Randomized, Open-Label Study of the Impact of Two Doses of Subcutaneous Recombinant Interleukin-2 on Viral Burden in Patients With HIV-1 Infection and CD4+ Cell Counts of ≥300/mm3: CPCRA 059:

Therapeutic potential of interleukin-2 in autoimmune diseases

Autoimmune diseases are characterized by dysregulation and aberrant activation of cells in the immune system. Therefore, restoration of the immune balance represents a promising therapeutic target in autoimmune diseases. Interleukin-2 (IL-2) can promote the expansion and differentiation of different immune cell subsets dose-dependently. At high doses, IL-2 can promote the differentiation and expansion of effector and memory T cells, whereas at low doses, IL-2 can promote the differentiation, survival, and function of regulatory T (T_reg) cells, a CD4⁺ T cell subset that is essential for the maintenance of immune homeostasis and immune tolerance. Therefore, IL-2 exerts immunostimulatory and immunosuppressive effects in autoimmune diseases. The immunoregulatory role of low-dose IL-2 has sparked excitement for the therapeutic exploration of modulating the IL-2-T_reg axis in the context of autoimmune diseases. In this review, we discuss recent advances in the therapeutic potential of IL-2 or IL-2-derived molecules in the treatment of autoimmune diseases.

Therapeutic vaccination for HIV: hopes and challenges

PURPOSE OF REVIEW

This review summarizes the recent landscape of HIV therapeutic vaccine research, emphasizing the results of randomized controlled trials that included analytical treatment interruption (ATI) to assess efficacy.

RECENT FINDINGS

Therapeutic vaccines for HIV are designed to re-educate the host immune response in HIV-infected individuals to better control viral replication in the absence of antiretroviral therapy. No therapeutic vaccine has yet to induce long-term HIV remission following ATI in a randomized controlled trial. This is likely because the vaccines have not elicited a broad enough immune response to suppress the diverse escape variants that emerge during viral rebound, and have not been used with effective agents to reduce the HIV reservoir. Recent studies in nonhuman primates using combination approaches are showing significant successes, with several candidates eliciting significant antiviral activity following ATI. Future studies pairing these vaccines with effective reservoir reduction hold great promise.

SUMMARY

Therapeutic vaccines aim to modulate the immune system of HIV-infected individuals to elicit sustained virologic control in the absence of antiretroviral therapy. Therapeutic vaccines that elicit broad immune responses have recently shown promise in randomized controlled trials and nonhuman primate studies.

Interleukin-2 as an adjunct to antiretroviral therapy for HIV-positive adults

BACKGROUND

Human immunodeficiency virus (HIV) continues to be a leading cause of morbidity and mortality, particularly in sub-Saharan Africa. Although antiretroviral drugs have helped to improve the quality of life and life expectancy of HIV-positive individuals, there is still a need to explore other interventions that will help to further reduce the disease burden. One potential strategy is the use of interleukin-2 (IL-2) in combination with antiretroviral therapy (ART). IL-2 is a cytokine that regulates the proliferation and differentiation of lymphocytes and may help to boost the immune system.

OBJECTIVES

To assess the effects of interleukin-2 (IL-2) as an adjunct to antiretroviral therapy for HIV-positive adults.

SEARCH METHODS

We searched the following sources up to 26 May 2016: the Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library; MEDLINE; Embase; the Web of Science; LILACS; the World Health Organization (WHO) International Clinical Trial Registry Platform (ICTRP); and ClinicalTrials.gov. We also checked conference abstracts, contacted experts and relevant organizations in the field, and checked the reference list of all studies identified by the above methods for any other potentially eligible studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) that evaluated the effects of IL-2 as an adjunct to ART in reducing the morbidity and mortality in HIV-positive adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened records and selected trials that met the inclusion criteria, extracted data, and assessed the risk of bias in the included trials. Where possible, we compared the effects of interventions using risk ratios (RR), and presented them with 95% confidence intervals (CI). We assessed the overall certainty of the evidence using the GRADE approach.

