Multiple CD4+ cell kinetic patterns and their relationships with baseline factors and virological responses in HIV type 1 patients receiving highly active antiretroviral therapy

Quantifying the Dynamics of HIV Decline in Perinatally Infected Neonates on Antiretroviral Therapy

BACKGROUND

Mathematical modeling has provided important insights into HIV infection dynamics in adults undergoing antiretroviral treatment (ART). However, much less is known about the corresponding dynamics in perinatally infected neonates initiating early ART.

SETTING

From 2014 to 2017, HIV viral load (VL) was monitored in 122 perinatally infected infants identified at birth and initiating ART within a median of 2 days. Pretreatment infant and maternal covariates, including CD4 T cell counts and percentages, were also measured.

METHODS

From the initial cohort, 53 infants demonstrated consistent decline and suppressed VL below the detection threshold (20 copies mL) within 1 year. For 43 of these infants with sufficient VL data, we fit a mathematical model describing the loss of short-lived and long-lived infected cells during ART. We then estimated the lifespans of infected cells and the time to viral suppression, and tested for correlations with pretreatment covariates.

RESULTS

Most parameters governing the kinetics of VL decline were consistent with those obtained previously from adults and other infants. However, our estimates of the lifespan of short-lived infected cells were longer than published values. This difference may reflect sparse sampling during the early stages of VL decline, when the loss of short-lived cells is most apparent. In addition, infants with higher pretreatment CD4 percentage or lower pretreatment VL trended toward more rapid viral suppression.

CONCLUSIONS

HIV dynamics in perinatally infected neonates initiating early ART are broadly similar to those observed in other age groups. Accelerated viral suppression is also associated with higher CD4 percentage and lower VL.

Comparative Immunovirological and Clinical Responses to Antiretroviral Therapy Between HIV-1 Group O and HIV-1 Group M Infected Patients

BACKGROUND

Little is known about impact of genetic divergence of human immunodeficiency virus type 1 group O (HIV-1/O) relative to HIV-1 group M (HIV-1/M) on therapeutic outcomes. We aimed to determine if responses to standardized combination antiretroviral therapy (cART) were similar between groups despite strain divergence.

METHODS

We performed an open nonrandomized study comparing the immunological, virological, and clinical responses to cART based on 2 nucleoside reverse transcriptase inhibitors plus 1 ritonavir-boosted protease inhibitor, in naive and paired HIV-1/O vs HIV-1/M infected (+) patients (ratio 1:2), matched on several criteria. The primary endpoint was the proportion of patients with undetectable plasma viral load (pVL, threshold 60 copies/mL) at week (W) 48. Secondary endpoints were the proportion of patients with undetectable pVL at W24 and W96 and CD4 evolution between baseline and W24, W48, and W96.

RESULTS

Forty-seven HIV-1/O+ and 94 HIV-1/M+ patients were included. Mean pVL at baseline was significantly lower by 1 log for HIV-1/O+ vs HIV-1/M+ patients. At W48, no significant difference was observed between populations with undetectable pVL and differences at W24 and W96 were not significant. A difference in CD4 gain was observed in favor of HIV-1/M at W48 and W96, but this was not significant when adjusted on both matched criteria and pVL at baseline.

CONCLUSIONS

Our data demonstrate similar immunovirological and clinical response between HIV-1/O+ and HIV-1/M+ patients. They also reveal significantly lower baseline replication for HIV-1/O variants, suggesting specific virological properties and physiopathology that now need to be addressed.

CLINICAL TRIALS REGISTRATION

NCT00658346.

CD127 Expression in Naive and Memory T Cells in HIV Patients Who Have Undergone Long-Term HAART

OBJECTIVE

To evaluate cluster of differentiation (CD)127 expression in T cells of patients with HIV-1 and the relationship of CD127 expression with disease progression.

METHODS

We divided 139 patients infected with human immunodeficiency virus type 1 (HIV-1) who had undergone highly active antiretroviral therapy (HAART) into 3 groups: patients with poor recovery (CD4⁺T < 350/μ;L, patients with general recovery (CD4⁺T =  350 - ∼600/μL) and patients with good recovery (CD4⁺T > 600/μL). Counts and percentages of naïve (CD45RA⁺) and memory (CD45RO⁺) T cells and CD127 expression were determined using flow cytometry.

