MVA-nef induces HIV-1-specific polyfunctional and proliferative T-cell responses revealed by the combination of short- and long-term immune assays.

Several vaccination trials are evaluating the modified vaccinia virus Ankara (MVA) as a delivery vector in various clinical settings. In this paper, we present the reevaluation of a therapeutic vaccination trial in human immunodeficiency virus (HIV)-1-infected individuals treated with highly active antiretroviral therapy using MVA-expressing HIV-1 nef. Immunogenicity of MVA-nef was assessed using multicolor flow cytometry. Vaccine-induced polyfunctionality and proliferative capacity, which are associated with nonprogressive HIV-1 infection, were detectable by combining two immune assays. By means of short-term polychromatic intracellular cytokine staining, we observed a significant increase in polyfunctional Nef-specific CD4 T cells expressing interferon-γ, interleukin (IL)-2 and CD154 after vaccination, whereas changes in the quality of CD8 T-cell response could not be observed. Only the additional use of a long-term polychromatic Carboxyfluorescein succinimidyl ester (CFSE)-based proliferation assay revealed vaccine-induced Nef-specific CD8, as well as CD4 T cells with proliferative capacity. The correlation between vaccine-induced IL-2 production by CD4 T cells and the increase in proliferating Nef-specific CD8 T cells suggests a causal link between these two functions. These results highlight the importance of combining sophisticated immunomonitoring tools to unravel concealed effects of immunological interventions and support the use of the poxvirus-derived MVA vector to stimulate highly functional HIV-1-specific T-cell responses. However, the clinical benefit of these functional T cells remains to be determined.

Metabolic and anthropometric changes one year after switching from didanosine/stavudine to tenofovir in HIV-infected patients.

BACKGROUND: Nucleoside analogues such as Didanosine and Stavudine are known to cause metabolic and body habitus changes during antiretroviral therapy. The most frequently observed are lactic acidosis, hypercholesterinaemia, hypertriglyceridaemia and lipodystrophy. METHODS: Over one year we monitored a cohort of 43 patients who switched from either Stavudine, Didanosine or the combination of both to Tenofovir. A group of 11 patients was kept on their original regimen and acted as control group. Blood samples were taken every 3 months from baseline, anthropometric measurements were performed at baseline, after 6 and 12 months. RESULTS: During observation the levels of lactic acid and cholesterol decreased significantly in the switch group while virologic and immunologic efficacy remained stable. Serum creatinine levels rose significantly in patients switched to Tenofovir, but remained within physiological limits. The mean skin fold thickness increased significantly by 1.8 mm in the switch group after 6 months (p < or =0.001 - p = 0.032). CONCLUSION: These results implicate an improvement of lipid profiles, serum lactate and lipodystrophy in HIV-positive patients after switch to Tenofovir. As a moderate increase in serum creatinine levels was observed, the renal function of patients on a Tenofovir-based regimen should be monitored closely.

Clinical news from the XVI International AIDS Conference: The attempt of a summing up.

Topics highlighted at the XVI International AIDS Conference in Toronto included HIV/AIDS vaccine research, entry inhibitors, integrase inhibitors, new NNRTIs and PIs, single-agent therapies, pre-exposure prophylaxis and microbicides. Beside the large scientific part, policy and funding were of great concern. Within this article we are trying to focus on topics with direct clinical relevance. This includes new epidemiological and resistance data, results from current studies investigating established and novel antiretroviral drugs and drug classes as well as new findings in therapy management and strategies.

Treatment interruption in HIV therapy: a SMART strategy?

Continuous HAART is standard of care for HIV-infected patients but lifelong adherence and tolerance are important concerns. Use of ART is associated with potential risks, e. g., adverse events, metabolic and cardiovascular complications, and HIV resistance. Stopping HIV therapy may reduce costs and side effects, but carries the risk of increased immune suppression and of emergence of resistance. Treatment interruption is a strategy of much interest, but its safety and efficacy have not been established. The clinical and biological characteristics that influence the outcome of structured treatment interruptions have not been fully clarified. In the following we will present the results of recent studies aimed to compare the long-term consequences of two antiretroviral-management strategies: continuous therapy versus scheduled treatment interruption.

