Immunological markers after long-term treatment interruption in chronically HIV-1 infected patients with CD4 cell count above 400 x 10(6) cells/l

The Impact of 6-month Micronutrient Supplementation on Viral, Immunological, and Mental Health Profile of a Cohort of Highly Active Antiretroviral Therapy-Naive HIV-Positive Patients in Northern Nigeria

Background:

HIV is a chronic disease with inflammatory reactions involving numerous elements of the immune system, resulting in an increased risk for other physical and psychiatric morbidities. Micronutrients, some of which possess anti-inflammatory properties, may help prevent the development of psychological disorders such as anxiety and depression in people living with HIV disease.

Objectives:

This study examined the profile of viral load, CD4 cell count, C-reactive protein, anxiety, and depression among highly active antiretroviral therapy (HAART)-naive HIV-positive patients receiving micronutrient supplementation over a 6-month period.

Materials and Methods:

A total of ninety HAART-naïve HIV-infected patients completed the Hospital Anxiety Depression Scale. Their blood samples were taken for serum viral load, CD4 cell count, and C-reactive protein at baseline. They all received a micronutrient supplement for 6 months, and 68 participants who remained in treatment at 6 months were reassessed with the same parameters.

Results:

After 6 months of micronutrient supplementation, the participants were found to have statistically significantly lower mean scores on the anxiety (t-test = 2.970, P = 0.003) and depression (t-test = 3.843, P = 0.001) subscales. They also had statistically significantly lower median CD4 cell count (P = 0.00) and C-reactive protein serum measures (P = 0.04). The median viral load decreased although the difference was not statistically significant.

Conclusion:

Micronutrient supplementation may reduce inflammatory reactions, anxiety, and depression in HAART-naive HIV-infected persons.

HPTN 071 (PopART): a cluster-randomized trial of the population impact of an HIV combination prevention intervention including universal testing and treatment: mathematical model

Background

The HPTN 052 trial confirmed that antiretroviral therapy (ART) can nearly eliminate HIV transmission from successfully treated HIV-infected individuals within couples. Here, we present the mathematical modeling used to inform the design and monitoring of a new trial aiming to test whether widespread provision of ART is feasible and can substantially reduce population-level HIV incidence.

Methods and Findings

The HPTN 071 (PopART) trial is a three-arm cluster-randomized trial of 21 large population clusters in Zambia and South Africa, starting in 2013. A combination prevention package including home-based voluntary testing and counseling, and ART for HIV positive individuals, will be delivered in arms A and B, with ART offered universally in arm A and according to national guidelines in arm B. Arm C will be the control arm. The primary endpoint is the cumulative three-year HIV incidence.

We developed a mathematical model of heterosexual HIV transmission, informed by recent data on HIV-1 natural history. We focused on realistically modeling the intervention package. Parameters were calibrated to data previously collected in these communities and national surveillance data.

We predict that, if targets are reached, HIV incidence over three years will drop by >60% in arm A and >25% in arm B, relative to arm C. The considerable uncertainty in the predicted reduction in incidence justifies the need for a trial. The main drivers of this uncertainty are possible community-level behavioral changes associated with the intervention, uptake of testing and treatment, as well as ART retention and adherence.

Conclusions

The HPTN 071 (PopART) trial intervention could reduce HIV population-level incidence by >60% over three years. This intervention could serve as a paradigm for national or supra-national implementation. Our analysis highlights the role mathematical modeling can play in trial development and monitoring, and more widely in evaluating the impact of treatment as prevention.

The immunological and virological consequences of planned treatment interruptions in children with HIV infection

OBJECTIVES

To evaluate the immunological and viral consequences of planned treatment interruptions (PTI) in children with HIV.

DESIGN

This was an immunological and virological sub-study of the Paediatric European Network for Treatment of AIDS (PENTA) 11 trial, which compared CD4-guided PTI of antiretroviral therapy (ART) with continuous therapy (CT) in children.

METHODS

HIV-1 RNA and lymphocyte subsets, including CD4 and CD8 cells, were quantified on fresh samples collected during the study; CD45RA, CD45RO and CD31 subpopulations were evaluated in some centres. For 36 (18 PTI, 18 CT) children, immunophenotyping was performed and cell-associated HIV-1 DNA analysed on stored samples to 48 weeks.

RESULTS

In the PTI group, CD4 cell count fell rapidly in the first 12 weeks off ART, with decreases in both naïve and memory cells. However, the proportion of CD4 cells expressing CD45RA and CD45RO remained constant in both groups. The increase in CD8 cells in the first 12 weeks off ART in the PTI group was predominantly due to increases in RO-expressing cells. PTI was associated with a rapid and sustained increase in CD4 cells expressing Ki67 and HLA-DR, and increased levels of HIV-1 DNA.

CONCLUSIONS

PTI in children is associated with rapid changes in CD4 and CD8 cells, likely due to increased cell turnover and immune activation. However, children off treatment may be able to maintain stable levels of naïve CD4 cells, at least in proportion to the memory cell pool, which may in part explain the observed excellent CD4 cell recovery with re-introduction of ART.

