Human pegivirus viremia in HCV/HIV co-infected patients: Direct acting antivirals exert anti-pegivirus effects.

BACKGROUND: Human pegivirus (HPgV) is a single-stranded RNA virus​ that is closely related to hepatitis C virus (HCV)​. HPgV has also been shown to infect patients with human immunodeficiency virus (HIV). The mechanisms and disease outcomes of HPgV infections are largely unknown, although it has been implicated in both cancer and neurological diseases. There are no established therapies for HPgV. OBJECTIVES: To estimate the prevalence of HPgV in a cohort of HCV/HIV co-infected patients undergoing treatment for HCV with direct acting antivirals (DAA) and investigate the effect of DAA therapy on HPgV infection. STUDY DESIGN: RNA was extracted from plasma samples collected at time points before, during, and after DAA. HPgV RNA abundance was quantified by droplet digital PCR assays targeting the NS5A and 5'UTR domains and confirmed by RT-qPCR. Clinical, demographic and treatment data were analysed. RESULTS: HPgV RNA was detected and quantified in 26 of 100 patients' plasma (26%) before starting DAA. Patients with detectable HPgV were more likely to be male, had higher peak HIV plasma levels, and a history of injection drug use. Patients receiving sofosbuvir/ledipasvir (n = 9) displayed significantly lower HPgV levels at time of DAA completion and had lower post-DAA HPgV rebound​ levels compared to patients receiving sofosbuvir/velpatasvir (n = 11) although both regimens significantly reduced viremia directly following DAA completion. Sustained suppression of HPgV was â€‹also observed among patients (n = 2) receiving pegylated-interferon. CONCLUSIONS: HPgV RNA ​was frequently detected in HCV/HIV co-infected patients and ​was​ supressed by DAA and pegylated interferon therapies with sofosbuvir-ledipasvir showing greatest antiviral activity. These findings suggest potential treatment strategies for HPgV infections​.

Infection of Glia by Human Pegivirus Suppresses Peroxisomal and Antiviral Signaling Pathways.

Human pegivirus (HPgV) infects peripheral leukocytes but was recently shown to be a neurotropic virus associated with leukoencephalitis in humans. In the present study, we investigated the neural cell tropism of HPgV as well as its effects on host immune responses. HPgV wild type (WT) and a mutant virus with a deletion in the HPgV NS2 gene (ΔNS2) were able to productively infect human astrocytes and microglia but not neurons or an oligodendrocyte-derived cell line. Of note, the ΔNS2 virus replicated better than WT pegivirus in astrocytes, with both viruses being able to subsequently infect and spread in fresh human astrocyte cultures. Infection of human glia by HPgV WT and ΔNS2 viruses resulted in suppression of peroxisome-associated genes, including PEX11B, ABCD1, PEX7, ABCD3, PEX3, and PEX5L, during peak viral production, which was accompanied by reduced expression of IFNB, IRF3, IRF1, and MAVS, particularly in ΔNS2-infected cells. These data were consistent with analyses of brain tissue from patients infected with HPgV in which we observed suppression of peroxisome and type I interferon gene transcripts, including PEX11B, ABCD3, IRF1, and IRF3, with concurrent loss of PMP70 immunoreactivity in glia. Our data indicate that human astrocytes and microglia are permissive to HPgV infection, resulting in peroxisome injury and suppressed antiviral signaling that is influenced by viral diversity. IMPORTANCE Human pegiviruses are detected in 1 to 5% of the general population, principally infecting leukocytes, although their effects on human health remain uncertain. Here, we show that human pegivirus infects specific neural cell types in culture and human brain and, like other neurotropic flaviviruses, causes suppression of peroxisome and antiviral signaling pathways, which could favor ongoing viral infection and perhaps confer susceptibility to the development of neurological disease.

Transmission of GB virus type C via transfusion in a cohort of HIV-infected patients.