MAIN RESULTS

Following a comprehensive literature search up to 26 May 2016, we identified 25 eligible trials. The interventions involved the use of IL-2 in combination with ART compared with ART alone. There was no difference in mortality apparent between the IL-2 group and the ART alone group (RR 0.97, 95% CI 0.80 to 1.17; 6 trials, 6565 participants, high certainty evidence). Seventeen of 21 trials reported an increase in the CD4 cell count with the use of IL-2 compared to control using different measures (21 trials, 7600 participants). Overall, there was little or no difference in the proportion of participants with a viral load of less than 50 cells/mL or less than 500 cells/mL by the end of the trials (RR 0.97, 95% CI 0.81 to 1.15; 5 trials, 805 participants, high certainty evidence) and (RR 0.96, 95% CI 0.82 to 1.12; 4 trials, 5929 participants, high certainty evidence) respectively. Overall there may be little or no difference in the occurrence of opportunistic infections (RR 0.79, 95% CI 0.55 to 1.13; 7 trials, 6141 participants, low certainty evidence). There was probably an increase in grade 3 or 4 adverse events (RR 1.47, 95% CI 1.10 to 1.96; 6 trials, 6291 participants, moderate certainty evidence). None of the included trials reported adherence.

AUTHORS' CONCLUSIONS

There is high certainty evidence that IL-2 in combination with ART increases the CD4 cell count in HIV-positive adults. However, IL-2 does not confer any significant benefit in mortality, there is probably no difference in the incidence of opportunistic infections, and there is probably an increase in grade 3 or 4 adverse effects. Our findings do not support the use of IL-2 as an adjunct to ART in HIV-positive adults. Based on our findings, further trials are not justified.

Immunotherapeutic restoration in HIV-infected individuals

While the development of combined active antiretroviral therapy (cART) has dramatically improved life expectancies and quality of life in HIV-infected individuals, long-term clinical problems, such as metabolic complications, remain important constraints of life-long cART. Complete immune restoration using only cART is normally unattainable even in cases of sufficient plasma viral suppression. The need for immunologic adjuncts that complement cART remains, because while cART alone may result in the complete recovery of peripheral net CD4+ T lymphocytes, it may not affect the reservoir of HIV-infected cells. Here, we review current immunotherapies for HIV infection, with a particular emphasis on recent advances in cytokine therapies, therapeutic immunization, monoclonal antibodies, immune-modulating drugs, nanotechnology-based approaches and radioimmunotherapy.

Changes in the levels of some acute-phase proteins in human immunodeficiency virus-1 infected patients, following interleukin-2 treatment

Intermittent interleukin (IL)-2 administration to human immunodeficiency virus (HIV)-1 infected patients is well documented and generally used, but there is limited information about the changes of acute-phase protein (APP) levels in response to this treatment. Fifteen patients undergoing highly active anti-retroviral therapy (HAART) treatment, with undetectable viral load, but low CD4+ cell count (<300/microl), have been treated with 3.6 M IU Proleukine administered twice daily by subcutaneous injection over 5 days. C-reactive protein (CRP), D-dimer, C3, C9, C1-inh and alpha-2HS glycoprotein levels were measured immediately before IL-2 administration, as well as on day 5 and 2-3 weeks thereafter. After IL-2 administration, both mean D-dimer and CRP levels increased significantly (P<0.001), but returned (P<0.001) to baseline within the subsequent 2-3 weeks. Alpha-2HS glycoprotein decreased immediately after IL-2 administration. No significant differences were detected in the levels of C3, C9 and C1-inh. A significant, positive correlation (r=0.5178, P=0.0008) was ascertained between the changes of CRP level, measured immediately before as well as 5 days after IL-2 administration, and changes in CD4 T cell counts measured 2-3 weeks before and after treatment, respectively. IL-2 administration induces rapid elevation of two major APPs (CRP, D-dimer). The positive correlation observed between the changes of CRP levels and CD4+ cell counts after IL-2 administration may indicate that the abrupt, but transitory overproduction of CRP might contribute to the CD4+ cell count-increasing effect of the drug and/ or may be associated with serious side effects.