Impact of age on markers of HIV-1 disease

Aging is a complicated process characterized by a progressive loss of homeostasis, which results in an increased vulnerability to multiple diseases. HIV-1-infected patients demonstrate a premature aging phenotype and develop certain age-related diseases earlier in their lifespan than what is seen in the general population. Age-related comorbidities may include the development of bone disease, metabolic disorders, neurologic impairment and immunosenescence. Age also appears to have an effect on traditional markers of HIV-1 disease progression, including CD4+ T-cell count and viral load. These effects are not only a consequence of HIV-1 infection, but in many cases, are also linked to antiretroviral therapy. This review summarizes the complex interplay between HIV-1 infection and aging, and the impact that aging has on markers of HIV-1 disease.

Effect of intermittent interleukin-2 therapy on CD4+ T-cell counts following antiretroviral cessation in patients with HIV

BACKGROUND

Interleukin (IL)-2 therapy impacts T-cell homeostasis. Whether IL-2 expanded CD4(+) T cells may persist following viral rebound has not been fully investigated.

METHODS

Patients with CD4(+) T cells 500/μl or more and HIV RNA less than 50 copies/ml were randomized to continue antiretroviral therapy (ART) either alone (n = 67) or combined with three IL-2 cycles (n = 81; 6 million units) twice daily for 5 days at weeks 0, 8, and 16 before stopping ART (week 24). Patients were followed up to 168 weeks.

RESULTS

At week 24, median CD4(+) T-cell counts were 1198 and 703 cells/μl in the IL-2 and control groups, respectively (P < 0.001). At week 72, 27% (IL-2 group) and 45% (control group; P = 0.03) of patients were in failure (defined as no interruption of ART at week 24, CD4 drop below 350 cells/μl or ART resumption). After week 24, a biphasic decline (before and after week 32) of CD4 was noted -106 and -7 cells/μl per month in controls and -234 and -17 in IL-2 group (all P ≤ 0.0001). At week 96, IL-2-expanded CD4(+)CD25(+) T cells remained higher than in the control group (26 vs. 16%, P = 0.006).

CONCLUSION

In IL-2-treated patients, CD4(+)CD25(+) T cells persisting despite viral replication allow a longer period of ART interruption.

[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.

The effect of aging, nutrition, and exercise during HIV infection

Medical advances continue to change the face of human immunodeficiency virus- acquired immunodeficiency syndrome (HIV/AIDS). As life expectancy increases, the number of people living with HIV rises, presenting new challenges for the management of a chronic condition. Aging, nutrition, and physical activity can influence outcomes in other chronic conditions, and emerging data show that each of these factors can impact viral replication and the immune system in HIV. HIV infection results in a decline of the immune system through the depletion of CD4+ T cells. From initial infection, viral replication is a continuous phenomenon. Immunosenescence, a hallmark of aging, results in an increased susceptibility to infections secondary to a delayed immune response, and this phenomenon may be increased in HIV-infected patients. Optimal nutrition is an important adjunct in the clinical care of patients with HIV. Nutritional interventions may improve the quality and span of life and symptom management, support the effectiveness of medications, and improve the patient's resistance to infections and other disease complications by altering immunity. Moderate physical activity can improve many immune parameters, reduce the risk of acute infection, and combat metabolic abnormalities. As people with HIV age, alternative therapies such as nutrition and physical activity may complement medical management.

Short-term antiretroviral therapy to prevent mother-to-child transmission is safe and results in a sustained increase in CD4 T-cell counts in HIV-1-infected mothers

BACKGROUND

Short-term antiretroviral therapy (START) to prevent mother-to-child transmission (MTCT) is currently recommended for all HIV-1-infected pregnant women. The objective of this study was to assess the effect on CD4 cell counts and viral load dynamics the withdrawal of START after birth could generate.

METHODS

This was a 5-year cohort study involving HIV-1-infected pregnant women who presented with CD4 counts >300 cells/microL and had received START to prevent MTCT.

RESULTS

Seventy-five pregnancies were assessed. In 24 cases, there was a history of antiretroviral therapy prior to prophylaxis. The median baseline CD4 count was 573 cells/microL. In 75% of cases, prophylaxis was started after 26.6 weeks of gestation. The median CD4 cell count increase over baseline during prophylaxis was 24.5%. In only five cases did HIV-1 viral load remain detectable during prophylaxis. After START, CD4 cell counts did not drop significantly, and the HIV-1 viral load plateau was near the baseline level. The estimated mean time for CD4 count to fall below 300 cells/microL was 3.5 years and was directly associated with high baseline CD4 cell count, as well as with CD4 increase after prophylaxis, whereas it was negatively correlated with previous use of antiretroviral (ARV) drugs and persistence of detectable HIV-1 viral load during prophylaxis.

CONCLUSIONS

A potent, well-tolerated prophylactic ARV regimen can improve CD4 cell counts during and after START. In women receiving such prophylaxis, there is a remarkable time interval for CD4 cell counts to drop to levels that indicate treatment.

Response to planned treatment interruptions in HIV infection varies across childhood

OBJECTIVE

To evaluate clinical, immunological and virological consequences of CD4-guided antiretroviral therapy (ART) planned treatment interruptions (PTIs) compared with continuous therapy in children with chronic HIV infection in the Paediatric European Network for Treatment of AIDS 11 trial.

