Showing papers by "Anders Sönnerborg published in 1998"

Multiple dideoxynucleoside analogue-resistant (MddNR) HIV-1 strains isolated from patients from different European countries.

Abstract: Objective: To study the prevalence of multiple dideoxynucleoside (ddN)-resistant (MddNR) HIV-1 in European patients under treatment with multiple ddN analogues, and to characterize MddNR strains genotypically and phenotypically. Design and methods: Blood samples from patients after ≥ 6 months of treatment with multiple ddN were screened for the MddNR mutation Q151M. After confirmation of MddNR in 15 patients from five European countries, genotypic resistance was evaluated by DNA sequencing of the reverse transcriptase (RT) gene. Phenotypic resistance was measured by the recombinant virus assay. Results were compared with the clinical evolution of the patients. Results: The prevalence of MddNR strains in European patients treated with multiple ddN analogues was 3.5%. Viruses typically contained amino acid substitutions V75F, F77L, F116Y and Q151M in the RT gene. A new mutation, S68G, was frequently associated with MddNR. Phenotypically, viruses displayed high-level resistance to zidovudine (ZDV), didanosine (ddl), zalcitabine (ddC), stavudine (d4T) and partial resistance to lamivudine (3TC) once multiple mutations were present. Under in-vivo treatment pressure, some MddNR strains additionally developed resistance to protease inhibitors or non-nucleoside RT inhibitors (NNRTI). Clinically, most patients had advanced HIV disease with low CD4 cell counts, high viral loads and a rapid progression, but two patients harbouring MddNR virus responded well to dual protease inhibitor associations. Conclusions: MddNR resistant HIV-1 can be found in European patients. MddNR is characterized by a specific set of drug resistance mutations, cross-resistance to most ddN analogues and a fast clinical progression. MddNR can be associated with protease inhibitor or NNRTI resistance.

Antiretroviral effect and safety of abacavir alone and in combination with zidovudine in HIV-infected adults. Abacavir Phase 2 Clinical Team.

Abstract: Objectives: To evaluate, over 12 weeks, the antiretroviral activity and safety of abacavir, used alone and in combination with zidovudine (ZDV), as treatment for HIV-1-infected subjects who had limited or no antiretroviral treatment. Design: Seventy-nine HIV-1-infected subjects, with CD4 cell counts 200-500 X 10 6 /l and <12 weeks of previous treatment with ZDV were enrolled in a multicenter study. Subjects were randomly assigned to one of four cohorts receiving abacavir monotherapy for the first 4 weeks (200, 400, or 600 mg every 8 h daily, or 300 mg every 12 h daily) and, thereafter, combination therapy of abacavir with 600 mg ZDV or ZDV placebo, administered in a double-blind manner for an additional 8 weeks. Methods: Antiretroviral activity was assessed by measuring changes in plasma HIV-1 RNA levels and CD4+ cell counts. Safety was assessed by monitoring clinical adverse events and laboratory abnormalities during the 12-week period and for 4 weeks post-treatment. Results: Treatment with abacavir, alone or in combination with ZDV, produced marked decreases in plasma HIV-1 RNA loads and increases in CD4+ cell counts in all groups. At week 4, median plasma HIV-1 RNA loads decreased by 1.11-1.77 log 10 copies/ml and median CD4+ cell counts increased by 63-111 X 10 6 /l in all groups. At week 12, median HIV-1 RNA loads decreased by 1.02-2.24 log 10 copies/ml (abacavir monotherapy) and by 1.81-2.01 log 10 copies/ml (abacavir-ZDV); median CD4+ cell counts increased by 79-195 X 10 6 /l (abacavir monotherapy) and by 93-142 X 10 6 /l (abacavir-ZDV). At week 12, the percentage of subjects who had plasma HIV-1 RNA levels below 400 and 40 copies/ml were 28 and 11%, respectively (abacavir monotherapy) and 69 and 22%, respectively (abacavir-ZDV). Eight subjects (10%) discontinued the study prematurely because of adverse events; nausea (n = 4) and hypersensitivity (n = 3) were the most common reasons for withdrawal. There were no deaths among the study subjects. Conclusions: In HIV-infected subjects who have received little or no prior antiretroviral therapy, treatment with abacavir alone or in combination with ZDV is well tolerated and resulted in sustained improvements in key immunologic and virologic efficacy parameters through 12 weeks.