BACKGROUND: GB virus C (GBV-C) infection is transmitted by blood exposure and associated with lower human immunodeficiency virus (HIV) load and slower HIV disease progression. Few studies describe predictors of acute GBV-C infection following transfusion in HIV-infected patients. METHODS: We used a limited-access database from the National Heart Lung and Blood Institute's Viral Activation Transfusion Study, a randomized controlled trial of leukoreduced versus nonleukoreduced transfusions received by HIV-infected, transfusion-naive patients. Blood samples from 489 subjects were tested for GBV-C markers in pretransfusion and posttransfusion samples. We estimated the risk of acquiring GBV-C RNA and predictors of GBV-C acquisition, using pooled logistic regression. RESULTS: GBV-C RNA was detected ≤120 days following the first transfusion in 22 (7.5%) of 294 subjects who were GBV-C negative before transfusion. The risk of GBV-C RNA acquisition increased with each unit transfused (odds ratio, 1.09; 95% confidence interval, 1.06-1.11). Lower baseline HIV load and use of antiretroviral therapy were associated with subsequent GBV-C RNA acquisition, after control for units of blood transfused. Leukoreduced status of transfused units was not associated with GBV-C transmission. CONCLUSIONS: Blood transfusion is associated with a significant risk of GBV-C acquisition among HIV-infected patients. Transmission of GBV-C by blood transfusion was inversely related to HIV load.

GB virus C infection among young, HIV-negative injection drug users with and without hepatitis C virus infection.

Our study examined the association between GB virus C (GBV-C) and (i) hepatitis C virus (HCV) infection status, (ii) biomedical indicators of liver disease (alanine and aspartate aminotransferases) and (iii) HCV RNA level among young injection drug users (IDUs) recruited using street outreach and respondent-driven methods. Cross-sectional and longitudinal analyses were completed. GBV-C (active or resolved) infection was significantly (P < 0.05) more prevalent among HCV antibody-positive (anti-HCV+) (65.1%) than antibody-negative (anti-HCV-) (32.3%) (OR = 3.9, 95% CI: 2.3-6.9) IDUs. The prevalence of resolved GBV-C infection was highest among those with chronic HCV infection (41.9%), followed by those with resolved HCV infection (34.4%) and significantly lower (P < 0.05) among anti-HCV participants (16.9%). Although not statistically significant (P = 0.13), a similar pattern was observed for active GBV-C infection. No association between GBV-C infection status and biomedical indicators of liver disease or HCV RNA level over time was observed. In conclusion, GBV-C infection prevalence was higher among anti-HCV+ compared to anti-HCV- young IDUs, similar to prior studies among older populations. In particular, chronically HCV-infected young IDUs had an increased rate of GBV-C clearance.

Effect of antiretroviral therapy and hepatitis c co-infection on changes in lipid levels in HIV-Infected patients 48 weeks after initiation of therapy.

Hepatitis C virus (HCV) commonly co-infects HIV-infected individuals. Antiretroviral therapy (ART) is associated with elevated serum lipid levels, and HCV infection is associated with low serum lipid levels. Fasting lipid levels were investigated in 1,434 ART-naïve HIV-infected people participating in the AIDS Clinical Trials Group (ACTG) Longitudinal Linked Randomized Trials (ALLRT) protocol who prospectively initiated ART with 3 agents. Subjects with elevated liver-associated enzymes (>5 x ULN) were excluded. Demographics, body mass index, HCV status, CD4 cell count, HIV RNA, liver enzymes, lipid levels, and glucose were assessed before and following 48 weeks of ART. HCV-positive subjects (n = 160; 11%) were older, more likely to be Black, have a history of intravenous drug use (IDU), have higher baseline liver-associated enzyme levels than the HCV-negative group (p < .001 for each), and to have diabetes at baseline (5% vs. 2%, p = .07). Lipid levels rose in both groups following ART, and the differences were not significant except that HDL levels increased significantly more in the HCV-positive group (p = .006). In summary, HCV infection did not appear to provide significant protection against ART-induced hyperlipidemia in this cohort of HIV-infected subjects prospectively enrolled in ART trials, although HDL levels rose to a greater degree.

Impact of GB virus type C infection on mother-to-child HIV transmission in the Women and Infants Transmission Study Cohort.