HIV-associated renal diseases and highly active antiretroviral therapy-induced nephropathy.

Renal disease is becoming an increasingly prevalent entity in human immunodeficiency virus (HIV)-infected patients; it occurs in a variety of clinical settings and is associated with histopathological changes. HIV-related renal impairment can present as acute or chronic kidney disease; it can be caused directly or indirectly by HIV and/or by drug-related effects that are directly nephrotoxic or lead to changes in renal function by inducing metabolic vaculopathy and renal damage. Acute renal failure is frequently caused by the toxic effects of antiretroviral therapy or nephrotoxic antimicrobial substances used in the treatment of opportunistic infections. Chronic renal disease can be caused by multiple pathophysiological mechanisms, leading to HIV-associated nephropathy, a form of collapsing focal glomerulosclerosis, thrombotic microangiopathy, and various forms of immune complex glomerulonephritis. The increase in life expectancy and alteration of lipid metabolism due to receipt of highly active antiretroviral therapy are expected to result in an increased prevalence of diabetes and hypertension and, thus, to secondary diabetic and hypertensive renal damage. Antiretroviral agents, such as indinavir and tenofovir, have been associated with nephrotoxic drug effects that have been shown to be reversible in most cases. In this article, we review the current knowledge about acute and chronic HIV-associated renal disease, metabolic alterations and related nephropathies, and toxic drug effects of combination antiretroviral pharmacotherapy.

What's New in HIV/AIDS? Chemokine receptor antagonists: a new era of HIV therapy?

Chemokine receptors are essential for human immunodeficiency virus (HIV) cell entry. CXCR4 and CCR5 are the two most relevant receptors and by inhibition of each of them a delayed onset of disease could be achieved. As both receptors are used at different stages of disease due to the domination of different HIV strains, a dual blockage of CXCR4 and CCR5 could be highly valuable for inhibiting viral transmission and replication.

What's new in HIV/AIDS? Neutralizing HIV antibodies: do they really protect?

Neutralizing antibodies work as a second line of defence. They are detected more or less in nearly every HIV-1-infected individual. 2G12, 2F5 and 4E10 represent antibodies with broadly neutralizing activity made from B cells of HIV- 1-infected humans. Unfortunately these antibodies are extremely rare and all attempts to elicit them via vaccine immunogens have failed. The discovery of autoreactive features of these antibodies could now explain why. Additionally, new results show the delayed viral rebound under antibody treatment in some HIV-1-infected individuals.

HIV genetic diversity: any implications for drug resistance?

At least nine different genetic HIV-1 subtypes and several circulating recombinant forms exist, which in addition to HIV-1 subgroups and HIV-2 account for the global AIDS pandemic. Even though HIV-1 subtype C and A predominate globally, antiretroviral drugs have been designed based on sequences of clade B reverse transcriptase (RT) and protease enzymes due to the domination of HIV-1 subtype B in highly industrialized countries. Since there is no clarity about possible effects of the genetic diversity of HIV-1 on therapy outcome and drug resistance, multiple studies have been performed with divergent results. Up to now this question remains to be answered.

[Options in HIV therapy: present and future]. / Therapieoptionen bei HIV Realität und Zukunft.

Highly active antiretroviral therapy (HAART) has markedly decreased HIV-associated mortality. It consists of a combination of three antiretroviral drugs from four different classes: nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, protease inhibitors and inhibitors of virus-cell fusion. Increasing resistance against antiretroviral drugs calls for the development of new compounds and drug classes. The growing understanding of molecular mechanisms in HIV-replication led to the identification of further steps which might serve as novel antiretroviral targets. Uninfected cells could be protected from HIV by inhibiting extracellular binding mechanisms. Improvement of existing antiretroviral drugs and further development of novel therapeutic targets will enrich antiretroviral treatment.

Susceptibility to HIV/AIDS: an individual characteristic we can measure?

