Nitric oxide production in HIV-1 infected patients receiving intermittent cycles of interleukin-2 and antiretrovirals.

BACKGROUND: Interleukin-2 (IL-2) has been investigated as an adjunct to antiretroviral therapy (ART) because of its well-demonstrated capacity of stably increasing the number of peripheral CD4+ T cell lymphocytes. However, IL-2-related adverse events (AEs), including fever, tachycardia, hypotension, and respiratory failure, are typically dose- and schedule-dependent and can potentially limit the application of IL-2 therapy in an outpatient setting. Nitric oxide (NO) is a potent vasodilator potentially responsible for some of the AEs caused by IL-2. PURPOSE: In this study, we determined NO production in a cohort of HIV-1 infected individuals receiving ART either alone or together with IL-2. METHOD: NO production, detected as plasma nitrate/nitrite levels by the Griess reaction, was evaluated in 3 groups of 10 individuals each. In the first group, subcutaneous (sc) administration of 12-15 million international units per day (MIU/d) of IL-2 was administered for 5 days every 8 weeks for 6 cycles together with ART; in the second group, IL-2 (6 MIU/d) was given sc for 5 days every 4 weeks for 12 cycles together with ART; whereas the third group received ART alone. RESULTS: At baseline, the plasma nitrate/nitrite levels in the 2 groups of patients who received high and low doses of the cytokine along with ART were 28.5 +/- 18.1 micromol/L and 34.2 +/- 29.0 micromol/L, respectively. These levels were comparable to those of patients treated with only ART (18.6 +/- 22.4 micromol/L) and to those of 20 healthy controls (19.9 +/- 5.9 micromol/L). No significant increase of plasma nitrate/nitrite levels was observed by administration of either ART or ART+IL-2. In addition, NO production was not associated significantly with different levels of tumor necrosis factor-alpha, IL-6, or soluble IL-2 receptor alpha chain in 9 individuals with WHO grade 2 and 3 AEs. CONCLUSION: Our results indicate that NO is unlikely to be responsible for most side effects of IL-2 therapy in HIV-1 infected individuals. Because both IL-2 and virus multiplication have been reported to independently stimulate NO production, concomitant ART may curtail NO production through inhibition of HIV-1 replication.

Circulating levels of granulocyte macrophage colony-stimulating factor in patients with the systemic inflammatory response syndrome.

OBJECTIVES: Granulocyte-macrophage colony stimulating factor (GM-CSF) is a key regulator cytokine that modulates the proliferation and maturation of polymorphonuclear and mononuclear progenitors. This study was designed to investigate and clarify the role of GM-CSF in 52 critically ill patients with systemic inflammatory response syndrome (SIRS). METHODS: Serum levels of GM-CSF were detected by an immunoenzyme assay. RESULTS: Our results clearly show that the serum concentrations of GM-CSF were significantly elevated in patients with infectious and noninfectious SIRS (33.2+/-45.7pg/ml, controls: 17.2+/-9.8pg/ml; p=0.0303). In addition, GM-CSF levels significantly decreased in patients with SIRS, particularly in patients with infectious SIRS, 5 and 7 days later. There was a clear tendency toward higher levels of GM-CSF in patients with poor, as compared with those having a good outcome of the disease. CONCLUSION: These results show that GM-CSF may play an important role in patients with infectious and noninfectious SIRS, and that GM-CSF levels progressively and significantly decrease in patients with infectious SIRS.

Circulating levels of FAS/APO-1 in patients with the systemic inflammatory response syndrome.

Resolution of inflammation/infection involves removal of neutrophils and other inflammatory cells by the induction of apoptosis. Fas/Apo-1 is a widely occurring apoptotic signal receptor molecule expressed by almost any type of cell, which is also released in a soluble circulating form. In this study we investigated the role of circulating Fas/Apo-1 in patients with systemic inflammatory response syndrome (SIRS). We evaluated 57 critically ill patients, 34 with infectious SIRS (sepsis and septic shock), and 23 patients with noninfectious SIRS. Circulating Fas/Apo-1 was determined by a commercially available immunoassay. Our results clearly show that levels of Fas/Apo-1 were significantly elevated in patients with infectious and noninfectious SIRS (10.4 +/- 8.1 pg/mL, controls: 5.0 +/- 0.7 pg/mL; p < 0.0001). In addition, Fas/Apo-1 levels were not able in predicting in predicting poor outcome of patients with SIRS. In conclusion, these results show that increased levels of Fas/Apo-1 from patients with SIRS is a mechanism which contribute to inflammatory response through accumulation of neutrophils at sites of inflammation/infection.

Interleukin-18 enhances HIV-1 production in a human chronically-infected T cell line (H9-V).