RESULTS

CD4⁺CD45RO⁺, CD4⁺CD45RA⁺, CD4⁺ CD45RO⁺ CD127⁺, and CD4⁺CD45RA⁺CD127⁺T-cell counts in patients with good recovery were higher than in patients with poor recovery and those with general recovery patients (P <.05). Percentages of CD45RO⁺ were increased, and percentages of CD45RA⁺ and CD127 in T cells were decreased in patients with poor and general recovery (P <.05). CD127 values were positively correlated with CD4⁺T-cell counts and percentages of CD45RA⁺ subsets (P <.05).

CONCLUSION

CD127 expression in T cells is decreased in patients with HIV-1 and is related to recovery of CD4⁺T-cell counts and to naïve subsets.

Evaluation of treatment outcomes for patients on first-line regimens in US President's Emergency Plan for AIDS Relief (PEPFAR) clinics in Uganda: predictors of virological and immunological response from RV288 analyses

OBJECTIVES

Viral load (VL) monitoring is recommended, but seldom performed, in resource-constrained countries. RV288 is a US President's Emergency Plan for AIDS Relief (PEPFAR) basic programme evaluation to determine the proportion of patients on treatment who are virologically suppressed and to identify predictors of virological suppression and recovery of CD4 cell count. Analyses from Uganda are presented here.

METHODS

In this cross-sectional, observational study, patients on first-line antiretroviral therapy (ART) (efavirenz or nevirapine+zidovudine/lamivudine) from Kayunga District Hospital and Kagulamira Health Center were randomly selected for a study visit that included determination of viral load (HIV-1 RNA), CD4 cell count and clinical chemistry tests. Subjects were recruited by time on treatment: 6-12, 13-24 or >24 months. Logistic regression modelling identified predictors of virological suppression. Linear regression modelling identified predictors of CD4 cell count recovery on ART.

RESULTS

We found that 85.2% of 325 subjects were virologically suppressed (viral load<47 HIV-1 RNA copies/ml). There was no difference in the proportion of virologically suppressed subjects by time on treatment, yet CD4 counts were higher in each successive stratum. Women had higher median CD4 counts than men overall (406 vs. 294 cells/μL, respectively; P<0.0001) and in each time-on-treatment stratum. In a multivariate logistic regression model, predictors of virological suppression included efavirenz use [odds ratio (OR) 0.47; 95% confidence interval (CI) 0.22-1.02; P=0.057], lower cost of clinic visits (OR 0.815; 95% CI 0.66-1.00; P=0.05), improvement in CD4 percentage (OR 1.06; 95% CI 1.014-1.107; P=0.009), and care at Kayunga vs. Kangulamira (OR 0.47; 95% CI 0.23-0.92; P=0.035). In a multivariate linear regression model of covariates associated with CD4 count recovery, time on highly active antiretroviral therapy (ART) (P<0.0001), patient satisfaction with care (P=0.038), improvements in total lymphocyte count (P<0.0001) and haemoglobin concentration (P=0.05) were positively associated, whereas age at start of ART (P=0.0045) was negatively associated with this outcome.

CONCLUSIONS

High virological suppression rates are achievable on first-line ART in Uganda. The odds of virological suppression were positively associated with efavirenz use and improvements in CD4 cell percentage and total lymphocyte count and negatively associated with the cost of travel to the clinic. CD4 cell reconstitution was positively associated with CD4 count at study visit, time on ART, satisfaction with care at clinic, haemoglobin concentration and total lymphocyte count and negatively associated with age.

Assessment of the impact of adherence and other predictors during HAART on various CD4 cell responses in resource-limited settings

OBJECTIVE

The aim of this study was to quantify, by modeling, the impact of significant predictors on CD4 cell response during antiretroviral therapy in a resource-limited setting.

