Wasna Sirirungsi

Uveitis in a tertiary ophthalmology centre in Thailand

Purpose: To determine the aetiology and clinical characteristics of patients with uveitis in a tertiary ophthalmology centre in northern Thailand. Methods: Standard ophthalmological examination and laboratory screening blood tests were performed in 200 consecutive new patients with uveitis. Patients were classified according to the location and aetiology of the uveitis. Specific clinical characteristics were recorded. Design: Prospective case series. Results: The case series included 106 male and 94 female patients with a mean age of 38 years. HIV-associated uveitis was noted in 31% (62/200), and included mostly patients with cytomegalovirus retinitis (85%, 53/62). In the non-HIV group, the most common anatomical type was anterior uveitis (34%, 47/138). Infectious uveitis was diagnosed in 22% (30/138) of non-HIV patients, and toxoplasmosis was the most common infection (12/138, 8.7%). The most common non-infectious clinical entities were Vogt–Koyanagi–Harada disease (20%, 22/108) and HLA-B27-associated acute anterior uveitis (9%, 10/108). Conclusions: The spectrum of uveitis in northern Thailand included 27% of HIV-infected patients with cytomegalovirus retinitis. Causes of non-HIV uveitis were similar to those often observed in the Far East, but the specific prevalences of these disorders were distinct from that found in India and Japan.

Early HIV-1 diagnosis using in-house real-time PCR amplification on dried blood spots for infants in remote and resource-limited settings.

Background:In resource-limited settings, most perinatally HIV-1-infected infants do not receive timely antiretroviral therapy because early HIV-1 diagnosis is not available or affordable. Objective:To assess the performance of a low-cost in-house real-time polymerase chain reaction (PCR) assay to detect HIV-1 DNA in infant dried blood spots (DBS). Methods:One thousand three hundred nineteen DBS collected throughout Thailand from non-breast-fed infants born to HIV-1-infected mothers were shipped at room temperature to a central laboratory.In-house real-time DNA PCR results were compared with Roche Amplicor HIV-1 DNA test (Version 1.5) results. In addition, we verified the Roche test performance on DBS sampled from 1218 other infants using as reference HIV serology result at 18 months of age. Results:Real-time DNA PCR and Roche DNA PCR results were 100% concordant. Compared with HIV serology results, the Roche test sensitivity was 98.6% (95% confidence interval: 92.6% to 100.0%) and its specificity at 4 months of age was 99.7% (95% confidence interval: 99.2% to 99.9%). Conclusions:In-house real-time PCR performed as well as the Roche test in detecting HIV-1 DNA on DBS in Thailand. Combined use of DBS and real-time PCR assays is a reliable and affordable tool to expand access to early HIV-1 diagnosis in remote and resource-limited settings, enabling timely treatment for HIV-1-infected infants.

Viral causes of unexplained anterior uveitis in Thailand

AimsTo assess the possible role of virus infection in patients with unexplained anterior uveitis (AU).MethodsIntraocular fluid and plasma samples of 30 HIV-negative AU patients who were unresponsive or poorly responsive to topical steroid therapy were analyzed for nucleic acid of cytomegalovirus (CMV), herpes simplex virus (HSV), and varicella zoster virus (VZV) by real-time polymerase chain reaction (PCR) and for intraocular antibodies against these viruses by Goldmann–Witmer coefficient (GWC) analysis. Of these 30 cases, 21 were tested for rubella virus by GWC analysis, 16 of which also had PCR assessment of aqueous for rubella virus.ResultsViral uveitis determined by either real-time PCR and/or GWC was documented in 20 out of 30 patients (67%). Of 30 paired samples tested by both methods for HSV, CMV, and VZV, 15 showed positive results (CMV (10), HSV (4), and VZV (1)). Real-time PCR was positive in 8/15 (53%), whereas GWC was positive in 10/15 (67%). Out of 10 CMV-positive patients, four had endotheliitis, two had Posner–Schlossman syndrome, and one Fuchs heterochromic uveitis syndrome (FHUS). Five out of 21 (24%) samples tested by GWC for Rubella virus were positive, three of which exhibited clinical features of FHUS.ConclusionsOur results indicate that CMV is a major cause of AU in Thailand and show that FHUS can be caused by both CMV and Rubella virus.

