Clinical and laboratory impact of concomitant syphilis infection during acute HIV.

INTRODUCTION: Cognitive impairment has been reported in people living with HIV-1 (PLWH) with prior syphilis, while PLWH who present with incident syphilis have reduced blood CD4 T-lymphocyte and elevated HIV-1 RNA levels. However, the clinical, virological and neurocognitive effects of syphilis during acute HIV-1 (AHI) remain unknown. METHODS: Pre-antiretroviral therapy laboratory outcomes and neurocognitive performance in a four-test battery in the SEARCH10/RV254 AHI cohort were compared according to syphilis status, determined by serum Treponema pallidum haemagglutination (TPHA), Venereal Disease Research Laboratory (VDRL) and syphilis treatment history. Impaired cognitive performance was defined as having z-scores ≤ -1 in at least two tests or ≤ -2 in at least one test. RESULTS: Out of 595 AHI participants (97% male, median age of 26 years and estimated duration of HIV-1 infection of 19 days), 119 (20%) had history of syphilis (TPHA-positive), of whom 51 (9%) had untreated syphilis (TPHA-positive/VDRL-positive/without prior treatment). Compared with those without syphilis (TPHA-negative), individuals with untreated syphilis had higher CD8 T-lymphocyte levels but not higher plasma HIV-1 RNA or lower CD4 T-lymphocyte levels. Taking into account estimated duration of HIV-1 infection (P < 0.001), and later Fiebig stages (III-V) (P < 0.001), those with untreated syphilis had higher CD8 T-lymphocyte levels (P = 0.049). Individuals with any syphilis (TPHA-positive), but not untreated syphilis, had higher odds of impaired cognitive performance than those without (P = 0.002). CONCLUSIONS: During AHI, individuals with any history of syphilis (TPHA-positive) had poorer cognitive performance than those without syphilis. However, syphilis was not associated with worsened HIV disease measures as described in chronic infection.

Adverse bone health and abnormal bone turnover among perinatally HIV-infected Asian adolescents with virological suppression.

OBJECTIVES: This study aimed to determine the prevalence of low bone mass and assess its relationship with abnormal bone turnover among HIV-infected Asian adolescents. METHODS: A multicentre, cross-sectional study was conducted at four paediatric HIV centres in Thailand and Indonesia. Perinatally HIV-infected adolescents aged 10-18 years receiving antiretroviral therapy (ART) with virological suppression (HIV RNA < 400 copies/mL) were enrolled. Study assessments included lumbar spine (L2-L4) dual-energy X-ray absorptiometry and measurement of bone turnover markers. Bone mineral density (BMD) and bone mineral apparent density (BMAD) Z-scores were calculated based on Thai normative age- and sex-matched references. Low bone mass was defined as BMD or BMAD Z-scores ≤ -2. RESULTS: Of 396 participants, 57% were female. The median age was 15.0 [interquartile range (IQR) 13.3-16.9] years, and 73% were in Tanner stage 3-5. At enrolment, the median CD4 T-cell count was 734 (IQR 581-907) cells/µL, and 37% were on protease inhibitor (PI)-based regimens. The overall prevalence of lumbar spine BMD and BMAD Z-scores ≤ -2 were 16.4% and 8.3%, respectively. Z-scores were lower with older age, female sex, body mass index (BMI) <5th percentile, boosted PI exposure and CD4 T-cell percentage < 15% before ART initiation. Increased bone turnover markers were inversely associated with BMD and BMAD Z-scores. CONCLUSIONS: Low bone mass was linked to older age, female sex, low BMI, boosted PI exposure, and poor immunological status before ART commencement in our cohort of perinatally HIV-infected Asian adolescents. Dysregulation of bone turnover was associated with bone demineralization. Screening for low bone mass should be implemented to identify individuals who might benefit from interventions to preserve bone health.

Determinants of epidermal nerve fibre density in antiretroviral-naïve HIV-infected individuals.