BACKGROUND: GB virus type C (GBV-C) viraemia is associated with a beneficial outcome in HIV-infected individuals in several though not all studies. GBV-C viraemia was examined in a matched case-control study of 133 HIV-infected pregnant women who transmitted HIV to their infants ('cases') and 266 non-transmitting controls. METHODS: HIV-infected children and controls were pair-matched for high-risk delivery, race and year of delivery. GBV-C status was determined in maternal plasma samples obtained at or within 3 months of delivery. RESULTS: Pregnant women with GBV-C viraemia (11% of those studied) had lower HIV RNA levels (P=0.01) and higher CD4 percentages (P=0.0006) [corrected] than women without GBV-C. A trend towards decreased mother-to-child transmission in the multivariate analysis was observed among GBV-C viraemic women delivering after highly active antiretroviral therapy (HAART) became available [odds ratio (OR) 0.30, 95% confidence interval (CI) 0.08-1.05; P=0.06], but not in women delivering prior to the widespread use of HAART. CONCLUSIONS: GBV-C viraemia was associated with a beneficial effect on CD4 percentage and HIV RNA level in these pregnant women, and was also associated with a trend towards reduced risk of mother-to-child HIV transmission among women after HAART became available. Further studies with larger or multiple cohorts are necessary to assess possible benefits in this population.

Risk factors for hepatitis C fibrosis: a prospective study of United States veterans compared with nonveterans.

Chronic hepatitis C virus (HCV) infection causes cirrhosis in many infected patients; however, a better understanding of the risk factors for fibrosis progression in high HCV prevalence groups such as US veterans is needed. We wished to compare the demographic, clinical characteristics, and independent variables that influence fibrosis in US veterans vs nonveterans with chronic HCV. HCV-seropositive US veterans (n = 459) and nonveterans (n = 395) prospectively completed a detailed medical, social and occupational questionnaire. Clinical factors for progressive liver disease were compared between veterans and nonveterans and fibrosis stage assessed on liver biopsies (168 veterans and 208 nonveterans). Using polychotomous logistic regression, fibrosis was analysed as both a progressive and categorical outcome to determine independent risk factors for both patient groups. Although veterans were significantly older and had higher lifetime alcohol consumption than nonveterans, their median fibrosis scores did not differ from nonveterans. By univariate analysis, alanine aminotransferase, necroinflammatory activity (NIA), and cryoglobulin positivity were associated with fibrosis in veterans and nonveterans (P < 0.05, all comparisons), whereas steatosis was associated with fibrosis only in nonveterans (P < 0.0001). By multivariate analysis, NIA was an independent risk factor for fibrosis in both groups (P < 0.01). However, fibrosis in nonveterans was also independently associated with steatosis, significant alcohol consumption and age (P < 0.04, all comparisons). Independent risk factors for fibrosis vary among high HCV prevalence groups such as veterans when compared with nonveterans. Understanding specific patient cohort effects is important for determining independent risk factors for disease progression in chronic HCV infection.

Effect of primer selection on estimates of GB virus C (GBV-C) prevalence and response to antiretroviral therapy for optimal testing for GBV-C viremia.

GB virus C (GBV-C; also called hepatitis G virus) is a common cause of infection associated with prolonged survival among HIV-infected individuals. The prevalences of GBV-C viremia vary widely in different studies, and there has been poor agreement among different laboratories performing GBV-C RNA detection in quality control studies. To determine the optimal method of measuring GBV-C RNA in clinical samples, samples obtained from 939 HIV-infected subjects were studied using reverse transcription (RT)-PCR methods amplifying four separate regions of the GBV-C genome. Primers amplifying the E2 coding region were 100% specific; however, their sensitivity was only 76.6%. In contrast, primers amplifying three additional conserved regions of the GBV-C genome (the 5' nontranslated region and the nonstructural protein-coding regions 3 and 5A) were more sensitive but produced higher rates of false-positive results. Using low-specificity primer sets influenced the significance of association between GBV-C viremia and response to antiretroviral therapy. Using a quantitative GBV-C RNA method, the GBV-C RNA concentration did not correlate with baseline or set point HIV RNA levels; however, a correlation between negative, low, and high GBV-C RNA levels and increasing reduction in HIV RNA following antiretroviral therapy was observed. Subjects with both GBV-C E2 antibody and viremia had significantly lower GBV-C RNA levels than did viremic subjects without E2 antibody. These studies demonstrate that accurate detection of GBV-C RNA by nested RT-PCR requires the use of primers representing multiple genome regions. Analyses based on testing with single primers do not lead to reliable conclusions about the association between GBV-C infection and clinical outcomes.