DESIGN

This was a multicentre, 72-week, open, randomized, phase II trial.

METHODS

One hundred and nine children with HIV-RNA below 50 copies/ml and CD4% of at least 30% (2-6 years) or at least 25% and CD4 cell count of at least 500 cells/microl (7-15 years) were randomized to continuous therapy (53) or PTI (56). In PTI, ART was restarted if confirmed CD4% was less than 20% or more than 48 weeks had been spent off ART. The primary outcome was Centers for Disease Control and Prevention (CDC) stage C event, death or CD4% less than 15% (and CD4 cell count less than 200 cells/microl for children aged 7-15 years).

RESULTS

At baseline, median (interquartile range) age was 9 (6-12) years, CD4% 37% (33-41), CD4 cell count 966 (793-1258) cells/microl, nadir CD4% before combination ART 18% (10-27), time on ART 6 (3-6) years and 26% were CDC stage C. After median (range) 130 (33-180) weeks of follow-up, 4 versus 48% of time was spent off ART in continuous therapy and PTI, respectively. No child died or had a new CDC stage C event; one (2%) continuous therapy versus four (7%) PTI children had a primary outcome based on CD4%/cell count (P = 0.2). Lower nadir CD4% predicted faster CD4% decline after stopping ART. Younger age and higher nadir CD4% predicted being off ART for at least 48 weeks and better CD4% recovery following PTI.

CONCLUSION

In this first paediatric trial of PTI, there were no serious clinical outcomes. Younger children had better CD4% recovery after PTIs. Immunology substudies and long-term follow-up in Paediatric European Network for Treatment of AIDS 11 trial are ongoing. Further research into the role of treatment interruption in children is required, particularly, as guidelines now recommend early ART for all infected infants.

Influence of a vaccination schedule on viral load rebound and immune responses in successfully treated HIV-infected patients

Vaccination is recommended for HIV-infected patients. Transient increases of viral load (VL) and risk of developing resistance to HAART have been described. In addition, VL rebounds could increase HIV-specific immune responses. Twenty-six successfully treated HIV-infected adults were randomized to receive a vaccination schedule or placebo during 12 months. Afterward, HAART was discontinued. Influences of vaccination over VL, genotypic mutations, different T cell subsets, and HIV-1-specific immune responses were evaluated. Patients did not present any secondary effect. No differences in incidence of detectable VL determinations were detected between groups [relative risk 0.54 (95% CI 0.23-1.26)]. No relevant resistance mutations were detected. The vaccinated group showed a significant drop in CD4(+) T cells (p = 0.046) associated with increases in activated T cells. HIV-1-specific lymphoproliferative responses increased more in the vaccinated group during the vaccination period. Viral rebound dynamics after interrupting HAART were similar in both groups. A vaccination schedule in successfully treated HIV patients was safe, was not associated with an increase in detectable VL, and did not increase the risk of developing resistance mutations. However, it induced an increase in T cell activation and a drop in CD4(+) T cells, although these changes did not influence the VL rebound dynamics after HAART interruption.

Prognostic factors of long-term CD4+count-guided interruption of antiretroviral treatment

Aim of the study was to determine predictors of the duration of antiretroviral treatment interruption in patients infected with HIV. This pilot prospective, open-label, multicenter trial comprised 62 HIV-seropositive subjects who decided voluntarily to interrupt therapy after two or more years of successful HAART. The primary end-point was the time to patients being free of therapy before reaching a CD4+ cell count < or =350/microl. Fifteen of 62 patients remained in treatment interruption for more than 180 days. Patients restarting therapy had higher HIV-DNA levels (P = 0.05), were treated more frequently with NNRTI-drugs (P = 0.02), had a shorter period of HAART (P = 0.046), and lower CD4+ cell counts after day 14 of interruption of treatment (P = 0.04). Multivariate regression analysis showed that less than 323 baseline proviral HIV-DNA cp/10(6) PBMCs and more than 564 CD4 cells/microl at day 14 after interruption were associated independently with a reduced risk of restarting treatment (P = 0.041 and P = 0.012, respectively). A score based on CD4+ cell counts at nadir, at baseline, at week 2 of treatment interruption, and on baseline HIV-DNA values can identify patients with a prolonged period free safely of treatment.

Rapid CD4+ cell decrease after transient cART initiated during primary HIV infection (ANRS PRIMO and SEROCO cohorts)

OBJECTIVE

To modelize the rate of CD4 cell count decline and its determinants after cessation of combination antiretroviral therapy (cART) started during primary HIV infection (PHI) and compare it with never-treated patients.

METHODS

Kinetics of CD4 counts were analyzed on the square root scale by using a mixed-effects model in 170 patients who received cART during PHI from the Primary Infection (PRIMO) cohort and 123 never-treated patients from the Seroconverters (SEROCO) cohort.