OBJECTIVES: Distal leg epidermal nerve fibre density (ENFD) is a validated predictor of small unmyelinated nerve fibre damage and neuropathy risk in HIV infection. As pre-existing damage may increase the risk of neuropathy following antiretroviral (ARV) therapy, particularly when the regimen contains stavudine (d4T), we assessed the relationship between ENFD and various parameters including mitochondrial factors in HIV-infected Thai individuals naïve to ARV therapy. METHODS: Distal leg and proximal thigh ENFDs were quantified in HIV-infected Thai individuals without neuropathy prior to randomization to a HIV clinical trial that focused on mitochondrial toxicity issues. We assessed their association with various clinical and immunovirological parameters as well as with peripheral blood mononuclear cell (PBMC) mitochondrial (mt) DNA copies/cell, oxidative phosphorylation (OXPHOS) complex I (CI) and complex IV (CIV) enzyme activities, and mt 8-oxo-deoxyguanine (8-oxo-dG) break frequencies. RESULTS: In 132 subjects, the median (interquartile range) ENFD (fibres/mm) values were 21.0 (16.2-26.6) for the distal leg and 31.7 (26.2-40.0) for the proximal thigh. By linear regression, lower CD4 count (P < 0.01), older age (P < 0.01), increased body mass index (BMI) (P = 0.04), increased height (P = 0.02), and higher PBMC OXPHOS activity as measured by CIV activity (P = 0.02) were associated with lower distal leg ENFD. CONCLUSIONS: Older age, increased height, higher BMI, poorer immunological status and higher PBMC OXPHOS activity are associated with lower distal leg ENFD in HIV-infected subjects free of neuropathy prior to initiation of first-time ARV therapy.

Failure to clear intra-monocyte HIV infection linked to persistent neuropsychological testing impairment after first-line combined antiretroviral therapy.

HIV-associated neurocognitive disorders (HAND) persist despite plasma HIV RNA suppression with antiretrovirals (ARV). Sequestered reservoirs in the central nervous system and circulating monocytes are theorized to contribute to persistent brain injury. We previously demonstrated that elevated intracellular HIV DNA from circulating cells was associated with HAND in ARV-treated and ARV-naive subjects. We now report that failure to suppress intra-monocyte HIV DNA 3.5 years after initiating ARV is linked to persistent HAND and subjects with dementia are least likely to suppress intra-monocyte HIV DNA at 3.5 years. These findings suggest that antiviral strategies may need to target intra-monocyte HIV DNA.

Cardiovascular risk assessment in persons with HIV infection in the developing world: comparing three risk equations in a cohort of HIV-infected Thais.

OBJECTIVE: There is growing concern regarding cardiovascular disease in HIV-infected individuals in developing countries such as Thailand. We evaluated the 10-year risk of coronary heart disease (CHD) in a Thai HIV-infected cohort using three cardiovascular risk equations, and assessed the level of agreement among their predictions. METHODS: We carried out a cross-sectional analysis of data on 785 Thai subjects followed prospectively in the HIV Netherlands Australia Thailand Collaboration (HIV-NAT) cohort study from 1996 to 2009. Cardiovascular risk factor history, along with relevant laboratory and clinical data, was collected at follow-up clinic visits. Ten-year risks of CHD were calculated using the Framingham, Ramathibodi-Electricity Generating Authority of Thailand (Rama-EGAT) and Data Collection on Adverse Effects of Anti-HIV Drugs (D:A:D) risk equations. RESULTS: The mean age of the patients was 41.0 years; 55% of the subjects were male. The mean duration of antiretroviral therapy was 7.7 years. The prevalence of cardiovascular risk factors was low, with the most common risk factor being low high-density lipoprotein (HDL) (36.3%). The prevalence of high cardiovascular risk scores (defined as 10-year risk of CHD≥10%) was also low: 9.9, 2.1 and 0.8%, by the Framingham, Rama-EGAT and D:A:D scoring systems, respectively. Only eight subjects (1.0%) had a history of CHD. Bland-Altman plots showed that the Framingham equation predicted a higher risk of CVD compared with the Rama-EGAT and D:A:D equations, which agreed relatively well. CONCLUSION: The predicted cardiovascular risk in this HIV-infected Thai cohort was relatively low. The agreement among the Rama-EGAT and D:A:D risk scores suggests that both equations may be appropriate estimators of cardiovascular risk in this population.