Effect of early and late GB virus C viraemia on survival of HIV-infected individuals: a meta-analysis.

OBJECTIVES: To conduct a meta-analysis to synthesize the evidence regarding the effect of co-infection with GB virus C (GBV-C) on survival of HIV-infected individuals, and to estimate the effect. METHODS: A Bayesian meta-analysis was conducted to synthesize evidence from eligible studies. Prospective survival studies of HIV-1-infected individuals, with outcome defined as time from baseline to all-cause death, were included and classified by whether GBV-C status was determined in early or late HIV disease. The primary measure was the hazard ratio (HR) of death for HIV-infected individuals with GBV-C infection versus those without GBV-C infection. RESULTS: Eleven studies from eight publications met the inclusion criteria. For studies with GBV-C status measured 2 years or less after HIV seroconversion (912 subjects), the combined HR was 0.88 [95% credible interval (CI) 0.30, 1.50]. For studies with GBV-C status measured more than 2 years after HIV seroconversion (1294 subjects), the combined HR was 0.41 (95% CI 0.23, 0.69). CONCLUSIONS: No conclusive evidence was found of an association between survival and GBV-C infection early in HIV disease. However, when GBV-C infection was present later in HIV disease, a significant reduction in the hazard for mortality was observed for those with co-infection. Potential explanations for this difference include a non-proportional benefit of GBV-C over time, possibly related to clearance of GBV-C infection early in HIV disease. The timing of GBV-C infection appears to account for the contradictory results of studies on the effect of GBV-C coinfection on survival of HIV-infected people.

Effect of GB virus C on response to antiretroviral therapy in HIV-infected Brazilians.

OBJECTIVES: GB virus C (GBV-C) infection is associated with delayed mortality in HIV-infected people in most, but not all, studies. Previous investigations of the effect of GBV-C viraemia on response to antiretroviral therapy (ART) were inconclusive. To determine the effect of GBV-C on ART, we retrospectively analysed plasma samples taken from patients in a prospective randomized clinical trial of ART in HIV-positive Brazilians. METHODS: GBV-C viraemia was characterized by testing stored serum samples from 175 participants by reverse transcriptase-polymerase chain reaction (RT-PCR). Subjects were randomized to receive indinavir (n=59), zidovudine and lamivudine (n=58), or zidovudine, lamivudine and indinavir (n=58). The effect of GBV-C viraemia on the average change in HIV viral load and CD4 count following initiation of therapy was evaluated in a multiple regression analysis. RESULTS: The prevalence of GBV-C viraemia was similar to that observed in previous studies (24%). HIV viral load decreased following ART to a significantly greater extent in patients with GBV-C viraemia (by 0.48 log(10) HIV-1 RNA copies/mL, P=0.009, adjusting for age, ART group, and baseline CD4 count). Although there was no significant difference in change in CD4 count between individuals with and without GBV-C viraemia overall, CD4 counts were higher following 48 weeks of therapy in GBV-C viraemic individuals receiving the least potent ART regimen (zidovudine and lamivudine) compared with those without GBV-C infection. CONCLUSIONS: GBV-C viraemia is associated with an enhanced reduction of HIV viral load in response to ART. In this study of treatment-naive individuals during 48 weeks of follow up, patients with GBV-C viraemia had reductions in HIV viral load that were approximately 0.5 log copies/mL greater than those found in patients without GBV-C viraemia. This is similar to reductions observed with nucleoside reverse transcriptase inhibitors.

Association of hypocholesterolaemia with hepatitis C virus infection in HIV-infected people.