Effects of intermittent IL-2 alone or with peri-cycle antiretroviral therapy in early HIV infection: the STALWART study

Background

The Study of Aldesleukin with and without antiretroviral therapy (STALWART) evaluated whether intermittent interleukin-2 (IL-2) alone or with antiretroviral therapy (ART) around IL-2 cycles increased CD4⁺ counts compared to no therapy.

Methodology

Participants not on continuous ART with ≥300 CD4⁺ cells/mm³ were randomized to: no treatment; IL-2 for 5 consecutive days every 8 weeks for 3 cycles; or the same IL-2 regimen with 10 days of ART administered around each IL-2 cycle. CD4⁺ counts, HIV RNA, and HIV progression events were collected monthly.

Principal Findings

A total of 267 participants were randomized. At week 32, the mean CD4⁺ count was 134 cells greater in the IL-2 alone group (p<0.001), and 133 cells greater in the IL-2 plus ART group (p<0.001) compared to the no therapy group. Twelve participants in the IL-2 groups compared to 1 participant in the group assigned to no therapy experienced an opportunistic event or died (HR 5.84, CI: 0.59 to 43.57; p = 0.009).

Conclusions

IL-2 alone or with peri-cycle HAART increases CD4⁺ counts but was associated with a greater number of opportunistic events or deaths compared to no therapy. These results call into question the immunoprotective significance of IL-2-induced CD4⁺ cells.

Trial Registration

ClinicalTrials.gov NCT00110812

Prospects for antisense peptide nucleic acid (PNA) therapies for HIV

Since the discovery and synthesis of a novel DNA mimic, peptide nucleic acid (PNA) in 1991, PNAs have attracted tremendous interest and have shown great promise as potential antisense drugs. They have been used extensively as tools for specific modulation of gene expression by targeting translation or transcription processes. This review discusses the present and future therapeutic potential of this class of compound as anti-HIV-1 drugs.

Interleukin-2 therapy in patients with HIV infection

BACKGROUND

Used in combination with antiretroviral therapy, subcutaneous recombinant interleukin-2 raises CD4+ cell counts more than does antiretroviral therapy alone. The clinical implication of these increases is not known.

METHODS

We conducted two trials: the Subcutaneous Recombinant, Human Interleukin-2 in HIV-Infected Patients with Low CD4+ Counts under Active Antiretroviral Therapy (SILCAAT) study and the Evaluation of Subcutaneous Proleukin in a Randomized International Trial (ESPRIT). In each, patients infected with the human immunodeficiency virus (HIV) who had CD4+ cell counts of either 50 to 299 per cubic millimeter (SILCAAT) or 300 or more per cubic millimeter (ESPRIT) were randomly assigned to receive interleukin-2 plus antiretroviral therapy or antiretroviral therapy alone. The interleukin-2 regimen consisted of cycles of 5 consecutive days each, administered at 8-week intervals. The SILCAAT study involved six cycles and a dose of 4.5 million IU of interleukin-2 twice daily; ESPRIT involved three cycles and a dose of 7.5 million IU twice daily. Additional cycles were recommended to maintain the CD4+ cell count above predefined target levels. The primary end point of both studies was opportunistic disease or death from any cause.