Association between Detection of HIV-1 DNA Resistance Mutations by a Sensitive Assay at Initiation of Antiretroviral Therapy and Virologic Failure

BACKGROUND Antiretroviral therapy (ART) has become more available throughout the developing world during the past 5 years. The World Health Organization recommends nonnucleoside reverse-transcriptase inhibitor-based regimens as initial ART. However, their efficacy may be compromised by resistance mutations selected by single-dose nevirapine (sdNVP) used to prevent mother-to-child transmission of human immunodeficiency virus (HIV)-1. There is no simple and efficient method to detect such mutations at the initiation of ART. METHODS One hundred eighty-one women who were participating in a clinical trial to prevent mother-to-child transmission and who started NVP-ART after they had received sdNVP or a placebo were included in the study. One hundred copies of each patients HIV-1 DNA were tested for NVP-resistance point-mutations (K103N, Y181C, and G190A) with a sensitive oligonucleotide ligation assay that was able to detect mutants even at low concentrations (> or = 5% of the viral population). Virologic failure was defined as confirmed plasma HIV-1 RNA >50 copies/mL after 6 to 18 months of NVP-ART. RESULTS At initiation of NVP-ART, resistance mutations were identified in 38 (26%) of 148 participants given sdNVP (K103N in 19 [13%], Y181C in 8 [5%], G190A in 28 [19%], and > or = 2 mutations in 15 [10%]), at a median 9.3 months after receipt of sdNVP. The risk of virologic failure was 0.62 (95% confidence interval [CI], 0.46-0.77) in women with > or = 1% resistance mutation, compared with a risk of 0.25 (95% CI, 0.17-0.35) in those without detectable resistance mutations (P < .001). Failure was independently associated with resistance, an interval of <6 months between sdNVP and NVP-ART initiation, and a viral load higher than the median at NVP-ART initiation. CONCLUSIONS Access to simple and inexpensive assays to detect low concentrations of NVP-resistant HIV-1 DNA before the initiation of ART could help improve the outcome of first-line ART.

Prevalence, Risk Factors, and Impact of Isolated Antibody to Hepatitis B Core Antigen and Occult Hepatitis B Virus Infection in HIV-1–Infected Pregnant Women

BACKGROUND Prevalence and risk factors for isolated antibody to hepatitis B core antigen (anti-HBc) and occult hepatitis B virus (HBV) infection are not well known in human immunodeficiency virus type 1 (HIV-1)-infected pregnant women. It is unclear if women with occult infections are at risk of transmitting HBV to their infants. METHODS HIV-1-infected and HBV surface antigen (HBsAg)-negative pregnant women were tested for antibody to HBsAg (anti-HBs) and anti-HBc using enzyme immunoassay. Women with isolated anti-HBc were assessed for occult HBV infection, defined as HBV DNA levels >15 IU/mL, using the Abbott RealTime HBV DNA assay. Infants born to women with isolated anti-HBc and detectable HBV DNA were tested at 4 months of age for HBV DNA. Logistic regression analysis was used to identify factors associated with isolated anti-HBc and occult HBV infection. RESULTS Among 1812 HIV-infected pregnant women, 1682 were HBsAg negative. Fourteen percent (95% confidence interval [CI], 12%-15%) of HBsAg-negative women had an isolated anti-HBc that was independently associated with low CD4 count, age >35 years, birth in northern Thailand, and positive anti-hepatitis C virus serology. Occult HBV infection was identified in 24% (95% CI, 18%-30%) of women with isolated anti-HBc, representing 2.6% (95% CI, 1.9%-3.5%) of HIV-1-infected pregnant women, and was inversely associated with HIV RNA levels. None of the women with isolated anti-HBc and occult HBV infection transmitted HBV to their infants. CONCLUSIONS HIV-1-infected pregnant women with isolated anti-HBc and occult HBV infection have very low HBV DNA levels and are thus at very low risk to transmit HBV to their infants.

Intraocular and plasma HIV-1 RNA loads and HIV uveitis.

Objective:The objective of this study was to analyze human immunodeficiency virus (HIV) dynamics across the blood–retinal barrier and to determine whether the high levels of HIV in the eye are associated with any ocular disorders in HIV-infected patients. Design:This study included a prospective case series of 40 HIV-positive patients with uveitis. Intervention:Clinical and laboratory examinations included plasma and intraocular HIV-1 RNA loads as well as the clinical manifestations of uveitis. Results:Intraocular HIV-1 RNA was detected in 32% (13/40) of HIV-positive patients with uveitis. Intraocular HIV-1 RNA loads were associated with high HIV-1 RNA plasma loads (P < 0.001) and not being on HAART therapy (P = 0.005). In addition, detectable intraocular HIV-1 RNA levels were higher in patients with the absence of retinal lesions (P = 0.008). In three patients, the HIV load in the eye largely exceeded that of plasma. These three patients had all bilateral anterior uveitis and/or vitritis without retinal lesions and exhibited no evidence of other intraocular infectious agents causing uveitis than HIV itself. Conclusion:The eye can form a sanctuary where HIV might replicate and cause an inflammatory reaction.