Variations in HIV-1 pol gene associated with reduced sensitivity to antiretroviral drugs in treatment-naive patients.

Abstract: Objective: Various drugs against the HIV-1 enzymes reverse transcriptase (RT) and protease have been introduced in the last few years: protease inhibitors, nucleoside RT inhibitors (NRTI) and non-NRTI (NNRTI). Several sequence variations associated with reduced drug sensitivity have been described in the HIV-1 pol gene. Design: To analyse the occurrence of mutations associated with drug resistance in treatment-naive individuals. Methods: RNA was extracted from sera of treatment-naive individuals, who were first diagnosed to be HIV-1 infected between August 1996 and February 1998. The pol region was amplified by RT-PCR and directly sequenced. Data on mutations associated with resistance to antiretroviral drugs were obtained from literature. Results: Fifty protease genes and 53 RT genes from 57 individuals were sequenced. In the RT we analysed 20 amino-acid positions associated with resistance to NRTI and NNRTI. In total, 1054 amino acids at critical positions were analysed and three (0.3%) mutations known to contribute to RTI resistance were detected. In the protease, 16 amino-acid positions associated with resistance to protease inhibitors were analysed. By analysing a total of 768 amino acids at key positions in the protease, 50 (7%) mutations were detected that were associated with reduced drug sensitivity. Thirty-one (61%) patients showed between one and six mutations at the analysed protease amino-acid positions. In eight out of 16 analysed amino-acid positions, up to 44% of all patients carried mutations associated with resistance to protease inhibitors. Conclusions: Very few pre-existing mutations to RTI were found, suggesting that the transmission of RT-resistant strains is still uncommon. However, about two-thirds of the patients had one or more mutations associated with resistance to protease inhibitors. In addition, at some amino-acid positions up to almost half of the patients carried variations claimed to contribute to protease inhibitor resistance. Most of these mutations are likely to reflect the natural polymorphism of the protease. Their impact on the long-term effect of antiretroviral treatment should be evaluated in future studies.

Characterization of the viral population during primary HIV-1 infection.

Abstract: Objective To study viral heterogeneity at a very early phase of primary HIV-1 infection. Design Samples were drawn very early during primary HIV-1 infection. A virus population-based approach was used to study the viral heterogeneity in the C2-V3 and p17 regions. Methods Plasma samples (n = 33) were obtained before or shortly after onset of acute symptoms in 15 patients. In all subjects, the first sample was drawn within 10 days after onset of symptoms. Peripheral blood mononuclear cells (PBMC) were available in two patients. The number of polymorphic sites in the C2-V3 (15 patients) and p17 regions (eight patients) were determined by direct sequencing. Results The sequence heterogeneity was restricted in most patients, although only two out of 15 patients had a completely homogeneous C2-V3 sequence. However, pronounced individual differences were seen. Rapid sequence changes occurred during the first month in two patients. In one patient, the major DNA species at day 12 later became the major species in plasma. Conclusions The viral population is seldom completely homogeneous during primary HIV-1 infection, although the heterogeneity is restricted in most, but not all, patients. These individual differences do not seem to be due to sex or viral subtype. Rapid changes of the virus population may occur during primary HIV-1 infection. The DNA species detected in PBMC do not only represent earlier viral quasispecies but are also a potential source of future viral RNA species.

Cerebrospinal fluid mononuclear cell counts influence CSF HIV-1 RNA levels.

Abstract: This study evaluated the relation between cerebrospinal fluid (CSF) mononuclear cells (MNC) and CSF HIV-1 RNA levels. HIV-1 RNA levels in plasma and CSF were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) in 58 consecutive patients with neurologic symptoms and late HIV-1 infection. The majority of the patients had no central nervous system (CNS) complication (n = 36), 11 had AIDS dementia complex (ADC) and 11 had CNS opportunistic infection (CNS OI). CSF cell counts were analyzed using a method that also evaluated hypocellular CSF (i.e., from 0.1 x 10(6) cells/L). A strong correlation was found between CSF MNC and CD4+ lymphocyte counts in blood (r = 0.58; p < .0001). HIV-1 RNA was detected in all plasma samples and in 38 of 58 (66%) of the cell-free CSF samples. CSF HIV-1 RNA was less frequently detected in patients with hypocellular CSF than in patients with normocellular or pleocytic CSF (13 of 28 patients [46%] versus 10 of 14 patients [71%] versus 15 of 16 patients [94%], respectively). The levels of CSF HIV-1 RNA correlated with the CSF MNC count (r = 0.61; p < .0001). The correlation also remained strong within the clinical subgroups of CNS asymptomatic patients (r = 0.55; p < .001) and ADC patients (r = 0.79; p < .001), but not among CNS OI patients (r = 0.19). Patients with CNS OI were found to have higher CSF HIV-1 RNA levels than the patients without evidence of CNS complication. Thus, a close relation was found between CSF HIV-1 RNA levels and CSF MNC counts. These data support the hypothesis that a substantial part of the virus in the CSF of HIV-1-infected patients is locally produced by CSF MNC.

