The Effect of Detectable HIV Viral Load among HIV-Infected Children during Antiretroviral Treatment: A Cross-Sectional Study

The RNA viral load of human immunodeficiency virus (HIV) is initially used to determine the status of the HIV infection. The goal of therapy following treatment failure is to achieve and maintain virologic suppression. A detectable viral load may relate to the progression of HIV infection. A cross-sectional survey was conducted from January 2013 to December 2014 at the Bamrasnaradura Infectious Diseases Institute, Thailand. The aim was to determine the prevalence of detectable HIV viral load (dVL) and analyze the factors associated with post-dVL conditions that occur independently of a switch to a new antiretroviral agent. The prevalence of dVL was 27% (27 of 101). The mean ages of dVL and non-dVL children were 12.0 and 12.3 years, respectively. Age, sex, body mass index for age z-scores, previous tuberculosis disease history and parental tuberculosis history of both groups were not significantly different (p > 0.05). The prevalence of poor adherence (<95%), influenza-like illness (ILI) and opportunistic infections were higher in dVL than non-dVL children (p < 0.05). The mean nadir CD4 cell count during the study was lower in dVL than non-dVL children (646 compared to 867, respectively; p < 0.05). Other factors were not significant (all p > 0.05). In multivariable analysis, dVL was significantly associated with ILI (odds ratio (OR) = 9.6, 95% confidence interval (CI) = 1.3–69.4), adherence (OR = 0.195, 95% CI = 0.047–0.811) and nadir CD4 during the study (OR = 1.102, 95% CI = 1.100–1.305). The prevalence of dVL was 27% with this dVL among HIV-infected children found to be associated with ILI, poor adherence and lower nadir CD4 during the study.

The validity of clinical practice guidelines for empirical use of oseltamivir for influenza in Thai children

BACKGROUND

Clinical practice guidelines for influenza have been implemented to maximise the appropriate use of empirical oseltamivir; however, good predictive values are required.

METHODS

Between October 2011 and September 2013, children aged < 15 years who presented at the Bamrasnaradura Infectious Diseases Institute with an influenza-like illness plus either (i) pneumonia or (ii) being in a higher risk group for influenza complications were prospectively enrolled. Respiratory specimens were taken for real-time polymerase chain reaction testing (RT-PCR). Clinical characteristics, laboratory data and oseltamivir therapy were recorded.

RESULTS

85 cases were enrolled. Of these, the proportions of those with pneumonia, who were aged < 2 years and who had underlying diseases were 74.1%, 56.5% and 38.8%, respectively. RT-PCR detected respiratory syncytial virusamong (35.3%), influenza (22.3by%), adenovirus (14.1%), human metapneumovirus (5.9%), para-influenza (3.5%) and no viruses (25.9 %). Pneumonia (OR 0.16, 95% CI 0.05-0.50) and having two clinical criteria (OR 0.24, 95% CI 0.08-0.76) were significantly negative predictors of influenza. Having cluster transmissions (OR 5.18, 95% CI 1.38-19.37) and a monocyte proportion >7% (OR 3.58, 95% CI 1.15-11.17) were significantly positive predictors of influenza. The mean (SD) percentage of influenza-like illness during the study period was 7.04 (2.02).

CONCLUSIONS

Clinical criteria guidelines yielded a low predictive value (22.3%) for influenza in children. Seasonality, cluster transmission, white blood cell and differential counts may be helpful in diagnosing influenza. Nonetheless, empirical oseltamivir should not be delayed for those in need.

Lack of transmission among healthcare workers in contact with a case of Middle East respiratory syndrome coronavirus infection in Thailand

Introduction

A hospital-associated outbreak of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) was reported. We aimed to assess the effectiveness of infection control measures among healthcare workers (HCWs) who were exposed to a MERS patient and/or his body fluids in our institute.

Methods

A descriptive study was conducted among HCWs who worked with a MERS patient in Bamrasnaradura Infectious Diseases Institute, Thailand, between 18 June and 3 July 2015. Contacts were defined as HCWs who worked in the patient’s room or with the patient’s body fluids. Serum samples from all contacts were collected within 14 days of last contact and one month later. Paired sera were tested for detection of MERS‐CoV antibodies by using an indirect ELISA.

Results

Thirty-eight (88.4 %) of 43 identified contacts consented to enroll. The mean (SD) age was 38.1 (11.1) years, and 79 % were females. The median (IQR) cumulative duration of work of HCWs in the patient’s room was 35 (20–165) minutes. The median (IQR) cumulative duration of work of HCWs with the patient’s blood or body fluids in laboratory was 67.5 (43.7–117.5) minutes. All contacts reported 100 % compliance with hand hygiene, using N95 respirator, performing respirator fit test, wearing gown, gloves, eye protection, and cap during their entire working period. All serum specimens of contacts tested for MERS-CoV antibodies were negative.

Conclusions

We provide evidence of effective infection control practices against MERS-CoV transmission in a healthcare facility. Strict infection control precautions can protect HCWs. The optimal infection control measures for MERS-CoV should be further evaluated.

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

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

Long-term seroprotective response of trivalent seasonal influenza vaccine in HIV-infected children, regardless of immunogenicity before immunisation

Influenza vaccination can reduce disease in HIV-infected children. The durability of the antibody response after trivalent influenza vaccine is important for management. The aim of this prospective study was to assess the durability of seroprotection for trivalent influenza vaccine strains and the factors effecting seroprotective response regardless of immunogenicity before trivalent influenza vaccine at one and six months after immunisation. Hemagglutination inhibition assay was done at one and six months. Seventy-five HIV-infected children were enrolled after vaccination. Four children were lost to follow-up. None of the children had confirmed influenza infection between immunisation and hemagglutination inhibition at six months after influenza vaccination. Seventy-one children were included in the final analysis and immunogenicity of trivalent influenza vaccine strains at one and six months. Of these, 27 (38%) had complete seroprotection (Group A) and 44 (62%) had non-complete seroprotection (Group B). Sex, age and the body mass index of both groups were not different from each other (p > 0.05). There was a higher mean CD4 level and more children with RNA ≤40 copies/mL among Group A compared with Group B (p < 0.05). Other factors did not differ significantly. The durability of the seroprotective response after trivalent influenza vaccine was associated with a high CD4 level and virological suppression before vaccination.

