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

Impact of influenza and pneumococcal vaccines on HIV persistence and immune dynamics during suppressive antiretroviral therapy

OBJECTIVE

We sought to determine if standard influenza and pneumococcal vaccines can be used to stimulate HIV reservoirs during antiretroviral therapy (ART).

DESIGN

A prospective, randomized, double-blinded, placebo-controlled, crossover trial of two clinically recommended vaccines (influenza and pneumococcal).

METHODS

Persons with HIV on ART ( N  = 54) were enrolled in the clinical trial. Blood was collected at baseline and days 2,4,7,14, and 30 postimmunizations. Levels of cellular HIV RNA and HIV DNA were measured by ddPCR. Expression of immunological markers on T cell subsets was measured by flow cytometry. Changes in unspliced cellular HIV RNA from baseline to day 7 postinjection between each vaccine and placebo was the primary outcome.

RESULTS

Forty-seven participants completed at least one cycle and there were no serious adverse events related to the intervention. We observed no significant differences in the change in cellular HIV RNA after either vaccine compared with placebo at any timepoint. In secondary analyses, we observed a transient increase in total HIV DNA levels after influenza vaccine, as well as increased T cell activation and exhaustion on CD4 + T cells after pneumococcal vaccine.

CONCLUSION

Clinically recommended vaccines were well tolerated but did not appear to stimulate the immune system strongly enough to elicit significantly noticeable HIV RNA transcription during ART.Clinicaltrials.gov identifier: NCT02707692.

Immunogenicity of an inactivated SARS-CoV-2 vaccine in people living with HIV-1: a non-randomized cohort study

BACKGROUND

Inactivated COVID-19 vaccines are safe and effective in the general population with intact immunity. However, their safety and immunogenicity have not been demonstrated in people living with HIV (PLWH).

METHODS

42 HIV-1 infected individuals who were stable on combination antiretroviral therapy (cART) and 28 healthy individuals were enrolled in this open-label two-arm non-randomized study at Hubei Provincial Center for Disease Control and Prevention, China. Two doses of an inactivated COVID-19 vaccine (BBIBP-CorV) were given on April 22, 2021 and May 25, 2021, respectively. The reactogenicity of the vaccine were evaluated by observing clinical adverse events and solicited local and systemic reactions. Humoral responses were measured by anti-spike IgG ELISA and surrogate neutralization assays. Cell-mediated immune responses and vaccine induced T cell activation were measured by flow cytometry.

FINDINGS

All the HIV-1 infected participants had a CD4⁺ T cell count >200 cells/μL both at baseline (659·0 ± 221·9 cells/μL) and 4 weeks after vaccination (476·9 ± 150·8 cells/μL). No solicited adverse reaction was observed among all participants. Similar binding antibody, neutralizing antibody and S protein specific T cell responses were elicited in PLWH and healthy individuals. PLWH with low baseline CD4⁺/CD8⁺ T cell ratios (<0·6) generated lower antibody responses after vaccination than PLWH with medium (0·6∼1·0) or high (≥1·0) baseline CD4⁺/CD8⁺ T cell ratios (P<0·01). The CD3⁺, CD4⁺ and CD8⁺ T cell counts of PLWH decreased significantly after vaccination (P<0·0001), but it did not lead to any adverse clinical manifestation. Moreover, we found that the general HIV-1 viral load among the PLWH cohort decreased significantly after vaccination (P=0·0192). The alteration of HIV-1 viral load was not significantly associated with the vaccine induced CD4⁺ T cell activation (P>0·2).

INTERPRETATION

Our data demonstrated that the inactivated SARS-CoV-2 vaccine was safe, immunogenic in PLWH who are stable on cART with suppressed viral load and CD4⁺ T cell count > 200 cells/μL. However, the persistence of the vaccine-induced immunities in PLWH need to be further investigated.

A Classifier to Predict Viral Control After Antiretroviral Treatment Interruption in Chronic HIV-1-Infected Patients

OBJECTIVES

To construct a classifier that predicts the probability of viral control after analytical treatment interruptions (ATI) in HIV research trials.

METHODS

Participants of a dendritic cell-based therapeutic vaccine trial (DCV2) constituted the derivation cohort. One of the primary endpoints of DCV2 was the drop of viral load (VL) set point after 12 weeks of ATI (delta VL12). We classified cases as "controllers" (delta VL12 > 1 log10 copies/mL, n = 12) or "noncontrollers" (delta VL12 < 0.5 log10 copies/mL, n = 10) and compared 190 variables (clinical data, lymphocyte subsets, inflammatory markers, viral reservoir, ELISPOT, and lymphoproliferative responses) between the 2 groups. Naive Bayes classifiers were built from combinations of significant variables. The best model was subsequently validated on an independent cohort.

