319 research outputs found
P18-14 LB. Vacc-4x HIV p24-like peptide vaccine-associated increase of CD4 T-cells in chronically infected HIV-1 patients on antiretroviral therapy
Cell-Mediated Immune Predictors of Vaccine Effect on Viral Load and CD4 Count in a Phase 2 Therapeutic HIV-1 Vaccine Clinical Trial.
In a placebo-controlled trial of the peptide-based therapeutic HIV-1 p24 <sup>Gag</sup> vaccine candidate Vacc-4x, participants on combination antiretroviral therapy (cART) received six immunizations over 18weeks, followed by analytical treatment interruption (ATI) between weeks 28 and 52. Cell-mediated immune responses were investigated as predictors of Vacc-4x effect (VE) on viral load (VL) and CD4 count during ATI.
All analyses of week 28 responses and fold-changes relative to baseline considered per-protocol participants (Vacc-4x:placebo=72:32) resuming cART after week 40. Linear regression models with interaction tests were used. VE was estimated as the Vacc-4x-placebo difference in log <sub>10</sub> -transformed VL (VE <sup>VL</sup> ) or CD4 count (VE <sup>CD4</sup> ).
A lower fold-change of CD4+ T-cell proliferation was associated with VE <sup>CD4</sup> at week 48 (p=0.036, multiplicity adjusted q=0.036) and week 52 (p=0.040, q=0.080). A higher fold-change of IFN-γ in proliferation supernatants was associated with VE <sup>VL</sup> at week 44 (p=0.047, q=0.07). A higher fold-change of TNF-α was associated with VE <sup>VL</sup> at week 44 (p=0.045, q=0.070), week 48 (p=0.028, q=0.070), and week 52 (p=0.037, q=0.074). A higher fold-change of IL-6 was associated with VE <sup>VL</sup> at week 48 (p=0.017, q=0.036). TNF-α levels (>median) were associated with VE <sup>CD4</sup> at week 48 (p=0.009, q=0.009).
These exploratory analyses highlight the potential value of investigating biomarkers in T-cell proliferation supernatants for VE in clinical studies
Cobalamin and folate status in infants and young children in a low-to-middle income community in India
Background: Population-based data on the prevalence of cobalamin and folate deficiency in India are lacking. Objective: The objective was to measure the prevalence of cobalamin and folate deficiency among children aged 6-30 mo residing in a low-to-middle income community in North India. Design: Children aged 6-30 mo (n = 2482) were identified through a community survey in a low-to-middle socioeconomic area in New Delhi, India. Non-fasting venous blood samples were collected before enrollment in another trial. Results: The median (interquartile range; IQR) cobalamin concentration in 6-11-mo-old children was substantially lower in breastfed (183; 120-263 pmol/L) than in nonbreastfed (334; 235-463 pmol/L) children. Cobalamin concentrations decreased progressively with increasing age in the nonbreastfed children. Median (IQR) plasma folate concentrations in the 6-11-mo-old group were higher in breastfed (20.3; 11.7-34.4 nmol/L) than in nonbreastfed (5.3; 3.4-7.7 nmol/L) children (P < 0.001). Folate concentrations decreased with increasing age in the breastfed children. In the nonbreastfed children, folate concentrations increased with increasing age. Low concentrations of plasma cobalamin (<150 pmol/L) were were detected in 36% of breastfed and 9% of nonbreastfed children (P < 0.001). The proportions of children with plasma folate concentrations <5 nmol/L in these 2 subgroups were 6% and 33%, respectively (P < 0.001). Conclusions: In north Indian preschool children, cobalamin and folate concentrations were commonly low and were associated with elevated total homocysteine and methylmalonic acid concentrations. Because low cobalamin and folate concentrations have functional consequences, population-based measures for improving cobalamin and folate concentrations need to be seriously considered
Folate, but not vitamin B-12 status, predicts respiratory morbidity in north Indian children
Background: Vitamin deficiencies are often part of malnutrition, which predisposes to acute lower respiratory tract infections. Objective: The objective was to measure the association between cobalamin and folate status and subsequent respiratory morbidity. Design: A prospective cohort study was conducted in 2482 children aged 6-30 mo nested in a zinc supplementation trial. We measured plasma concentrations of folate, cobalamin, methylmalonic acid, and total homocysteine (tHcy) and followed the children for 4 mo. Results: We observed 1176 episodes of acute lower respiratory tract infections. Children with folate concentrations in the lowest quartile (interquartile range: 6.4-20.0 nmol/L) had a 44% higher incidence [adjusted incidence rate ratio (IRR): 1.44; 95% CI: 1.23, 1.70] of acute lower respiratory tract infections than did children in the other 3 quartiles. For tHcy, the IRR was 1.24 (1.07, 1.40) in a comparison of those in the highest quartile with those in the other quartiles. Breastfeeding was associated with high folate concentrations and protection against subsequent respiratory tract infections. This protection was significantly and substantially reduced after adjustment for plasma folate concentrations at baseline. Compared with the children in the other 3 quartiles, the IRR for being in the lowest quartile of cobalamin was 1.13 (0.76, 1.03) and for being in the highest quartile of methylmalonic acid was 1.12 (0.96, 1.31). Conclusions: Poor folate status appears to be an independent risk factor for lower respiratory tract infections in young children. This study also suggests that the protective effect of breastfeeding is partly mediated by folate provided through breast milk
SARS-CoV-2 Infection in Pregnant Women and Their Newborns.