Cooperative Oligonucleotides Mediating Direct Capture of Hepatitis C Virus RNA from Serum

Abstract: A novel method for direct capture of hepatitis C virus (HCV) RNA from clinical samples has been developed. This approach takes advantage of the cooperative interactions between adjacently hybridized oligonucleotides. Here, this cooperative effect was combined with solid-phase technology, whereby a capture probe was covalently coupled to magnetic beads and a second probe, which anneals adjacent to the capture probe site, was prehybridized in solution to the target. When these contiguously hybridized probes were used for the extraction of HCV RNA from clinical samples, the capture efficiency was increased up to 25-fold in comparison to capture with a single probe. The applicability of this sample preparation assay was further investigated by performing a comparative study with both a conventional guanidinium extraction method and a commercial quantitative assay.

Comparison of 3 Quantitative HCV RNA Assays - Accuracy of Baseline Viral Load to Predict Treatment Outcome in Chronic Hepatitis C

Abstract: The correlation between 3 assays for hepatitis C virus (HCV) RNA quantification and their respective accuracy in predicting the response to interferon and interferon/ribavirin therapy was evaluated by analysing pre-treatment sera from 100 patients. A total of 97%, 100%, and 98% of the patients tested positive by the branched DNA 2.0 assay (Quantiplex), a multi-cycle reversed transcriptase polymerase chain reaction quantitative assay (Superquant) and the Roche Amplicor Monitor assay, respectively. The correlations between the assays, in all patients and in the major genotypes 1, 2, and 3, were significant, although the levels detected by the Amplicor Monitor assay were more than 1 log lower than by the other assays. Sustained virological responders to interferon therapy, but not to combination therapy, had lower baseline viral levels than long-term non-responders (p = 0.002 by Quantiplex 2.0; p = 0.008 by Superquant; p = 0.06 by Roche Amplicor Monitor). Pre-treatment viral load greater than 3 x 10(6) Eq or copies/ml by the Quantiplex 2.0 and Superquant assays and greater than 100,000 copies/ml by the Amplicor Monitor assay predicted long-term non-response in 94%, 93% and 91% of the interferon treated patients, respectively. In conclusion, acceptable correlations between available commercial quantitative assays were found. High baseline viral load predicted long-term non-response to interferon monotherapy, whereas it did not to interferon/ribavirin combination therapy.

Variation in the hepatitis C virus NS5a region in relation to hypervariable region 1 heterogeneity during interferon treatment.

Abstract: The putative interferon sensitivity determining region (ISDR) in the NS5a region of the hepatitis C virus (HCV) was analyzed in 13 interferon alpha (IFN-α) treated patients representing genotypes 1a, 1b, and 2b. These patients had previously been followed longitudinally during treatment with respect to viral load and to virus heterogeneity using the hypervariable region 1 (HVR1) sequence as a marker. In the present study, the NS5a region was analyzed for nonresponders and sustained responders using direct DNA sequencing. While the previous results of analyzing viral composition and load showed evidence of selection, no corresponding selection of specific NS5a ISDR sequences was observed in the nonresponders, and identical ISDR sequences were observed among both sustained responders and nonresponders. Thus, we cannot verify a correlation between ISDR sequence and the observed selection of IFN-α-resistant quasispecies demonstrated as a restriction of HVR1 heterogeneity. This indicates that the potential for using ISDR as a diagnostic or prognostic marker during IFN-α treatment is limited. J. Med. Virol. 56:33–38, 1998. © 1998 Wiley-Liss, Inc.

Nonsynonymous mutations within the human immunodeficiency virus type 1 p17 gene are clustered to sequences binding to the host human leukocyte antigen class I molecules.

