delta.