Expression of arginase I and inducible nitric oxide synthase in the peripheral blood and lymph nodes of HIV­positive patients.

Arginase I (Arg I) and inducible nitric oxide synthase (iNOS) are important in regulating immune functions through their metabolites. Previous studies have revealed that the expression of Arg I is increased and the expression of iNOS is reduced in the serum and peripheral blood mononuclear cells of human immunodeficiency virus (HIV)­infected patients. As one of the most important immune organs and HIV replication sites, whether similar changes are present in the lymph nodes following HIV infection remains to be elucidated. To investigate this, the present study collected lymph node and blood specimens from 52 HIV­infected patients to measure the expression levels of Arg I and iNOS by immunohistochemistry and fluoresence­based flow cytometry. Compared with control subjects without HIV infection, the patients with HIV had significantly higher expression levels of Arg I in the lymph nodes and higher frequencies of Arg I+ CD4+ T cells and CD8+ T cells in the blood and lymph nodes, and these results were contrary the those of iNOS in the corresponding compartments. The expression levels of Arg I in the lymph nodes and blood were negatively associated with peripheral CD4+ T cell count and positively associated with viral load. However, the expression levels of iNOS in the lymph nodes and blood were positively associated with peripheral CD4+ T cell count and negatively associated with viral load. These results showed that alterations in the expression levels of Arg I and iNOS in the peripheral T cells and peripheral nodes of HIV infected patients are associated with disease progression in these patients. These results indicate a potential to therapeutic strategy for delaying disease progression through regulating and manipulating the expression levels of Arg I and iNOS in patients infected with HIV.

Association between ALT level and the rate of cardio/cerebrovascular events in HIV-positive individuals: the D: A: D study.

BACKGROUND: An inverse association between serum alanine aminotransferase (ALT) levels and the risk of myocardial infarction (MI) has been reported in the general population. We investigated associations between ALT levels and the risk of various cardiovascular and cerebrovascular outcomes in a large cohort study of HIV-positive individuals. METHODS: Using Poisson regression, we investigated associations between the latest ALT level and MI, coronary heart disease (CHD), and stroke, after adjusting for known confounders and cumulative/recent exposure to antiretroviral drugs. Analyses were also performed for the end points of all-cause/liver-related mortality and new-onset diabetes mellitus. RESULTS: By February 2011, participants had experienced 541 MIs, 804 CHD, and 258 stroke events. The MI rate decreased from 3.1/1000 person-years among those with ALT ≤18 U/L to 2.1/1000 person-years among those with ALT >60 U/L. After adjustment for confounders, each 2-fold increment in ALT was associated with a 19% drop in the MI rate {relative rate, 0.81 [95% confidence interval (CI): 0.74 to 0.89], P = 0.0001}. A weaker inverse association was seen for CHD with no indication of a linear association between ALT levels and stroke (P = 0.72). Adjusted relative rates were 0.88 (95% CI: 0.81 to 0.97) and 0.70 (95% CI: 0.54 to 0.92) in those who were hepatitis C virus negative and hepatitis C virus positive, respectively, and 0.72 (95% CI: 0.58 to 0.89) and 0.84 (0.77 to 0.93) in injection drug users and non-injection drug users, respectively. Liver-related mortality and diabetes both demonstrated a positive association with ALT levels, whereas all-cause mortality showed a U-shaped relationship. CONCLUSIONS: Higher ALT levels are associated with lower MI risk in HIV-positive individuals, but with higher risks of liver-related mortality and diabetes mellitus.

Characterization of rare lens epithelium-derived growth factor/p75 genetic variants identified in HIV-1 long-term nonprogressors.