Abstract: We have analyzed the relation between intrapatient variabilities of the p17 gene and the location of known host p17 cytotoxic T lymphocyte (CTL) epitopes in five patients infected with human immunodeficiency virus type 1 (HIV-1). All patients were typed with respect to the human leukocyte antigen (HLA) class I type. One to seven previously fine-mapped p17 CTL epitopes corresponded to the HLA class I restriction elements of each patient. An average of 28+/-16% of the p17 gene of each patient encoded CTL epitopes corresponding to the HLA restriction elements of the host. Twenty full-length p17 gene clones were sequenced from each patient. The intrapatient homology between the p17 sequences ranged from 96.4 to 98.9%. The interpatient homology between the consensus sequences of each patient ranged from 83.1 to 91.6%. A total of 246 nucleotide differences within the 100 p17 clones was noted. Fifteen (16%) of 96 synonymous substitutions were found within host CTL epitopes, whereas 72 (48%) of 150 nonsynonymous nucleotide changes were found within CTL epitopes corresponding to the HLA restriction elements of the host (p 20% of the clones) were determined to be more common at positions contained within these CTL epitopes (p < 0.01). The present data suggest that the evolution of the p17 gene is influenced by contact areas with the host HLA class I molecules.

HIV-1 nef mutations and clinical long-term nonprogression. A molecular epidemiology study.

Abstract: OBJECTIVES To analyze HIV-1 nef gene mutations in a cohort of Italian and Swedish long-term nonprogressors (LTNP) and to investigate whether particular amino acid substitutions are associated with LTNP. STUDY DESIGN/METHODS nef alleles from 21 LTNP and 8 progressor controls were amplified by polymerase chain reaction (PCR) and sequenced. The amino acid sequences were compared with the previously reported sequences of 16 North American LTNP and of 28 patients with progressive infection. RESULTS An untruncated intact open reading frame was observed as major sequence in all LTNP and controls. None of the amino acid substitutions in known biologically functional sites was linked to LTNP. A valine/isoleucine at the variable position 11 was associated with both European (P = .0001) and American (P = .001) LTNP. The interpatient nef variation was lower among European LTNP (P = .002) than in European progressor controls. CONCLUSIONS Nef amino acid heterogeneity is lower among LTNP, probably reflecting the lower HIV-1 replication rate. Nef gene defects appear uncommon in both Swedish and Italian LTNP, although the presence of a valine/isoleucine at position 11 is statistically associated with a lower probability to progress to disease.

Pronounced anti-HIV-1 activity of foscarnet in patients without cytomegalovirus infection.

Abstract: Combined therapy using reverse transcriptase (RT) and protease inhibitors is the current established treatment for HIV-1 infection. Foscarnet is an RT inhibitor that is a product analogue, in contrast to the widely used nucleoside analogues. In this study, the anti-HIV-1 effect of foscarnet, 50 mg three times per day administered intravenously for 4 weeks, was evaluated in 10 patients with minor or no symptoms. Serious adverse events developed in 2 patients, although most patients experienced some side effects. The levels of HIV-1 RNA decreased from a median value of 4.7 to 2.6 10log copies/ml. The effect was sustained through 4 weeks. One week after cessation of treatment, HIV-1 RNA levels increased to baseline. In contrast, no increase in the number of CD4+ cells was observed. The anti-HIV-1 effect was considered to be a direct effect on HIV-1 replication because no patient had concomitant cytomegalovirus (CMV) infection.

Detection of hepatitis G virus RNA in persons with and without known risk factors for blood-borne viral infections in Sweden and Honduras

Abstract: We analyzed 224 and 163 serum samples from individuals in Sweden and Honduras, respectively, for the presence of the hepatitis G virus (HGV or GB virus-C) RNA. HGV infection in both Sweden and Honduras was related to common risk factors for blood-borne infections, despite a surprisingly high frequency in groups without known risk factors.

Genetic Evidence for Mother-to-Infant Transmission of Hepatitis G Virus

Abstract: Mother-to-infant transmission of hepatitis G virus (HGV [or GBV-C]) was studied in sera from 42 mothers at high risk for bloodborne infections and from their 45 infants (3 twin pairs). Seven (17%) of the mothers had HGV RNA in serum by a polymerase chain reaction assay. One of the 8 (12.5%) infants born to HGV-infected mothers became positive for HGV at 3 months of age. He remained HGV-infected throughout the study (42 months), with no signs of liver disease. His twin sister remained HGV-negative despite the presence of serum and salivary HGV in both the mother and the brother. Analysis of HGV sequences from the infected mother and the infected child confirmed a genetic link between the virus of the mother and the infected child. Thus, mother-to-infant transmission of HGV, presumably occurring at partus, may cause persistent HGV viremia.