RESULTS

After cART interruption in the PRIMO cohort, the CD4 cell count fell rapidly during the first 5 months and more slowly thereafter. The timing of treatment initiation had no influence on the rate of CD4 cell decline. In contrast, a larger increase in CD4 cell counts during cART was associated with a steeper decline and a larger loss of CD4 cells after treatment interruption. The mean CD4 cell loss 3 years postinterruption was 383 cells per microliter. In the SEROCO cohort, the CD4 T-cell decline was less steep (3-year CD4 loss 239 cells/microL). As a result, the mean CD4 cell counts were similar (416 cells/microL) 3 years after cART interruption (PRIMO) or after infection (SEROCO).

CONCLUSIONS

These data question the benefit of a limited course of cART even when initiated within 3 months after PHI diagnosis.

Immune correlates of CD4 decline in HIV-infected patients experiencing virologic failure before undergoing treatment interruption

Background

The advantage of treatment interruptions (TIs) in salvage therapy remains controversial. Regardless, characterizations of the correlates of CD4 count fall during TI are important to identify since patients with virologic failure commonly stop antiretroviral (ARV) therapy. The objective of this study was to determine the predictive value of pre-TI proliferative capacity and cell surface markers for CD4 count change in HIV-infected patients experiencing virologic failure before undergoing TI.

Methods

Peripheral blood mononuclear cells (PBMCs) from 13 HIV-infected patients experiencing virologic failure at baseline time points before the TI were tested for proliferation using the 5,6-carboxyfluorescein diacetate succinimidyl ester (CFSE) dilution assay and a Gag p55 peptide pool, staphylococcus enterotoxin B (SEB), cytomegalovirus (CMV) recall antigen, and anti-CD3 antibody as stimuli. CD28 and CD57 expression on CD4+ and CD8+ T-cells was measured.

Results

The median changes in the CD4+ T-cell count and viral load from baseline to the TI time point corresponding to the CD4 count nadir were -44 cells/mm³ {Interquartile range (IQR) -17, -104} and +85,332 copies/mL (IQR +11,198, +283,327), respectively. CD4+ T-cell proliferation to CMV, pre-TI CD4+ T-cell count, and percent CD4+CD57+ cells correlated negatively with CD4 count change during TI (r = -0.59, p = 0.045, r = -0.61, p = 0.030 and r = -0.69, p = 0.0095, respectively; Spearman correlation). The presence of HIV-specific proliferative responses was not associated with a reduced decline in CD4 count during TI.

Conclusion

The use of pre-TI immune proliferative responses and cell surface markers may have predictive value for CD4 count decline during TI.

Clinical outcomes after an unstructured treatment interruption in children and adolescents with perinatally acquired HIV infection

OBJECTIVE

An unstructured treatment interruption in children with perinatally acquired HIV infection is an issue with unresolved significance. The objective of this study was to investigate the actual prevalence and clinical outcomes of a treatment interruption in children and adolescents with perinatally acquired HIV-1 infection.

METHODS

Clinical data were analyzed for 72 children and adolescents who had HIV-1 infection and stopped their medications at 4 academic centers in the United States between January 2000 and September 2004.

RESULTS

Among 405 patients with perinatal HIV-1 infection, 72 (17.8%) experienced a treatment interruption during the observation period. The mean age of patients at the time of the treatment interruption was 12.8 years, and the mean length of the treatment interruption was 14 months. Medication fatigue was the most common reason for a treatment interruption. The CD4+ T-cell percentage nadir before the treatment interruption did not predict CD4+ T-cell percentage declines during the treatment interruption; however, the CD4+ T-cell percentage gain from nadir to the time of the treatment interruption predicted CD4+ T-cell percentage declines during the treatment interruption. During the median follow-up of 19 months (range: 6-48 months), 48 (67%) patients resumed antiretroviral medications. As expected, there was a continuous CD4+ T-cell percentage decrease and plasma HIV-1 RNA increase during the observation period. Overall, 7 (10%) patients were admitted to the hospital; 2 (3%) patients experienced an AIDS-defining illness.

CONCLUSIONS

An unstructured treatment interruption seems to be a major issue for youth with perinatally acquired HIV-1 infection. Patients who experienced the greatest rise in CD4+ T-cell percentage on treatment had the largest CD4+ T-cell percentage decline after the treatment interruption. Close monitoring is required when a treatment interruption occurs in children and adolescents with HIV infection.

Role for plasmacytoid dendritic cells in anti-HIV innate immunity

The role of plasmacytoid dendritic cells (pDC) in anti-HIV immunity is mostly represented by the production of type I IFN in response to HIV infection in vitro and in vivo. This production is decreased in HIV-1 infected patients at the time of primary infection and during chronic disease in association with progression of disease. Circulating pDC counts are decreased concomitantly with type I IFN, and both factors correlate inversely overall with viral loads and positively with CD4+ T-cell counts. These parameters might be used in clinical immunology to monitor treatment and as predictive factors of immune control of HIV-1 replication to help decide whether to interrupt antiretroviral treatment. They may be related to control of HIV replication as well as to pathogenesis of infection, perhaps in setting the balance between immunity or tolerance to the virus. A better understanding of these parameters is required while attempts to use IFN-alpha or ligands of Toll-like receptors found on pDC are being made.