RESULTS

Controllers had significantly higher pre-antiretroviral treatment VL [110,250 (IQR 71,968-275,750) vs. 28,600 (IQR 18737-39365) copies/mL, P = 0.003] and significantly lower proportion of some T-lymphocyte subsets than noncontrollers: prevaccination CD4CD45RA+RO+ (1.72% vs. 7.47%, P = 0.036), CD8CD45RA+RO+ (7.92% vs. 15.69%, P = 0.017), CD4+CCR5+ (4.25% vs. 7.40%, P = 0.011), and CD8+CCR5+ (14.53% vs. 27.30%, P = 0.043), and postvaccination CD4+CXCR4+ (12.44% vs. 22.80%, P = 0.021). The classifier based on pre-antiretroviral treatment VL and prevaccine CD8CD45RA+RO+ T cells was the best predictive model (overall accuracy: 91%). In an independent validation cohort of 107 ATI episodes, the model correctly identified nonresponders (negative predictive value = 94%), while it failed to identify responders (positive predictive value = 20%).

CONCLUSIONS

Our simple classifier could correctly classify those patients with low probability of control of VL after ATI. These data could be helpful for HIV research trial design.

Virological Outcome Measures During Analytical Treatment Interruptions in Chronic HIV-1-Infected Patients

Background

Analytical treatment interruptions (ATIs) are essential in research on HIV cure. However, the heterogeneity of virological outcome measures used in different trials hinders the interpretation of the efficacy of different strategies.

Methods

We conducted a retrospective analysis of viral load (VL) evolution in 334 ATI episodes in chronic HIV-1-infected patients collected from 11 prospective studies. Quantitative (baseline VL, set point, delta set point, VL, and delta VL at given weeks after ATI, peak VL, delta peak VL, and area under the rebound curve) and temporal parameters (time to rebound [TtR], set point, peak, and certain absolute and relative VL thresholds) were described. Pairwise correlations between parameters were analyzed, and potential confounding factors (sex, age, time of known HIV infection, time on ART, and immunological interventions) were evaluated.

Results

The set point was lower than baseline VL (median delta set point, –0.26; P < .001). This difference was >1 log10 copies/mL in 13.9% of the cases. The median TtR was 2 weeks; no patients had an undetectable VL at week 12. The median time to set point was 8 weeks: by week 12, 97.4% of the patients had reached the set point. TtR and baseline VL were correlated with most temporal and quantitative parameters. The variables independently associated with TtR were baseline VL and the use of immunological interventions.

Conclusions

TtR could be an optimal surrogate marker of response in HIV cure strategies. Our results underline the importance of taking into account baseline VL and other confounding factors in the design and interpretation of these studies.

Clinical trials of antiretroviral treatment interruption in HIV-infected individuals

: Despite the benefits of antiretroviral therapy (ART) for people living with HIV, there has been a long-standing research interest in interrupting ART as a strategy to minimize adverse effects of ART as well as to test interventions aiming to achieve a degree of virological control without ART. We performed a systematic review of HIV clinical studies involving treatment interruption from 2000 to 2017 to describe the differences between treatment interruption in studies that contained and didn't contain an intervention. We assessed differences in monitoring strategies, threshold to restart ART, duration and adverse outcomes of treatment interruption, and factors aimed at minimizing transmission. We found that treatment interruption has been incorporated into 159 clinical studies since 2000 and is increasingly being included in trials to assess the efficacy of interventions to achieve sustained virological remission off ART. Great heterogeneity was noted in immunological, virological and clinical monitoring strategies, as well as in thresholds to recommence ART. Treatment interruption in recent intervention studies were more closely monitored, had more conservative thresholds to restart ART and had a shorter treatment interruption duration, compared with older treatment interruption studies that didn't include an intervention.

Humoral and cell-mediated immune responses after a booster dose of HBV vaccine in HIV-infected children, adolescents and young adults

OBJECTIVE

HBV vaccine induces protective antibodies only in 23-56% of HIV-infected children. The aim of our study is to evaluate the immunologic effects of a booster dose of HBV vaccine in HIV-infected youth.

DESIGN

53 young HIV-infected patients in whom HBV vaccination did not elicit protective Ab titers were enrolled. All patients were on ART with optimal immunological and viral response.