Polymorphisms in Fas gene is associated with HIV-related lipoatrophy in Thai patients

The present study aimed to evaluate the role of genetic polymorphisms in the emergence of lipoatrophy or lipodystrophy in HIV-infected patients with antiretroviral therapy (ART) in Thailand. Position 455 upstream of the Apolipoprotein C3 gene (ApoC3 T-455C, rs2854116), codon 64 of the Beta3 adrenergic receptor gene (ARβ3 Tcod64C, rs4994), and position 670 upstream of the Fas gene (Fas A-670G, rs1800682) were genotyped in 829 HIV-infected Thai patients who had started ART. Crude and adjusted incidence rate ratios (IRR) were calculated using Poisson regression. The serum levels of cholesterol, triglycerides, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) were also analyzed. Multivariate analysis revealed an association between the Fas -670AA genotype, but not the ApoC3 -455 or ARβ3 cod64 genotypes, with the incidence of lipoatrophy after adjusting for gender and stavudine (d4T)-containing regimens (IRR=1.72, 95% CI=1.20-2.45, p=0.003). However, ApoC3 -455C homozygous patients showed elevated serum levels of triglycerides, while this genotype did not affect serum total cholesterol, HDL, or LDL levels in patients with lipoatrophy or lipodystrophy. In contrast, the ARβ3 cod64 genotype did not show any significant association with the serum levels of cholesterol, triglycerides, HDL, or LDL. In conclusion, Fas -670AA affected the incidence of lipoatrophy in HIV-1-infected Thai patients, while the ApoC3 -455C allele affected the serum levels of triglycerides. These results confirmed the role of genetics in the development of ART-related metabolic disorders.

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

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

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

Background

Cytochrome P450 2B6 (CYP2B6) metabolizes efavirenz and nevirapine, the major core antiretroviral drugs for HIV in Thailand. Rifampicin, a critical component of tuberculosis (TB) therapy is a potent inducer of CYP enzyme activity. Polymorphisms of CYP2B6 and CYP3A4 are associated with altered activity of hepatic enzyme in the liver and pharmacokinetics resulting in treatment efficacy. This study aimed to investigate whether CYP2B6 or CYP3A4 polymorphisms had effects on plasma efavirenz and nevirapine concentrations when co-administered with rifampicin in HIV/TB co-infected Thai adults.

Results

We studied 124 rifampicin recipients with concurrent HIV-1/TB coinfection, receiving efavirenz (600 mg/day) (n = 65) or nevirapine (400 mg/day) (n = 59) based antiretroviral therapy (ART). The frequencies of GG, GT and TT genotypes of CYP2B6-G516T were 38.46%, 47.69% and 13.85% in efavirenz group and 44.07%, 52.54% and 3.39% in nevirapine group, respectively. The mean 12-hour post-dose plasma efavirenz concentration in patients with TT genotype at weeks 6 and 12 of ART and 1 month after rifampicin discontinuation (10.97 ± 2.32, 13.62 ± 4.21 and 8.48 ± 1.30 mg/L, respectively) were significantly higher than those with GT (3.43 ± 0.29, 3.35 ± 0.27 and 3.21 ± 0.22 mg/L, respectively) (p < 0.0001) or GG genotypes (2.88 ± 0.33, 2.45 ± 0.26 and 2.08 ± 0.16 mg/L, respectively) (p < 0.0001). Likewise, the mean 12-hour post-dose plasma nevirapine concentration in patients carrying TT genotype at weeks 6 and 12 of ART and 1 month after rifampicin discontinuation (14.09 ± 9.49, 7.94 ± 2.76 and 9.44 ± 0.17 mg/L, respectively) tended to be higher than those carrying GT (5.65 ± 0.54, 5.58 ± 0.48 and 7.03 ± 0.64 mg/L, respectively) or GG genotypes (5.42 ± 0.48, 5.34 ± 0.50 and 6.43 ± 0.64 mg/L, respectively) (p = 0.003, p = 0.409 and p = 0.448, respectively). Compared with the effects of CYP2B6-516TT genotype, we could observe only small effects of rifampicin on plasma efavirenz and nevirapine levels. After 12 weeks of both drug regimens, there was a trend towards higher percentage of patients with CYP2B6-TT genotype who achieved HIV-1 RNA levels <50 copies/mL compared to those with GT or GG genotypes. This is the first report to demonstrate the effects of CYP2B6 G516T polymorphisms on plasma efavirenz and nevirapine concentrations when co-administered with rifampicin in HIV/TB co-infected Thai adults.

Conclusions

CYP2B6-TT genotype had impact on plasma efavirenz and nevirapine concentrations, while rifampicin co-administration had only small effects.

HLA-Cw*04 allele associated with nevirapine-induced rash in HIV-infected Thai patients

Background

A high incidence of rash has been reported in HIV-1 patients who received the anti-retroviral drug nevirapine. In addition, several studies have suggested that polymorphisms of human leukocyte antigen (HLA) genes may play important roles in nevirapine-induced rash. The aim of the present study was to evaluate the effects of different HLA-C alleles on rash associated with nevirapine in patients who started highly active anti-retroviral therapy (HAART) containing nevirapine in Thailand.

Results

A case-control study was carried out involving HIV-1 patients under treatment at Bamrasnaradura Infectious Diseases Institute, Nonthaburi, Thailand between March 2007 and March 2008. The study included all HIV/AIDS patients being treated with nevirapine-containing regimens. The study population comprised 287 HIV/AIDS patients of whom 248 were nevirapine-tolerant and 39 developed rash after nevirapine treatment. From the nevirapine-tolerant patients, 60 were selected as the control group on the basis of age, sex, and therapy history matched for nevirapine-induced rash cases. We observed significantly more HLA-Cw*04 alleles in nevirapine-induced rash cases than in nevirapine-tolerant group, with frequencies of 20.51% and 7.50%, respectively (P = 0.009). There were no significant differences between the rash and tolerant groups for other HLA-C alleles except for HLA-Cw*03 (P = 0.015).

Conclusion

This study suggests that HLA-Cw*04 is associated with rash in nevirapine treated Thais. Future screening of patients' HLA may reduce the number of nevirapine-induced rash cases, and patients with alleles associated with nevirapine-induced rash should be started on anti-retroviral therapy without nevirapine.

A randomized trial comparing plasma drug concentrations and efficacies between 2 nonnucleoside reverse-transcriptase inhibitor-based regimens in HIV-infected patients receiving rifampicin: the N2R Study

BACKGROUND

To our knowledge, to date, no prospective, randomized, clinical trial has compared standard doses of efavirenz- and nevirapine-based antiretroviral therapy among patients with concurrent human immunodeficiency virus type 1 (HIV-1) infection and tuberculosis (TB) who are receiving rifampicin.