Clinical analysis of dendritic cell subsets: the dendritogram

Dendritic cells (DCs) are crucial in adaptive immunity because they are the only antigen-presenting cells that can present antigens to naive T lymphocytes. Plasmacytoid DCs (pDC) are also the main producers of type I Interferons in response to infection. We have shown that circulating myeloid DC (mDC) and pDC numbers are reduced in chronic as well as primary HIV infection. Data from different laboratories indicate that pDC counts, obtained by flow cytometry and rare event analysis, correlate inversely with the viral load, may be an early marker of recovery after antiretroviral treatment, and may predict better immune control of HIV replication. PDC counts may also be predictive of severe illness in dengue virus infection or of successful treatment against Mycobacterium tuberculosis. DC counts, or the "dendritogram", may therefore become useful in the clinical assessment of different infectious diseases.

Rapid CD4 decline after interruption of non-nucleoside reverse transcriptase inhibitor-based antiretroviral therapy in a resource-limited setting

Background

Non-nucleoside reverse transcriptase inhibitor (NNRTI) with stavudine and lamivudine is widely used as the first-line antiretroviral therapy (ART) in resource-limited settings. Lipodystrophy is common and options for switching ART regimen are limited; this situation can lead to patients' poor adherence and antiretroviral resistance. Treatment interruption (TI) in patients with high CD4 cell counts, lipodystrophy, and limited options may be an alternative in resource-limited settings. This study aimed to determine time to resume ART after TI and predictors for early resumption of ART in a resource-limited setting.

Methods

A prospective study was conducted in January 2005 to December 2006 and enrolled HIV-infected patients with HIV-1 RNA <50 copies/mL, CD4 > 350 cells/mm³, and willing to interrupt ART. CD4 cell count, HIV-1 RNA, lipid profile, and lipodystrophy were assessed at baseline and every 3 months. ART was resumed when CD4 declined to <250 cells/mm³ or developed HIV-related symptoms. Patients were grouped based on ART regimens [NNRTI or protease inhibitor (PI)] prior to TI.

Results

There were 99 patients, 85 in NNRTI group and 14 in PI group. Mean age was 40.6 years; 46% were males. Median duration of ART was 47 months. Median nadir CD4 and baseline CD4 were 151 and 535 cells/mm³, respectively. Median CD4 change at 3 months after TI were -259 (NNRTI) and -105 (PI) cells/mm³ (p = 0.038). At 13-month median follow-up, there was no AIDS-defining illness; 38% (NNRTI) and 29% (PI) of patients developed HIV-related symptoms. ART was resumed in 51% (NNRTI) and 36% (PI) of patients (p = 0.022). By Kaplan-Meier analysis, median time to resume ART was 5.5 (NNRTI) and 14.2 (PI) months (log rank test, p = 0.026). By Cox's regression analysis, NNRTI-based ART (HR 4.9; 95%CI, 1.5–16.3), nadir CD4 <100 cells/mm³ (HR 2.7; 95%CI 1.4–5.3) and baseline CD4 <500 cells/mm³ (HR 1.6; 95%CI, 1.2–3.1) were predictors for early ART resumption.

Conclusion

TI of NNRTI-based ART leads to rapid CD4 decline and high probability of early ART resumption and should be avoided. It is necessary to scale-up the options for HIV-infected patients with lipodystrophy in resource-limited settings.

Predictors of disease progression in HIV infection: a review

During the extended clinically latent period associated with Human Immunodeficiency Virus (HIV) infection the virus itself is far from latent. This phase of infection generally comes to an end with the development of symptomatic illness. Understanding the factors affecting disease progression can aid treatment commencement and therapeutic monitoring decisions. An example of this is the clear utility of CD4+ T-cell count and HIV-RNA for disease stage and progression assessment. Elements of the immune response such as the diversity of HIV-specific cytotoxic lymphocyte responses and cell-surface CD38 expression correlate significantly with the control of viral replication. However, the relationship between soluble markers of immune activation and disease progression remains inconclusive. In patients on treatment, sustained virological rebound to >10,000 copies/mL is associated with poor clinical outcome. However, the same is not true of transient elevations of HIV RNA (blips). Another virological factor, drug resistance, is becoming a growing problem around the globe and monitoring must play a part in the surveillance and control of the epidemic worldwide. The links between chemokine receptor tropism and rate of disease progression remain uncertain and the clinical utility of monitoring viral strain is yet to be determined. The large number of confounding factors has made investigation of the roles of race and viral subtype difficult, and further research is needed to elucidate their significance. Host factors such as age, HLA and CYP polymorphisms and psychosocial factors remain important, though often unalterable, predictors of disease progression. Although gender and mode of transmission have a lesser role in disease progression, they may impact other markers such as viral load. Finally, readily measurable markers of disease such as total lymphocyte count, haemoglobin, body mass index and delayed type hypersensitivity may come into favour as ART becomes increasingly available in resource-limited parts of the world. The influence of these, and other factors, on the clinical progression of HIV infection are reviewed in detail, both preceding and following treatment initiation.

Antiretroviral therapy interruption guided by CD4 cell counts and plasma HIV-1 RNA levels in chronically HIV-1-infected patients

OBJECTIVE

We evaluated the safety of CD4 cell count and plasma HIV-1 RNA (pVL)-guided treatment interruptions (GTI) and determined predictors of duration of treatment interruption.

