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Biomedical subjects

A Sönnerborg

Publications and source records attributed to A Sönnerborg.

At least 37 records · Page 2Linked to original sources
PubMed2000

Proviral HIV-1 dynamics and evolution in patients receiving efficient long-term antiretroviral combination therapy.

OBJECTIVES: Different experimental approaches have shown that, despite plasma viral loads under the threshold of detection, HIV-1 frequently continues to replicate in patients receiving potent antiretroviral therapy. However, whether this low-grade viral replication is sufficient for the generation of new major quasispecies has not been studied. Thus, in order to evaluate the extent of variation in the major proviral HIV-1 population, we monitored proviral DNA sequences in such patients over a time period of up to 30 months. METHODS: DNA was extracted from peripheral blood mononuclear cells (PBMC) and the V3 region was amplified by nested polymerase chain reaction (PCR) and directly sequenced. Additionally, both HIV-1 RNA and DNA levels and CD4+ T-lymphocyte counts were monitored. RESULTS: Analysing the V3 gene sequences of 17 patients, we observed a sequence evolution in nine patients. Interestingly, the majority of these changes (77%) occurred in the first interval following the initiation of therapy and despite signs of ongoing replication the proviral DNA levels continued to decrease in all patients. CONCLUSIONS: Our data suggest that, although available data report that HIV-1 continues to replicate in patients with undetectable viraemia, the extent of viral replication in many of these patients is not sufficient to result in changes in the major viral population.

Adult↗
PubMed2000

Rapid and simple determination of indinavir in serum, urine, and cerebrospinal fluid using high-performance liquid chromatography.

A method for analysis of indinavir in serum, cerebrospinal fluid, and urine was developed. The method is based on liquid-liquid extraction followed by high performance liquid chromatography with UV detection. The method has a shorter analysis time than previously published methods, and it is sensitive enough to measure levels in all three fluids under routine clinical conditions. The method is linear up to 32 micromol/L, the limit of detection is 0.01 micromol/L, and recovery of the method is 86%. The interassay coefficient of variation at 2.0 micromol/L was 2.8%, and no internal standard is needed. Over 700 clinical samples have been analyzed by this method, and concomitant antiviral drugs do not interfere with the assay. Paroxetin and dipyridamol are the only two compounds encountered to elute with retention times similar to that of indinavir. Examples of chromatograms and a pharmacokinetic curve are given. The method is well suited for routine therapeutic drug monitoring as well as for pharmacokinetic studies for research purposes.

Anti-HIV Agents↗
PubMed2000

Variability and immunogenicity of human immunodeficiency virus type 1 p24 gene quasispecies.

Despite the conserved nature of the human immunodeficiency virus type 1 (HIV-1) gag gene, multiple quasispecies of the p24 gene coexist in HIV-1-infected patients. We cloned and sequenced 31 p24 genes from four HIV-1-infected patients. The intrapatient homology between the p24 genes ranged from 97.1 to 99.1%, whereas the interpatient homology ranged from 91.5 to 93.8%, suggesting a host-specific evolution. Synonymous and nonsynonymous nucleotide changes were evenly distributed in the p24 gene, with 27 and 28%, respectively, located within host human leukocyte antigen class I recognition sites. This would suggest only a minor influence from the host cytotoxic T-cell response on the evolution of the p24 gene. The importance of minor variations within p24 was analyzed by designing DNA-based immunogens from two distinct p24 quasispecies genes simultaneously derived from one patient. In plasmid-immunized H-2(b), H-2(d), and H-2(k) haplotype mice, a clear influence from the host major histocompatibility complex was noted on the immune responses, fully consistent with those noted when a recombinant p24 protein is used as the immunogen. The two p24 DNA immunogens did not differ in their immunogenicity, indicating that the limited genetic variability (<1%) had little influence on the immune responses.

Acquired Immunodeficiency Syndrome↗
PubMed1999

HIV-1 exposed dendritic cells show increased pro-inflammatory cytokine production but reduced IL-1ra following lipopolysaccharide stimulation.