Susceptibility to HIV-1 infections is, beside other factors, determined by individual host genetic variants like HLA class I alleles, CCR5 and CCR2 variants and levels of CCR5 binding chemokines. A new approach to determine the individual risk of acquiring an HIV infection or to estimate the disease progression could now be possible. In a recent study, a significant interindividual and interpopulation difference in the copy number of a segmental duplication encompassing the gene encoding CCL3L1, a potent human immunodeficiency virus-1 (HIV- 1)-suppressive chemokine was found. Possession of a CCL3L1 copy number lower than the population average was associated with markedly enhanced HIV/acquired immunodeficiency syndrome (AIDS) susceptibility. This could lead to a screening test that identifies people who have a higher or lower susceptibility to HIV/ AIDS, potentially enabling clinicians to adapt treatment regimens. Also, this is particularly important for assessment of the efficacy of a protective vaccine.

Immune reconstitution inflammatory syndrome (IRIS)--another new disease entity following treatment initiation of HIV infection.

After the introduction of highly active antiretroviral therapy (HAART) in 1995 it took 3 years to recognize the new syndrome of lipodystrophy as a long-term complication of HAART [1]. It was found to be a direct toxic consequence of the various drugs used in combination regimens. Another 2 years later, an additional syndrome was described in patients who recently initiated HAART-the immune reconstitution inflammatory syndrome (IRIS) [2-4]. Although already recognized in the pre-HIV era in patients with treatment for tuberculosis [5, 6] and leprosy [7], it became substantially more frequent in HIV-infected patients on HAART. The term IRIS describes a collection of different inflammatory disorders which are associated with paradoxical deterioration of various preexisting infectious processes following commencement of HAART in HIV-infected patients. These preexisting infections in individuals with IRIS may have been previously diagnosed and treated or may have been symptomless and later revealed by the patient's improved capacity to mount an inflammatory response.

AIDS, multicentric Castleman's disease, and plasmablastic leukemia: report of a long-term survival.

Plasmablastic leukemia (PL) as a complication of human herpes virus 8 (HHV8)-associated Castleman's disease is marked by a rapid and fatal outcome. In patients with AIDS, survival of 7 to 14 days after diagnosis has been reported. Prompt splenectomy and chemotherapy might lead to a significant survival benefit. Here we report a case of long-term survival in a patient with AIDS and multicentric Castleman's disease (MCD) complicated by PL.

Can science solve the global AIDS problem?

Recently, the 15th International AIDS Conference took place in Bangkok, Thailand. This conference used to be an almost exclusively science-oriented conference reporting on new developments in diagnostic tools, drug discovery, and other medical advances, making it a "must attend" event for most scientists. In the year 2000, this congress was hosted by South Africa in Durban, for the first time in a developing country - focusing on the particular needs of poor countries and also stressing that scientific approaches are not the only relevant and important aspects of this global epidemic. While many scientist (including this author) perceived the changing emphasis of the meeting with regret ("only science will solve this problem"), the immediate view on the epidemic in areas with poor resources has proven beyond doubt that HIV is far more than just a viral infection. With the latest conference taking place in Bangkok, several particular aspects were demonstrated: after Africa, Asia is the largest hot spot in the worldwide spread of HIV with the highest increase in infections. Also, this country can serve as an admirable example of political will and successful battle to constrain the epidemic despite a serious lack of resources.

HAART-prolonged life of HIV-infected patients should not be shortened by hepatitis C.

As highly active antiretroviral treatment (HAART) prolongs the life of HIV-infected individuals and reduces mortality associated with opportunistic infections, liver diseases have become a major challenge in the management of these patients. up to 45% of deaths of persons with HIV are related to endstage liver disease, some of which might have been avoided with a less hesitant approach to hepatitis C treatment in the setting of HIV/ hepatitis C (HCV) coinfection.

Kinetics of lactate metabolism after submaximal ergometric exercise in HIV-infected patients.