RESULTS

In the SILCAAT study, 1695 patients (849 receiving interleukin-2 plus antiretroviral therapy and 846 receiving antiretroviral therapy alone) who had a median CD4+ cell count of 202 cells per cubic millimeter were enrolled; in ESPRIT, 4111 patients (2071 receiving interleukin-2 plus antiretroviral therapy and 2040 receiving antiretroviral therapy alone) who had a median CD4+ cell count of 457 cells per cubic millimeter were enrolled. Over a median follow-up period of 7 to 8 years, the CD4+ cell count was higher in the interleukin-2 group than in the group receiving antiretroviral therapy alone--by 53 and 159 cells per cubic millimeter, on average, in the SILCAAT study and ESPRIT, respectively. Hazard ratios for opportunistic disease or death from any cause with interleukin-2 plus antiretroviral therapy (vs. antiretroviral therapy alone) were 0.91 (95% confidence interval [CI], 0.70 to 1.18; P=0.47) in the SILCAAT study and 0.94 (95% CI, 0.75 to 1.16; P=0.55) in ESPRIT. The hazard ratios for death from any cause and for grade 4 clinical events were 1.06 (P=0.73) and 1.10 (P=0.35), respectively, in the SILCAAT study and 0.90 (P=0.42) and 1.23 (P=0.003), respectively, in ESPRIT.

CONCLUSIONS

Despite a substantial and sustained increase in the CD4+ cell count, as compared with antiretroviral therapy alone, interleukin-2 plus antiretroviral therapy yielded no clinical benefit in either study. (ClinicalTrials.gov numbers, NCT00004978 [ESPRIT] and NCT00013611 [SILCAAT study].)

Defective human immunodeficiency virus-specific CD8+ T-cell polyfunctionality, proliferation, and cytotoxicity are not restored by antiretroviral therapy

Identifying the functions of human immunodeficiency virus (HIV)-specific CD8+ T cells that are not merely modulated by the level of virus but clearly distinguish patients with immune control from those without such control is of paramount importance. Features of the HIV-specific CD8+ T-cell response in antiretroviral-treated patients (designated Rx <50) and untreated patients (long-term nonprogressors [LTNP]) matched for very low HIV RNA levels were comprehensively examined. The proliferative capacity of HIV-specific CD8+ T cells was not restored in Rx <50 to the level observed in LTNP, even though HIV-specific CD4+ T-cell proliferation in the two patient groups was comparable. This diminished HIV-specific CD8+ T-cell proliferation in Rx <50 was primarily due to a smaller fraction of antigen-specific cells recruited to divide and not to the numbers of divisions that proliferating cells had undergone. Exogenous interleukin-2 (IL-2) induced proliferating cells to divide further but did not rescue the majority of antigen-specific cells with defective proliferation. In addition, differences in HIV-specific CD8+ T-cell proliferation could not be attributed to differences in cellular subsets bearing a memory phenotype, IL-2 production, or PD-1 expression. Although polyfunctionality of HIV-specific CD8+ T cells in Rx <50 was not restored to the levels observed in LTNP despite prolonged suppression of HIV RNA levels, per-cell cytotoxic capacity was the functional feature that most clearly distinguished the cells of LTNP from those of Rx <50. Taken together, these data suggest that there are selective qualitative abnormalities within the HIV-specific CD8+ T-cell compartment that persist under conditions of low levels of antigen.

Comparisons of CD8+ T cells specific for human immunodeficiency virus, hepatitis C virus, and cytomegalovirus reveal differences in frequency, immunodominance, phenotype, and interleukin-2 responsiveness