METHOD

All patients received a booster dose of HBV vaccine (HBVAXPRO 10 μg i.m.). HBV-specific Ab titer, viral load and CD4+ T cells were measured at baseline (T0), T1, T6 and T12 months. In a subgroup of 16 patients HBV-specific cell mediated immune responses were evaluated at baseline, at T1 and T6.

RESULTS

The booster dose induced seroconversion in 51% of patients at T1, 57% at T6, and49% at T12; seroconversion rate was significantly correlated with CD4+T cells at T0 and to the CD4 nadir. The booster dose induced HBV-specific cell mediated immunity at T6 mainly in Responders (Rs): Effector Memory CD8+T cells, HBV-specific TNFα-, IFNγ-, granzyme secreting CD8+ T cells and IL2-secreting CD4+ T cells were significantly increased in Rs compared to T0. In Non Responders (NRs), HBV-specific IL2-secreting CD4+ T cells, Central and Effector Memory CD8+ T cells were the only parameters modified at T6.

CONCLUSIONS

Seroconversion induced by a booster dose of vaccine correlates with the development of T cell immunological memory in HIV-infected patients who did not respond to the standard immunization. Alternate immunization schedules need to be considered in NRs.

Immune Activation by Mycobacterium tuberculosis in HIV-Infected and -Uninfected Subjects

INTRODUCTION

This study investigates the influence of Mycobacterium tuberculosis infection on immune activation biomarkers, both in HIV-infected and -uninfected subjects.

METHODS

Forty-eight treatment-naive HIV-infected patients and 74 HIV-uninfected subjects were recruited and divided into groups according to their M. tuberculosis infection status: latent tuberculosis infection (LTBI), active tuberculosis (TB), and no evidence of M. tuberculosis infection. The expression of cellular markers CD38 and HLA-DR on circulating CD8 T lymphocytes and the plasmatic levels of soluble markers interleukin-6, sCD14, and D-Dimer were measured and compared between groups. The HIV-infected patients with no evidence of M. tuberculosis or with LTBI who initiated antiretroviral treatment were tested again for these biomarkers once viral suppression was reached.

RESULTS

In both HIV-infected and -uninfected groups, patients with TB had higher levels of immune activation markers than subjects with LTBI and with no evidence of M. tuberculosis. Among the HIV-uninfected subjects, no significant difference in biomarker level was found between those presenting LTBI and those with no evidence of M. tuberculosis. The effect of LTBI on activation biomarkers in the HIV-infected groups was inconclusive because of the small number of individuals in the HIV+/LTBI group. sCD14 and D-Dimer levels were significantly higher in the TB-only group than in the HIV-only group.

DISCUSSION

Although TB is associated with an increase in biomarkers of immune activation, the effect of LTBI is less evident. Further investigation is warranted, and according to our results, soluble markers may offer greater sensitivity for the evaluation of M. tuberculosis-associated immune activation than cellular markers.

Standard vaccines increase HIV-1 transcription during antiretroviral therapy

OBJECTIVES

Curative strategies using agents to perturb the HIV reservoir have demonstrated only modest activity, whereas increases in viremia after standard vaccination have been described. We investigated whether vaccination against non-HIV pathogens can induce HIV transcription and thereby play a role in future eradication strategies.

DESIGN

A randomized controlled trial (NCT00329251) was performed to compare the effects of clinical vaccines with placebo on HIV transcription and immune activation.

METHODS

Twenty-six HIV-infected individuals on suppressive antiretroviral therapy were randomized to receive a vaccination schedule (n = 13) or placebo (n = 13). Cell-associated RNA and DNA were extracted from peripheral blood mononuclear cells, and HIV was quantified by droplet digital PCR using primers for gag and 2-LTR (for HIV DNA), unspliced gag RNA (gag usRNA), multispliced tat-rev RNA (tat-rev msRNA) and polyA mRNA.

RESULTS

Significant increases in gag usRNA after influenza/hepatitis B vaccination (P = 0.02) and in gag usRNA (P = 0.04) and polyA mRNA (P = 0.04) after pneumococcus/hepatitis B vaccination were seen in vaccinees but not controls. HIV DNA and plasma HIV RNA did not change in either group. Increases in CD4 and CD8 T-cell activation markers (P = 0.08 and P < 0.001, respectively) and HIV-specific CD8 responses (P = 0.04 for p24 gag, P = 0.01 for p17 gag and P = 0.04 for total gag) were seen in vaccinees but not controls.

CONCLUSION

In this study, vaccination was associated with increases in HIV cell-associated RNA and HIV-specific responses during antiretroviral therapy. Using standard vaccines to stimulate HIV transcription may therefore be a useful component of future eradication strategies.