OBJECTIVES: Dendritic cells (DC) are potential first target cells in sexually transmitted HIV-1 infection. They are also considered to be central in the activation of naive T cells, which thereupon can become permissive for HIV-1. In addition, activated DC express effector molecules, which likely contribute to the direction of T helper (Th1/Th2)-specific immune responses. METHODS: The capacity of cytokine and chemokine production in in vitro DC infected and uninfected with HIV-1 was assessed by enzyme-linked immunosorbent assay (ELISA) and by in situ immunocytochemical detection at the single cell level. Fluorescent in situ 5'-nuclease assay (FISNA) was used for quantitative evaluation of HIV-1 gag-positive cells. RESULTS: Macrophage-tropic HIV-1 effectively infected 20-40% of in vitro cultured DC. However, this activity alone did not induce detectable cytokine or chemokine protein expression in DC. In contrast, lipopolysaccharide (LPS) stimulation of these HIV-1-infected DC resulted in a significantly increased level of cells producing tumour necrosis factor alpha (TNF-alpha) and interleukin (IL) 1beta but reduced frequencies of cells producing IL-1 receptor antagonist (IL-1ra) compared with the LPS-stimulated but uninfected DC cultures (P < 0.05). Furthermore, an extensive production of the beta-chemokines [RANTES, macrophage inflammatory proteins (MIP) 1alpha and 1beta] was detected in DC in response to both LPS and HIV-1 plus LPS. CONCLUSIONS: These findings indicate that HIV-1 infected DC may have an increased proinflammatory activity. Elevated production of cytokines such as TNF-alpha and IL-1beta and reduced IL-1ra may contribute to enhanced replication of HIV-1 in bystander T cells. Gram-negative bacterial infection and gut-associated bacterial translocation in HIV-1-infected individuals may also result in endotoxin-mediated reactivation of HIV-1 in bystander CD4 CD45RO T cells caused by the increased production of proinflammatory cytokines in DC.

Cells, Cultured↗
PubMed1999

HIV viral load and response to antileishmanial chemotherapy in co-infected patients.

OBJECTIVE: To investigate whether clearance of Leishmania parasites from tissue aspirate smears in patients with HIV and visceral leishmaniasis (VL) co-infection treated with pentavalent antimonials is influenced by initial HIV viral load and to assess the effect of active VL on HIV viral load and replication in vivo. METHODS: Leishmania parasites were identified in Giemsa-stained smears prepared from tissue aspirates. Parasite index was determined by quantifying Leishmania donovani bodies in smears. HIV-1 RNA was quantitated by using the nucleic acid sequence-based amplification technique with a limit of detection of 500 copies/ml. All patients were treated with pentavalent antimonials at 20 mg pentavalent antimony (Sb(V))/kg daily for a total of 28 days. None of the patients received specific anti-retroviral therapy. RESULTS: Seventeen patients (73.9%) showed good initial response to anti-leishmanial treatment and the remaining six (26.1%) had very poor response. Among the good responders, 11 (64.7%) had no demonstrable Leishmania donovani bodies in post-therapy tissue aspirate smear preparations, and in the remaining six (35.3%) their parasite loads were reduced to very low levels. Patients with poor response had persistently high parasite index despite completion of anti-leishmanial chemotherapy. Poor responders had pre-treatment median HIV viral load that was >160-fold higher than responders to anti-leishmanial chemotherapy; [410000 copies/ml (quartile range, 33000-530000) and 2500 copies/ml (quartile range 500-297500), respectively]. Furthermore, compared with pre-treatment viral concentrations, patients with good response showed marked reduction in post-treatment viral load. In contrast, post-treatment HIV viral concentrations were markedly increased among patients with poor response to anti-leishmanial therapy. CONCLUSIONS: The results suggest that pre-treatment HIV viral load influences response to anti-leishmanial chemotherapy and active VL is associated with increased viral replication in vivo, supporting the notion that dual infection plays an important role in the pathogenesis and disease progression of either infection.

AIDS-Related Opportunistic Infections↗
PubMed1999

Long-term effects of antiretroviral combination therapy on HIV type 1 DNA levels.