METHODS

Modeling was used to determine which antiretroviral therapy response predictors (baseline CD4 cell count, clinical state, age, and adherence) significantly influence immunological response in terms of CD4 cell gain compared to a reference value at different periods of monitoring.

RESULTS

At 6 months, CD4 cell response was significantly influenced by baseline CD4 count alone. The probability of no increase in CD4 cells was 2.6 higher in patients with a baseline CD4 cell count of ≥200/mm(3). At 12 months, CD4 cell response was significantly influenced by both baseline CD4 cell count and adherence. The probability of no increase in CD4 cells was three times higher in patients with a baseline CD4 cell count of ≥200/mm(3) and 0.15 times lower with adherent patients. At 18 months, CD4 cell response was also significantly influenced by both baseline CD4 cell count and adherence. The probability of no increase in CD4 cells was 5.1 times higher in patients with a baseline CD4 cell count of ≥200/mm(3) and 0.28 times lower with adherent patients. At 24 months, optimal CD4 cell response was significantly influenced by adherence alone. Adherence increased the probability (by 5.8) of an optimal increase in CD4 cells. Age and baseline clinical state had no significant influence on immunological response.

CONCLUSION

The relationship between adherence and CD4 cell response was the most significant compared to that of baseline CD4 cell count. Counseling before initiation of treatment and educational therapy during follow-up must always help to strengthen adherence and optimize the efficiency of antiretroviral therapy in a resource-limited setting.

Early postseroconversion CD4 cell counts independently predict CD4 cell count recovery in HIV-1-postive subjects receiving antiretroviral therapy

BACKGROUND

The relationship between CD4 T-cell counts determined soon after seroconversion with HIV-1 (baseline CD4), nadir CD4, and CD4 levels attained during highly active antiretroviral therapy (HAART) is unknown.

METHODS

Longitudinal, including baseline (at or soon after HIV diagnosis), intermediate (nadir), and distal (post-HAART) CD4 T-cell counts were assessed in 1085 seroconverting subjects who achieved viral load suppression from a large well-characterized cohort. The association of baseline with post-HAART CD4 T-cell count was determined after adjustment for other relevant covariates.

RESULTS

A higher baseline CD4 T-cell count predicted a greater post-HAART CD4 T-cell count, independent of the nadir and other explanatory variables. Together, baseline and nadir strongly predicted the post-HAART CD4 count such that a high baseline and lower nadir were associated with a maximal immune recovery after HAART. Likelihood of recovery of the baseline count after HAART was significantly higher when the nadir/baseline count ratio was consistently ≥ 0.6.

CONCLUSIONS

Among viral load suppressing seroconverters, the absolute CD4 T-cell count attained post-HAART is highly dependent on both baseline and nadir CD4 T-cell counts. These associations further support the early diagnosis and initiation of HAART among HIV-infected persons.

[Modeling of antiretroviral response from taxonomy of CD4 cells count trajectories in profound immunodeficiency setting]

Modeling of CD4 cells counts response was performed through a Non-Hierarchical-descendant process with profoundly immunocompromised symptomatic patients under nevirapine or efavirenz-based antiretroviral regimen in Abidjan. Similar CD4 cells count trajectories have been modelled in meta-trajectories linked to patients' classes. Global immunological response is similar between "nevirapine group" and "efavirenz group" but the model showed an internal variation of this response in each group. In the both groups, some variables presented a significant variation between classes: average CD4, CD4 Nadir, CD4 peak and average gain of CD4. In "nevirapine group", these following parameters vary significantly between classes: mean weight, mean haemoglobin count and mean increase in haemoglobin count and sex. It's also important to note that, all meta-trajectories began with distinctive categories of baseline CD4 cells counts. Other explanatory factors must be sought because the characteristics we have chosen to describe patients'classes, are not exhaustive.

Metabolic and anthropometric parameters contribute to ART-mediated CD4+ T cell recovery in HIV-1-infected individuals: an observational study

BACKGROUND

The degree of immune reconstitution achieved in response to suppressive ART is associated with baseline individual characteristics, such as pre-treatment CD4 count, levels of viral replication, cellular activation, choice of treatment regimen and gender. However, the combined effect of these variables on long-term CD4 recovery remains elusive, and no single variable predicts treatment response. We sought to determine if adiposity and molecules associated with lipid metabolism may affect the response to ART and the degree of subsequent immune reconstitution, and to assess their ability to predict CD4 recovery.