Sublingual allergen immunotherapy in HIV-positive patients

HIV infection is a relative contraindication for allergic immunotherapy (AIT). In the last decade, highly active antiretroviral therapy (HAART) has improved the immune function and life expectancy in HIV-infected patients whose respiratory allergic incidence is similar to the general population. We evaluated the safety and clinical effectiveness of sublingual immunotherapy in a group of grass pollen-allergic HAART-treated HIV-positive patients. Thirteen patients received sublingual immunotherapy (SLIT) tablet (Oralair, Stallergenes©) and symptomatic therapy and were compared with nine patients receiving symptomatic therapy alone. Clinical benefits were evaluated by the analysis of total combined score (TCS), sum of symptom-medication score, and a quality of life (QoL) questionnaire. HIV viral load and peripheral TCD4 lymphocytes were analyzed at the beginning and at the end of the study. Clinical efficacy data showed a significant improvement in SLIT-treated patients compared to controls (TCS: P = 0.0001; QoL: P = 0.03). We did not observe any significant alteration of TCD4 cell counts and viral load (VL) in both groups. Our preliminary data showed that SLIT therapy in viro-immunological controlled HAART treated HIV positive patients was efficacious, safe and well tolerated.

HIV-1 Reservoir Dynamics after Vaccination and Antiretroviral Therapy Interruption Are Associated with Dendritic Cell Vaccine-Induced T Cell Responses

HIV-1-specific immune responses induced by a dendritic cell (DC)-based therapeutic vaccine might have some effect on the viral reservoir. Patients on combination antiretroviral therapy (cART) were randomized to receive DCs pulsed with autologous HIV-1 (n = 24) (DC-HIV-1) or nonpulsed DCs (n = 12) (DC-control). We measured the levels of total and integrated HIV-1 DNA in CD4 T cells isolated from these patients at 6 time points: before any cART; before the first cART interruption, which was at 56 weeks before the first immunization to isolate virus for pulsing DCs; before and after vaccinations (VAC1 and VAC2); and at weeks 12 and 48 after the second cART interruption. The vaccinations did not influence HIV-1 DNA levels in vaccinated subjects. After the cART interruption at week 12 postvaccination, while total HIV-1 DNA increased significantly in both arms, integrated HIV-1 DNA did not change in vaccinees (mean of 1.8 log10 to 1.9 copies/10(6) CD4 T cells, P = 0.22) and did increase in controls (mean of 1.8 log10 to 2.1 copies/10(6) CD4 T cells, P = 0.02) (P = 0.03 for the difference between groups). However, this lack of increase of integrated HIV-1 DNA observed in the DC-HIV-1 group was transient, and at week 48 after cART interruption, no differences were observed between the groups. The HIV-1-specific T cell responses at the VAC2 time point were inversely correlated with the total and integrated HIV-1 DNA levels after cART interruption in vaccinees (r [Pearson's correlation coefficient] = -0.69, P = 0.002, and r = -0.82, P < 0.0001, respectively). No correlations were found in controls. HIV-1-specific T cell immune responses elicited by DC therapeutic vaccines drive changes in HIV-1 DNA after vaccination and cART interruption. (This study has been registered at ClinicalTrials.gov under registration no. NCT00402142.)

IMPORTANCE

There is an intense interest in developing strategies to target HIV-1 reservoirs as they create barriers to curing the disease. The development of therapeutic vaccines aimed at enhancing immune-mediated clearance of virus-producing cells is of high priority. Few therapeutic vaccine clinical trials have investigated the role of therapeutic vaccines as a strategy to safely eliminate or control viral reservoirs. We recently reported that a dendritic cell-based therapeutic vaccine was able to significantly decrease the viral set point in vaccinated patients, with a concomitant increase in HIV-1-specific T cell responses. The HIV-1-specific T cell immune responses elicited by this therapeutic dendritic cell vaccine drove changes in the viral reservoir after vaccinations and significantly delayed the replenishment of integrated HIV-1 DNA after cART interruption. These data help in understanding how an immunization could shift the virus-host balance and are instrumental for better design of strategies to reach a functional cure of HIV-1 infection.

Hepatitis B vaccination for reducing morbidity and mortality in persons with HIV infection

BACKGROUND

Hepatitis B vaccine has been recommended for use in people living with HIV (PLHIV) mostly because of the similarities in routes of infection and their prevalence in the same geographic areas. PLHIV may not develop sero-protection after receiving standard hepatitis B vaccine due to their compromised immune status.