HIV-1 RNA and DNA levels were measured in 58 patients, of whom 37 and 11, respectively, received triple or double combination therapy. At baseline, strong correlations were found between the number of HIV-1 DNA copies per 106 CD4+ cells, the plasma HIV-1 RNA levels, and the isolation rate of HIV-1 from blood cells. In comparison with HIV-1 RNA, a much slower decline in HIV-1 DNA levels was seen, which probably represents a long lifetime of provirus-bearing CD4+ cells. In 10 untreated patients, the proviral load was stable. In patients receiving triple therapy, a significant decline in HIV-1 DNA was seen independent of whether the proviral load was expressed as copies per 106 CD4+ cells or as copies per milliliter of blood. In contrast, a decline was seen only when the proviral load was expressed as copies per 10(6) CD4+ cells in patients given two drugs. The difference between the two patient categories is likely to be due to a more frequent infection of CD4+ cells during therapy in the patients with double therapy. Interpretation of changes in HIV-1 DNA levels is thus dependent on how the proviral burden is expressed. Further studies should evaluate whether changes in HIV-1 DNA load can be used as markers of viral replication during efficient antiretroviral combination therapy.

Adult↗
PubMed1999

Long terminal repeat promoter/enhancer activity of different subtypes of HIV type 1.

Transcription of the HIV-1 provirus genome is regulated by a complex interplay between viral regulatory proteins and cellular transcription factors that interact with the viral long terminal repeat (LTR) region of HIV-1. However, several cellular transcription factors have been identified that can interact with the HIV-1 LTR; the significance of all of these factors is not clearly understood. In this study we have characterized the LTR region of different subtypes of HIV-1 with regard to nucleotide sequence and promoter activity. The LTR regions of HIV-1 from peripheral blood mononuclear cells of 29 infected individuals originating from 10 different geographical regions were sequenced and further analyzed for promoter/enhancer activity in transient transfection of HeLa cells, in the context of a reporter gene and in the context of the complete virus genome. We found several subtype-specific LTR sequences of the various HIV-1 strains, such as an insertion that created a potential third NF-kappaB site in the LTR of the subtype C strains. The USF-binding site in the NRE also contained subtype-specific sequences. Interestingly, the promoter/enhancer activities of the subtype C LTRs were higher than the activities of the other subtypes analyzed here (subtypes A, B, D, E, and G), suggesting that the potential third NF-kappaB site may confer higher LTR activity or that the subtype C NRE may be less potent. Thus, our data suggest that genetic diversity of the LTR may result in HIV-1 subtypes with different replicative properties.

Adult↗
PubMed1999

Perforin is not co-expressed with granzyme A within cytotoxic granules in CD8 T lymphocytes present in lymphoid tissue during chronic HIV infection.

BACKGROUND: Residual HIV-1-infected cells are poorly eliminated from lymphoid tissue (LT) reservoirs by effector cytotoxic T lymphocytes (eCTL) despite antiretroviral therapy. Perforin and granzyme A (grA) constitute major effector molecules within eCTL granules that induce apoptosis and lysis of virally infected cells. OBJECTIVE: Expression of perforin and grA was studied at the single cell level in LT and blood from 16 patients infected with HIV-1 (stage A1-C) who were not taking antiretroviral therapy. METHOD: Immunohistochemical analysis by in situ imaging of cells from blood and LT. RESULTS: Quantitative in situ imaging showed that perforin-expressing CD8 T cells comprised 0.3-1.5% of total cells within the LT from recent HIV-1 seroconverters, while grA was found in 2.1-7.2% of total cells. However, despite high-level grA upregulation (1.5-4.5% of total cells) compared with that in non-infected individuals (0.4-0.9%), perforin expression remained low (< 0.1% of total cells) (P < 0.02) in LT from patients with chronic HIV-1 infection (stage A2-C). This contrasted with findings in peripheral blood mononuclear cells (PBMC) from the same HIV-1 infected cohort where perforin was detected in 13-31% of all PBMC, which was 10- to 100-fold higher than in lymphoid tissue (P < 0.001); grA was found in 14-32% of total PBMC. Two-colour staining showed that granular expression of perforin and grA was restricted to CD8 T cells in over 90% of total cells in both LT and blood. CONCLUSIONS: These findings indicate that cytotoxic perforin expression is impaired at local sites of HIV replication within lymphoid tissue. Since perforin is required together with grA for granule-mediated cytolysis, the low perforin expression in the LT may limit the ability of eCTL to eliminate HIV-1 infected cells in lymphoid tissue.