METHODS

We studied a cohort of 69 (48 females and 21 males) HIV-infected, treatment-naïve South African subjects initiating antiretroviral treatment (d4T, 3Tc and lopinavir/ritonavir). We collected information at baseline and six months after viral suppression, assessing anthropometric parameters, dual energy X-ray absorptiometry and magnetic resonance imaging scans, serum-based clinical laboratory tests and whole blood-based flow cytometry, and determined their role in predicting the increase in CD4 count in response to ART.

RESULTS

We present evidence that baseline CD4+ T cell count, viral load, CD8+ T cell activation (CD95 expression) and metabolic and anthropometric parameters linked to adiposity (LDL/HDL cholesterol ratio and waist/hip ratio) significantly contribute to variability in the extent of CD4 reconstitution (ΔCD4) after six months of continuous ART.

CONCLUSIONS

Our final model accounts for 44% of the variability in CD4+ T cell recovery in virally suppressed individuals, representing a workable predictive model of immune reconstitution.

Measures of site resourcing predict virologic suppression, immunologic response and HIV disease progression following highly active antiretroviral therapy (HAART) in the TREAT Asia HIV Observational Database (TAHOD)

OBJECTIVES

Surrogate markers of HIV disease progression are HIV RNA in plasma viral load (VL) and CD4 cell count (immune function). Despite improved international access to antiretrovirals, surrogate marker diagnostics are not routinely available in resource-limited settings. Therefore, the objective was to assess effects of economic and diagnostic resourcing on patient treatment outcomes.

METHODS

Analyses were based on 2333 patients initiating highly active antiretroviral therapy (HAART) from 2000 onwards. Sites were categorized by World Bank country income criteria (high/low) and annual frequency of VL (> or = 3, 1-2 or <1) or CD4 (> or = 3 or <3) testing. Endpoints were time to AIDS/death and change in CD4 cell count and VL suppression (<400 HIV-1 RNA copies/mL) at 12 months. Demographics, Centers for Disease Control and Prevention (CDC) classification, baseline VL/CD4 cell counts, hepatitis B/C coinfections and HAART regimen were covariates. Time to AIDS/death was analysed by proportional hazards models. CD4 and VL endpoints were analysed using linear and logistic regression, respectively.

RESULTS

Increased disease progression was associated with site-reported VL testing less than once per year [hazard ratio (HR)=1.4; P=0.032], severely symptomatic HIV infection (HR=1.4; P=0.003) and hepatitis C virus coinfection (HR=1.8; P=0.011). A total of 1120 patients (48.2%) had change in CD4 cell count data. Smaller increases were associated with older age (P<0.001) and 'Other' HIV source exposures, including injecting drug use and blood products (P=0.043). A total of 785 patients (33.7%) contributed to the VL suppression analyses. Patients from sites with VL testing less than once per year [odds ratio (OR)=0.30; P<0.001] and reporting 'Other' HIV exposures experienced reduced suppression (OR=0.28; P<0.001).

CONCLUSION

Low measures of site resourcing were associated with less favourable patient outcomes, including a 35% increase in disease progression in patients from sites with VL testing less than once per year.

The lymph node in HIV pathogenesis

Since the earliest days of the AIDS epidemic, clinicians and researchers have recognized the importance of lymphoid tissue both in the clinical manifestations of disease and in its pathogenesis. Generalized lymphadenopathy was one of the earliest harbingers of AIDS in the United States and over the past 27 years an increasing body of evidence has implicated the lymphoid organs as central to the pathogenesis of immune deficiency in chronic HIV-1 infection. In this essay, we will review some of the data that have been accumulated and propose a testable model that may reconcile them.

Early and delayed benefits of HIV-1 suppression: timeline of recovery of innate immunity effector cells

OBJECTIVE

The kinetics of recovery for innate immune effectors following antiretroviral therapy are unknown.