OBJECTIVES

To evaluate the efficacy of hepatitis B virus vaccine in PLHIV compared to placebo or no vaccine.

SEARCH METHODS

We searched 6 English language databases in July 2012, and updated the search in June 2013 and August 2014. We searched the grey literature, conference proceedings, specialised web sites, and contacted experts in the field.

SELECTION CRITERIA

Randomised controlled trials of hepatitis B vaccine compared to placebo or no vaccine, evaluating relevant outcomes of efficacy and safety.

DATA COLLECTION AND ANALYSIS

Two review authors independently sought and extracted data on study design, participants, hepatitis B infection, hepatitis B related morbidity and mortality, anti-HBs immunogenicity and adverse effects related to vaccines from published articles or through correspondence with authors. Data were analysed qualitatively.

MAIN RESULTS

One double-blind randomised controlled trial with 26 participants who were on antiretroviral therapy (ART), comparing hepatitis B vaccine to placebo conducted in Spain met our eligibility criteria and was included in this review. The study ran for three years and participants were followed up on a monthly basis. The study reported adequate humoral response to vaccine at 12 months and no local or systematic side effects in both intervention and control groups. This humoral response was lost when the participants stopped taking ART. The sample size of the study was small and the study was conducted in a high income setting unlike the areas of highest burden of hepatitis B and HIV co-infections.

AUTHORS' CONCLUSIONS

The evidence from this study is insufficient to support any recommendations regarding the use of hepatitis B vaccine in PLHIV. Neither does this evidence demonstrate that hepatitis B vaccine is unsafe in PLHIV. Further randomised controlled trials in high prevalence areas are required to generate evidence on the long term efficacy and safety of hepatitis B vaccine in PLHIV with and without ART. Different regimens and routes of administration should also be explored.

Effects of different antigenic stimuli on thymic function and interleukin-7/CD127 system in patients with chronic HIV infection

BACKGROUND

We tested if an increase in immune activation and a decrease in CD4⁺ T cells induced by different antigenic stimuli could be associated with changes in the thymic function and the interleukin (IL)-7/CD127 system.

METHODS

Twenty-six HIV-infected patients under combined antiretroviral therapy (cART) were randomized to receive, during 12 months, a complete immunization schedule (7 vaccines and 15 doses) or placebo. Thereafter, cART was interrupted during 6 months. Changes in the thymic function and the IL-7/CD127 system after 3 different antigenic stimuli (vaccines, episodes of low-level intermittent viremia before cART interruption, or viral load rebound after cART interruption) were assessed.

RESULTS

During the period on cART, neither vaccines nor low-level viremia influenced thymic function or IL-7/CD127 system parameters. By analyzing the cohort as a whole while on cART, a significant improvement was observed in the thymic function as measured by an increase in the thymic volume (P = 0.024), T-cell receptor excision circle-bearing cells (P = 0.012), and naive CD4⁺ and CD8⁺ T cells (P = 0.069 both). No significant changes were observed in the IL-7/CD127 system. After cART interruption, a decrease in T-cell receptor excision circles (P < 0.001) and naive CD8⁺ T cells (P < 0.001), an increase in IL-7 and expression of CD127 on naive and memory CD4⁺ T cells (P = 0.028, P = 0.088, and P = 0.04, respectively), and a significant decrease in CD127 on naive and memory CD8⁺ T cells (P = 0.01, P = 0.006, respectively) were observed.

CONCLUSIONS

Low-level transient antigenic stimuli during cART were not associated with changes in the thymic function or the IL-7/CD127 system. Conversely, viral load rebound very early after cART interruption influenced the thymic function and the IL-7/CD127 system. Clinical Trials.gov number NCT00329251.

Safety, tolerability, and immunogenicity of the novel antituberculous vaccine RUTI: randomized, placebo-controlled phase II clinical trial in patients with latent tuberculosis infection

Objectives

To evaluate the safety, tolerability and immunogenicity of three different doses (5, 25 and 50 µg) of the novel antituberculous vaccine RUTI compared to placebo in subjects with latent tuberculosis infection.