HIV-1 drug resistance mutations in children after failure of first-line nonnucleoside reverse transcriptase inhibitor-based antiretroviral therapy.

OBJECTIVES: The aim of the study was to assess the prevalence, predictors and patterns of genotypic resistance mutations in children after failure of World Health Organization-recommended initial nonnucleoside reverse transcriptase inhibitor (NNRTI)-based treatment regimens. METHODS: We carried out a multicentre retrospective study of genotyping tests performed for all HIV-infected children at eight paediatric centres in Thailand who experienced failure of NNRTI therapy at a time when virological monitoring was not routinely available. RESULTS: One hundred and twenty children were included in the study. Their median age (interquartile range) was 9.1 (6.8-11.0) years, the median duration of their NNRTI regimens was 23.7 (15.7-32.6) months, their median CD4 percentage was 12% (4-20%), and their median plasma HIV RNA at the time of genotype testing was 4.8 (4.3-5.2) log(10) HIV-1 RNA copies/mL. The nucleoside reverse transcriptase inhibitor (NRTI) resistance mutations found were as follows: 85% of the children had M184V/I, 23% had at least four thymidine analogue mutations, 12% had the Q151M complex, 5% had K65R, and 1% had the 69 insertion. Ninety-eight per cent of the children had at least one NNRTI resistance mutation, and 48% had etravirine mutation-weighted scores ≥4. CD4 percentage <15% prior to switching regimens [odds ratio (OR) 5.49; 95% confidence interval (CI) 2.02-14.93] and plasma HIV RNA>5 log(10) copies/mL (OR 2.46; 95% CI 1.04-5.82) were independent predictors of at least four thymidine analogue mutations, the Q151M complex or the 69 insertion. CONCLUSIONS: In settings without routine viral load monitoring, second-line antiretroviral therapy regimens should be designed assuming that clinical or immunological failure is associated with high rates of multi-NRTI resistance and NNRTI resistance, including resistance to etravirine.

HIV-associated gut dysbiosis is independent of sexual practice and correlates with noncommunicable diseases.

Loss of gut mucosal integrity and an aberrant gut microbiota are proposed mechanisms contributing to chronic inflammation and increased morbidity and mortality during antiretroviral-treated HIV disease. Sexual practice has recently been uncovered as a major source of microbiota variation, potentially confounding prior observations of gut microbiota alterations among persons with HIV (PWH). To overcome this and other confounding factors, we examine a well-powered subset of AGEhIV Cohort participants comprising antiretroviral-treated PWH and seronegative controls matched for age, body-mass index, sex, and sexual practice. We report significant gut microbiota differences in PWH regardless of sex and sexual practice including Gammaproteobacteria enrichment, Lachnospiraceae and Ruminococcaceae depletion, and decreased alpha diversity. Men who have sex with men (MSM) exhibit a distinct microbiota signature characterized by Prevotella enrichment and increased alpha diversity, which is linked with receptive anal intercourse in both males and females. Finally, the HIV-associated microbiota signature correlates with inflammatory markers including suPAR, nadir CD4 count, and prevalence of age-associated noncommunicable comorbidities.

Anal squamous intraepithelial lesions among HIV positive and HIV negative men who have sex with men in Thailand.