To better understand the components of an effective immune response to human immunodeficiency virus (HIV), the CD8(+) T-cell responses to HIV, hepatitis C virus (HCV), and cytomegalovirus (CMV) were compared with regard to frequency, immunodominance, phenotype, and interleukin-2 (IL-2) responsiveness. Responses were examined in rare patients exhibiting durable immune-mediated control over HIV, termed long-term nonprogressors (LTNP) or elite controllers, and patients with progressive HIV infection (progressors). The magnitude of the virus-specific CD8(+) T-cell response targeting HIV, CMV, and HCV was not significantly different between LTNP and progressors, even though their capacity to proliferate to HIV antigens was preserved only in LTNP. In contrast to HIV-specific CD8(+) T-cell responses of LTNP, HLA B5701-restricted responses within CMV pp65 were rare and did not dominate the total CMV-specific response. Virus-specific CD8(+) T cells were predominantly CD27(+)45RO(+) for HIV and CD27(-)45RA(+) for CMV; however, these phenotypes were highly variable and heavily influenced by the degree of viremia. Although IL-2 induced significant expansions of CMV-specific CD8(+) T cells in LTNP and progressors by increasing both the numbers of cells entering the proliferating pool and the number of divisions, the proliferative capacity of a significant proportion of HIV-specific CD8(+) T cells was not restored with exogenous IL-2. These results suggest that immunodominance by HLA B5701-restricted cells is specific to HIV infection in LTNP and is not a feature of responses to other chronic viral infections. They also suggest that poor responsiveness to IL-2 is a property of HIV-specific CD8(+) T cells of progressors that is not shared with responses to other viruses over which immunologic control is maintained.

Immunological response to peptide nucleic acid and its peptide conjugate targeted to transactivation response (TAR) region of HIV-1 RNA genome

Anti-human immunodeficiency virus-1 (HIV-1) polyamide (peptide) nucleic acids (PNAs) conjugated with cell-penetrating peptides (CPPs) targeted to the viral genome are potent virucidal and antiviral agents. Earlier, we have shown that the anti-HIV-1 PNA(TAR)-penetratin conjugate is rapidly taken up by cells and is nontoxic to mice when administered at repeat doses of as high as 100 mg/kg body weight. In the present studies we demonstrate that naked PNA(TAR) is immunologically inert as judged by the proliferation responses of splenocytes and lymph node cells from PNA(TAR)-immunized mice challenged with the immunizing antigen. In contrast, PNA(TAR)-penetratin conjugate is moderately immunogenic mainly due to its penetratin peptide component. Cytokine secretion profiles of the lymph node cells from the conjugate-immunized mice showed marginally elevated levels of proinflammatory cytokines, which are known to promote proliferation of T lymphocytes. Since the candidate compound, PNA(TAR)-penetratin conjugate displays potent virucidal and antiviral activities against HIV-1, the favorable immunological response together with negligible toxicity suggest a strong therapeutic potential for this class of compounds.

Long-term effects of intermittent interleukin-2 therapy in chronic HIV-infected patients (ANRS 048-079 Trials)

OBJECTIVE

Interleukin (IL)-2 therapy leads to significant CD4 cell increases in HIV-infected patients. Since phase III trials are ongoing, studies supporting the long-term feasibility of this strategy are needed.

METHODS

We studied the long-term outcomes of 131 patients treated with IL-2 in two studies initiated either before (ANRS 048) or following (ANRS 079) the advent of HAART.

RESULTS

At the last assessment (median follow-up 3.4 years), these patients experienced a gain of 428 cells/microl and a decrease in plasma HIV RNA to 1.70 log10 copies/ml. In both studies, high CD4 cell counts were maintained with a median of ten 5-day cycles of subcutaneous IL-2. Median time since the last cycle was 2 years. At last assessment, 59% of 048 patients maintained a non-HAART regimen. Detailed analysis at week 170 showed that median CD4 cell counts were 856 (048) and 964 (079) cells/microl. This corresponded to a gain from baseline of 515 (048) and 627 (079) cells/microl. The median viral load decreases from baseline and corresponded to 1.70 (048) and 1.88 (079) log10 copies/ml. Comparisons across the studies showed that CD4 gains and viral load changes were similar whether HAART or non-HAART was used. The frequency of cycling, but not CD4 cell counts, viral loads or antiviral regimen at baseline, was predictive of long-term CD4 gain (P = 0.03).

CONCLUSION

Altogether, these observations support IL-2 as a long-term therapeutic strategy in HIV infection.