Methods and Findings

Double-blind, randomized, placebo-controlled Phase II Clinical Trial (95 patients randomized). Three different RUTI doses and placebo were tested, randomized both in HIV-positive (n = 47) and HIV-negative subjects (n = 48), after completion of one month isoniazid (INH) pre-vaccination. Each subject received two vaccine administrations, 28 Days apart. Five patients withdrew and 90 patients completed the study. Assessment of safety showed no deaths during study. Two subjects had serious adverse events one had a retinal detachment while taking INH and was not randomized and the other had a severe local injection site abscess on each arm and was hospitalized; causality was assessed as very likely and by the end of the study the outcome had resolved. All the patients except 5 (21%) patients of the placebo group (3 HIV+ and 2 HIV−) reported at least one adverse event (AE) during the study. The most frequently occurring AEs among RUTI recipients were (% in HIV+/−): injection site reactions [erythema (91/92), induration (94/92), local nodules (46/25), local pain (66/75), sterile abscess (6/6), swelling (74/83), ulcer (20/11), headache (17/22) and nasopharyngitis (20/5)]. These events were mostly mild and well tolerated. Overall, a polyantigenic response was observed, which differed by HIV− status. The best polyantigenic response was obtained when administrating 25 µg RUTI, especially in HIV-positive subjects which was not increased after the second inoculation.

Conclusion

This Phase II clinical trial demonstrates reasonable tolerability of RUTI. The immunogenicity profile of RUTI vaccine in LTBI subjects, even being variable among groups, allows us considering one single injection of one of the highest doses in future trials, preceded by an extended safety clinical phase.

Trial Registration

ClinicalTrials.gov NCT01136161

Influence of episodes of intermittent viremia ("blips") on immune responses and viral load rebound in successfully treated HIV-infected patients

Presenting episodes of intermittent viremia (EIV) under combination antiretroviral therapy (cART) is frequent, but there exists some controversy about their consequences. They have been described as inducing changes in immune responses potentially associated with a better control of HIV infection. Conversely, it has been suggested that EIV increases the risk of virological failure. A retrospective analysis of a prospective, randomized double-blinded placebo-controlled study was performed. Twenty-six successfully treated HIV-infected adults were randomized to receive an immunization schedule or placebo, and after 1 year of follow-up cART was discontinued. The influence of EIV on T cell subsets, HIV-1-specific T cell immune responses, and viral load rebound, and the risk of developing genotypic mutations were evaluated, taking into account the immunization received. Patients with EIV above 200 copies/ml under cART had a lower proportion of CD4(+) and CD4(+)CD45RA(+)RO(-) T cells, a higher proportion of CD8(+) and CD4(+)CD38(+)HLADR(+) T cells, and higher HIV-specific CD8(+) T cell responses compared to persistently undetectable patients. After cART interruption, patients with EIV presented a significantly higher viral rebound (p=0.007), associated with greater increases in HIV-specific lymphoproliferative responses and T cell populations with activation markers. When patients with EIV between 20 and 200 copies/ml were included, most of the differences disappeared. Patients who present EIV above 200 copies/ml showed a lower CD4(+) T cell count and higher activation markers under cART. After treatment interruption, they showed greater specific immune responses against HIV, which did not prevent a higher virological rebound. EIV between 20 and 200 copies/ml did not have this deleterious effect.

Prospects for treatment of latent HIV

Recent advances in antiretroviral therapy (ART) have drastically improved the quality of life for people with HIV infection. However, owing to the persistence of latent HIV in the presence of therapy, patients must remain on therapy indefinitely. Currently, the solution to the HIV pandemic rests on the prevention of new infections and many decades of ART for the steadily expanding number of people infected worldwide. ART is costly, requires ongoing medical care, and can have side effects, thereby preventing its universal availability. Therefore, to escape the ironic burdens of therapy, efforts have begun to develop treatments for latent HIV infection. Current approaches propose either complete eradication of infection or induction of a state of stringent control over viral replication without ART. This review will discuss these strategies in detail and their potential for clinical development.

Short communication: HIV antigen-specific reactivation of HIV infection from cellular reservoirs: implications in the settings of therapeutic vaccinations

Therapeutic vaccinations using human immunodeficiency virus (HIV) antigens in HIV-infected patients on antiretroviral therapy (ART) have so far been attempted with the purpose of inducing CTL response. However, they can also be useful as a strategy for activation of latent HIV reservoir, which is thought to be mainly comprised of latently infected HIV-specific memory CD4 cells, eventually leading to elimination of the virus. The present study was carried out to explore the ability of different HIV antigens to activate HIV replication as assessed by intracellular P24 detection as well as to induce T cell responses in terms of cytokine expression by flow cytometry after stimulation of PBMCs from HIV-infected patients. HIV antigens were found to be able to activate most of the CD4 T cells harboring proviral DNA. HIV-1 Pol and Env were responsible for induction of higher HIV replication in terms of both magnitude and frequency followed by Gag and Nef. As opposed to this, Pol and Env contributed to fewer numbers of polyfunctional CD8 cells desirable for elimination of HIV-infected cells in comparison to Gag and Nef. Thus, HIV antigens may provide a strategy for the activation of a latent reservoir. It was observed that HIV replication started as early as half an hour after in vitro activation indicating a stringent need for maintaining effective concentrations of antiretroviral drugs to prevent further spread of HIV during this process. HIV-infected cells were found to be responsible for higher IL-10 secretion after activation, which could also serve as one of the reasons for suppressed CD8 responses to Pol and Env as more HIV-infected CD4 cells would be secreting IL-10 in response to these antigens. Since IL-10 blockade helped to improve immune responses in terms of cytokine secretion, it should be considered in settings of therapeutic vaccination to improve CTL responses, which will ultimately limit the persistence of the viral reservoir.