OBJECTIVES: To evaluate the prevalence and risk factors of anal squamous intraepithelial lesions (ASIL), the putative anal cancer precursor, in Asian HIV positive and HIV negative men who have sex with men (MSM). METHODS: Men who underwent anal Pap smear reported clinical, sociodemographic and behavioural information collected through questionnaire and interview between January 2007 and April 2008. Chi(2) and logistic regression were used to evaluate ASIL prevalence and risk factors among HIV positive and HIV negative MSM. RESULTS: Of the 174 MSM (mean age 32.1 years), 118 (67.8%) were HIV positive. Overall, 27% had abnormal anal cytology: 13.2% had atypical squamous cells of undetermined significance (ASC-US), 11.5% had low-grade squamous intraepithelial lesion (LSIL) and 2.3% had high-grade squamous intraepithelial lesion (HSIL). Prevalence of ASIL was higher among HIV positive than HIV negative MSM (33.9% vs 12.5%; p = 0.003). Among HIV positive MSM, 16.1% had ASC-US, 14.4% had LSIL and 3.4% had HSIL and 7.1%, 5.4% and 0% in HIV negative MSM, respectively. Anal condyloma was detected in 22% of HIV positive and 16.1% (9/56) of HIV negative MSM (p = 0.5). In HIV positive MSM, anal condyloma (OR 3.42, 95% CI 1.29 to 9.04; p = 0.01) was a significant risk factor for ASIL. Highly active antiretroviral therapy use and CD4+ T cell count were not associated with ASIL. CONCLUSIONS: One-third of HIV positive and 12.5% of HIV negative MSM had ASIL. Thus, as greater numbers of HIV positive MSM live longer due to increasing access to HAART worldwide, effective strategies to screen and manage anal precancerous lesions are needed.

Preference for CD4-guided versus continuous HARRT in Thailand.

Nineteen patients who completed a 27-month CD4-guided structured treatment interruption (STI) trial that showed similar efficacy in STI and continuous arms were asked to choose CD4-guided versus continuous HAART after the study ended. Six chose STI and 13 chose continuous HAART. Reasons for not choosing STIs were fear of developing HIV-related illnesses (38%), fear of CD4 drop (30.8%), fear of viral load increase (7.7%) and ease (7.7%). Those who preferred CD4-guided HAART had a higher median CD4 count nadir during STI and fewer on-off cycles. This study provides an important insight into the preference of patients towards STI in a resource-limited setting.

Cervical cytological abnormalities and HPV infection in perinatally HIV-infected adolescents.

BACKGROUND: Behaviourally HIV-infected adolescent females are at higher risk for abnormal cervical cytology and HPV infection compared to those who are uninfected, but data on perinatally HIV-infected adolescent females are lacking. METHODS: Cervical cytology, HPV infection and E6/E7 mRNA were assessed in sexually active 12-24-year-old adolescent females: perinatally HIV-infected (group 1, n = 40), behaviourally HIV-infected (group 2, n = 10), and HIV-uninfected (group 3, n = 10). RESULTS: Median age was lower in group 1 (18 years) than in groups 2 (24 years) and 3 (20.5 years) (P < 0.001), and median time since sexual debut was shorter: 2 vs 5 vs 4 years (P < 0.001). More trial participants in group 1 than group 2 were on antiretrovirals (90% vs 70%; P <0.001). Abnormal cervical cytology (atypical squamous cells of undetermined significance and higher) was observed in 30% (group 1), 40% (group 2) and 30% (group 3) (P = 0.92), whereas high-risk HPV infection was observed in 45%, 45% and 40%, respectively (P = 1.00). Positive E6/E7 mRNA was found in 28% of group 1, but not in other groups. High-risk HPV infection predicted abnormal cytology in all groups [OR 6.77, 95% confidence interval (CI) 1.99-23.0; P = 0.001). Additionally, plasma HIV RNA ≥50 copies/mL (OR 13.3, 95% CI 1.16-153.06; P = 0.04) predicted abnormal cytology in HIV-infected adolescent females. CONCLUSIONS: Despite the younger age and shorter time since sexual debut, cervical cytological abnormalities and HPV infection were as common in perinatally HIV-infected as in behaviourally infected and uninfected adolescents. HPV vaccination, pre-cancer screening and antiretroviral treatment in HIV-infected female adolescents should be implemented to minimise the risk of cervical cancer.

The EPIICAL project: an emerging global collaboration to investigate immunotherapeutic strategies in HIV-infected children.