METHODS

Chronically HIV-1-infected adults with sustained CD4 cell counts > 500 cells/microl and pVL < 50 copies/ml were randomly assigned to either continue with standard antiretroviral therapy (control group, n = 101) or to interrupt therapy aimed at maintaining CD4 cell counts > 350 cells/microl and pVL < 100,000 copies/ml (GTI group, n = 100). Both groups were followed for 2 years.

RESULTS

There were no AIDS-defining illnesses or deaths in either group. Compared to controls, subjects interrupting therapy reduced treatment exposure by 67%, but suffered significantly more adverse events related to the intake of medication or to therapy interruption [relative hazard, 2.71; 95% confidence interval (CI), 1.64-4.49; P < 0.001), mainly due to an excess in mononucleosis-like symptoms. While GTI subjects demonstrated improvements in the psychosocial spheres of quality of life and pain reporting, GTI had no effect on the physical aspects of quality of life. Although both groups had a similar hazard for developing CD4 cell count < 200 cells/microl; at least 10% of subjects on GTI had CD4 cell counts < 350 cells/microl at every time point. Drug resistance mutations were detected in 36% of subjects but were selected de novo only in subjects interrupting non-nucleoside reverse transcriptase inhibitor therapy. Lower CD4 cell count nadir, higher set-point pVL and prior exposure to suboptimal regimens were all independent predictors of the need to reinitiate treatment.

CONCLUSIONS

Overall, GTI were not as safe as continuing therapy. Despite achieving some improvements in quality of life, GTI did not reduce the overall rate of management-related adverse events.

Highly active antiretroviral therapy interruption: predictors and virological and immunologic consequences

OBJECTIVE

To characterize the magnitude and the predictors of highly active antiretroviral therapy (HAART) interruption (TI) and to investigate its immunologic and virological consequences.

METHODS

Using Concerted Action on Seroconversion to AIDS and Death in Europe data from 8,300 persons with well-documented seroconversion dates, we identified subjects with stable first HAART (for at least 90 days) not initiated during primary infection. A TI was defined as an interruption of all antiretroviral therapy drugs for at least 14 days.

RESULTS

Of 1,551 subjects starting HAART, 299 (19.3%) interrupted treatment. Median (interquartile range) duration of the TI was 189 (101-382) days. The cumulative probability (95% confidence interval) of TI at 2 years was 15.9% (14.0%-18.1%). Women were more likely to have a TI than men in the same exposure group (35.8% vs 24.2% among drug users, 22.1% vs 13.3% among heterosexuals; P < 0.05). Higher baseline viremia and poor immunologic response to HAART were associated with higher probabilities of TI. Median (interquartile range) individual CD4 cell loss during TI was 94 (1-220) cells/microL. Older age at HAART (>40 yr), lower pre-HAART nadir (<200 cells/microL), and lower CD4 at start of TI (<350 cells/microL) were significantly associated with greater relative CD4 loss during TI.

CONCLUSIONS

We estimate that almost 1 in 6 subjects on HAART interrupts treatment by 2 years. Further research is needed to investigate the reasons why TI is higher in women. We have identified characteristics of subjects with the greatest risk for CD4 loss in whom TI may have greater risks.

Type I interferon production in HIV-infected patients

Type I IFNs display multiple biological effects. They have a strong antiviral action, not only directly but also indirectly through activation of the immune system. They may also have actions that are deleterious for the host. The cells that produce type I IFN are mostly plasmacytoid dendritic cells (pDC), but this depends on the viral stimulus. The migration and distribution of pDC into lymphoid organs, driven by chemokine interactions with their ligands, determines interaction with different cell types. In HIV infection, IFN production in vitro is impaired during primary infection and later in association with opportunistic infections. Circulating pDC numbers are decreased in parallel. These parameters may be used to help assess the prognosis of the disease and to monitor treatment.

Thymic volume predicts CD4 T-cell decline in HIV-infected adults under prolonged treatment interruption

OBJECTIVE

To analyze the predictive capacity of thymic volume in CD4 T-cell loss after treatment interruption in HIV-infected patients with high nadir CD4 count.

METHODS

Thirty-nine HIV-infected patients with CD4 counts greater than or equal to 500 cells/microL, nadir CD4 counts greater than or equal to 250 cells/microL, and plasma viral loads less than 50 copies/mL for at least the past 12 months began a treatment interruption program. The event of interest for this study was the decrease of CD4 count below 350 cells/microL. Kaplan-Meier curves were used for all time-to-event analyses, and log-rank tests were used for comparison between groups in the univariate analysis. All variables with statistical association with CD4 T-cell loss were analyzed using multivariate Cox proportional hazards regression models.

RESULTS

Twenty-three percent of the patients had a decrease in CD4 count to less than 350 cells/microL. In the univariate analysis, only thymic volume was statistically significant with this event (P = 0.02). Nadir CD4 count nearly reached statistical significance. However, age, sex, HCV coinfection, CD4 count, T-cell receptor excision circle-bearing cells, and early viral load rebound did not show statistical differences. Thymic volume and CD4 T-cell loss were independently associated using Cox proportional hazards regression model (P = 0.04; relative risk, 0.76; 95% confidence interval, 0.59-0.99).