Vaccination against viral hepatitis of HIV-1 infected patients

Reciprocal interactions between HIV and HAV or HBV can increase risk of morbidity and mortality in HIV disease and/or worsened the natural course of the hepatitis viruses. Hepatitis A vaccination is recommended for HIV infected patients at risk for exposure or severe disease: men who have sex with men, injecting drug users, patients with chronic liver disease and patients traveling in high endemic countries. As for healthy adults the scheme of vaccination is two doses 6 or 12 mo apart, nevertheless, seroconversion rates are lower. A third dose could improve the seroconversion rates. Hepatitis B vaccination is recommended for all HIV infected persons lacking prior immunity. As the immune response to hepatitis B vaccines is impaired in HIV-infected adults, four double doses of hepatitis B vaccine could enhance serological response. To assume a higher immune response, vaccines should be administered in HIV-infected patients with undetectable HIV viral load and high CD4 cell count.

Effect of therapeutic HIV recombinant poxvirus vaccines on the size of the resting CD4+ T-cell latent HIV reservoir

OBJECTIVES

Therapeutic HIV vaccinations may alter the size of the resting memory CD4 T-cell latent HIV reservoir as HIV establishes latency when memory responses are formed, including those toward HIV. Alternatively, latently infected CD4 T cells maybe killed, while exiting the reservoir upon activation.

METHODS

The effect of therapeutic immunization with modified vaccinia Ankara and Fowlpox-based HIV vaccines on the latent reservoir was examined in 19 young adults who were receiving effective antiretroviral therapy. Correlations between size of the reservoir [measured in infectious units per million (IUPM)] resting CD4 T cells and HIV-specific immune responses, including immune activation were examined. Decay of the reservoir was assessed using random-effects model.

RESULTS

A modest transient decrease in the size of the reservoir was observed at week 40 [mean -0.31 log(10) IUPM (95% confidence interval: -0.60 to -0.03; P = 0.03] following HIV vaccinations. The estimated half-life (T1/2) of the reservoir during the 40 weeks following vaccination was 9.8 months and statistically different from zero (P = 0.02), but 35.3 months and not different from zero (P = 0.21) over 72 weeks of study. Latent reservoir size at baseline was not correlated with HIV-specific CD4, CD8 responses or immune activation, but became correlated with CD4 IFNγ (r = 0.54, P = 0.02) and IL-2 responses at 6 weeks after immunization (r = 0.48, P = 0.04).

CONCLUSION

Therapeutic HIV vaccinations led to a transient increase in decay of latently infected CD4 T cells. Further studies of therapeutic HIV vaccines may provide important insights into facilitating decay of the latent reservoir.

Safety and immunogenicity of a monovalent 2009 influenza A/H1N1v vaccine adjuvanted with AS03A or unadjuvanted in HIV-infected adults: a randomized, controlled trial

BACKGROUND

Human immunodeficiency virus (HIV)-infected patients have decreased immune response to vaccines. Few data are available about pandemic flu vaccination in this population.

METHODS

We conducted a multicenter, patient-blinded, randomized trial in a cohort of HIV-infected adults. Patients received 2 injections 21 days apart of a AS03(A)-adjuvanted H1N1v vaccine containing 3.75 μg hemagglutinin (HA) or a nonadjuvanted H1N1v vaccine containing 15 μg HA to assess hemagglutination inhibition (HI) response and safety.