Review: immunologic response to protease inhibitor-based highly active antiretroviral therapy: a review

A substantial body of evidence indicates that CD4 cell count is an important independent prognostic indicator for progression of HIV disease. Consequently, in addition to plasma HIV RNA levels, CD4 cell count change is considered to be a key surrogate marker for disease progression in clinical practice and in clinical studies. Given the relationship between changes in CD4 count and disease progression, it is notable that protease inhibitor (PI)-based highly active antiretroviral therapy (HAART) can rapidly increase CD4 cell count early in treatment in both therapy-naïve and -experienced patients, and can sustain clinically relevant levels beyond 24 weeks. A number of trials with a follow-up of more than 3 years allow us to conclude that the gains in CD4 counts are maintained in a durable manner. This review evaluated randomized studies of PI-based and PI-boosted HAART (published between January 1996 and February 2006) to determine the effect of PI-based therapy on CD4 cell count. Only studies that assessed CD4 response in the overall patient population were included. Four mechanisms have been proposed to account for the rapid increase in CD4 cell count that occurs with HAART: CD4 cell redistribution from lymphatic tissues, increased CD4 cell production, reduction of apoptotic CD4 cells and the recovery of hematopoietic activity in bone marrow. Further research is required to clarify the relative importance of these mechanisms and ways in which they might be enhanced.

Quantitative longitudinal analysis of T cell receptor repertoire expression in HIV-infected patients on antiretroviral and interleukin-2 therapy

We have developed a single-step reverse transcriptase kinetic PCR assay (kRT-PCR) to accurately determine the expression of each of the 24 TCRbetaV gene families in CD8(+) cells. We analyzed the long-term effects of highly active antiretroviral therapy (HAART) on the stability of the CD8(+) T cell receptor (TCR) repertoire in a cohort of 15 treated and 10 untreated individuals diagnosed with human immunodeficiency virus (HIV) infection. The CD4(+) TCR repertoire was studied in a second cohort receiving interleukin-2 infusions in addition to HAART. Analysis was based on kinetic (quantitative) reverse-transcription PCR (kRT-PCR) of the TCR variable B gene (TCRbetaV). Expression of each of the 24 Vbeta families was assessed at baseline immediately after infection and following initiation of HAART at 2, 4, 12, 24, and up to 192 weeks in 24-week intervals. Statistically significant family-specific expression changes were observed between treated and untreated individuals for 10 TCRbetaV families. Overall, when compared to untreated patients, a more stable expression of TCR genes was observed for HAART-treated individuals. Interestingly, this difference did not correlate with either CD4 or CD8 counts, which follow the expected curves for treated and untreated patients. When we applied our quantitative analysis to IL-2-treated patients we observed a rapid polyclonal activation of the repertoire. These results suggest that homeostasis in the T cell receptor repertoire is more robust in those patients who stay on HAART for a long time and confirm the polyclonal stimulating capacity of IL-2.

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.

Interruption of antiretroviral therapy blunts but does not abrogate CD4 T-cell responses to interleukin-2 administration in HIV infected patients

BACKGROUND

Intermittent administration of interleukin (IL)-2 to HIV infected patients leads to CD4 T-cell expansions that are associated with decreased CD4 T-cell turnover. IL-2 is under evaluation in antiretroviral therapy (ART) interruption studies, but it is unclear how the emergence of viremia may affect CD4 expansions.

METHODS

CD4 T-cell responses were evaluated in 27 HIV infected patients on long-term intermittent IL-2 therapy who underwent ART interruption immediately after an IL-2 cycle ('IL-2/off') and compared with responses from a previous IL-2 cycle while on continuous ART ('IL-2/on'). Immunophenotypic analysis, including intracellular Ki67 staining, of cryopreserved peripheral blood mononuclear cells was performed.

RESULTS

CD4 T-cell increases, in naive and central memory CD4 T-cell subsets, were observed in the IL-2/on (106 and 327 cells/microl, respectively) and IL-2/off (84 and 184 cells/microl, respectively) cycles 1 month following IL-2 administration. These increases were greater during the IL-2/on cycle (P = 0.05, P = 0.01, respectively). In both cycles, the change in CD4 T-cell count correlated with the change in CD4/CD25 T cells. In the IL-2/off cycle, the change in the proportion of CD4 T cells expressing Ki67 was associated with both the changes in viral load (r = 0.64, P = 0.001) and the changes in CD4 T cells (r = -0.56, P = 0.01).

