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Biomedical subjects

Kees Brinkman

Publications and source records attributed to Kees Brinkman.

At least 19 recordsLinked to original sources
PubMed2026

HIV immunological nonresponders show low SKAP1 concentration and DNA hypermethylation in the SKAP1 promotor region.

OBJECTIVE: The aim of this study was to improve understanding of biological pathways underlying inadequate CD4 + T-cell restoration after initiating antiretroviral treatment as these so called Immunological nonresponders are at increased risk for morbidity and mortality while treatment options are lacking. DESIGN: We compared baseline multiomics data from 88 Immunological nonresponders and 1467 immunological responders that participated in the 2000HIV study, separated into a discovery and validation cohort. METHODS: We measured expression levels of 2367 plasma proteins, comparing the immunological responders and nonresponders. As this highlighted low Src kinase-associated phosphoprotein 1 (SKAP1) levels in Immunological nonresponders, we measured intracellular SKAP1 levels in CD4 + T-cells, investigated DNA methylation and assessed single-nucleotide polymorphisms (SNPs). We also explored whether HIV or CMV infection may influence SKAP1 expression. RESULTS: SKAP1 plasma levels were significantly lower in Immunological nonresponders in both cohorts. SKAP1 plasma concentrations reflected intracellular levels in CD4 + T-cells. DNA methylation analysis showed significant hypermethylation at the SKAP1 promotor region. Three SNPs close to the SKAP1 gene were associated with poor Immunological response. Preliminary data suggest that HIV or CMV may influence SKAP1 levels. CONCLUSION: Our data show decreased SKAP1 concentrations in immunological nonresponders, potentially driven by hypermethylation of the SKAP1 promoter. Downregulation of SKAP1, which is known to play a role in T cell proliferation and migration, may therefore contribute to the poor restoration of CD4 + cell count after ART.

Humans↗
PubMed2007

Effects of active treatment discontinuation in patients with a CD4+ T-cell nadir greater than 350 cells/mm3: 48-week Treatment Interruption in Early Starters Netherlands Study (TRIESTAN).

OBJECTIVE: To evaluate the safety and efficacy of discontinuing highly active antiretroviral therapy (HAART) in HIV-1-positive patients who initiated HAART at a CD4+ T-cell count >350 cells/mm. METHODS: Eligible patients were identified from the Dutch AIDS Therapy Evaluation, The Netherlands (ATHENA) national observational cohort. Interruption or continuation of HAART was offered to all. RESULTS: Of 71 patients enrolled, 46 (64%) interrupted HAART (STOP group) and 25 (36%) continued HAART (control group). The median CD4+ T-cell nadirs at the start of HAART were 469 (interquartile range [IQR]: 430-720) cells/mm3 and 510 (IQR: 440-637) cells/mm3, respectively. At week 48, the median plasma HIV RNA level in the STOP group had stabilized at approximately pre-HAART values (4.55 log10, IQR: 4.2-4.9 copies/mL), but the CD4+ T-cell count still exceeded the pre-HAART count (563 cells/mm3, IQR: 450-710 cells/mm3). Only 5 patients (11%) had reinitiated HAART after 48 weeks, all for personal reasons. No Centers for Disease Control and Prevention category events or death occurred after interruption. In 6 (13%) of 46 patients, mild symptoms of acute retroviral rebound syndrome (ARVS) were identified. No improvement was observed in mental or physical health scores. In 37% of patients, nonnucleoside reverse transcriptase inhibitor drug concentrations were still detectable 1 week after stopping. CONCLUSIONS: Although HAART can safely be interrupted in patients with a high CD4 T-cell nadir, no improvement in quality of life was established. Patients can experience ARVS, the risk for development of resistance after treatment interruption is realistic, and there is a potential hazard of HIV transmission to sexual partners. We would not actively advise stopping treatment in patients who started treatment too early according to current guidelines.

Adult↗
PubMed2007

Trends in HIV postexposure prophylaxis prescription and compliance after sexual exposure in Amsterdam, 2000-2004.