Human immunodeficiency virus–hepatitis C virus co-infection in pregnant women and perinatal transmission to infants in Thailand

OBJECTIVES The objectives of this study were to assess the prevalence and factors associated with hepatitis C virus (HCV) infection in human immunodeficiency virus (HIV)-infected and -uninfected Thai pregnant women and the rate of HCV transmission to their infants. PATIENTS AND METHODS Study subjects included 1435 HIV-infected pregnant women and their infants, enrolled in a perinatal HIV prevention trial, and a control group of 448 HIV-uninfected pregnant women. Women were screened for HCV antibodies with an enzyme immunoassay. Positive results were confirmed by recombinant immunoblot and HCV RNA quantification. Infants were tested for HCV antibodies at 18 months or for HCV RNA at between 6 weeks and 6 months. RESULTS Of the HIV-infected women, 2.9% were HCV-infected compared to 0.5% of HIV-uninfected women (p=0.001). Only history of intravenous drug use was associated with HCV infection in HIV-infected women. Ten percent of infants born to co-infected mothers acquired HCV. The risk of transmission was associated with a high maternal HCV RNA (p=0.012), but not with HIV-1 load or CD4 count. CONCLUSIONS Acquisition of HCV through intravenous drug use partially explains the higher rate of HCV infection in HIV-infected Thai women than in HIV-uninfected controls. Perinatal transmission occurred in 10% of infants of HIV-HCV-co-infected mothers and was associated with high maternal HCV RNA.

Clinical Manifestations of Human Immunodeficiency Virus-Induced Uveitis

PURPOSE To describe the clinical manifestations of patients with human immunodeficiency virus (HIV)-induced uveitis in Thailand. DESIGN Prospective cohort study of 6 patients with HIV-induced uveitis. PARTICIPANTS Six patients (8 eyes) with HIV-induced uveitis who had an extremely high intraocular: plasma HIV-1 RNA ratio. METHODS The clinical manifestations and laboratory findings are reported of 6 consecutive patients with HIV-induced uveitis who had an extremely high intraocular-to-plasma HIV-1 RNA ratio and were diagnosed between July 2009 and May 2011. MAIN OUTCOME MEASURES Clinical manifestations and laboratory findings. RESULTS Human immunodeficiency virus-induced uveitis was diagnosed in 4 men and 2 women with an average age of 41 years at presentation. None of the patients were receiving highly active anti-retroviral therapy (HAART) or had clinical or laboratory evidence, or both, of opportunistic infections. The mean plasma load was 218 688 copies/ml (median, 137 500 copies/ml; range, 24 900-540 000 copies/ml), and the mean intraocular HIV load was 20 937 755 copies/ml (median, 7 499 000 copies/ml; range, 2 460 000-89 800 000 copies/ml). The average CD4 cell count was 192 cells/μl (median, 248 cells/μl; range, 5-342 cells/μl). All the patients had decreased vision, and none had conjunctival hyperemia. The anatomic location of uveitis was anterior in all patients, and associated vitreitis was present in 4 patients; none exhibited retinal lesions or scars. Anterior segment inflammation and keratic precipitates were observed in all patients, and none responded to topical corticosteroid therapy. After the administration of HAART, the intraocular inflammation disappeared entirely within several weeks in all of the patients and the intraocular and plasma HIV loads decreased. CONCLUSIONS Human immunodeficiency virus-induced uveitis should be suspected in HAART-naïve, HIV-positive patients or in those in whom this treatment fails and who have anterior uveitis without any retinal lesions and exhibit no response to topical corticosteroids. The concurrent determination of HIV load in the intraocular fluids and plasma may clarify the cause of HIV-associated uveitis.

The diagnostic value of intraocular fluid analysis by polymerase chain reaction in Thai patients with uveitis

Uveitis is a major cause of severe visual impairment throughout the world and can be initiated by various infectious and non-infectious causes. Early recognition of specific infections is important as the treatment with antimicrobial agents might stop the progression or even cure the eye disease. To determine the infectious causes of uveitis in Thailand, intraocular fluid samples of 100 HIV-negative patients and 47 HIV-positive patients with uveitis were examined using real-time PCR analysis for herpes simplex virus, varicella zoster virus, cytomegalovirus and Toxoplasma gondii. Positive PCR results were found in 33/100 (33%) HIV-negative patients and in 33/47 (70%) HIV-positive patients with uveitis. In Thailand, cytomegalovirus was identified as the most frequent cause of infectious uveitis in both HIV-negative and HIV-positive patients (49 and 91%, respectively). PCR analysis of intraocular samples in uveitis was a valuable diagnostic assay. The pattern of uveitis observed in the Far East differs from that found in the West.