CONCLUSIONS

IL-2 administration followed by ART interruption led to significant, although blunted, CD4 T-cell increases. IL-2 induced CD4 T-cell increases in the setting of emergent viremia were associated with decreased CD4 T-cell activation that counteracted the viremia-induced increases in CD4 T-cell activation.

Quality of Life in a Clinical Trial of Highly Active Antiretroviral Therapy Alone or With Intravenous or Subcutaneous Interleukin-2 Administration

OBJECTIVE

To assess the impact of subcutaneous and intravenous interleukin-2 (IL-2) on health-related quality of life (HRQOL) in adults with HIV-1 receiving highly active antiretroviral therapy (HAART).

DESIGN

Randomized clinical trial.

SETTING

Twenty-two institutions from the Adult AIDS Clinical Trials Group.

PATIENTS

One hundred forty-eight HIV-infected adults randomized, with baseline HRQOL data.

METHODS

HAART (indinavir plus 2 nucleoside analogues) for 12 weeks, followed by 72 weeks of continued HAART alone, HAART plus subcutaneous IL-2, or HAART plus intravenous IL-2.

OUTCOME MEASURES

Scores for 8 dimensions of HRQOL, an unweighted summary score, and a visual analogue health rating score.

RESULTS

The IL-2 subcutaneous group had the best mean change in 6 of 8 dimension subscales and in the summary scale at 28 weeks (16 weeks after baseline). At 52 weeks, the IL-2 subcutaneous group had the best mean change in all the subscales and the summary scale. The differences were statistically significant for 3 subscales and the summary scale. Midcycle changes were statistically significantly worse for the subcutaneous IL-2 group for 4 subscales and the summary scale.

CONCLUSIONS

We found evidence of a short-term but not long-term adverse impact of IL-2 on HRQOL and some evidence of long-term benefit for the subcutaneous group.

Differential effect of interleukin-2 treatment on primary and secondary immunizations in HIV infected individuals

OBJECTIVES

As interleukin (IL)-2 therapy increases CD4 cell counts in HIV infected subjects, it emerged as a candidate for the partial restoration of immune competence in this disease.

METHODS

We studied the frequencies of antigen-specific T cells using single cell resolution cytokine ELISPOT assays and titers of specific antibodies before and after immunization of HIV infected subjects who were treated with HAART or HAART plus IL-2.

RESULTS

Subjects seronegative to hepatitis A were vaccinated with hepatitis A antigen. In the non-IL-2 treated group, hepatitis A-specific T cells producing IL-2 and IL-4 along with specific antibodies were induced, showing that these subjects are immune competent and capable of mounting a primary immune response. Additional IL-2 treatment had no significant effect on this primary T cell response; however, booster immunizations with tetanus toxoid or the gp120 depleted HIV vaccine Remune induced higher frequencies of specific interferon (IFN)-gamma producing T cells in IL-2 treated subjects. No impact of IL-2 treatment on these secondary B cell responses was seen.

CONCLUSION

Overall, our study showed that IL-2 therapy had no immune enhancing effect on the induction of a primary response, but increased the frequency of IFN-gamma producing memory cells after booster immunization.

The Use of Interleukin-2 in Human Immunodeficiency Virus Infection

Advances in antiretroviral therapy for human immunodeficiency virus (HIV) have led to reductions in HIV-related morbidity and mortality. Although antiretroviral therapy has shown success in suppressing viral loads, it does not adequately restore the immune system in all individuals infected with HIV. In light of this incomplete success, interleukin (IL)-2 is being evaluated as adjunctive therapy to antiretroviral therapy. The agent has demonstrated mixed yet promising results in restoring immune function in patients who are HIV positive.