METHODS

Rifampicin recipients with concurrent HIV-1 infection and TB were randomized to receive antiretroviral therapy that included either efavirenz (600 mg per day) or nevirapine (400 mg per day). Efavirenz and nevirapine concentrations at 12 h after dosing (C12) were monitored at weeks 6 and 12. CD4+ cell counts and HIV-1 RNA levels were assessed every 12 weeks.

RESULTS

One hundred forty-two patients were randomized into 2 groups equally. The mean body weight of patients was 53 kg, the mean CD4+ cell count was 65 cells/mm3, and the median HIV-1 RNA level was 5.8 log10 copies/mL. At weeks 6 and 12, the mean C12 of efavirenz (+/- standard deviation) were 4.27+/-4.49 and 3.54+/-3.78 mg/L, respectively, and those for nevirapine were 5.59+/-3.48 and 5.6+/-2.65 mg/L, respectively. Interpatient variability in the efavirenz group was 2.3-fold greater than that in the nevirapine group (coefficient of variation, 107% vs. 47%). At week 12, 3.1% of patients in the efavirenz group and 21.3% in the nevirapine group had C12 values that were less than the recommended minimum concentrations (odds ratio, 8.396; 95% confidence interval, 1.808-38.993; P= .002). Intention-to-treat analysis revealed that 73.2% and 71.8% of patients in the efavirenz and nevirapine groups, respectively, achieved HIV-1 RNA levels <50 copies/mL at week 48, with respective mean CD4+ cell counts of 274 and 252 cells/mm3 (P> .05). Multivariate analysis revealed that patients with low C12 values and those with a body weight <55 kg were 3.6 and 2.4 times more likely, respectively, to develop all-cause treatment failure (P< .05).

CONCLUSIONS

Antiretroviral therapy regimens containing efavirenz (600 mg per day) were less compromised by concomitant use of rifampicin than were those that contained nevirapine (400 mg per day) in patients with concurrent HIV-1 infection and TB. Low drug exposure and low body weight are important predictive factors for treatment failure.

Characteristics of HIV-infected tuberculosis patients in Thailand

To improve understanding about the epidemiology and clinical features of HIV-associated tuberculosis (TB) infection we conducted a prospective, multi-center observational study of HIV-infected TB patients in Thailand. We enrolled HIV-infected patients diagnosed with TB at public health facilities from three provinces and the national infectious diseases referral hospital in Thailand. Patients underwent standardized interviews, evaluations, and laboratory testing at the beginning of TB treatment. We analyzed demographic and clinical characteristics of patients and stratified our findings by level of immune-suppression and whether antiretroviral therapy (ART) was used before TB diagnosis. Of 769 patients analyzed, pulmonary TB was diagnosed in 461 (60%). The median CD4+ T-lymphocyte (CD4) count was 63 cells/microl [interquartile range (IQR), 23-163.5] and the median HIV RNA viral load was 308,000 copies/ml (IQR, 51,900-759,000) at the time of TB diagnosis. Methamphetamine use was reported by 304 patients (40%), marijuana by 267 patients (35%), and injection drug use by 199 patients (26%). Three hundred three patients (40%) reported having been previously incarcerated. Among sexually active patients, 142 (42%) reported never using condoms at all. Patients with CD4 counts <200 cells/microl were significantly more likely than patients with CD4 counts > or =200 cells/microl to have extra-pulmonary TB, fever, fatigue, muscle weakness, no hemoptysis, tachycardia, low body mass index, jaundice, or no pleural effusion. Of the 94 patients that received ART before TB diagnosis, the median time from ART initiation to TB diagnosis was 105 days (IQR, 31-468). HIV-infected patients who developed TB after ART initiation were more likely than other HIV-infected TB patients to have extra-pulmonary TB, a normal chest radiograph, low HIV RNA viral load, or a history of previous TB treatment.

Durability of stavudine, lamivudine and nevirapine among advanced HIV-1 infected patients with/without prior co-administration of rifampicin: a 144-week prospective study

BACKGROUND

To date, data on the durability of a regimen of stavudine, lamivudine and nevirapine are very limited, particularly from the resource-limited settings.

METHODS

A prospective cohort study was conducted among 140 antiretroviral-naïve patients who were enrolled to initiate d4T, 3TC and NVP between November 2004 and March 2005. The objectives were to determine immunological and virological responses after 144 weeks of antiretroviral therapy. Seventy patients with tuberculosis also received rifampicin during the early period of antiviral treatment (TB group).

RESULTS

Of all, median (IQR) baseline CD4 cell count was 31 (14-79) cells/mm3; median (IQR) baseline HIV-1 RNA was 433,500 (169,000-750,000) copies/mL. The average body weight was 55 kilograms. By intention-to-treat analysis at 144 weeks, the overall percentage of patients who achieved plasma HIV-1 RNA <50 copies/mL was 59.3% (83/140). In subgroup analysis, 61.4% (43/70) patients in TB group and 57.1% (40/70) patients in control group achieved plasma HIV-1 RNA <50 copies/mL (RR = 1.194, 95%CI = 0.608-2.346, P = 0.731). Eight (5.8%) patients discontinued d4T due to neuropathy and/or symptomatic lactic acidosis.

CONCLUSION

The overall durability and efficacy of antiviral response of d4T, 3TC and NVP are satisfied and they are not different between HIV-1 infected patients with and without co-administration of rifampicin due to tuberculosis. However, stavudine-related adverse effects are concerns.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT00703898.

LightCycler real-time PCR for rapid detection and quantitation of Mycobacterium leprae in skin specimens

Diagnosis of leprosy is usually based on clinical features and skin smear results including the number of skin lesions. Mycobacterium leprae is not cultivable and bacterial enumeration by microscopic examination is required for leprosy classification, choice in choosing and monitoring chemotherapy regimens, and diagnosis of relapse. However, detection and quantification using standard microscopy yields results of limited specificity and sensitivity. We describe an extremely sensitive and specific assay for the detection and quantification of M. leprae in skin biopsy specimens. Primers that amplified a specific 171-bp fragment of M. leprae 16S rRNA gene were chosen and specificity was verified by amplicon melting temperature. The method is sensitive enough to detect as low as 20 fg of M. leprae DNA, equivalent to four bacilli. The assay showed 100% concordance with clinical diagnosis in cases of multibacillary patients, and 50% of paucibacillary leprosy. The entire procedure of DNA extraction and PCR could be performed in c. 3 h. According to normalized quantitative real-time PCR, the patients in this study had bacilli numbers in the range of 1.07 x 10(2) -1.65 x 10(8) per 6-mm3 skin biopsy specimen. This simple real-time PCR assay is a facile tool with possible applications for rapid detection and simultaneous quantification of leprosy bacilli in clinical samples.