DESIGN AND METHODS

Multiple sequential cryopreserved samples (viremic and ART-suppressed) from 66 patients enrolled in the Women's Interagency HIV Study or Multicenter AIDS Cohort Study cohorts (median follow-up, 700 days) were analyzed to determine natural killer, dendritic and T-cell changes by flow cytometry. Functional parameters were also measured in a subset of samples. Changes over time were analyzed by mixed-effect modeling based on a linear spline with a single knot at 270 days.

RESULTS

Following viral suppression, a rapid rise in CD4 and white blood cell counts and a decline in T-cell activation were confirmed. However, natural killer cell subsets increased after 270 days of therapy, with a negative effect by baseline CD4%. CD123+ plasmacytoid but not myeloid dendritic cells showed a trend to increase during the first 270 days with a positive effect of baseline CD4%; plasmacytoid dendritic cell-induced interferon-alpha production significantly increased by end of follow-up.

CONCLUSIONS

The kinetics of natural killer and plasmacytoid dendritic cell recovery are markedly different from those of T-cell subsets, indicative of early and delayed benefits of suppressive regimens.

Association of CD4+ T-lymphocyte counts and new thymic emigrants in HIV-infected children during successful highly active antiretroviral therapy

BACKGROUND

In a cohort of children receiving highly active antiretroviral therapy (HAART) with sustained plasma HIV-1 RNA < 50 copies/mL, children who reached undetectable RNA after week 8 (slow responders, median: week 20) had higher HIV-1 intracellular DNA (HIV-1 DNA) and equal or greater CD4+ T-lymphocyte counts compared with children who reached undetectable plasma HIV-1 RNA by week 8 (rapid responders) throughout HAART.

OBJECTIVE

To determine whether levels of T-cell receptor excision circles (TRECs) could explain the apparent inconsistency between the quantity of HIV-1 DNA and CD4+ T-lymphocyte counts in HIV-1-infected children receiving HAART with sustained virologic suppression.

METHODS

T-cell receptor excision circles and HIV-1 DNA and plasma HIV-1 RNA were quantified longitudinally by PCR in 31 children (median age, 5.6 years) with sustained undetectable plasma HIV-1 RNA for >104 weeks of HAART.

RESULTS

There was a positive correlation between TREC and HIV-1 DNA during HAART, notably at weeks 48 and 80 (P < .004). During the early stage of HAART, TREC levels positively correlated with CD4+ T-lymphocyte percentages (P < .02) and naive CD4+ T-lymphocyte counts (P < .001) and percentages (P = .05). Median TREC levels were consistently equal or higher in slow responders compared with rapid responders (P < .001) despite slow responders having consistently greater quantities of HIV-1 DNA.

CONCLUSION

To maintain adequate levels of CD4+ T-lymphocytes, children with high HIV-1 DNA maintain high levels of TREC while receiving HAART. Thus, a thymic control mechanism is required to maintain new CD4+ T lymphocytes in the presence of persistent virus.

CLINICAL IMPLICATIONS

The TREC level is a useful marker of thymic function in HIV-infected children.

Thymic volume is associated independently with the magnitude of short- and long-term repopulation of CD4+ T cells in HIV-infected adults after highly active antiretroviral therapy (HAART)

Age is one of the main factors involved in the rapidity and the magnitude of CD4(+) T cell repopulation in human immunodeficiency virus (HIV)-infected patients on highly active antiretroviral treatment (HAART). Improved thymic function has been suggested as the main factor associated with CD4(+) T cell restoration after HAART. This work was undertaken to determine, among host factors, the predictor variable at baseline involved in the magnitude of short- and long-term recovery of CD4(+) T cells after HAART. HIV-RNA levels and CD4(+) T cell numbers were determined in 54 HIV-infected adults at baseline and at weeks 4, 12, 48 and 96 after HAART. T cell subpopulations were determined by flow cytometry, thymic volume by computed tomography, T cell receptor excision circle (TREC)-bearing cells by quantitative polymerase chian reaction (PCR) and interleukin (IL)-7 levels by enzyme linked immunosorbent assay at baseline. The phenotype of patients' isolates was determined by infecting GHOST cells expressing CCR5 and CXCR4. The possible interference of phenotype with thymic function was also analysed. Baseline thymic volume was associated independently with the magnitude of short- and long-term recovery of CD4(+) T cells after HAART, despite the patients' viral phenotype. The measurement of thymic volume before therapy may predict the magnitude of T cell increase. This result could have important clinical implications not only in HIV-infected patients, but also in other scenarios of T cell depletion such as bone marrow transplantation and chemotherapy.