No relationship between drug transporter genetic variants and tenofovir plasma concentrations or changes in glomerular filtration rate in HIV-infected adults

Host genetics of drug transporters located in the renal tubule may contribute towards tenofovir disoproxil fumarate (TDF)-associated kidney disease susceptibility1, 2. Genetic variants in the ATP-binding cassette (ABC) transporters ABCC2 (1249 G>A) and ABCC4 (3463A>G) have been associated with a greater decline in creatinine clearance (CrCL) over 96 weeks of TDF-based treatment3. High plasma tenofovir (TFV) trough concentrations have been correlated with a decrease in glomerular filtration rate4. A recent study in Thailand reported that tenofovir ‘mid-dose’ plasma concentrations were significantly lower in ABCC2 -24 CT/TT carriers compared to CC carriers after 24 weeks of TDF/3TC/EFV treatment and independently associated with decreased glomerular rate after 48 weeks5. We investigated the association between drug transporter genetic polymorphisms implicated in tenofovir excretion and/or associated nephrotoxicity with TFV plasma concentrations and changes in kidney glomerular filtration rate in antiretroviral naive HIV-infected adults initiating TDF as part of a NNRTI-based regimen. This was a retrospective analysis of adults enrolled in an observational cohort study in Thailand [NCT00433030]. Criteria for treatment initiation were: CDC clinical stage B/C or CD4 <250 cells/mm3. Tenofovir-DF was prescribed 300 mg once-daily. Patients were follow-up monthly during the first 3 months of treatment and then 3-monthly thereafter. A single random blood sample was collected at each visit and plasma frozen at -70°C. The exact time of last drug intake and blood draw were recorded. Creatinine clearance was calculated using the Cockcroft–Gault equation to estimate glomerular filtration rate (eGFR). Local institutional review boards approved the protocol and signed informed consent was obtained from all subjects. Human genomic DNA isolated from EDTA cell pellets stored at −20°C. Ten Single Nucleotide Polymorphisms (SNPs) linked with TFV excretion and/or associated nephrotoxicity were genotyped: ABCC2: -24C>T (rs717620), 1249G>A (rs2273697), 3563 T>A (rs8187694), 3972C>T (rs3740066) and 4544 G>A (rs8187710); ABCC4: 3463 A>G (rs1751034); ABCC10: G>A (rs9349256), 2843 T>C (rs2125739) and SLC22A2: -1604 T>C (rs3127573), G>A, (rs316009). Primers/probes were designed by the TaqMan® “Assays-by-Design®” SNP Genotyping Assay Service (Applied Biosystems, CA, USA) and SNPs identified using Real-time PCR. Plasma TFV concentrations were measured using a validated reversed-phase high-performance liquid chromatography assay6. This assay was internally validated and the average accuracy was 99–102% and precision (inter/intra-assay) was <5% of the coefficient of variation. Population means and variances of TFV pharmacokinetic parameters were estimated using non-linear mixed effects regression (Monolix v4.2, http://www.lixoft.eu)7. Individual patient characteristics including weight, sex, age, body mass index, serum creatinine and CrCL were evaluated for their inclusion in the model using a stepwise forward inclusion and backward elimination procedure. Validity of the model was evaluated using a visual predictive check. Post-hoc subject specific pharmacokinetic parameters were used to estimate individual TFV trough concentrations (C24) and area-under the concentration time curve (AUC0-24h). With ~240 subjects, we had 90% power to detect a difference in TFV C24 of 0.02 μg/mL between combined variants (homo- and heterozygous) and homozygosity of the common allele provided at least 6% (~14 subjects) were in the combined variant group (using a two-sided test, with a standard deviation of 0.02 μg/mL). Differences in TFV C24 between variants (homo- and heterozygous) and homozygosity of the common allele were assessed by Wilcoxon rank-sum tests (due to non-normal C24 distribution). To control the false discovery rate (FDR) q-values were determined8. CrCL was assumed normally distributed so t-tests were used to compare differences in change in CrCL between variants and homozygosity of the common allele (adjusted for baseline CrCL level). All statistical tests performed were two-sided using STATA (v11.1).