Viral hepatitis and HIV-associated tuberculosis: risk factors and TB treatment outcomes in Thailand

Background

The occurrence of tuberculosis (TB), human immunodeficiency virus (HIV), and viral hepatitis infections in the same patient poses unique clinical and public health challenges, because medications to treat TB and HIV are hepatotoxic. We conducted an observational study to evaluate risk factors for HBsAg and/or anti-HCV reactivity and to assess differences in adverse events and TB treatment outcomes among HIV-infected TB patients.

Methods

Patients were evaluated at the beginning, during, and at the end of TB treatment. Blood samples were tested for aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (BR), complete blood count, and CD4+ T lymphocyte cell count. TB treatment outcomes were assessed at the end of TB treatment according to international guidelines.

Results

Of 769 enrolled patients, 752 (98%) had serologic testing performed for viral hepatitis: 70 (9%) were reactive for HBsAg, 237 (31%) for anti-HCV, and 472 (63%) non-reactive for both markers. At the beginning of TB treatment, 18 (26%) patients with HBsAg reactivity had elevated liver function tests compared with 69 (15%) patients non-reactive to any viral marker (p = 0.02). At the end of TB treatment, 493 (64%) were successfully treated. Factors independently associated with HBsAg reactivity included being a man who had sex with men (adjusted odds ratio [AOR], 2.1; 95% confidence interval [CI], 1.1–4.3) and having low TB knowledge (AOR, 1.8; CI, 1.0–3.0). Factors most strongly associated with anti-HCV reactivity were having injection drug use history (AOR, 12.8; CI, 7.0–23.2) and living in Bangkok (AOR, 15.8; CI, 9.4–26.5). The rate of clinical hepatitis and death during TB treatment was similar in patients HBsAg reactive, anti-HCV reactive, both HBsAg and anti-HCV reactive, and non-reactive to any viral marker.

Conclusion

Among HIV-infected TB patients living in Thailand, markers of viral hepatitis infection, particularly hepatitis C virus infection, were common and strongly associated with known behavioral risk factors. Viral hepatitis infection markers were not strongly associated with death or the development of clinical hepatitis during TB treatment.

Effectiveness and metabolic complications after 96 weeks of a generic fixed-dose combination of stavudine, lamivudine, and nevirapine among antiretroviral-naive advanced HIV-infected patients in Thailand: A prospective study

BACKGROUND

Generic fixed-dose combination (FDC) antiretroviral therapy (ART) has been widely used in resource-limited settings. Treatment based on these combinations provide low pill burden and are less expensive.

OBJECTIVE

The aim of this study was to determine the long-term effectiveness and metabolic complications of a generic FDC of stavudine (d4T)/lamivudine (3TC)/ nevirapine (NVP), among ART-naive HIV-infected patients.

METHODS

A prospective study was conducted among patients who were initiated on d4T/3TC/NVP between November 2004 and March 2005. Plasma HIV-1 RNA, CD4 and alanine transaminase were assessed every 12 weeks. Fasting plasma glucose (FPG) and lipid profile were determined at 96 weeks. Adverse events and genotypic drug resistance were recorded. The primary outcome of interest was the proportion of patients who achieved plasma HIV-1 RNA <50 copies/mL after 96 weeks of ART and analyzed by intent-to-treat (ITT) and on-treatment (OT) populations.

RESULTS

There were 140 patients (mean [SD] age, 35.7 [7.6] years; male, 67.9%) enrolled in the study. Median (interquartile range [IQR]) baseline CD4 was 31 (14-79) cells/mm(3) and HIV-1 RNA count was 433,500 (169,000-750,000) copies/mL. At week 96, 87 patients (ITT, 62.1%; OT, 87.0%) achieved HIV-1 RNA -50 copies/mL. Median (IQR) CD4 at 96 weeks was 328 (229-450) cells/mm(3). The reasons for drug discontinuation were as follows: drug resistance (9.3%), lost to follow-up (9.3%), NVP- related rashes (7.9%), death (5.0%), d4T-related adverse events (3.6%), and transferred to another hospital (2.1%). At 96 weeks, 25 patients (28.7%) had low-density lipoprotein cholesterol (LDL-C) >130 mg/dL, 7 (8.0%) had LDL-C >160 mg/dL, 6 (6.9%) had triglycerides >400 mg/dL, and 2 (2.3%) had FPG >126 mg/dL. Eleven patients (12.6%) had a lactic acid level >2.5 mmol/L. Eight patients (9.2%) needed to take antihypertensive agents. Of 13 patients who developed virologic failure, 76.9% and 61.5% had M184V/I and Y181C/I mutations, respectively.

CONCLUSIONS

Initiation of this FDC ofd4T/3TC/NVP in these ART-naive patients with advanced HIV infection and low baseline CD4 cell count was effective at 96 weeks of follow-up with regard to virologic and immunologic responses. However, long-term metabolic complications, particularly dyslipidemia, were common and should be closely monitored.

Polymorphisms in CCR5 chemokine receptor gene in Japan

Mutations in the human CC chemokine receptor 5 (CCR5) gene may alter the expression or function of the protein product, thereby altering chemokine binding/signalling or human immunodeficiency virus type 1 (HIV-1) infection of the cells that normally express CCR5 protein. We performed a systematic survey of natural sequence variations in an 8.1-kb region of the entire CCR5 gene as well as CCR2V64I in 50 Japanese subjects and evaluated the effects of those variations on CCR5 promoter activity. We also analysed CCR5 promoters and CCR2V64I in 80 more Japanese and 186 Thais. There was no 32-bp deletion observed in Caucasians, but two types of non-synonymous substitutions were found in CCR5 genes of Japanese. Our results showed several novel characteristics of the CCR2-CCR5 haplotype structure that were not reported from studies on Caucasians and African-Americans. Specifically, we were able to show that the G allele at position -2852 from the CCR5 open reading frame in Japanese and Thais is the representative of the CCR5 promoter haplotype that was reported to be associated with rapid progression to acquired immune deficiency syndrome (AIDS) in HIV-1-infected individuals. Furthermore, nearly all non-synonymous polymorphisms in Japanese CCR5 occurred in haplotypes with elevated promoter activity. We thus hypothesized that there was a certain selective pressure favouring low levels of CCR5 expression during human evolution.