CD4 Lymphocyte Count↗
PubMed1999

Indinavir-based treatment of HIV-1 infected patients: efficacy in the central nervous system.

OBJECTIVE: To study the pharmacokinetic properties and clinical efficacy of the HIV-1 protease inhibitor (PI) indinavir in the central nervous system (CNS). DESIGN: Twenty-five consecutive HIV-1 infected patients on combination therapy that included indinavir, had cerebrospinal fluid (CSF) and plasma samples taken on 32 different occasions, at different times after indinavir administration. CSF and viral load data obtained from these treated patients were compared with those from 36 untreated HIV-1 infected patients of similar immunological and demographic pre-treatment status. METHODS: Concentrations of indinavir were measured in CSF and plasma by high-pressure liquid chromatography with ultraviolet light detection and the data were used in pharmacokinetic modelling. RESULTS: The concentration of indinavir in plasma varied with time over a dose interval by about two orders of magnitude, whereas the concentration in CSF was relatively stable. The median concentration of indinavir in CSF was 210 nmol/l, which is above the 95% inhibitory concentration in vitro. Findings from the pharmacokinetic modelling indicate that indinavir is actively transported out of the CSF (P <0.001 compared with a passive transport-only model). In the PI-treated group there was a reduction in viral load to below 50 copies/ml in most subjects and a normalization of the CSF cell content and IgG-index. CONCLUSIONS: This study has shown that one PI, indinavir, is present in the CSF at therapeutic concentrations, and is likely to contribute to the antiretroviral activities observed within the CNS.

Adult↗
PubMed1999

No association of HIV type 1 long terminal repeat sequence pattern with long-term nonprogression and in vivo viral replication levels in European subjects.

The HIV-1 long terminal repeat (LTR) promotes and modulates proviral transcription in the infected cell. It has been suggested that truncations and even point mutations in functional sites of the LTR are associated with low viral replication and attenuated pathogenesis in HIV-1-infected long-term nonprogressors (LTNPs). We performed a detailed analysis of LTR sequences from proviral DNA of 21 Italian and Swedish, well-characterized LTNPs and of 15 progressor patients. No truncation was found and no correlation was identified between specific LTR mutations and disease progression. We also failed to find a significant correlation between phylogenetic distance and clinical status. Although HIV-1 LTR interpatient heterogeneity among LTNPs and subjects with HIV-1 RNA levels <500 copies/ml tended to be lower, no sequence mutation was correlated with in vivo viral loads. Our results suggest that HIV-1 LTR defects are rare among Italian and Swedish LTNPs.

Adolescent↗
PubMed1999

Phenotypic characteristics of human immunodeficiency virus type 1 subtype C isolates of Ethiopian AIDS patients.

It has been estimated that, to date, about 48% of all HIV-infected people in the world carry HIV-1 subtype C virus. Therefore, it is of great importance to gain better knowledge about the genetic and biological characteristics of this virus subtype. In the present study, the biological properties of HIV-1 isolates obtained from nine Ethiopian patients with AIDS were studied. DNA sequencing of the V3 loop of gp120 classified the isolates as subtype C. In primary isolation cultures, virus infection was accompanied by syncytium formation and cell lysis. Interestingly, when examining the growth in primary monocyte-macrophage cultures, initial low-level virus replication was followed by a nonproductive state, from which virus could be rescued by cocultivation with Jurkat(tat) cells. Furthermore, none of the isolates replicated in T cell lines (CEM, MT-2, HuT-78, and H9) or in the promonocytic cell line U937 clone 2. All isolates could use CCR5 as coreceptor, whereas no isolates could use CCR2b, CCR3, CCR5, CXCR4, Bonzo/STRL33, or BOB/GPR15. The genotype of the V3 region correlated with the MT-2 negative/non-syncytium-inducing (NSI) phenotype. Comparative studies revealed that the scarcity of CXCR4 usage as well as other phenotypic characteristics of subtype C isolates distinguish this subtype. On the basis of these data, we suggest that in addition, factors other than viral phenotype may govern the pathogenic potential of subtype C isolates.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Limited humoral immunity in hepatitis C virus infection.