OBJECTIVE: Lens epithelium-derived growth factor (LEDGF)/p75 is a cellular binding partner of HIV-1 integrase and a crucial cofactor for HIV-1 replication. Here, we study two LEDGF/p75 exonic variants I436S and T473I, identified in HIV-1 long-term nonprogressors, together with Q472L. METHODS: In-vitro binding assays, cell culture complementation, and functional rescue. RESULTS: Binding affinities of wild-type, I436S, T473I, and Q472L LEDGF/p75 for HIV-1 integrase were comparable. All LEDGF/p75 variants bound equally well to LEDGF/p75 interacting partners JPO2 and PogZ. In addition, HIV-1 replication was evaluated in human somatic LEDGF/p75-knockout cells and LEDGF/p75-knockdown cells complemented with either wild-type LEDGF/p75 or the respective LEDGF/p75 variants. All variants rescued HIV-1 replication to wild-type levels, whereas LEDGF/p75 D366N, defective for interaction with HIV-1 integrase, did not. CONCLUSION: Although identified in a cohort of long-term nonprogressors, our study did not indicate that the I436S or T473I mutation in LEDGF/p75 affects the interaction with HIV-1 integrase.

Erythrocyte inosine triphosphatase activity is decreased in HIV-seropositive individuals.

BACKGROUND: Inosine triphosphatase (ITPase) is encoded by the polymorphic gene ITPA and maintains low intracellular levels of the inosine nucleotides ITP and dITP. The most frequently reported polymorphisms are ITPA c.94C>A (rs 1127354) and ITPA c. 124+21 A>C (rs7270101). Some nucleoside-analogues used in the treatment of HIV-seropositive (HIV+) patients are potential substrates for ITPase. Therefore, the frequency of ITPA SNPs and ITPase activity were studied in a population of HIV+-patients. METHODS: The study population consisted of 222 patients, predominantly Caucasian males, >95% using HAART. Erythrocyte ITPase activity was determined by measuring the formation of IMP from ITP. ITPA genotype was determined by sequencing genomic DNA. Distribution of ITPase activity, genotype-phenotype correlation and allele frequencies were compared to 198 control subjects. The effect of nucleoside analogues on ITPase activity was studied using lymphoblastic T-cell cultures and human recombinant ITPase. Enzyme kinetic experiments were performed on erythrocyte ITPase from HIV+ patients and controls. RESULTS: No difference was observed in the allele frequencies between the HIV+-cohort (± HAART) and the control population. HIV+ carriers of the wild type and ITPA c.94C>A had significantly lower ITPase activities than control subjects with the same genotype (p<0.005). This was not observed in ITPA c. 124+21 A>C carriers. Nucleoside analogues did not affect ITPase activity in cell culture and human recombinant ITPase. CONCLUSION: ITPA population genetics were identical in HIV+ and control populations. However, the majority of HIV+-patients had decreased erythrocyte ITPase activity compared to controls, probably due to decreased amounts of ITPase protein. It seems unlikely that ITPase activity is decreased due to nucleoside analogues (HAART). Long-term effects of HIV-infection altering ITPase protein expression or stability may explain the phenomenon observed.

Analysis of serum adenosine deaminase (ADA) and ADA1 and ADA2 isoenzyme activities in HIV positive and HIV-HBV co-infected patients.

OBJECTIVES: To determine adenosine deaminase (ADA) activity as a possible diagnostic marker in HIV and HIV-HBV co-infected patients. DESIGN AND METHODS: Blood samples were collected from 72 healthy, 33 HIV positive and 30 HIV-HBV co-infected subjects. Blood CD4+ cell count was recorded and serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total ADA, and ADA1 and ADA2 isoenzyme activities were determined. RESULTS: Serum ALT, AST, total ADA and ADA2 isoenzyme activities were significantly higher in HIV positive and HIV-HBV co-infected groups compare to the control (p<0.05), whereas serum ALP showed no differences between groups. CD4+ cell counts markedly decreased in all patients and showed a significant inverse correlation with ADA activities (R(2)=0.589, p<0.001). CONCLUSIONS: Serum ADA was significantly increased in HIV and HIV-HBV co-infections. Therefore, because of its low cost and simplicity to perform, ADA activity might be considered as a useful diagnostic tool among the other markers in these diseases.

Evaluation of cerebrospinal fluid adenosine deaminase activity in HIV-seropositive subjects and its association with lactate dehydrogenase and protein levels.