OBJECTIVE: To study the impact of hepatitis C virus (HCV) status on serum cholesterol levels in HIV-infected patients. METHODS: We retrospectively analysed data from the 881 participants of the Veterans Ageing Cohort 3 Site Study. Four different models were constructed using total cholesterol, low-density lipid (LDL) cholesterol, high-density lipid (HDL) cholesterol and triglycerides as dependent variables. The relevant covariates included HCV antibody status, HIV medication class, CD4 count, HIV viral load, glucose level, lipid-lowering drug use, gender, race, age, liver function test results, ethanol use, drug use, and HIV exposure category. Variables excluded from the final model included niacin use, gender, race, age, current ethanol use, and HIV exposure category. RESULTS: Of the 881 HIV-positive patients enrolled in the study, 700 (79%) were screened for HCV antibody, with 300 (42.8%) HCV antibody positive and 400 (57.2%) HCV antibody negative. A positive HCV antibody status was independently associated with lower total cholesterol levels (P=0.001) and LDL cholesterol levels (P<0.001) but not with lower HDL cholesterol or triglyceride levels. HCV-positive patients had predicted LDL levels 19 mg/dL lower than those of HCV-negative subjects. HCV infection was also associated with a decreased use of lipid-lowering medication, and protease inhibitor use was associated with increased LDL and total cholesterol levels. CONCLUSIONS: HCV infection has been associated with lower cholesterol levels in HIV-negative individuals, and the same appears to be true with HIV-infected patients. This is an interesting finding given that HCV particles bind to LDL receptors in vitro and also because HCV-lipid interactions appear to be important in the HCV replication cycle.

Effect of coinfection with GB virus C on survival among patients with HIV infection.

BACKGROUND: Previous studies have suggested that people with human immunodeficiency virus (HIV) infection who are coinfected with GB virus C (GBV-C, or hepatitis G virus) have delayed progression of HIV disease. GBV-C is related to hepatitis C virus but does not appear to cause liver disease. METHODS: We examined the effect of coinfection with GBV-C on the survival of patients with HIV infection. We also evaluated cultures of peripheral-blood mononuclear cells infected with both viruses to determine whether GBV-C infection alters replication in vitro. RESULTS: Of 362 HIV-infected patients, 144 (39.8 percent) had GBV-C viremia in two tests. Forty-one of the patients with GBV-C viremia (28.5 percent) died during the follow-up period, as compared with 123 of the 218 patients who tested negative for GBV-C RNA (56.4 percent; P<0.001). The mean duration of follow-up for the entire cohort was 4.1 years. In a Cox regression analysis adjusted for HIV treatment, baseline CD4+ T-cell count, age, sex, race, and mode of transmission of HIV, the mortality rate among the 218 HIV-infected patients without GBV-C coinfection was significantly higher than that among the 144 patients with GBV-C coinfection (relative risk, 3.7; 95 percent confidence interval, 2.5 to 5.4). HIV replication, as measured by the detection of p24 antigen in culture supernatants, was reproducibly inhibited in cultures of peripheral-blood mononuclear cells by GBV-C coinfection. Coinfection did not alter the surface expression of HIV cellular receptors on peripheral-blood mononuclear cells, as determined by flow cytometry. CONCLUSIONS: GBV-C infection is common in people with HIV infection and is associated with significantly improved survival.

Characterization of hepatitis C virus (HCV) and HCV E2 interactions with CD81 and the low-density lipoprotein receptor.

Hepatitis C virus (HCV) or HCV-low-density lipoprotein (LDL) complexes interact with the LDL receptor (LDLr) and the HCV envelope glycoprotein E2 interacts with CD81 in vitro. However, E2 interactions with LDLr and HCV interactions with CD81 have not been clearly described. Using sucrose gradient-purified low-density particles (1.03 to 1.07 g/cm(3)), intermediate-density particles (1. 12 to 1.18 g/cm(3)), recombinant E2 protein, or control proteins, we assessed binding to MOLT-4 cells, foreskin fibroblasts, or LDLr-deficient foreskin fibroblasts at 4 degrees C by flow cytometry and confocal microscopy. Viral entry was determined by measuring the coentry of alpha-sarcin, a protein synthesis inhibitor. We found that low-density HCV particles, but not intermediate-density HCV or controls bound to MOLT-4 cells and fibroblasts expressing the LDLr. Binding correlated with the extent of cellular LDLr expression and was inhibited by LDL but not by soluble CD81. In contrast, E2 binding was independent of LDLr expression and was inhibited by human soluble CD81 but not mouse soluble CD81 or LDL. Based on confocal microscopy, we found that low-density HCV particles and LDL colocalized on the cell surface. The addition of low-density HCV but not intermediate-density HCV particles to MOLT-4 cells allowed coentry of alpha-sarcin, indicating viral entry. The amount of viral entry also correlated with LDLr expression and was independent of the CD81 expression. Using a solid-phase immunoassay, recombinant E2 protein did not interact with LDL. Our data indicate that E2 binds CD81; however, virus particles utilize LDLr for binding and entry. The specific mechanism by which HCV particles interact with LDL or the LDLr remains unclear.