Evaluation of HIV-1 viral load detection by modified a commercial real-time PCR reagent used for Light Cycler 1.2 instrument

OBJECTIVE

Commercial TaqMan real-time PCR reagent was modified and applied on Light Cylcer 1.2 for quantifying HIV-1 RNA in plasma and compared with the reference method; COBAS AmpliPrep/COBAS Amplicor HIV-1 monitor test version 1.5.

MATERIAL AND METHOD

Three hundred and eight frozen and fresh plasma samples were used for evaluation. Sequential specimens were also tested for follow-up cases.

RESULTS

The correlation between HIV-1 RNA values obtained by reference and modified method with automated and manual sample preparation were significant with r = 0.916 and 0.908 (p < 0.001, p < 0.001) respectively with similar agreement log of mean bias (0.5 versus 0.48). High degree of correlation and agreement were observed between the assays in blind fresh plasma, r = 0.953 (p < 0.001) with 0.15 log difference in HIV-1 RNA level. Among follow-up samples, both methods gave 100% concordant results.

CONCLUSION

This modified protocol provided evidence for using modified commercial real-time PCR reagent for HIV-1 RNA quantitative detection as a monitoring tool for HIV/AIDS patients in Thailand.

A three-base-deletion polymorphism in the upstream non-coding region of human interleukin 7 (IL-7) gene could enhance levels of IL-7 expression

Interleukin 7 (IL-7) is a key factor in the survival, development and proliferation of B and T lymphocytes. Elevation of plasma IL-7 has been reported in several lymphopenia cases such as HIV-1 patients. After patients started to receive antiretroviral drugs and their CD4(+) cell counts had recovered, IL-7 in plasma decreased to normal levels. There are considerable variations in the levels of plasma IL-7 as well as the rate of CD4(+) T-cell restoration. Although pre-treatment plasma IL-7 levels have been shown to be prognostic for the rate of post-treatment CD4(+) T-cell restoration, the mechanisms responsible for the variations in plasma IL-7 and rate of CD4(+) T-cell restoration are still completely unknown. In the study here, we searched for genetic polymorphisms that might affect levels of IL-7 gene expression. For this purpose, we used 1658-bp PCR-amplified fragments of the IL-7 gene containing 1470 bp of the upstream non-coding region obtained from 151 Japanese and 234 Thai subjects. We found two novel human genetic polymorphisms in the upstream non-coding region of the IL-7 gene. The luciferase reporter assay demonstrated that one of those polymorphisms could increase the gene expression of IL-7. We speculate that this polymorphism, a three base ATC deletion just upstream of an out-of-frame ATG codon in the upstream non-coding region of the IL-7 gene, reduces the efficiency of translation from the upstream, out-of-frame ATG, resulting in increased translation efficiency from the authentic ATG of IL-7. Although the frequency of this allele is very low, it would be interesting to analyse this polymorphism in HIV-1-infected individuals with different rates of immune reconstitution after treatment with a highly active antiretroviral therapy.

Characterization of CCR5 chemokine receptor gene polymorphisms in Japanese and Thai populations (45.11)

Variations in the human CCR5 gene may alter the expression and/or function of the protein product, thereby altering chemokine binding/signaling or HIV infection of the cells that normally express CCR5 protein. We performed a systematic survey of genetic variations in the entire CCR5 gene as well as CCR2V64I in 50 Japanese subjects and evaluated the effects of those variations on CCR5 promoter activity. We also analyzed CCR5 promoter and CCR2V64I genotypes in 80 more Japanese and 186 Thais. Two types of non-synonymous substitutions in Japanese CCR5 gene were found. Our results showed several novel characteristics of the CCR2-CCR5 haplotype structure that were not reported from studies on Caucasians and African-Americans. Specifically, we were able to show that the G allele at position -2852 from the CCR5 translational start codon in Japanese and Thais is the representative of the CCR5 promoter haplotype that was reported to be associated with rapid progression to AIDS in HIV-infected individuals. Furthermore, nearly all non-synonymous polymorphisms in Japanese CCR5 gene occurred in haplotypes with elevated promoter activity. We thus hypothesized that there was certain selective pressure favoring low levels of CCR5 expression during human evolution.

Safety and efficacy of a generic fixed-dose combination of stavudine, lamivudine and nevirapine antiretroviral therapy between HIV-infected patients with baseline CD4 <50 versus CD4 > or = 50 cells/mm3

Background

Antiretroviral therapy (ART) with a generic fixed-dose combination (FDC) of stavudine (d4T)/lamivudine (3TC)/nevirapine (NVP) is widely used in developing countries. The clinical data of this FDC among very advanced HIV-infected patients is limited.

Methods

A retrospective cohort study was conducted among ART-naïve HIV-infected patients who were initiated a generic FDC of d4T/3TC/NVP between May 2004 and October 2005. Patients were categorized into 2 groups according to the baseline CD4 (group A: <50 cell/mm³ and group B: ≥ 50 cell/mm³).

Results

There were 204 patients with a mean ± SD age of 37.1 ± 8.9 years, 120 (58.8%) in group A and 84 (41.2%) in group B. Median (IQR) CD4 cell count was 6 (16–29) cells/mm³ in group A and 139 (92–198) cells/mm³ in group B. Intention-to-treat analysis at 48 weeks, 71.7% (86/120) of group A and 75.0% (63/84) of group B achieved plasma HIV RNA <50 copies/ml (P = 0.633). On-treatment analysis, 90.5% (87/96) in group A and 96.9% (63/65) in group B achieved plasma HIV RNA <50 copies/ml (P = 0.206). At 12, 24, 36 and 48 weeks of ART, mean CD4 were 98, 142, 176 and 201 cells/mm³ in group A and 247, 301, 336 and 367 cells/mm³ in group B, respectively. There were no differences of probabilities to achieve HIV RNA <50 copies/ml (P = 0.947) and CD4 increment at 48 weeks between the two groups (P = 0.870). Seven (9.6%) patients in group A and 4 (8.5%) patients in group B developed skin reactions grade II or III (P = 1.000). ALT at 12 weeks was not different from that at baseline in both groups (P > 0.05).

Conclusion

Initiation of FDC of d4T/3TC/NVP in HIV-infected patients with CD4 <50 and ≥ 50 cells/mm³ has no different outcomes in terms of safety and efficacy. FDC of d4T/3TC/NVP can be effectively used in advance HIV-infected patients with CD4 <50 cells/mm³.