The EPIICAL (Early-treated Perinatally HIV-infected Individuals: Improving Children's Actual Life with Novel Immunotherapeutic Strategies) project arises from the firm belief that perinatally infected children treated with suppressive antiretroviral therapy (ART) from early infancy represent the optimal population model in which to study novel immunotherapeutic strategies aimed at achieving ART-free remission. This is because HIV-infected infants treated within 2-3 months of life have a much reduced viral reservoir size, and rarely show HIV-specific immunity but preserve normal immune development. The goal of EPIICAL is the establishment of an international collaboration to develop a predictive platform using this model to select promising HIV therapeutic vaccine candidates, leading to prioritisation or deprioritisation of novel immunotherapeutic strategies. To establish this platform, the EPIICAL Consortium aims to: develop predictive models of virological and immunological dynamics associated with response to early ART and to treatment interruption using available data from existing cohorts/studies of early-treated perinatally HIV-infected children; optimise methodologies to better characterise immunological, virological and genomic correlates/profiles associated with viral control; test novel immunotherapeutic strategies using in vivo proof-of-concept (PoC) studies with the aim of inducing virological, immunological and transcriptomic correlates/profiles equivalent to those defined by the predictive model. This approach will strengthen the capacity for discovery, development and initial testing of new therapeutic vaccine strategies through the integrated efforts of leading international scientific groups, with the aim of improving the health of HIV-infected individuals.

Predictors of clinical progression in HIV-1-infected adults initiating combination antiretroviral therapy with advanced disease in the Asia-Pacific region: results from the TREAT Asia HIV observational database.

The majority of HIV-infected patients in developing countries commences combination antiretroviral therapy (cART) with advanced disease. We examined predictors of disease progression in patients initiating cART with CD4 count ≤200 cells/mm(3) in the TREAT Asia HIV Observational Database. The main outcome measure was progression to either an AIDS-defining illness or death occurring 6 months after initiation of cART. We used survival analysis methods. A total of 1255 patients contributed 2696 person years of follow-up; 73 were diagnosed with AIDS and 9 died. The rate of progression to the combined end point was 3.0 per 100 person years. The factors significantly associated with a higher risk of disease progression were Indian ethnicity, infection through intravenous drug use, lower CD4 count, and hemoglobin ≤130 g/dL at 6 months. In conclusion, measurements of CD4 count and hemoglobin at month 6 may be useful for early identification of disease progression in resource-limited settings.

Correlation of selenium and zinc levels to antiretroviral treatment outcomes in Thai HIV-infected children without severe HIV symptoms.

BACKGROUND/OBJECTIVES: Deficiencies in antioxidants contribute to immune dysregulation and viral replication. To evaluate the correlation of selenium (Se) and zinc (Zn) levels on the treatment outcomes in HIV-infected children. SUBJECTS/METHODS: HIV-infected Thai children 1-12 years old, CD4 15-24%, without severe HIV symptoms were included. Se and Zn levels were measured by graphite furnace atomic absorption spectrometry at baseline and 48 weeks. Deficiency cutoffs were Se <0.1 µmol/l and Zn <9.9 µmol/l. Serum ferritin and C-reactive protein (CRP) were measured every 24 weeks. No micronutrient supplement was prescribed. RESULTS: In all, 141 children (38.3% male) with a median (interquartile range (IQR)) age of 7.3 (4.2-9.0) years were enrolled. Median baseline CD4% was 20%, HIV-RNA was 4.6 log(10)copies/ml. At baseline, median (IQR) Se and Zn levels were 0.9 (0.7-1.0) µmol/l and 5.9 (4.8-6.9) µmol/l, respectively. None had Se deficiency while all had Zn deficiency. Over 48 weeks, 97 initiated antiretroviral therapy (ART) and 81% achieved HIV-RNA <50 copies/ml with 11% median CD4 gain. The mean change of Se was 0.06 µmol/l (P=0.003) and Zn was 0.42 µmol/l (P=0.003), respectively. By multivariate analysis in children who received ART, predictors for greater increase of CD4% from baseline were lower baseline CD4% (P<0.01) and higher baseline Zn level (P=0.02). The predictors for greater decrease of HIV-RNA from baseline were higher baseline HIV-RNA and higher ferritin (both P<0.01). No association of CRP with the changes from baseline of CD4% or HIV-RNA was found. CONCLUSION: In HIV-infected Thai children without severe immune deficiency who commenced ART, no correlation between Se and ART treatment outcomes was found. Higher pre-ART Zn levels were associated with significant increases in CD4% at 48 weeks.

Genital shedding of HIV after scheduled treatment interruption.