Elevated phenotypic switching and drug resistance of Candida albicans from human immunodeficiency virus-positive individuals prior to first thrush episode.

Strains of Candida albicans obtained from human immunodeficiency virus (HIV)-positive individuals prior to their first episode of oral thrush were already in a high-frequency mode of switching and were far more resistant to a number of antifungal drugs than commensal isolates from healthy individuals. Switching in these isolates also had profound effects both on susceptibility to antifungal drugs and on the levels of secreted proteinase activity. These results suggest that commensal strains colonizing HIV-positive individuals either undergo phenotypic alterations or are replaced prior to the first episode of oral thrush. They also support the suggestion that high-frequency phenotypic switching functions as a higher-order virulence trait, spontaneously generating in colonizing populations variants with alterations in a variety of specific virulence traits.

Full-length GB virus C (Hepatitis G virus) RNA transcripts are infectious in primary CD4-positive T cells.

GB virus C (GBV-C or hepatitis G virus) is a recently described flavivirus which frequently leads to chronic viremia in humans. Although GBV-C is associated with acute posttransfusion hepatitis, it is not clear if the virus is pathogenic for humans. We constructed a full-length cDNA from the plasma of a person with chronic GBV-C viremia. Peripheral blood mononuclear cells (PBMCs) transfected with full-length RNA transcripts from this GBV-C clone resulted in viral replication. This was demonstrated by serial passage of virus from cell culture supernatants, detection of increasing concentrations of positive- and negative-sense GBV-C RNA over time, and the detection of the GBV-C E2 antigen by confocal microscopy. In addition, two types of GBV-C particles were identified in cell lysates; these particles had buoyant densities of 1.06 and 1.12 to 1.17 g/ml in sucrose gradients. PBMCs sorted for expression of CD4 contained 100-fold-more GBV-C RNA than CD4-negative cells. Taken together, these data demonstrate that RNA transcripts from GBV-C full-length cDNA are infectious in primary CD4-positive T cells. In contrast, RNA transcripts from an infectious hepatitis C virus clone did not replicate in the same cell culture system. Infectious RNA transcripts from GBV-C cDNA should prove useful for studying viral replication and may allow identification of differences between GBV-C and hepatitis C virus cultivation in vitro.

Fluorescence-based quantitative methods for detecting human immunodeficiency virus type 1-induced syncytia.

Cell fusion induced by human immunodeficiency virus type 1 (HIV-1) is usually assessed by counting multinucleated giant cells (syncytia) visualized by light microscopy. Currently used methods do not allow quantification of syncytia, nor do they estimate the number of cells involved in cell fusion. We describe two fluorescence-based methods for the detection and quantification of HIV-1-induced in vitro syncytium formation. The lymphoblastoid cell lines MT-2 and SupT1 were infected with syncytium-inducing (SI) HIV-1 isolates. Syncytia were detected by DNA staining with propidium iodide using flow cytometry to determine cell size or by two-color cytoplasmic staining of infected cell populations by using fluorescence microscopy. Both methods were able to detect and quantify HIV-induced syncytia. The methods could distinguish between SI and non-SI HIV isolates and could be used with at least two separate types of CD4(+) T-cell lines. Small syncytia can be readily identified by the two-color cytoplasmic staining method. Both methods were also shown to be useful for evaluating antiretroviral compounds, as demonstrated by the accurate assessment of HIV inhibition by azidothymidine (zidovudine), dideoxycytidine (zalcytibine), and hydroxyurea. These fluorescence-based assays allow a rapid and practical method for measuring HIV replication and anti-HIV activity of potential inhibitory compounds.