Nevirapine Levels after Discontinuation of Rifampicin Therapy and 60‐Week Efficacy of Nevirapine‐Based Antiretroviral Therapy in HIV‐Infected Patients with Tuberculosis

Seventy patients with human immunodeficiency virus (HIV) and tuberculosis coinfection who initiated nevirapine-based antiretroviral therapy and had trough nevirapine levels determined while receiving rifampicin were enrolled in a study. After discontinuation of rifampicin therapy, mean nevirapine levels (+/- standard deviation) increased from 5.4+/-3.5 mg/L to 6.4+/-3.4 mg/L (P=.047), but no nevirapine-related adverse events occurred. There was no statistically significant difference in 60-week antiviral efficacy between these patients and patients receiving nevirapine-based antiretroviral therapy alone (P>.05).

Plasma Nevirapine Levels and 24‐Week Efficacy in HIV‐Infected Patients Receiving Nevirapine‐Based Highly Active Antiretroviral Therapy with or without Rifampicin

Seventy human immunodeficiency virus (HIV)-infected patients receiving rifampicin and 70 HIV-infected patients not receiving rifampicin were enrolled to receive 400 mg of nevirapine-based highly active antiretroviral therapy per day. Mean plasma nevirapine levels at 8 and 12 weeks were lower in patients receiving rifampicin (P=.048). However, virological and immunological outcomes at 24 weeks were not different between the 2 groups (P>.05).

Usage of dried blood spots for molecular diagnosis and monitoring HIV-1 infection

The usage of dried blood spots as specimens for diagnosis and monitoring of HIV-1 infection in Thailand was evaluated. EDTA blood samples, which were collected from 100 HIV seronegative and 109 HIV seropositive individuals, were tested on dried blood spots; Whatman, Schleicher and Schuell (S&S) No. 903 and S&S IsoCode filter paper. Nucleic acid was extracted and used as a template for HIV-1 proviral DNA detection by an "in-house" multiplex PCR and a commercial Amplicor HIV-1 PCR test (Roche, version 1.0). HIV-1 RNA qualitative (QL) and quantitative (QT) detection was determined by Nucleic Acid Sequence Based Amplification (NASBA). The average DNA per blood spot recovered from Whatman and S&S IsoCode was not statistically different (p = 0.512) with a range of 218.9+/-46.84 and 225.63+/-88.33 microg, respectively. The concordance of HIV-1 proviral DNA detection by PCR from dried blood spots Whatman and S&S IsoCode was 94% versus 89.4% for sensitivity and 100% versus 100% for specificity. The sensitivity and specificity of HIV-1 RNA QL detection in dried blood spots was 89.7 and 97.5%, respectively. The HIV-1 RNA QT from dried blood spots showed a good correlation in paired dried blood spots and plasma with Pearson correlation, r = 0.817 (R2 = 0.667, P < 0.05). The data showed that dried blood spots could be used for the diagnosis and monitoring of HIV-1 infection.

A multicenter evaluation of the PanLeucogating method and the use of generic monoclonal antibody reagents for CD4 enumeration in HIV-infected patients in Thailand

BACKGROUND

The current method of CD4 enumeration in Thailand, based on the three-tube, three-color method recommended by the Centers for Disease Control and Prevention, is expensive and thus unavailable to most patients who have the human immunodeficiency virus (HIV). Less expensive, simpler protocols (i.e., PanLeucogating and primary CD4 gating) have been described but require more published validation data to gain widespread acceptance. We describe a multicenter evaluation of the PanLeucogating method.

METHODS

The PanLeucogating method using generic reagents was evaluated in comparison with the standard three-tube, three-color method using commercial reagents. Percentage of CD4+ T cells among lymphocytes and absolute CD4+ T-cell counts were determined in 611 HIV-infected individuals recruited from four sites. Linear regression and Bland-Altman tests were used for statistical analysis.

RESULTS

The correlation of percentage of CD4+ T cells and absolute CD4+ T-cell counts obtained with the PanLeucogating strategy and the standard predicate method was high (r2 = 0.96 and 0.95, respectively, for the entire study population and r2 > 0.95 and 0.93, respectively, for each study group). Absolute CD4+ T-cell counts of the overall study pool and of the two subdivisions of absolute CD4+ T-cell counts (i.e., 0-250 cells/microl and > 250 cells/microl) derived from the two methods demonstrated excellent agreement, with mean biases of +18 cells/microl, +11 cells/microl, and +24 cells/microl, respectively.

CONCLUSIONS

These observations demonstrate that CD4 enumeration by PanLeucogating is reliable and can be performed to an identical standard in a quality-assured network of collaborating laboratories as a new cost-effective approach to HIV monitoring.

Human immunodeficiency virus type 1 subtype and other factors associated with extrapulmonary Cryptococcosis among patients in Thailand with AIDS

Delineating factors associated with extrapulmonary cryptococcosis (EPC), a major disease burden among Thailand's AIDS patients, can clarify its pathogenesis and guide preventive interventions. From November 1993 through June 1996, enhanced surveillance of 2261 human immunodeficiency virus (HIV)-seropositive patients in a hospital near Bangkok showed EPC among 561 of 1553 AIDS patients (36.1%). Univariate analysis results were confirmed by multivariate analyses of data on 1259 patients. Logistic regression models identified factors significantly associated with EPC to be male sex (adjusted odds ratio [aOR], 2.0; 95% confidence interval [CI], 1.3-2.9), age <33 years (aOR, 1.5; 95% CI, 1.2-1.9), severe immunosuppression (aOR, 1.8; 95% CI, 1.3-2.6), not injecting drugs (aOR, 3.0; 95% CI, 1.7-5.5), and infection with HIV-1 circulating from CRF01_AE (formerly subtype E) versus subtype B (aOR, 2.3; 95% CI, 1.2-4.5). The association with CRF01_AE may result from undetermined markers of exposure or viral subtype effects on host immune responses. Better understanding of the epidemiology of EPC may reduce EPC incidence through targeted primary prevention and treatment.