There remain a number of uncertainties globally about the risks posed to women who are infected with SARS-CoV-2 during pregnancy. Furthermore, our understanding of the spread of COVID-19 in Sub-Saharan Africa is limited, owing to low testing rates in many parts of the continent. PeriCOVID Africa, in conjunction with the WHO/HRP Alliance, plans to address these knowledge gaps by harnessing research infrastructures in place in five sub-Saharan African countries in order to screen more than 50,000 pregnant women and their infants for SARS-CoV-2, while monitoring pregnancy and neonatal outcomes. We anticipate that the results of this study will provide much needed information about the risks that SARS-CoV-2 poses to pregnant women and their babies, as well as establishing potential routes of mother-to-child transmission
The Depsipeptide Romidepsin Reverses HIV-1 Latency In Vivo.
UNLABELLED: Pharmacologically-induced activation of replication competent proviruses from latency in the presence of antiretroviral treatment (ART) has been proposed as a step towards curing HIV-1 infection. However, until now, approaches to reverse HIV-1 latency in humans have yielded mixed results. Here, we report a proof-of-concept phase Ib/IIa trial where 6 aviremic HIV-1 infected adults received intravenous 5 mg/m2 romidepsin (Celgene) once weekly for 3 weeks while maintaining ART. Lymphocyte histone H3 acetylation, a cellular measure of the pharmacodynamic response to romidepsin, increased rapidly (maximum fold range: 3.7-7.7 relative to baseline) within the first hours following each romidepsin administration. Concurrently, HIV-1 transcription quantified as copies of cell-associated un-spliced HIV-1 RNA increased significantly from baseline during treatment (range of fold-increase: 2.4-5.0; p = 0.03). Plasma HIV-1 RNA increased from <20 copies/mL at baseline to readily quantifiable levels at multiple post-infusion time-points in 5 of 6 patients (range 46-103 copies/mL following the second infusion, p = 0.04). Importantly, romidepsin did not decrease the number of HIV-specific T cells or inhibit T cell cytokine production. Adverse events (all grade 1-2) were consistent with the known side effects of romidepsin. In conclusion, romidepsin safely induced HIV-1 transcription resulting in plasma HIV-1 RNA that was readily detected with standard commercial assays demonstrating that significant reversal of HIV-1 latency in vivo is possible without blunting T cell-mediated immune responses. These finding have major implications for future trials aiming to eradicate the HIV-1 reservoir.
TRIAL REGISTRATION: clinicaltrials.gov NTC02092116
Immunization with HIV protease peptides linked to syngeneic erythrocytes
New potent vaccine adjuvants are desirable for increasing the efficacy of novel vaccine modalities such as DNA and peptides. We therefore tested if syngeneic erythrocytes could serve as delivery vectors for selected HIV peptides and compared the potency of these constructs to immunization with peptides in phosphate buffered saline or in incomplete Freunds adjuvant. Immunization of mice with peptides in a low dose (5 ng) coupled to erythrocytes induced a weak immune response in mice. These peptides alone (5 μg) gave no immune responses, while formulating the peptides (50 μg) in IFA induced strong homologous immunity as well as prominent cross reactivity to a related mutant epitope. Thus, vaccine delivery using syngeneic erythrocytes, although attractive for clinical use, might be of limited value due to the low amount of antigen that can be loaded per erythrocyte
Quality of T-cell responses versus reduction in viral load: results from an exploratory phase II clinical study of Vacc-4x, a therapeutic HIV vaccine
Background
Immunization with Vacc-4x, a peptide-based therapeutic
vaccine for HIV-1, has shown a statistically significant
reduction in viral load set point compared to placebo
during treatment interruption in an exploratory phase II
clinical study enrolling 135 subjects (NCT00659789).
This vaccine aims to induce sustained cell-mediated
immune responses to conserved domains on HIV p24.