The purpose of this study was to investigate the role of ADA as additional marker of HIV infection as well as its association with other biochemical markers. This study included 55 patients, 26 being diagnosed as HIV positive and 29 patients diagnosed as HIV negative. Glucose, total protein, lactate dehydrogenase, and adenosine deaminase (ADA) activity were measured on cerebrospinal fluid (CSF). ADA activity on CSF was statistically different in HIV-seropositive subjects compared with HIV-negative subjects. The sensitivity and specificity of ADA activity on CSF was 50 and 82.76%, respectively. ADA activity was positively correlated with lactate dehydrogenase and protein in patients with HIV positive and it was negatively correlated with glucose levels. ADA determination in CSF could add information about inflammatory processes in patients with HIV infection.

The cytolytic enzymes granyzme A, granzyme B, and perforin: expression patterns, cell distribution, and their relationship to cell maturity and bright CD57 expression.

Cytolytic enzymes (CEs) are critical mediators of anti-viral and -tumor immunity; however, as a number of molecules belong to this enzyme family, our understanding of CEs remains limited. Specifically, it remains unclear what combinations of granzymes and perforin (Perf) are expressed by various immune cells and how CE content relates to cellular differentiation. Using polychromatic flow cytometry, we simultaneously measured expression of the most common human CEs [granzyme A (gA), granzyme B (gB), and Perf] alongside markers of alphabeta and gammadelta T cell maturation (CD45RO, CCR7, CD27, CD57). Additionally, we measured CE content in NK cell subsets (defined by their expression of CD16 and CD56). We found that among a wide variety of immune cells, CE content was linked to cellular maturity. Moreover, common expression patterns were shared across cell types, such that gB+ cells always contained gA, and Perf+ cells were primarily gA+ gB+. Most importantly, CD57 expression correlated strongly with simultaneous expression of gA, gB, and Perf. Thus, the use of CD57 provides a means to easily isolate viable cells with high cytolytic potential, without the need for lethal fixation/permeabilization techniques.

Peas, beans, and the Pythagorean theorem - the relevance of glucose-6-phosphate dehydrogenase deficiency in dermatology.

Glucose-6-phosphate (G6PD) deficiency is a common disease characterized by acute hemolysis induced by oxidative stress. More than 400 million subjects throughout the world carry the hereditary enzyme defect with the highest prevalences in Africa, Asia, and the Mediterranean region. In individuals affected by the erythrocytic enzymatic disorder, besides infectious diseases and diet, acute hemolytic crisis can be triggered by numerous drugs frequently used for the treatment of dermatoses. Taking into account the increasing number of immigrants from geographic regions with high prevalences of G6PD deficiency, dermatologists should be alert to the presence of disease.

The prevalence and risk factors for abnormal liver enzymes in HIV-positive patients without hepatitis B or C coinfections.

BACKGROUND: Abnormal liver enzymes (LFTs) are frequently seen in HIV patients. Because HCV and HBV overshadow other possible variables, little is known about the prevalence and predictive factors of abnormal LFTs in the absence of viral hepatitis. AIMS: To determine the prevalence and factors associated with abnormal LFTs defined as >1.25 ULN. METHODS: A retrospective analysis of HIV clinic patients was performed. Variables were determined at the time of abnormal LFTs or by history and included diabetes mellitus (DM), hypertension (HTN), dyslipidemia, HCV and HBV status, metabolic syndrome (MS), and HAART use (NRTI, NNRTI, and PI). RESULTS: Patients without HCV/HBV (n = 679/1,208) were younger, Caucasian, had a BMI >30 and had dyslipidemia. The prevalences of elevated LFTs in those without HCV/HBV were AST 20%, ALT 15%, and ALP 43% compared to 64%, 46%, and 63% in those with HCV (all P < 0.0001), and 98% were mild-moderate (grade 1-2). While AST was highly correlated with ALT, neither was associated with increased ALP. In those without HCV/HBV, increased AST was associated with HTN, HIV RNA, and absence of PI use; increased ALT was associated with HTN, HIV RNA, CD4 < 200, MS, and absence of PI use, while increased ALP was associated with age, BMI, CD4%, DM, and NRTI use. CONCLUSIONS: Mild-moderate increased liver enzymes are common in HIV patients without HCV/HBV and absence of PI use is independently associated with elevations in both AST and ALT, while features typical of hepatic steatosis (DM and BMI) are only associated with increased ALP.