CONCLUSIONS

In this study, we demonstrate for the first time that thymic volume predicts CD4 T-cell loss in patients with nadir CD4 count greater than or equal to 250 cells/muL under treatment interruption.

A pilot study evaluating time to CD4 T-cell count <350 cells/mm(3) after treatment interruption following antiretroviral therapy +/- interleukin 2: results of ACTG A5102

BACKGROUND

Although an intermittent antiviral treatment (ART) strategy may limit long-term toxicity and cost, there is concern about the risk for virologic failure, selection of drug resistance mutations, and disease progression. By boosting CD4 T-cell counts, interleukin 2 (IL-2) could safely prolong the duration of treatment interruption (TI) in a CD4-driven strategy.

METHODS

The AIDS Clinical Trials Group (ACTG) study A5102 evaluated 3 cycles of IL-2 before TI, on clinical and immunologic outcomes, using a CD4 T-cell count of <350 cells/mm as the threshold for restarting ART. Forty-seven HIV-infected subjects on potent ART with CD4 T-cell counts of > or =500 cells/mm or more and HIV RNA levels of less than 200 copies/mL were randomized to arm A (ART + three 5-day cycles of IL-2 at 4.5 million U, Sc, BID every 8 weeks, n = 23) or arm B (ART alone, n = 24) for 18 weeks (step 1). At the end of step 1, subjects with a CD4 T-cell count of > or =500 cells/mm or more stopped ART until a CD4 count of <350 cells/mm (step 2). CD4 T-cell count, time to return of viremia, and the emergence of drug resistance mutations after TI were compared between study arms.

RESULTS

IL-2 recipients maintained higher CD4 counts during TI for 48 weeks with a waning of the CD4 effect by 72 weeks. A sustained CD4 T-cell count of more than 350 cells/mm and more durable TI were associated with a higher nadir CD4 T-cell count before ART and higher naive CD4 T-cell count at entry. After TI, a higher viral set point and drug resistance mutations at virologic rebound were associated with a shorter time to CD4 T-cell count of less than 350 cell/mm. There were no differences in the magnitude of virologic rebound (at week 8 of step 2, median log10 HIV RNA level was 4.23 for arm A and 4.21 for arm B) or the steady-state HIV-1 RNA level after week 8.

CONCLUSIONS

IL-2 before TI did not prolong time to CD4 of less than 350 cells/mm. A TI strategy utilizing a CD4 T-cell threshold of less than 350 cells/mm for restarting ART appears generally safe with most subjects in both arms remaining off ART for more than 1 year. Implications of our results for TI strategies include the potential advantage of starting ART at higher CD4 T-cell levels while avoiding any drug resistance and evaluating immunomodulators or drugs to reduce T-cell activation and HIV-1 RNA rebound during the TI.

Immunovirologic consequences and safety of short, non-structured interruptions of successful antiretroviral treatment

OBJECTIVES

The aim was to evaluate the safety of short antiretroviral treatment interruptions and their virologic and immunologic consequences in HIV-infected adults on highly active antiretroviral treatment (HAART) with suppressed viral replication. The viral efficacy upon reintroduction was also evaluated.

PATIENTS AND METHODS

All patients with undetectable viral load while on HAART were prospectively followed to detect any treatment interruption. We analysed viral and cellular kinetics, incidence of resistance mutations, clinical outcome and results after therapy resumption.

RESULTS

Twenty patients were included, mean time since HIV diagnosis was 95 months and time with undetectable viral load 16 months. Treatment was interrupted because of adverse effects, cancer, tuberculosis or patient will. Treatment was reintroduced after 4 weeks using, if possible, the same combination. HIV viral load was detectable on day 28 after interruption in 18 patients (90%). Median of CD4 cell count (p25-p75) decreased from 478/mm3 (96-716) to 257/mm3 (118-663) (p=0.5). Resistance mutations were found in 9 patients (45%) after interruptions. Treatment was reintroduced in 14 patients; all of them achieved viral suppression.

CONCLUSIONS

In patients receiving HAART who have undetectable viral load, an interruption, no longer than 4 weeks, due to any intercurrent problem seems to be safe. Response to resumption can usually be achieved. Due to the frequent development of resistance, a genotypic test during interruption might be helpful.

Safe Treatment Interruptions in Patients With Nadir CD4 Counts of More Than 350 Cells/μL

OBJECTIVE

To evaluate clinical, immunologic, and virologic performance of patients with nadir CD4 counts of >350 cells/microL upon treatment interruption.

DESIGN

Randomized, open-label clinical trial of 48 weeks' duration.

METHODS

Patients on effective highly active antiretroviral therapy, with nadir CD4 counts of >350 cells/microL and peak viral loads of <50,000 copies/mL were randomized to continue therapy or to interrupt antiretroviral medication. End points for patients with treatment interruption were CD4 counts of <350 cells/microL, viral loads of >1 log above the pretherapy values, or clinical symptoms attributable to HIV, at which point treatment was restarted. In the continuation group, the end points were virologic failure, opportunistic infections, and treatment discontinuation due to toxicities.