Methods
After 6 immunizations on ART over 28 weeks, treatment
was interrupted for up to 24 weeks (Vacc-4x n=88;
placebo n=38). Immunological analyses (ELISPOT, proliferation,
intracellular cytokine staining (ICS)) to HIV p24
were carried out at central laboratories. The HLA class I
profile (Vacc-4x n=73, placebo n=32) was also determined.
Results
For subjects that remained off ART until week 52 (Vacc-4x
n=56, placebo n=25), there was a log 0.44 reduction in
viral load set point between the Vacc-4x and placebo
groups (p=0.0397). There was a similar distribution of
HLA class I alleles in the two treatment arms, with the
exception of the B35 allele (27% of Vacc-4x subjects versus
8% placebo subjects). The viral load of ELISPOT positive
Vacc-4x subjects was significantly lower than that of placebo
subjects (p=0.023). There was no significant difference
in T-cell proliferation responses between Vacc-4x and placebo groups, however, the percentage of subjects showing
proliferative CD4 and CD8 T-cell responses to Vacc-4x
peptides increased over time only for the Vacc-4x group.
ICS analysis showed a predominance of CD8-mediated
T-cell responses to p24 that were significantly increased
from baseline for the Vacc-4x group (p<0.043) but not for
the placebo group(p>0.05). There was also a trend towards
higher numbers of polyfunctional T-cells in the Vacc-4x
group compared to the placebo group (p=0.188).
Conclusion
These findings suggest Vacc-4x immunization can influence
the quality of immune responses to HIV-1 p24 irrespective
of HLA status, and contribute to a reduction in viral load
When is a randomised controlled trial health equity relevant? Development and validation of a conceptual framework
Background Randomised controlled trials can provide evidence relevant to assessing the equity impact of an intervention, but such information is often poorly reported. We describe a conceptual framework to identify health equity-relevant randomised trials with the aim of improving the design and reporting of such trials.Methods An interdisciplinary and international research team engaged in an iterative consensus building process to develop and refine the conceptual framework via face-to-face meetings, teleconferences and email correspondence, including findings from a validation exercise whereby two independent reviewers used the emerging framework to classify a sample of randomised trials.Results A randomised trial can usefully be classified as 'health equity relevant' if it assesses the effects of an intervention on the health or its determinants of either individuals or a population who experience ill health due to disadvantage defined across one or more social determinants of health. Health equity-relevant randomised trials can either exclusively focus on a single population or collect data potentially useful for assessing differential effects of the intervention across multiple populations experiencing different levels or types of social disadvantage. Trials that are not classified as 'health equity relevant' may nevertheless provide information that is indirectly relevant to assessing equity impact, including information about individual level variation unrelated to social disadvantage and potentially useful in secondary modelling studies.Conclusion The conceptual framework may be used to design and report randomised trials. The framework could also be used for other study designs to contribute to the evidence base for improved health equity
Perinatal Mortality in Eastern Uganda: A Community Based Prospective Cohort Study
To achieve a child mortality reduction according to millennium development goal 4, it is necessary to considerably reduce neonatal mortality. We report stillbirth and early neonatal mortality risks as well as determinants of perinatal mortality in Eastern Uganda.A community-based prospective cohort study was conducted between 2006 and 2008. A total of 835 pregnant women were followed up for pregnancy outcome and survival of their children until 7 days after delivery. Mother's residence, age, parity, bed net use and whether delivery took place at home were included in multivariable regression analyses to identify risk factors for perinatal death.The stillbirth risk was 19 per 1,000 pregnancies and the early neonatal death risk 22 per 1,000 live births. Overall, the perinatal mortality risk was 41 [95%CI: 27, 54] per 1,000 pregnancies. Of the deaths, 47% followed complicated deliveries and 24% preterm births. Perinatal mortality was 63/1,000 pregnancies among teenage mothers, 76/1,000 pregnancies among nulliparous women and 61/1,000 pregnancies among women delivering at home who, after controlling for potential confounders, had a 3.7 (95%CI: 1.8, 7.4) times higher perinatal mortality than women who gave birth in a health facility. This association was considerably stronger among nulliparous women [RR 8.0 (95%CI: 2.9, 21.6)] than among women with a previous live birth [RR 1.8 (95%CI: 0.7, 4.5)]. All perinatal deaths occurred among women who did not sleep under a mosquito net. Women living in urban slums had a higher risk of losing their babies than those in rural areas [RR: 2.7 (95%CI: 1.4, 5.3)].Our findings strengthen arguments for ensuring that pregnant women have access to and use adequate delivery facilities and bed nets
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