Hepatitis C virus (HCV) infection and cryoglobulinemia: analysis of whole blood and plasma HCV-RNA concentrations and correlation with liver histology.

The influence of cryoprecipitate (CP) on liver histology and peripheral titers of hepatitis C virus (HCV) RNA was evaluated for 115 patients with chronic hepatitis. Fifty-four patients had measurable CP levels whereas 61 did not. Assessment of liver biopsies for grade of fibrosis revealed that patients with CP had increased fibrosis (P <.001) and incidence of cirrhosis (P =.001) compared with those without CP. In contrast, there was not a significant difference in the inflammatory activity score between the 2 groups. HCV RNA in whole blood (WB) and plasma (Pl) was evaluated in patients with or without CP by end-point-limiting dilution titer. Among patients with CP, WB titers were significantly higher than Pl titers (P <.001); however, there was no difference in WB or Pl titers in patients without CP (P =.068). Histological activity and fibrosis scores of patients from either group were compared with peripheral viral titers of WB and Pl, percentage of CP, rheumatoid factor (RF) titer, and serum alanine transaminase (ALT). There were significant correlations between the amount of fibrosis and the percentage of CP and rheumatoid factor titer, yet neither of the latter parameters was correlated with inflammatory activity. These data suggest that patients with CP and chronic hepatitis owing to HCV are more likely to have progressive disease than patients without CP. Furthermore, the presence of CP in patients infected with HCV appears to influence the amount of virus detected in patient Pl, suggesting that WB assays may be more reliable for HCV-RNA quantitation in patients with CP.

Hepatitis A virus-specific humoral and cellular immune responses following immunization with a formalin-inactivated hepatitis A vaccine.

To evaluate proliferative T cell responses elicited by a formalin-inactivated HAV vaccine, we immunized 10 subjects with an inactivated HAV vaccine, and measured HAV antibody titers and HAV-specific T cell proliferation. gamma-Interferon production by PBMC's was evaluated in selected subjects. By week 30, seroconversion (geometric mean titer=2299 mIU/ml), and HAV-specific proliferation was detected in all subjects. HAV also induced gamma-interferon in the three subjects studied. These data indicate that the inactivated HAV vaccine induces proliferative T cell responses in addition to HAV antibody. This may be important for protection against hepatitis A, and suggests that recall memory for HAV antigen is elicited by the vaccine.

Comparison of a neural network approach with five traditional methods for predicting creatinine clearance in patients with human immunodeficiency virus infection.

STUDY OBJECTIVE: To compare the results of an artificial neural network approach with those of five published creatinine clearance (Cl(cr)) prediction equations and with the measured (true) Cl(cr) in patients infected with the human immunodeficiency virus (HIV). DESIGN: Six-month prospective study. SETTINGS: Two university medical centers. PATIENTS: Sixty-five HIV-infected patients: 18 relatively healthy outpatients and 47 inpatients. INTERVENTIONS: All subjects had urine collected for 24 hours to determine Cl(cr). MEASUREMENTS AND MAIN RESULTS: The 16 input variables were age, ideal body weight, actual body weight, body surface area, height, and the following blood chemistries: sodium, potassium, aspartate aminotransferase, alanine aminotransferase, red blood cell count, platelet count, white blood cell count, glucose, serum creatinine, blood urea nitrogen, and albumin. The only output variable was Cl(cr). A training set of 55 subjects was used to develop the relationship between input variables and the output variable. The trained neural network was then used to predict Cl(cr) of a validation set of 10 subjects. Mean differences between predicted Cl(cr) and actual Cl(cr) (bias) were 4.1, 28.7, 29.4, 26.0, 31.8, and 55.8 ml/min/1.73 m2 for the artificial neural network, Cockcroft and Gault, Jelliffe 1, Jelliffe 2, Mawer et al, and Hull et al methods, respectively. CONCLUSION: The accuracy of predicting Cl(cr) in subjects with HIV infection by the artificial neural network is superior to that of the five equations that are currently used in clinical settings.