This study assessed genital shedding of HIV in patients on intermittent combination antiretroviral therapy (cART) and assessed predictors of having detectable genital HIV RNA in 156 Thai patients with CD4 > 350 cells/µL and HIV RNA ≤50 copies/mL who were randomized to continuous therapy (CT, n = 65) or CD4-guided cART (n = 91). There were 383 matched genital and plasma HIV RNA samples (CT: 158, CD4 guided: 225). In 14 samples collected within eight weeks of treatment interruption, detectable HIV RNA was present in 29% of genital samples and 71% of plasma samples. In 55 samples collected after eight weeks of treatment interruption, detectable HIV RNA was present in 60% of genital samples and 98% of plasma samples. In 110 samples collected up to 96 weeks after treatment re-initiation, detectable genital HIV RNA was found in 8% of samples and all of these were within the first 17 weeks. Independent predictors of detectable genital HIV RNA were increasing age and increasing concentrations of HIV RNA in plasma. These findings support the role of cART in maintaining undetectable HIV RNA in genital secretions.

HIV DNA and cognition in a Thai longitudinal HAART initiation cohort: the SEARCH 001 Cohort Study.

OBJECTIVES: The extent to which highly active antiretroviral therapy (HAART) era cognitive disorders are due to active processes, incomplete clearance of reservoirs, or comorbidities is controversial. This study aimed to determine if immunologic and virologic factors influence cognition after first-time HAART in Thai individuals with HIV-associated dementia (HAD) and Thai individuals without HAD (non-HAD). METHODS: Variables were captured longitudinally to determine factors predictive of degree of cognitive recovery after first-time HAART. Neuropsychological data were compared to those of 230 HIV-negative Thai controls. RESULTS: HIV RNA and CD4 lymphocyte counts were not predictive of HAD cross-sectionally or degree of cognitive improvement longitudinally. In contrast, baseline and longitudinal HIV DNA isolated from monocytes correlated to cognitive performance irrespective of plasma HIV RNA and CD4 lymphocyte counts pre-HAART (p < 0.001) and at 48 weeks post HAART (p < 0.001). Levels exceeding 3.5 log(10) copies HIV DNA/10(6) monocyte at baseline distinguished all HAD and non-HAD cases (p < 0.001). At 48 weeks, monocyte HIV DNA was below the level of detection of our assay (10 copies/10(6) cells) in 15/15 non-HAD compared to only 4/12 HAD cases, despite undetectable plasma HIV RNA in 26/27 cases. Baseline monocyte HIV DNA predicted 48-week cognitive performance on a composite score, independently of concurrent monocyte HIV DNA and CD4 count (p < 0.001). CONCLUSIONS: Monocyte HIV DNA level correlates to cognitive performance before highly active antiretroviral therapy (HAART) and 48 weeks after HAART in this cohort and baseline monocyte HIV DNA may predict 48-week cognitive performance. These findings raise the possibility that short-term incomplete cognitive recovery with HAART may represent an active process related to this peripheral reservoir.

Ferritin levels during structured treatment interruption of highly active antiretroviral therapy.

OBJECTIVE: The aim of the study was to investigate the influence of highly active antiretroviral therapy (HAART) on iron status and, conversely, the influence of iron status on the response to HAART. METHODS: Ferritin levels were retrospectively determined in stored plasma from 138 HAART-naïve, moderately immunosuppressed HIV-infected Thai patients participating in a structured treatment interruption trial. Ferritin levels were determined at three predefined time-points: (1) HAART initiation; (2) HAART discontinuation; and (3) HAART resumption. RESULTS: At baseline, 31% and 16% of the HIV-infected patients included in the study had high (>200 ng/mL) and low (<30 ng/mL) ferritin levels, respectively. Ninety-five per cent of patients with low ferritin levels were female. Ferritin decreased significantly during the interruption phase of HAART (-8.8 ng/mL; P=0.0005) but remained elevated in 62% of the patients with high baseline levels. A low baseline ferritin level was associated with a shorter time (P=0.041) to reach the CD4 cell target for HAART interruption (350 cells/microL), compared with a normal or high baseline ferritin level. Moreover, in a multivariate model, the relative risk (RR) of arriving at this CD4 cell target was significantly higher [RR 1.81; 95% confidence interval (CI) 1.05-3.14] in patients with low baseline ferritin. It is unlikely that inflammation affected ferritin in our patients, as mean levels of C-reactive protein were not elevated in patients with either high or low ferritin levels. CONCLUSIONS: Both high and low ferritin levels were highly prevalent in moderately immunosuppressed HIV-positive Thai patients. Structured treatment interruption of HAART resulted in a significant decrease in overall ferritin levels. Furthermore, subjects with low baseline ferritin levels had a faster and greater CD4 response to HAART, suggesting a potential beneficial effect of iron deficiency on immunological recovery after initiation of HAART.