OBJECTIVES: It is unknown whether high levels of lactate result from enhanced production or decreased degradation. We therefore investigated differences in the kinetics of plasma lactic acid in HIV-infected patients receiving or not receiving highly active antiretroviral therapy (HAART) and in uninfected controls after submaximal ergometric exercise. METHODS: Ten healthy controls, 11 HIV-infected therapy-naïve patients, 15 HIV-infected patients on HAART with normal baseline lactate levels, and nine HIV-infected patients on HAART with elevated baseline lactate levels >2 mmol/L performed 10 min of ergometric exercise, with a heart rate of 200 beats/min minus age. Lactate levels were measured at baseline, at the end of exercise and 15, 30, 45, 60 and 120 min thereafter. RESULTS: Mean baseline lactate levels were 1.4, 1.5, 1.5 and 2.8 mmol/L in the controls, the therapy-naïve patients, the patients on HAART with normal lactate levels and the patients on HAART with elevated lactate levels, respectively. Maximum lactate levels after exercise were similar in all groups (9.7, 9.4, 9.0 and 10.1 mmol/L, respectively). Significant differences were found in the slope of lactate decline between controls and untreated individuals (P=0.038) and between patients on HAART with normal baseline lactate and patients on HAART with elevated baseline lactate (P=0.028). CONCLUSIONS: Differences in lactate metabolism do exist between healthy controls and HIV-infected therapy-naïve individuals. Thus, HIV infection in itself may influence lactate levels. Elevated baseline lactate levels are associated with a delayed decline of lactate after exercise. These results could be explained by impaired lactate clearance. Lactate production upon exercise does not seem to be affected by baseline lactate levels.

Platelets, a typical source of error in real-time PCR quantification of mitochondrial DNA content in human peripheral blood cells.

Nucleoside analogues can induce toxic effects on mitochondria by inhibiting the human DNA polymerase-gamma. The clinically observed toxicities can range from slightly increased serum lactate levels to potentially severe and fatal lactic acidosis. A growing interest exists for detection of changes in mitochondrial (mt) DNA content in patients receiving antiretroviral therapy (HAART). Most studies use peripheral blood mononuclear cell (PBMC) fractions to investigate mt DNA content via Real-Time PCR in patients, not accounting platelets falsifying the mitochondrial (mt)DNA:nuclear (n)DNA-ratio. In this study we suggest a procedure to eliminate disturbing platelets totally. 8 healthy controls (G1), 6 therapy-naive HIV-infected patients (G2) and 9 HIV-infected patients under HAART (G3) were examined for mtDNA:nDNA-ratio using Real-Time PCR technology. Different blood collection and/or PBMC isolation strategies were analysed for variances of outcome at examinations of the same blood donor. Using DNA prepared of whole blood specimens, mtDNA:nDNA-ratios showed no differences in all investigated groups (G1, G2, G3). Comparing mtDNA:nDNA-ratios of platelet-depleted PBMC fractions of G1 with G2 revealed a reduction of 22% (p = 0.128) and a steeper reduction of 40% (p = 0.0036) comparing specimens of G1 with G3. Scrutinising differently processed specimens within the groups themselves, in G2 whole blood versus platelet-containing PBMC specimens showed a difference in mtDNA:nDNA-ratios of 26% (p = 0.0406), whereas a comparison of whole blood versus platelet-free PBMC specimens led to a comparatively more distinct reduction of 35% (p = 0.0089). The same effect was seen in G3, where whole blood versus platelet-containing PBMC specimens revealed a reduction of 32% (p = 0.01) and whole blood versus platelet-free PBMC specimens showed a 42% (p = 0.0011) decrease. Furthermore analysing each single patient in relation to the different methods, a minor fluctuation margin could be found using platelet-free PBMC specimens for Real-Time PCR. Using platelet-free PBMCs for mt DNA content detection, a correlation of low mtDNA:nDNA-ratios to clinical signs, like elevated lactate levels or lipodystrophy, could be observed. Light-microscopic evaluation for platelets, comparing platelet-containing PBMC fractions versus platelet-depleted PBMC fractions reinforced the Real-Time PCR results. Our data demonstrate that the first step of the blood sample collection/preparation is critical for valid illustration of mt DNA content in HIV-infected patients using ultra-sensitive Real-Time PCR technology. The use of serum tubes for blood collection is an easy and low-cost alternative to expensive cell sorting for elimination of disturbing platelets. Using platelet-free PBMC fractions for measurement mt DNA content could be a surrogate marker for clinical signs mediated by HAART.