Coexisting members of HIV-1 p17 gene quasispecies represent proteins with distinct antigenicity and immunogenicity.

Abstract: Background: Despite the comparatively conserved nature of the HIV-1 gag gene, countless quasispecies of the p17 gene coexist in HIV-1-infected patients It is not known if the minor genetic differences in quasispecies will affect immune recognition Objective: To characterize the antigenicity and immunogenicity of three different members of HIV-1 p17 quasispecies Methods: Three members of HIV-1 p17 gene quasispecies, one from patient A (clone 9; qsA9) and two from patient E (clones 5 and 8; qsE5 and qsE8), were expressed and purified from Escherichia coli The antigenicity of the p17 proteins was analysed using sera from HIV-1 -infected individuals, and the immunogenicity was evaluated using sera and lymphocytes from primed mice of three different haplotypes Results: The antigenicity of the qsE5 and qsE8 p17 recombinant proteins were distinct when tested for reactivity with human p17 antibodies The qsE5 and qsE8 p17 were equally immunogenic in H-2 d mice, but not in H-2 b and H-2 k mice In H-2 b mice the qsE8 protein induced higher levels of anti-p17 IgG2a, IgG2b and IgG3 than the qsE5 protein Corroborating the IgG subclass pattern, H-2 b -restricted qsE5-specific T cells produced higher in vitro levels of interferon-y, but not of interleukin (IL)-4, IL-5 and IL-6, than qsE8-specific T cells, suggesting a more pronounced T-helper (TH)1-like response Conclusions: The p17 gene quasispecies coexisting in the same patient at the same time may represent antigenically and immunogenically distinct proteins despite sequence homologies of above 90% Subsequently, subtle differences between two p17 protein quasispecies are enough to prime different TH1/TH2 subsets These findings will have implications for therapeutic HIV-1 immunizations

Detection of hepatitis G virus/GB virus C after allogeneic bone marrow transplantation

Abstract: Abnormal liver function before allogeneic BMT has been associated with VOD. Hepatitis G virus/GB virus C (HGV) is a recently discovered virus suggested to be a cause of non-A, non-B, non-C, non-D and non-E hepatitis. The aim of this retrospective study was to analyze the risk for liver complications and time to engraftment in patients infected with HGV. Fifty patients transplanted in 1995 were examined with RT-PCR for HGV on samples collected before, and between 3 and 6 months after BMT. Seven patients had HGV detected before BMT. No patient became infected during or early after the BMT. There were no differences in either pre- or post-transplant liver function abnormalities, VOD, or time to neutrophil engraftment in patients who did or did not have HGV detected before BMT. We conclude that the importance of HGV infection for the development of post-transplant complications is limited.

Low Relative Frequencies of CD26+ CD4+ Cells in Long-Term Nonprogressing Human Immunodeficiency Virus Type 1-Infected Subjects

Abstract: A broad antibody panel was used for immunophenotyping of human immunodeficiency virus type 1 (HIV-1)-infected patients who were long-term nonprogressors (LTNP). The LTNP were compared with patients in the early phase of infection and patients who had progressed to advanced immunodeficiency. Changes in CD8+ subset distribution were observed mainly at acquisition of HIV-1 infection, whereas CD4+ subset changes appeared during progression of HIV-1 infection. The decreasing levels of CD4+ cells were characterized by an increasing frequency of cells expressing the activation markers HLA-Dr and CD45RO but not the CD28 surface antigen. The LTNP exhibited significant changes compared to HIV-negative patients in almost all markers. Compared to patients in the early phase of infection, the only difference was a relatively lower frequency of CD4+ cells expressing CD26 among the LTNP. The results show that HIV-1-infected persons who have no signs of immunodeficiency despite many years of infection have an immunophenotypic pattern that is substantially different from that of noninfected persons. Despite the long duration of infection, the LTNP exhibit a pattern similar to that of newly infected persons, with the exception of lower expression of CD26 on CD4+ cells.