RESULTS

A total of 309 patients were randomized, and 306 were vaccinated. After the first vaccine dose, HI titers ≥1:40 were observed in 93.4% of the patients in the adjuvanted group (A group) (n = 155) and in 75.5% in the nonadjuvanted group (B group) (n = 151) (P < .001); seroconversion rates were 88.8% and 71.2%, and factor increases in geometric mean titers (GMT) of 21.9 and 15.1, respectively. After 2 injections, 98.6% of patients of the A group and 92.1% of the B group demonstrated HI titers ≥1:40 (P = .018); seroconversion rates were 96.5% and 87.1%, respectively, and factor increases in GMT were 45.5 and 21.2, respectively. The majority of adverse events were mild to moderate in severity; no impact on CD4+ cell count or viral load has been detected.

CONCLUSIONS

In HIV-1-infected adults, the AS03(A)-adjuvanted H1N1v vaccine yielded a higher immune response than did the nonadjuvanted one, with no impact on HIV infection.

The reconstitution of the thymus in immunosuppressed individuals restores CD4-specific cellular and humoral immune responses

Infection with HIV-1 frequently results in the loss of specific cellular immune responses and an associated lack of antibodies. Recombinant growth hormone (rGH) administration reconstitutes thymic tissue and boosts the levels of peripheral T cells, so rGH therapy may be an effective adjuvant through promoting the recovery of lost cellular and T-cell-dependent humoral immune responses in immunosuppressed individuals. To test this concept, we administered rGH to a clinically defined group of HIV-1-infected subjects with defective cellular and serological immune responses to at least one of three commonly employed vaccines (hepatitis A, hepatitis B or tetanus toxoid). Of the original 278 HIV-1-infected patients entering the trial, only 20 conformed to these immunological criteria and were randomized into three groups: Group A (n = 8) receiving rGH and challenged with the same vaccine to which they were unresponsive and Groups B (n = 5) and C (n = 7) who received either rGH or vaccination alone, respectively. Of the eight subjects in Group A, five recovered CD4 cellular responses to vaccine antigen and four of these produced the corresponding antibodies. In the controls, three of the five in group B recovered cellular responses with two producing antibodies, whereas three of the seven in Group C recovered CD4 responses, with only two producing antibodies. Significantly, whereas seven of ten patients receiving rGH treatment in Group A (six patients) and B (one patient) recovered T-cell responses to HIVp24, only two of six in Group C responded similarly. In conclusion, reconstitution of the thymus in immunosuppressed adults through rGH hormone treatment restored both specific antibody and CD4 T-cell responses.

Therapeutic immunization in HIV infected Ugandans receiving stable antiretroviral treatment: a Phase I safety study

Therapeutic immunizations in HIV infection may boost immunity during antiretroviral treatment. We report on the first therapeutic vaccine trial in Uganda, Africa. This open label Phase I trial was designed to assess the safety, tolerability and immunogenicity of a therapeutic HIV-1 vaccine candidate. Thirty HIV positive volunteers receiving a stable regimen of antiretroviral therapy with CD4 counts >400 were recruited for the safety evaluation of LFn-p24C, a detoxified anthrax-derived polypeptide fused to the subtype C HIV gag protein p24. The vaccine was well tolerated and HIV RNA levels remained undetectable following three immunizations. CD4 counts in vaccine recipients were significantly higher compared to the control individuals after 12 months. HIV-specific responses were associated with higher gain in CD4 counts following LFn-p24C immunizations. Volunteers were subsequently asked to undergo a 30-day period of observed treatment interruption. 8/24 (30%) individuals showed no evidence of viral rebound during treatment interruption. All demonstrated prompt suppression of viral load following resumption of ART. Our data demonstrate the safety of LFn-p24C and suggest that adjunct therapeutic immunization may benefit select individuals in further boosting an immune response.

Effects of highly active antiretroviral therapy on vaccine-induced humoral immunity in HIV-infected adults

OBJECTIVES

The acquisition of adequate vaccine-induced humoral immunity is especially important in HIV-infected individuals, who are at increased risk of infections. The aim of the study was to assess the safety of administering a complete vaccination programme to successfully treated HIV-infected adults and to evaluate specific humoral responses and the effect of highly active antiretroviral therapy (HAART) interruption on these responses.

METHODS

A placebo-controlled, double-blind clinical trial was designed and 26 HIV-infected adults enrolled. Study participants were randomized to receive either a complete immunization schedule with commercial vaccines or placebo for 12 months. HAART was then discontinued for 6 months. Specific humoral responses were evaluated at baseline, at month 12 and after HAART interruption and compared between groups.

RESULTS

There were neither local nor systemic secondary effects related to vaccination. Specific humoral responses to vaccines were adequate, but a loss of immunoglobulin G titres was observed after HAART interruption in 12 study participants.

CONCLUSIONS

HAART interruption may cause impairment of previously acquired vaccine-induced immunity in HIV-infected adults.