BACKGROUND & AIMS: The extremely high rate of chronicity to hepatitis C virus (HVC) infection suggests an inefficient immune response. The humoral immune response to HCV was evaluated in 60 patients with chronic HCV infection and in 12 patients acutely infected with HCV. METHODS: A number of recombinant HCV antigens including the core, envelope 2 (E2), nonstructural (NS) 3, NS4, and NS5 proteins, and NS4a and E2-HVR-1 peptides were used in enzyme-linked immunoassays. RESULTS: Immunoglobulin (Ig) G antibody responses to these viral antigens, except for the HCV core, were highly restricted to the IgG1 isotype. The prevalence of antibodies of the IgG1 isotype specific for the HCV core, E2, E2-HVR1, NS3 (helicase domain), NS4, and NS5 antigens was 97%, 98%, 28%, 88%, 33%, and 68%, respectively. Antibodies of the IgG3 isotype specific for E2, E2-HVR-1, NS3, NS4, and NS5 were detected in a minority of serum samples. The IgG2 and IgG4 isotypes were rarely if ever detected. Furthermore, antibody responses to HCV viral antigens were of relatively low titer and, with the exception of anti-HCV core, were delayed in appearance until the chronic phase of infection. CONCLUSIONS: The IgG1 restriction, low titer, and delayed appearance of antibody responses elicited during HCV infection suggest that the immunogenicity of HCV proteins is limited in the context of natural infection. Inasmuch as recombinant HCV viral antigens perform as relatively normal immunogens in small animals, we suggest that the defective humoral immune responses during HCV infection may be attributable to an "immune avoidance" strategy.

Acute Disease↗
PubMed1999

Pain in ambulatory HIV-infected patients with and without intravenous drug use.

The prevalence of pain in 211 HIV-infected patients with and without intravenous drug use was assessed and the prognostic information inherent in pain reporting was evaluated, using a questionnaire on pain and HIV-related symptoms combined with data on disease classification, route of HIV transmission, CD4+ lymphocyte counts in blood (CD4) and mortality rates at 15 months after completing the questionnaire. The pain prevalence was significantly higher among intravenous drug users (IDUs) compared with non-IDUs [76/89 (85%) vs 87/122 (71%);p<0.05], especially among the patients classified as asymptomatic [43/53 (81%) vs 35/59 (59%);p = 0.01]. No significant difference was found among AIDS patients. In non-IDUs, a strong correlation was found between HIV disease stages according to the Centers for Disease Control classification (CDC) and pain prevalence (CDC A: 59%vs B: 74%vs C: 96%, p<0.001), and between the number of concurrent pain sites and both the CD4 levels (no pains: CD4 0.26 x 10(9)/l vs 1-2 pain sites: CD4 0.22 vs>2 pain sites: CD4 0.09;r = 0.35, p<0.001), and the mortality rate [no pains: 2/35 (6%) vs 1-2 pain sites: 8/45 (18%) vs> 2 pain sites: 12/42 (29%), p<0.01]. In IDUs, no such correlations were found. Our data demonstrates differences in the development, prevalence and prognostic value of pain among HIV-infected patients, with and without intravenous drug use, clearly indicating the need to differentiate risk groups in pain related studies. Copyright 1999 European Federation of Chapters of the International Association for the Study of Pain.

Journal Article↗
PubMed1999

The anti-HBs response after 2 different accelerated intradermal and intramuscular schemes for hepatitis B vaccination.

To study early seroconversion rates after hepatitis B vaccination intramuscular (i.m.) and low-dose intradermal (i.d.) vaccination was compared when given either according to the registered 0, 4, 8 weeks scheme (scheme A), or to an accelerated 0, 2, 6 weeks scheme (scheme B). Medical staff received either 2 microg i.d. or 20 microg i.m. of a recombinant hepatitis B vaccine, in a non-randomized open trial. Two weeks after the third dose i.m. vaccinees overall had significantly higher rates of protective anti-HBs levels (anti-HBs > or = 10 IU/I), (23/30, 77%) compared with i.d. vaccinees (75/166, 45%) (p < 0.001). We conclude that when rapid protection against hepatitis B virus (HBV) infection is desirable, such as for post-exposure prophylaxis, an accelerated low-dose i.d. vaccination schedule cannot be used.

Administration, Cutaneous↗