MDR1 gene polymorphisms and phase 1 viral decay during HIV-1 infection: an adult AIDS Clinical Trials Group study

Human CD4+ T cells express P-glycoprotein (P-gp), the ATP binding cassette efflux transporter encoded by MDR1. A common MDR1 single-nucleotide polymorphism in exon 26 (C3435T), which is linked to an exon 21 polymorphism (G2677T/A) and reportedly alters expression, has been associated with greater CD4+ T-cell increases during antiretroviral therapy. P-gp overexpression prevents apoptosis and inhibits HIV-1 replication in model systems, suggesting a potential effect on T-cell turnover. This study explored relationships between MDR1 polymorphisms and phase 1 viral decay among 31 HIV-infected individuals initiating antiretroviral therapy. Position 3435 genotypes were CC in 7 (23%), CT in 14 (45%), and TT in 10 (32%). Position 2677 genotypes were GG in 8 (26%), GT in 18 (58%), and TT in 5 (16%). There was no significant relationship between allelic variants in either exon 26 or 21 and phase 1 or phase 2 viral decay, changes in lymphocyte subsets over time, or plasma trough ritonavir concentrations. It is concluded with 95% confidence that phase 1 viral decay differences between exon 26 TT and CC groups are unlikely to exceed 18%.

The study of long-term HIV dynamics using semi-parametric non-linear mixed-effects models

Modelling HIV dynamics has played an important role in understanding the pathogenesis of HIV infection in the past several years. Non-linear parametric models, derived from the mechanisms of HIV infection and drug action, have been used to fit short-term clinical data from AIDS clinical trials. However, it is found that the parametric models may not be adequate to fit long-term HIV dynamic data. To preserve the meaningful interpretation of the short-term HIV dynamic models as well as to characterize the long-term dynamics, we introduce a class of semi-parametric non-linear mixed-effects (NLME) models. The models are non-linear in population characteristics (fixed effects) and individual variations (random effects), both of which are modelled semi-parametrically. A basis-based approach is proposed to fit the models, which transforms a general semi-parametric NLME model into a set of standard parametric NLME models, indexed by the bases used. The bases that we employ are natural cubic splines for easy implementation. The resulting standard NLME models are low-dimensional and easy to solve. Statistical inferences that include testing parametric against semi-parametric mixed-effects are investigated. Innovative bootstrap procedures are developed for simulating the empirical distributions of the test statistics. Small-scale simulation and bootstrap studies show that our bootstrap procedures work well. The proposed approach and procedures are applied to long-term HIV dynamic data from an AIDS clinical study.

Increased thymic mass and circulating naive CD4 T cells in HIV-1-infected adults treated with growth hormone

OBJECTIVE

To determine whether treatment with growth hormone (GH) enhances thymopoiesis in individuals infected with HIV-1.

METHODS

Five HIV-1-infected adults were treated with GH for 6-12 months in a prospective open-label study. Immunological analyses were performed before GH treatment and repeated at 3 month intervals after GH initiation. Thymic mass was analysed using computed tomography with quantitative density and volume analysis. Analysis of circulating lymphocytes, including naive and memory T cell subsets, was performed using multiparameter flow cytometry.

RESULTS

GH treatment was associated with a marked increase in thymic mass in all GH recipients. Circulating naive CD4 T cells also increased significantly in all patients during GH therapy, suggesting an enhancement of thymopoiesis.

CONCLUSION

GH has significant effects on the human immune system, including the reversal of thymic atrophy in HIV-1-infected adults. De-novo T cell production may thus be inducible in immunodeficient adults.