RESULTS

Twenty patients were randomized to stop therapy and 16 patients to continue. Median CD4 counts at baseline were 643 cells/microL for the interruption group and 633 cells/microL for the continuation group. No end points were reached in the interruption group. By week 8, viral load returned to values comparable to those of pretherapy in all patients in the interruption group and remained stable until week 48. CD4 counts dropped in the interruption group (median loss of 156 cells/microL) at week 48. Significant decreases in venous lactate were observed in the interruption group.

CONCLUSIONS

Treatment interruptions in patients with nadir CD4 counts of >350 cells/microL seem safe for at least 48 weeks. Pretherapy viral load appears as a valuable tool to predict its level at week 48.

Safety and factors predicting the duration of first and second treatment interruptions guided by CD4+ cell counts in patients with chronic HIV infection

OBJECTIVES

To evaluate the safety of treatment interruption (TI) guided by CD4+ count in HIV-infected patients followed-up prospectively.

METHODS

Patients on HAART with a CD4+ cell count >500 cells/mm3 discontinued therapy with instructions to start therapy again before their CD4+ count dropped below 200 cells/mm3.

RESULTS

We report data on 112 HIV-infected patients. The median follow-up after starting the first TI was 34.7 months (IQR: 23.1-43.8). The median duration of the first TI was 12 months (IQR: 5.2-25). In the multivariate analysis the factor which most strongly correlated with the duration of the first TI was the CD4+ cell count at the end of the TI. Among the 34 patients who had completed a second TI, the duration of the two periods of interruption was similar if the treatment was recommenced at the end of the first TI at a CD4+ count higher than the nadir count.

CONCLUSIONS

The strategy of TI is safe if the criteria for restarting therapy are applied correctly. The factor with the greatest influence on the duration of the first TI is the number of CD4+ cells at the end of the TI.

Long-Term Follow-Up of Asymptomatic HIV-Infected Patients Who Discontinued Antiretroviral Therapy

BACKGROUND

Whether asymptomatic human immunodeficiency virus (HIV)-infected patients can interrupt treatment remains unknown.

METHODS

We performed a prospective, observational study of 46 patients who started therapy with >300 CD4+ cells/mm3 and/or <70,0000 HIV-1 RNA copies/mL. Patients had been receiving highly active antiretroviral therapy (HAART) for at least 6 months. HAART was discontinued, and plasma HIV-1 RNA loads and CD4+ cell counts were determined at 4-month intervals.

RESULTS

At the time of HAART discontinuation, the median CD4+ cell count was 793 cells/mm3, and all patients had undetectable viral loads. A rapid decrease of 173 cells/mm3 in the median CD4+ cell count was observed during the first 4 months after HAART was stopped, followed by a slower decrease of 234 cells/mm3 between months 5 and 20. The decrease in the median CD4+ cell count early after HAART discontinuation was inversely correlated with the increase that occurred during receipt of therapy (r=-0.653) and with the count at the time of HAART discontinuation (r=-0.589). The decrease in the median CD4+ cell count after the fourth month without HAART was correlated with the nadir count before HAART initiation (r=-0.349) and the increase during treatment (r=-0.322). The median follow-up duration was 20 months. After 12, 24, and 36 months of observation, 33 patients (71.7%), 22 patients (47.8%), and 16 patients (34.7%), respectively, remained free of therapy. Adverse clinical events were not seen, and all patients who reinitiated HAART responded rapidly.

CONCLUSION

Selected asymptomatic HIV-infected patients can safely discontinue therapy for prolonged periods of time.

Can highly active antiretroviral therapy be interrupted in patients with sustained moderate HIV RNA and > 400 CD4+ cells/µl? Impact on immunovirological parameters

Because the effects of treatment interruption on patients with >400 CD4(+) cells/microl and prolonged moderate HIV loads is unknown, their HIV1 RNA and DNA loads, plasma, and PBMC resistance mutations and CD4+ kinetics were studied during 12 months of treatment interruption. Fifty-seven patients were included: 28 with undetectable (median 40 months) and 29 with moderate (>1 year) HIV1 RNA levels (3.3 log10 copies/ml) at the baseline M0. HIV1 RNA and CD4+ counts were determined monthly. PBMC HIV1 DNA was quantified (real-time PCR) and its reverse transcriptase (RT) and protease (PR) genotypes analyzed (M0, M6, M12). Regardless of HIV1 RNA detectability at the baseline M0, all patients had comparable HIV1 RNA (median 4.6), DNA (median 2.9), CD4+ (median 455) at month 12 (M12). The decisive moment was month 1 (M1), when the HIV1 RNA increase and CD4 decline stabilized, rendering M0 differences non-significant and predicting outcome. The lower the CD4+ nadir was before HAART, the steeper the CD4+ decline at M1. HIV1 DNA shifted to wild-type genotype in 47% (M6) and 79% (M12) of RT; 64% of PR major resistance mutations disappeared (M12). Treatment interruption is possible, regardless of the baseline M0 HIV RNA status, but it must take into consideration the CD4+ nadir, an outcome predictor, to initiate HAART before too severe depletion to preserve the possibility of treatment interruption. HIV1 DNA genotyping helps monitor patients with undetectable HIV RNA at M0.