The efficacy of combined zidovudine and lamivudine compared with that of combined zidovudine, lamivudine and nelfinavir in asymptomatic and early symptomatic HIV-infected children

In this 6-month prospective study, we compared the efficacy of two treatment regimens: double-drug therapy with zidovudine (ZDV) and lamivudine (3TC) and triple-drug therapy with ZDV plus 3TC plus nelfinavir (NFV), in the treatment of asymptomatic and early symptomatic HIV-infected children. Twenty-five children were enrolled in this study and were divided into 2 groups: group A, consisting of 13 children who were given ZDV+3TC; group B, consisting of 12 children who were given ZDV+3TC+NFV. Serial determinations of weight, CD4-cell count, HIV RNA or plasma viral load (VL) and complete blood counts (CBC), liver function tests (LFT), blood urea nitrogen (BUN) tests, creatinine and serum amylase tests were performed at study entry and at 1, 3 and 6 months. The side-effects of drugs were recorded. Over the 6-month period, the median weight increase in group B (24%) was higher than in group A (2%). The median CD4-cell count increase from baseline in group B (94.5%) was better than in group A (9.4%). The reduction of VL below baseline in group B (1.2 log10; 20.8%) was also better than in group A (0.72 log10; 13.8%). However, these differences were not statistically significant (p>0.05). Both combination regimens could not completely suppress HIV RNA below detectable limits (<400 copies/ml). Both groups tolerated the regimens well; no side-effects or toxicities occurred. The efficacy levels of triple-drug therapy (ZDV+3TC+NFV) and double-drug therapy (ZDV+3TC) were not different. There were no side-effects and no deaths during the 6-month study period.

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.

A prevalence of Cryptosporidium infections among Thai HIV-infected patients

The prevalence of Cryptosporidium in 156 HIV-infected Thai patients who had acute diarrheal illness at Bamrasnaradura Infectious Diseases Hospital, was studied. This cross-sectional study was performed from March to August in year 2001. The patients ranged in age from 1 month-65 years old. A stool sample from each subject was stained to find the oocysts by modified Ziehl Nelson carbolfuchsin staining. According to the present study, a diagnosis of Cryptosporidium parvum infection was found in 20 patients (11 males and 9 females). The prevalence of cryptosporidiosis in the present series was 12.8 per cent (10.0% in males and 19.1% in females). This infection rate between males and females was not significantly different. Comparing this prevalence to a report in the previous 5 years in the same hospital, the same high rate can be seen.

Clinical disease associated with HIV-1 subtype B' and E infection among 2104 patients in Thailand

BACKGROUND

Two HIV-1 envelope subtypes have accounted for virtually all infections in Thailand: subtype B' (Thai B), found mainly in injection drug users (IDU), and subtype E, found in over 90% of sexually infected persons and an increasing proportion of IDU in recent years. It remains unclear whether there are differences in pathogenesis associated with these HIV-1 subtypes.

METHODS

From November 1993 to June 1996, demographic, risk, clinical, and laboratory data were collected by enhanced surveillance from HIV-infected inpatients (> or =14 years) at an infectious disease hospital near Bangkok. HIV-1 subtype was determined by V3-loop peptide enzyme immunoassay (EIA). Because of confounding, multivariate analyses were stratified by risk category and controlled for sex and age.

RESULTS

The infecting HIV-1 subtype was determined for 2104 (94.9%) of 2217 HIV-infected patients with complete data: 284 (13.5%) were subtype B', 1820 (86.5%) were E. Specimens from 113 (5.1%) patients were non-reactive or dually reactive on peptide EIA and were excluded. Among IDU, 199 (67.2%) had subtype B', and 97 (32.7%) had E. IDU accounted for 70.1% (199/284) of patients with subtype B' and 5.3% (97/1820) of those with E. Patients infected with HIV-1 subtypes B' or E had similar spectrums of opportunistic infections (OI), levels of immunosuppression, and in-hospital mortality rates. Of patients who did not inject drugs, more patients infected with subtype E had extrapulmonary cryptococcosis than those with subtype B' (adjusted odds ratio, 2.6; 95% confidence interval, 1.28-5.37).

CONCLUSION

HIV-1 subtypes B' and E seem to be associated with similar degrees of immunosuppression and, with one exception, with similar OI patterns. These data do not suggest an association between HIV-1 subtype and differences in pathogenicity.

Clinical presentation of hospitalized adult patients with HIV infection and AIDS in Bangkok, Thailand

OBJECTIVE

To characterize the clinical spectrum of disease and immune status of adult HIV-1-infected patients in Bangkok.

DESIGN

Cross-sectional survey of hospital admissions.

METHODS

From November 1993 through June 1996, demographic, clinical, and laboratory data were collected from HIV-infected inpatients (> or =14 years old) at an infectious diseases hospital.

RESULTS

Of 16,717 persons admitted, 3112 (18.6%) were HIV-seropositive, 2261 of whom were admitted for the first time. Of 2261, 1926 (85.2%) were male, 1942 (85.9%) had been infected heterosexually or by means not related to drug use, 319 (14.1%) were injection drug users (IDUs), and 1553 (68.7%) had AIDS. The most common AIDS-defining conditions were extrapulmonary cryptococcosis (EPC; 38.4%), tuberculosis (TB; 37.4%), and wasting syndrome (WS; 8.1%). IDUs were more likely (p < .05) to have TB or WS but less likely (p < .05) to have EPC or Pneumocystis carinii pneumonia than patients with no history of injection drug use. Lymphocyte counts were measured for 2047 (90.5%) patients; 81.8% had < or =1500 lymphocytes/microl.

CONCLUSION

These HIV-infected patients were admitted with severe immunosuppression. Cryptococcosis and TB are major problems and differ in prevalence among IDUs and persons infected sexually. Clinical and immunologic information is critical in improving the lives of HIV-infected persons in Asia through prevention, treatment, and prophylaxis.

Role of maternal humoral immunity in vertical transmission of HIV-1 subtype E in Thailand

The significance of the maternal humoral immune response in relation to vertical transmission of HIV-1 was investigated in 123 mothers infected with subtype E from Thailand. Antibody binding titers to HIV-1 env domains (monomeric gp120, the CD4/gp120 binding site [BS], V3 loop, and gp41) and antibody-mediated neutralization of primary and T-cell line-adapted (TCLA) subtypes B and E HIV-1 isolates were investigated. No correlation between maternal anti HIV-1 antibodies at delivery and vertical transmission of HIV-1 subtype E was found. However, a trend to higher titer antibody-mediated cross-neutralization of a heterologous subtype B TCLA isolate, HIV-1MN, was observed in nontransmitting mothers postpartum. The HIV-1-specific antibody titers in these infected mothers increased significantly from delivery to 6 months postpartum (p < .05), but this was only partially attributable to hemodilution and an additional factor or factors appear to affect humoral immunity to HIV-1 during late pregnancy.