Three populations of cells with dendritic morphology exist in peripheral blood, only one of which is infectable with human immunodeficiency virus type 1.

Conflicting data have been reported with regard to the infectability, dysfunction, and depletion of dendritic cells (DCs) in human immunodeficiency virus (HIV) disease. These discrepancies could potentially be explained by the existence of multiple subsets of cells with dendritic morphology in peripheral blood. The isolation of DCs in humans is accomplished through negative selection until a morphologically pure population is obtained. Recently, DC precursors purified from peripheral blood by negative selection have been observed to develop into functionally and morphologically mature DCs. In this report we identify three populations of cells in peripheral blood that have or can develop a dendritic morphology. The first population, when allowed to mature in culture, develops a dendritic morphology and gains the expression of HB15, a marker of DCs in blood, thymus, skin, and lymphoid organs. The second population expresses HB15 and has the phenotypic and morphologic characteristics of mature DCs. The third population is morphologically very similar to mature DCs but does not share the same T-cell-stimulatory activity and is the only population that is infectable with HIV. Understanding the heterogeneity of cells of dendritic lineage and/or morphology in the peripheral blood will aid in understanding their role as antigen-presenting cells in general and as potential participants in the immunopathogenesis of HIV disease.

Pharmacokinetic study of saquinavir hard gel caps/ritonavir in HIV-1-infected patients: 1600/100 mg once-daily compared with 2000/100 mg once-daily and 1000/100 mg twice-daily.

OBJECTIVES: A pharmacokinetic comparison of three dosing regimens of saquinavir/ritonavir was carried out: 1600/100 mg once-daily with 1000/100 mg twice-daily, and 1600/100 mg once-daily with 2000/100 mg once-daily. METHODS: Twenty patients on saquinavir hard gel caps/ritonavir 1600/100 mg once-daily in combination with two nucleoside reverse transcriptase inhibitors for at least 4 weeks were enrolled and randomized to either saquinavir hard gel caps/ritonavir 1000/100 mg twice-daily or 2000/100 mg once-daily. Two pharmacokinetic curves were plotted, at baseline (day 0) and 7 days after the switch. Plasma concentrations were measured at 0, 2, 4, 6, 8, 10, 12 (and 24 for once-daily dosing) hours after drug intake by validated high-performance liquid chromatographic assay (HPLC). The area under the plasma concentration-time curve (AUC0-24 or AUC0-12), maximum and minimum concentration (Cmax and Cmin) and elimination half-life were calculated using a non-compartmental model. RESULTS: Compared with saquinavir/ritonavir 1600/100 mg once-daily dosing, the saquinavir AUC and Cmin improved significantly when dosed as 1000/100 mg twice-daily (53% and 299%, respectively), and as 2000/100 mg once-daily (71% and 65%, respectively). Low Cmin in three subjects at baseline was corrected after switch to the other dosages. Saquinavir/ritonavir 2000/100 mg once-daily was also associated with a significant increase in saquinavir Cmax (52%) compared with saquinavir/ritonavir 1600/100 mg once-daily. CONCLUSIONS: Saquinavir/ritonavir when dosed as 2000/100 mg once-daily or 1000/100 mg twice-daily achieves higher saquinavir plasma levels compared with saquinavir/ritonavir 1600/100 mg once-daily. Taking the convenience of once-daily dosing into consideration, dosage of 2000/100 mg once-daily may be preferred.