Glutathione, glutathione peroxidase, and selenium status in HIV-positive and HIV-negative adolescents and young adults.

BACKGROUND: Antioxidant nutrient deficiencies may hasten the progression of HIV disease by impairing antioxidant defenses. OBJECTIVE: The objective of the study was to determine whether HIV infection is associated with poor selenium status and low antioxidant protection by glutathione and glutathione peroxidase (GPX). DESIGN: In a cross-sectional study of 365 HIV-positive and HIV-negative adolescents and young adults, we examined the relation of plasma selenium, whole-blood glutathione, and whole-blood GPX to HIV status, disease severity, immune activation, and oxidative damage. RESULTS: Selenium deficiency (plasma selenium < 0.070 microg/mL) was not seen in any subjects, and plasma selenium in 244 HIV-positive subjects (0.120 +/- 0.0013 microg/mL) did not differ significantly (P = 0.071) from that in 121 HIV-negative subjects (0.125 +/- 0.0020 microg/mL) . However, multiple regression analysis after adjustment for covariates showed a significant (P = 0.002) negative association between HIV-associated immune activation (plasma neopterin) and plasma selenium concentrations. GPX activity was highest in HIV-positive subjects taking antiretroviral therapy (median: 14.2; 25th, 75th percentiles: 11.1, 18.7 U/mL; n = 130), intermediate in HIV-positive subjects not taking antiretroviral therapy (11.8; 9.4, 15.1 U/mL; n = 114), and lowest in HIV-negative subjects (10.6; 8.6, 12.7 U/mL; n = 121; P < 0.05 for all comparisons). GPX was also positively associated with malondialdehyde, a marker of oxidative damage. CONCLUSIONS: Subjects had adequate selenium status, although HIV-related immune activation was associated with lower plasma selenium concentrations. GPX activity appears to have been induced by the oxidative stress associated with HIV infection and use of antiretroviral therapy. Thus, young, well-nourished subjects can mount a compensatory antioxidant response to HIV infection.

Serum adenosine deaminase enzyme and plasma platelet factor 4 activities in active pulmonary tuberculosis, HIV-seropositive subjects and cancer patients.

The aim of this study was to determine the serum adenosine deaminase (ADA) and plasma platelet factor (PF-4) activities in patients with active pulmonary tuberculosis, HIV seropositive subjects, cancer patients (acute and chronic type lymphoblastic leukaemia) and to compare them with the results of healthy individuals. Eighty-eight subjects were enrolled in this study, 24 patients with active pulmonary tuberculosis, 20 patients with HIV seropositive subjects, 24 patients with cancer, 12 patients with acute type lymphoblastic leukaemia, 12 patients with chronic type lymphoblastic leukaemia) patients and 20 healthy individuals. ADA activity was determined in serum samples using colorimetric method and plasma PF4 activity was measured by using a sandwich-type enzyme immunoassay. When all study groups were compared with the control group, mean serum ADA activities were found to be significantly (p<0.01) higher in the sera of patients with active pulmonary tuberculosis (median, range: 39 IU/l), HIV seropositive subjects (median, range: 31 IU/l) than in the sera of cancer patients (median, range: 15) and healthy controls (median, range: 32 IU/l). Plasma PF-4 activities in active pulmonary tuberculosis patients (median, range: 84 IU/ml) were found to be significantly elevated when compared to HIV seropositive subjects (median, range: 59 IU/ml), cancer patients (median, range 55 IU/ml) and healthy individuals (median, range: 56 IU/ml) (p<0.01). Serum ADA and plasma PF-4 activities showed significant alteration in patients with active pulmonary tuberculosis compared to patients with HIV seropositive subjects, cancer patients and healthy individuals. In conclusion, we suggest that serum ADA and PF-4 activities can be used in the diagnosis of tuberculosis as an supplementary laboratory test in combination with clinical and laboratory findings. Further controlled studies are necessary to determine the importance of the PF-4 and ADA activities in patients with active pulmonary tuberculosis, HIV seropositive subjects and cancer patients.