Interleukin-18 (IL-18) is a recently identified immunoregulatory cytokine expressed by activated macrophages, that induces production of interferon-gamma (IFN-gamma) and Th-1 development. Recently some investigators reported controversial in vitro data on IL-18 stimulation of HIV-1 replication in several cell lines. In the present study the effect of IL-18 on HIV replication in a human chronically HIV-1-infected lymphocytic T cell line (H9-V) was investigated. HIV-1 replication was determined by an immunoassay method in order to evaluate the content of p24 antigen in the cell culture supernatants. Stimulation of H9-V cells with IL-18 resulted in increased production of p24, especially at concentrations of 0.01 microg ml(-1) and 0.10 microg ml(-1). Moreover a significant and persistent IL-18 stimulation of HIV-1 replication was observed at a concentration of 0.01 microg ml(-1) during a 7-day period. Pre-treatment of IL-18 with a specific neutralizing monoclonal antibody significantly reduced HIV-1 replication. These experiments show that IL-18 promotes the increase of HIV-1 replication in human chronically-infected lymphocytic T cells and confirm the role of IL-18 as a proimflammatory cytokine in stimulating and maintaining HIV-1 replication during the course of the disease. In a successive set of experiments, since one of the main activities of IL-18 is the induction of IFN-gamma, we evaluated the effect of this biological modifier on H9-V cells. In particular, IFN-gamma shows a significant effect on cell replication and on reduction of CD4 and CD71 surface expression.

Role of Th1 and Th2 cytokines in immune response to uncomplicated Plasmodium falciparum malaria.

The relative balance between Th1 and Th2 cytokines appears crucial, since the role of cytokines has been evaluated in several studies by comparison of clinically heterogeneous groups of patients. The aim of this study is to determine the role of proinflammatory Th1 cytokines, interleukin-12 (IL-12) and gamma interferon (IFN-gamma), and anti-inflammatory Th2 cytokines, IL-4 and IL-10, in a homogeneous group of patients with uncomplicated Plasmodium falciparum malaria. Levels of IL-12, IFN-gamma, Il-4, and IL-10 in serum for 20 adult patients and 15 healthy control subjects were determined by an immunoenzymatic assay. Serum levels of Th1 cytokines, IL-12 (8.6 +/- 2.8 pg/ml; controls, 3.2 +/- 0.7 pg/ml) and IFN-gamma (39.2 +/- 67.6 pg/ml; controls, 8.4 +/- 6.3 pg/ml), were significantly increased at admission; 3 days later, levels of IL-12 in serum remained significantly high (8.8 +/- 2.6 pg/ml), whereas IFN-gamma levels returned to control values. The anti-inflammatory response of Th2 cytokines (IL-10 and IL-4) was distinct. Levels of IL-10 in serum were not significantly increased at day 0 and day 3 (306.6 +/- 200.4 pg/ml and 56.6 +/- 38.4 pg/ml, respectively; controls, 17.4 +/- 9.0 pg/ml). In contrast, levels of IL-4 in serum were not increased on admission (3.4 +/- 1.2 pg/ml; controls, 2.4 +/- 0.8 pg/ml), but at day 3 a moderate and significant increase of IL-4 levels was observed (4.5 +/- 1.7 pg/ml). In conclusion, the increase of Th1 cytokine IL-12 and IFN-gamma levels during the acute phase of uncomplicated P. falciparum malaria may reflect an early and effective immune response regulated by proinflammatory Th1 cytokines, and in particular IFN-gamma may play a role in limiting progression from uncomplicated malaria to severe and life-threatening complications.

Antiretroviral drug resistance testing in patients with HIV-1 infection: a meta-analysis study.

BACKGROUND: HIV-1 resistance tests, both phenotype and genotype, have been entering clinical practice during the last years, but limited prospective studies have been reported in antiretroviral-treated patients with virological failure. PURPOSE: A meta-analysis of randomized controlled trials (RCTs) published or presented at the most important international conferences until February 2001 was performed to estimate the impact of resistance-guided antiretroviral therapy on virological outcome. METHOD: A search for RCTs was performed by using a MEDLINE database, Internet sources, and international conference presentations and was updated September 2001. All RCTs available, including four RCTs on genotype resistance testing, one RCT on phenotype resistance testing, and one RCT on genotypic and phenotypic testing, were analyzed. The rate of patients with undetectable viremia at 3 months was reported in all RCTs and the rate at 6 months was reported in 4 of 6 RCTs. RESULTS: The rate of patients with undetectable viral load after 3 months was 42.6% in patients who were treated based on genotype results and was 33.2% in patients who were treated based on standard of care (SOC; odds ratio [OR] 1.7; 95% CI: 1.3-2.2). At 6 months, undetectable viremia was observed in 38.8% and 28.7% of the patients, respectively (OR: 1.6; 95% CI: 1.2-2.2). In 142 patients, expert advice was provided to optimize clinical use of genotypic data. The higher rate of viral suppression was achieved in this subgroup of patients (50.7% vs. SOC 35.8%; OR 2.4; 95% CI 1.5-3.7). In contrast, undetectable viremia was achieved in 37.5% patients who were treated based on phenotype results versus 33.8% patients who were treated based on SOC (OR 1.1; 95% CI 0.8-1.6). CONCLUSION: These results support the use of a genotypic test in patients experiencing virological failure during antiretroviral treatment. Expert interpretation of the test may increase the probability of virological response.