Characterization of sera from subjects infected with HIV-1 subtypes B and E in Thailand by antibody binding and neutralization

The range and specificity of the humoral immune response to HIV-1 subtypes B and E was investigated in Thai samples. Sera from HIV-1-positive subjects, consisting of subtypes B (n = 24) and E (n = 138), were characterized in relation to the neutralization of primary isolates and T-cell line-adapted (TCLA) strains and binding to monomeric gp120, the CD4/gp120 binding site (BS), and V3 peptides. A subtype-specific pattern of antibody binding was observed with the exception of the CD4/gp 120MN BS. Neutralization of TCLA strains (n = 4) was strongly type-specific (p = .002); however, neutralization of primary isolates (n = 8) was weak and group specific. Thus, the subtype specificity of B and E sera in the neutralization of TCLA strains, but not primary isolates, supports the dominance of the V3 region in TCLA virus neutralization but does not support the distinction of subtypes B and E as discrete neutralization serotypes in Thailand.

The reference range of CD4+ and CD8+ T-lymphocytes in healthy non-infected infants born to HIV-1 seropositive mothers; a preliminary study at Siriraj Hospital

The results of CD4+, CD8+ T-lymphocyte values as percentage, number, and ratio were studied in infants aged 1 to 29 months. The 283 subsequent blood samples from 89 infants born to HIV-1 seropositive mothers were investigated. From 208 sequential samples of 70 healthy non-infected infants, the reference values of CD4+ and CD8+ T-lymphocytes have been established and compared to Caucasian reference values. The results were analysed in 4 difference age groups (1-5, 6-11, 12-17 and > or = 18 months). At age 12 months, CD4 number and percentage declined significantly while CD8 percent increased. At age 6 months CD4/CD8 ratio decreased. Of 19 infected infants CD4+ percentage and number as well as CD4/CD8 ratio declined at age 6 months and showed significant differences from uninfected infants. A significantly elevated CD8 percentage was demonstrated in infected infants at age of 12 months. In 9 infants who showed symptoms at age 6-18 months, the CD4 and CD8 values were different from the reference range and 6 of 9 patients showed lower CD4 percentage, CD4 number and reversed CD4/CD8 ratio before the symptoms appeared. In 10 infants who were asymptomatic at age 18 months, there was no evidence of immunosuppression at age 6 months or before. After age 6 months, lymphocyte subset values of some asymptomatic infected children were beyond the reference range. These preliminary findings should be very useful for monitoring children born to HIV infected mothers. The results of CD4+ and CD8+ T-lymphocytes in uninfected infants could be used as reference values for the Thai and other Southeast Asian pediatric populations.

Nontyphoidal Salmonella diarrhea in Thai children: a study at Bamrasnaradura Hospital, Nonthaburi, Thailand

From July 1, 1994 to June 30, 1996, 394 children with Nontyphoidal Salmonella diarrhea were studied at Bamrasnaradura Infectious Disease Hospital in Thailand. The ages ranged from 1 month to 12 years (mean, 1.4 years). Eighty-seven per cent of patients were in the first 2 years of life. Diarrhea, mostly acute with watery stool and fever were the most common presenting symptoms. The duration of diarrhea ranged from 1 to 20 days (mean, 5.2 days). Salmonella group B was the most common serogroup (56.1%). Most isolates were multiresistant strains, however, they were all sensitive to norfloxacin. Four (1%) patients were HIV-infected. Pneumonia found in 2 patients (0.5%) and septicemia in 1 patient (0.3%). None of the patients died. We conclude that nontyphoidal Salmonella diarrhea in children is still endemic in Thailand, especially among infants and high multidrug resistance occurs.

Seroprevalence of human herpesvirus 6 and 7 infections in the Thai population

Seroprevalence of human herpesvirus 6 (HHV-6) and 7 (HHV-7) was estimated in the Thai population using indirect immunofluorescence assay to determine serum antibodies to HHV-6 and HHV-7. A total of 333 serum samples obtained from umbilical cord blood and venous blood of healthy persons at Siriraj Hospital and Krabi Hospital during 1990-1993 were investigated. Of 73 infants aged 0-1 month, 73% and 78% were found tob e positive for HHV-6 and HHV-7 antibodies, respectively. Antibody to HHV-6 was detected in age groups 2-3 months (38%), 4-5 months (14%), 6 months (44%), 7-11 months (66%), 1-2 year (84%), 3-4 years (82%), 5-9 years (83%), 10-19 years (83%), 20-29 years (80%), 30-39 years (67%), and over 40 years (58%), respectively. This positive rates of HHV-7 antibody in age groups 2-3 months, 4-5 months, 6 months, 7-11 months, 1-2 years, 3-4 years, 5-9 years, 10-19 years, 21-29 years, 30-39 years, and over 40 years were 50%, 21%, 10%, 37%, 47%, 82%, 75%, 72%, 72%, 67%, and 67%, respectively. At 6 months of age as the starting time of infections, 34% (14/41) and 9% (3/41) of infants had presumed primary infections of HHV-6 and HHV-7, respectively. In the follow-up study, 53% (20/38) of children were infected with HHV-6 prior to HHV-7 and only 5% vice versa. Eighty-four percent of children had acquired antibody to HHV-6 by 1-2 years old while 82% of children had acquired antibody to HHV-7 by 3-4 years old. These results suggest that HHV-6 and HHV-7 are prevalent viruses in the Thai population. The infections of both viruses begin at 6 months of age. However, infection of HHV-7 in most children begins later. The data also provided evidence that antigenic distinction between HHV-6 and HHV-7 existed with a limited cross-reactivity in an antibody test. The antibody responses to HHV-6 and HHV-7 occurred independently.

Group C rotavirus infections in patients with diarrhea in Thailand, Nepal, and England

Atypical rotavirus obtained from fecal specimens of six patients with diarrhea from Thailand, Nepal, and England were characterized by using polyacrylamide gel electrophoresis and immune electron microscopy. The electropherotypes were characteristic of the porcine reference group C rotavirus strain but demonstrated considerable strain-to-strain variation. Human convalescent group C sera had a high titer (1:320) when tested against the human isolates and a low titer (1:40) when tested against a porcine reference strain (Cowden). When porcine antiserum (Cowden) was tested against the human isolates, the titers ranged from 1:40 to 1:320, indicating significant antigenic diversity between strains. Group C rotavirus appears to have a worldwide distribution as an agent associated with diarrhea in children and adults.