Liver fibrosis in HIV-positive patients with hepatitis C virus: role of persistently normal alanine aminotransferase levels.

BACKGROUND: Liver fibrosis requiring treatment in HIV/hepatitis C virus (HCV)-coinfected patients with persistently normal alanine aminotransferase (ALT) values (PNAL) is currently not well defined; in this study clinical and histologic features of PNAL were compared with those of subjects with elevated ALT (EAL). METHODS: A total of 326 liver biopsies of HIV/HCV-coinfected patients, performed from 1997-2003, were retrospectively identified. Subjects with at least 3 consecutive normal ALT determinations during a prebiopsy follow-up of 12 months were grouped as PNAL (24 patients) and compared with EAL subjects (302 patients). Liver biopsy was classified with the modified Ishak score. RESULTS: Age, HCV viral load, and genotype, CD4 T-cell count, and antiretroviral drugs did not show a statistical difference between the 2 groups. Statistical significance was found when comparing mean grading (1.4 +/- 1.8 vs. 7.2 +/- 2.6, P < 0.0001) and staging (1.4 +/- 1.79 vs. 2.5 +/- 1.7, P < 0.0003) between PNAL and EAL subjects. The proportion of PNAL patients fulfilling histologic criteria for anti-HCV treatment (25% with stage 2-6) was also significantly different from EAL subjects (69%; P = 0.0001). At multivariate analysis, only age, CD4 count (>500 vs. < or =500 cells/mL), and patient's group (EAL vs. PNAL) were found to be independently associated with a fibrosis score of > or =2. CONCLUSION: Liver fibrosis requiring treatment was found in 25% of HIV/HCV-coinfected subjects with PNAL values.

Porphyria cutanea tarda in a patient with HIV-infection.

Several recent reports have described porphyria cutanea tarda (PCT) occurring in patients with HIV infection. Current evidence suggests that HIV infection may impair the hepatic cytochrome oxidase system, which could lead to an aberration in porphyrin metabolism and subsequently cause porphyria. We report a case of PCT in an HIV-infected patient who had multiple risk factors for this disorder.

Prevalence of protease and reverse transcriptase drug resistance mutations over time in drug-naïve human immunodeficiency virus type 1-positive individuals in Rio de Janeiro, Brazil.

The prevalence of mutations that confer resistance to protease inhibitors and to nucleoside and nonnucleoside reverse transcriptase inhibitors in 49 blood samples from drug-naïve human immunodeficiency virus type 1-infected blood donors living in Rio de Janeiro state, Brazil, in 1998 was evaluated genotypically and phenotypically.

Characteristics of HIV-1 Nef regions containing multiple CD8+ T cell epitopes: wealth of HLA-binding motifs and sensitivity to proteasome degradation.

First and foremost among the many factors that influence epitope presentation are the degradation of Ag, which results in peptide liberation, and the presence of HLA class I molecules able to present the peptides to T lymphocytes. To define the regions of HIV-1 Nef that can provide multiple T cell epitopes, we analyzed the Nef sequence and determined that there are 73 peptides containing 81 HLA-binding motifs. We tested the binding of these peptides to six common HLA molecules (HLA-A2, -A3, -A24, -B7, -B8, and -B35), and we showed that most of them were efficient binders (54% of motifs), especially peptides associating with HLA-A3, -B7/35, and -B8 molecules. Nef peptides most frequently recognized by T cells of HIV-1-infected individuals were 90-97, 135-143, 71-81, 77-85, 90-100, 73-82, and 128-137. The frequency of T cell recognition was not directly related to the strength of peptide-HLA binding. The generation of Nef epitopes is crucial; therefore, we investigated the digestion by the 20S proteasome of a large peptide, Nef(66-100). This fragment was efficiently cleaved, and NH(2)-terminally extended precursors of epitope 71-81 were recognized by T cells of an HIV-1-infected individual. These results suggest that a high frequency of T cell recognition may depend on proteasome cleavage.

Severe bleeding complications in HIV-positive haemophiliac patients treated with protease inhibitors.