IL-2–induced CD4+ T-cell expansion in HIV-infected patients is associated with long-term decreases in T-cell proliferation

Administration of interleukin 2 (IL-2) leads to selective and sustained CD4+ T-cell expansions in patients infected with HIV. It has been hypothesized that persistent CD4+ T-cell proliferation is the primary mechanism maintaining these expansions. T-cell proliferation was studied by ex vivo bromodeoxyuridine (BrdU) incorporation and intracellular Ki67 staining in HIV-infected patients treated with antiretroviral therapy (ART) with or without IL-2. In contrast to the tested hypothesis, HIV-infected patients treated with IL-2 had lower CD4+ T-cell proliferation compared to patients treated with ART alone. Independently of viral load changes, administration of IL-2 led to a decrease in basal CD4+ T-cell proliferation. Total numbers of CD4+ T cells with naive and recall, but not effector, memory phenotype were increased. The degree of CD4+ T-cell expansion correlated with the decreases in proliferation and a strong association was seen between these decreases and the expansion of the CD4+/CD25+ subset. Intermittent IL-2 in HIV-infected patients leads to expansions of CD4+/CD25+ T cells with naive and recall memory phenotypes that strongly correlate with decreases in proliferation. These data suggest that decreased T-cell proliferation is central in the CD4+ T-cell expansions induced by IL-2.

Effect of pregnancy and human immunodeficiency virus infection on intracellular interleukin-2 production patterns

Human immunodeficiency virus type 1 (HIV-1) infection decreases the production of interleukin-2 (IL-2) from CD4+ and CD8+ T cells. Recombinant IL-2 (rIl-2) has been given to HIV-infected individuals to generate significant increases in CD4+ T-cell counts. There are limited data regarding the effects of pregnancy and HIV infection on IL-2 production in humans. To investigate the effects of human pregnancy, HIV infection, and HIV therapy on IL-2 production, we evaluated 61 women. Intracellular IL-2 production by CD4+ T cells from nonpregnant HIV-infected women was significantly lower than in that in uninfected women (45% +/- 8% versus 52% +/- 8%, P = 0.04). In contrast, there was no difference in levels of intracellular IL-2 production between HIV-infected and uninfected pregnant women. These observations suggest that pregnancy may down-regulate IL-2 production regardless of HIV infection status. Future studies should evaluate IL-2 production patterns in larger cohorts of women so that the physiological significance of IL-2 down-regulation in pregnancy can be further evaluated. This information is essential to assess the possible use of IL-2 supplementation therapy as a means of enhancing immune responses among HIV-infected pregnant women.

Grade 4 events are as important as AIDS events in the era of HAART

OBJECTIVE

To estimate incidence and predictors of serious or life-threatening events that are not AIDS defining, AIDS events, and death among patients treated with highly active antiretroviral therapy (HAART) in the setting of 5 large multicenter randomized treatment trials conducted in the United States.

METHODS

Data were analyzed from 2,947 patients enrolled from December 1996 through December 2001. All patients were to receive antiretrovirals throughout follow-up. Data collection was uniform for all main outcome measures: serious or life-threatening (grade 4) events, AIDS, and death.

RESULTS

During follow-up, 675 patients experienced a grade 4 event (11.4 per 100 person-years); 332 developed an AIDS event (5.6 per 100 person-years); and 272 died (4.6 per 100 person-years). The most common grade 4 events were liver related (148 patients, 2.6 per 100 person-years). Cardiovascular events were associated with the greatest risk of death (hazard ratio = 8.64; 95% CI: 5.1 to 14.5). The first grade 4 event and the first AIDS event were associated with similar risks of death, 5.68 and 6.95, respectively.

CONCLUSIONS

Grade 4 events are as important as AIDS events in the era of HAART. To adequately evaluate the impact of HAART on morbidity, comorbidities and other key factors must be carefully assessed.