The availability of more potent drugs for the treatment of human immunodeficiency virus (HIV) infection has led to the development of aggressive drug regimens, including the widespread use of HIV protease inhibitors. Several reports have indicated increased bleeding complications in haemophiliac patients after starting treatment with protease inhibitors. We present two cases of exceptionally severe hemorrhagic events in HIV-positive patients with haemophilia A after starting HIV protease inhibitors, resulting in significant morbidity and mortality. One patient developed a progressive paranephric pseudotumor becoming symptomatic only one month after the start of ritonavir. The second patient presented with an intracranial bleed, resulting in his death within forty-eight hours, nineteen weeks after he was started on nelfinavir. Both patients showed an excellent antiviral response to the HIV-protease inhibitors with significant decrease in their HIV-RNA titers. Potentially serious hemorrhagic complications that require emergent intervention may occur in HIV-positive haemophiliac patients undergoing therapy with protease inhibitors. Clinicians should be alert to these complications.

Liquid chromatographic determination of urinary 6beta-hydroxycortisol to assess cytochrome p-450 3A activity in HIV positive pregnant women.

Assessing the activity of CYP3A4 is important for predicting the pharmacokinetic behavior of protease inhibitors in HIV positive patients, especially in pregnant women. The endogenous hormonal ratio of 6beta-hydroxycortisol (beta-OHF) to cortisol (F) in the urine is an index for metabolic enzyme activity of cytochrome p-450 (CYP) 3A4. Because the ratio is a unique way to assess the enzyme activity without using any exogenous probes for this isozyme, it is practical for use in pregnant women. In this paper, we describe a method using high performance liquid chromatography (HPLC) for 6beta-OHF in urine from pregnant women to estimate the ratio of 6beta-OHF/F. Urinary 6beta-OHF was measured by using C18-cartridge solid phase extraction and isocratic HPLC. Aliquots (1 ml) of urine samples spiked with internal standard, 6beta-hydroxyprednisolone (6beta-OHPSL), were alkalinized with NaOH, then applied to C18-cartridges, which were washed with water and hexane and eluted with ethyl acetate. After the effluents were dried and reconstituted in 10% acetonitrile, the samples were analyzed by HPLC using an isocratic mobile phase (acetic acid/acetonitrile/50 mM potassium dihydrogenphosphate: 0.2/9/90.8; v/v) and ultraviolet detection at 245 nm. The recoveries of 6beta-OHF from C18 cartridges were 93.2 and 93.9% when the authentic 6beta-OHF was added to the urine sample at the concentration of 50 and 300 ng/ml, respectively. Intra- and inter-day variations estimated at concentrations of 113-674 ng/ml were 2.9-5.6 and 4.9-8.1%, respectively. The method was applied to morning urine samples collected from HIV-positive pregnant women managed with protease inhibitor containing anti-retroviral regimens.

Genotype and phenotype of cytochrome P450 2D6 in human immunodeficiency virus-positive patients and patients with acquired immunodeficiency syndrome.

OBJECTIVE: To examine the distribution of the cytochrome P450 (CYP) CYP2D6 phenotype and its relation to genotype, concomitant medication, and disease state in human immunodeficiency virus (HIV)-positive patients. DESIGN: A cross sectional study with a longitudinal component compared individual genotypes for CYP2D6 to the CYP2D6 phenotype. METHODS: Sixty-one predominately male Caucasian, HIV-positive patients were recruited and CYP2D6 genotypes [extensive metabolizer (EM) or poor metabolizer (PM)] determined by polymerase chain reaction (PCR)-based amplification, followed by restriction fragment-length analysis. The patients were also phenotyped using dextromethorphan (DM) to determine their respective enzyme activity and assigned either a CYP2D6 EM or PM phenotype. Complete medical and treatment histories were compiled. A total of 44 patients were tested longitudinally. RESULTS: Fifty-nine patients (97%) possessed an EM genotype, consistent with previously observed distributions in demographically similar populations. In healthy seronegative populations, genotype and phenotype have been shown to be essentially interchangeable measures of CYP2D6 activity. In this cohort, 2 of the 59 patients with an EM genotype expressed a PM phenotype. In addition, 4 EM patients were less extensive DM metabolizers than any of the patients receiving medication known to inhibit CYP2D6. This apparent shift toward the PM phenotype from the EM genotype was associated with the presence of active illness. CONCLUSION: Changes may occur in HIV-positive patients such that their CYP2D6 activity approaches that of PMs, despite having an EM genotype. Neither active disease nor drug interactions alone explain the shift.

In vivo administration of recombinant IL-2 to individuals infected by HIV down-modulates the binding and expression of the transcription factors ying-yang-1 and leader binding protein-1/late simian virus 40 factor.

Leader binding protein-1 (LBP-1)/late SV40 factor (LSF) and ying yang-1 (YY1) transcription factors are involved in the regulation of HIV expression. In particular, YY1 and LBP-1 have been shown to cooperate in repressing HIV-1-long terminal repeat reporter gene expression by in vitro cotransfection experiments. However, no information is available on the levels of expression and activation of these transcription factors in PBMC of HIV-infected individuals. Therefore, we have evaluated the expression and DNA binding activity of YY1 and LBP-1 (LSF) in PBMC of HIV-infected individuals before, during, and after administration of IL-2 in association with antiretroviral therapy (ART), a regimen under consideration for broad clinical use in this disease based on its ability to stably raise the absolute number of circulating CD4+ T lymphocytes. Both YY1- and LBP-1 (LSF)-DNA binding were profoundly down-modulated during administration of IL-2/ART, and a proteolytic activity probably responsible for the reduced expression of the two cellular transcription factors was found activated in PBMC of individuals receiving the immunotherapeutic regimen. This study is the first evidence of modulation of cellular transcription factors following IL-2/ART administration and provides a potential correlate of the transient raises in plasma viremia early reported in patients receiving IL-2 in the absence of ART, thus underscoring the importance of always administering this cytokine to HIV-infected individuals together with potent antiretrovirals.

Effect of fusidic acid on the hepatic cytochrome P450 enzyme system.

OBJECTIVE: To investigate the effects of fusidic acid therapy on the hepatic cytochrome P450 (CYP450) enzyme system. METHODS: Thirty HIV-seropositive L-methadone-substituted i.v. drug abusers (stage CDC/WHO B2 - 3 with CD4+-counts ranging from 65 to 293/microl) were randomized into 3 groups (A - C). Ten patients were treated with fusidic acid 500 mg/day over a period of 14 (group A) or 28 days (group B), respectively. Patients in group C served as a control group and did not receive any medication apart from L-methadone. In order to investigate the hepatic monooxygenase system, pharmacokinetics were determined in all patients before initiation and 14 and 28 days after starting therapy with fusidic acid. The concentration of antipyrine and its 3 main metabolites (norantipyrine (NORA), 4-hydroxyantipyrine (OHA), 3-hydroxymethylantipyrine (HMA)) in plasma and urine were measured by high-performance liquid chromatography (HPLC). RESULTS: No effects on antipyrine pharmacokinetics and pharmacokinetics of antipyrine metabolites were found in group A after 14 days of fusidic acid intake and in the control group without therapy. However, in contrast an activation of the CYP450 enzyme system was observed in group B after 28 days of fusidic acid therapy with an increase of total antipyrine clearance (43.0 +/- 7.62 ml/min to 51.0 +/- 9.03 ml/min) as well as clearances to all metabolites (NORA 7.11 +/- 1.75 to 8.60 +/-2.10 ml/min, OHA 11.5 +/- 2.89 to 14.0 +/- 3.97 ml/min, HMA 4.05 +/- 0.99 to 4.94 +/- 1.27 ml/min). Antipyrine half-life was significantly reduced (12.3 +/- 2.8 h to 9.4 +/- 2.2 h) and some patients developed clinical signs of L-methadone underdosage. CONCLUSIONS: Our results suggest that fusidic acid has a time-dependent activating effect on the CYP450 enzyme system. Especially in treatment of patients who are frequently under multidrug regimens such as HIV-positive patients drug interactions should be taken into consideration.