OBJECTIVE: The objective of this study was to evaluate trends in HIV postexposure prophylaxis (PEP) requests after sexual exposure, compliance, and outcome of follow-up HIV tests. STUDY DESIGN: The authors conducted a retrospective analysis of all HIV PEP requests after sexual exposure between January 1, 2000, and December 31, 2004, in Amsterdam. RESULTS: In 5 years, there was a very modest increase in PEP requests, of which most (75%) came from men who have sex with men (MSM). Although 70% reported side effects, 85% completed their PEP course. Sexual assault victims less often completed their course (odds ratio [OR] = 0.1; 95% confidence interval [CI] = 0.05-0.4, P = 0.001). People who used HIV PEP more often complied with follow-up tests than people who did not use PEP (OR = 3.5; 95% CI = 1.6-7.9, P = 0.002). One HIV seroconversion was found caused by a later exposure than that for which PEP was given. CONCLUSIONS: Despite a widely available PEP program in Amsterdam, the number of PEP requests remained low. Most people completed their PEP course; compliance with follow-up HIV testing was high.

Adolescent↗
PubMed2006

Highly active antiretroviral therapy (HAART) among HIV-infected drug users: a prospective cohort study of sexual risk and injecting behaviour.

AIMS: To study sexual risk and injecting behaviour among HIV-infected drug users (DU) receiving highly active antiretroviral therapy (HAART). DESIGN AND SETTING: As part of an ongoing prospective cohort study, HIV-infected DU who commenced HAART (n=67) were matched with those not starting HAART (n=130) on CD4 cell counts, duration of cohort participation, age and calendar year of visit. Immunological and virological responses of the HAART-treated DU were compared with the HAART-treated homosexual men from the same cohort (n=212). MEASUREMENTS: Trends in behaviour and therapeutic response were tested with a logistic regression model adjusted for repeated measurements and a piecewise random effects model, respectively. FINDINGS: Non-HAART users reported more episodes of injecting than HAART users. In both groups injecting declined over time with no effect of HAART initiation. Before HAART initiation an increase in sexual risk behaviour was observed among those who had been assigned to receive HAART; their sexual risk behaviour declined thereafter. No change in sexual risk behaviour was found among non-HAART users. Relative to homosexual men, DU had a similar initial therapeutic response, but DU started HAART at lower CD4 cell counts and higher viral load levels. Conclusion DU who are treated with HAART are not increasing their risk behaviour, and their early response to HAART is similar to homosexual men. However, before the treated DU received HAART they were seen to inject less often than those not treated with HAART. This suggests that selection of potential HAART starters is based on limited drug use. Although the DU who commence HAART are a selected group, our results show that HIV-infected DU can be treated effectively.

Adult↗
PubMed2005

Natural controlled HIV infection: preserved HIV-specific immunity despite undetectable replication competent virus.

Long-term non-progressive HIV infection, characterized by low but detectable viral load and stable CD4 counts in the absence of antiviral therapy, is observed in about 5% of HIV-infected patients. Here we identified four therapy naïve individuals who are strongly seropositive for HIV-1 but who lack evidence of detectable HIV p24 antigen, plasma RNA, and proviral DNA in routine diagnostic testing. With an ultrasensitive PCR, we established that frequencies of pol proviral DNA sequences were as low as 0.2-0.5 copies/10(6) PBMC. HIV could not be isolated using up to 30x10(6) patient PBMC. One individual was heterozygous for CCR5 Delta32, but CCR5 expression on CD4+ T cells was normal to high in all four individuals. In vitro R5 and X4 HIV-1 susceptibility of CD8-depleted PBMC of all study subjects was significantly lower than the susceptibility of CD8-depleted PBMC of healthy blood donors. All individuals expressed protective HLA-B*58s alleles and showed evidence of HIV-specific cellular immunity either by staining with HLA-B*57 tetramers folded with an HIV RT or gag peptide or after stimulation with HIV-1 p24 gag, RT, or nef peptides in ELIspot analysis. HIV-specific CD4+ T helper cells were demonstrated by proliferation of CD4+ T cells and intracellular staining for IL-2 and IFNgamma after stimulation with an HIV-gag peptide pool. Sera of all individuals showed antibody-mediated neutralization of both R5 and X4 HIV-1 variants. These data implicate that very low-level antigen exposure is sufficient for sustained HIV-specific immunity and suggest the possibility of a multi-factorial control of HIV infection.

Adult↗
PubMed2005

Prophylaxis and follow-up after possible exposure to HIV, hepatitis B virus, and hepatitis C virus outside hospital: evaluation of policy 2000-3.

PROBLEM: Prophylactic treatment and follow-up after exposure to HIV, hepatitis B, and hepatitis C outside hospital needs to be improved. BACKGROUND AND SETTING: Until January 2000, people in Amsterdam could report exposure outside hospital to either a hospital or the municipal health service. If they reported to the municipal health service, they were then referred to hospitals for HIV prophylaxis, whereas the municipal health service handled treatment and follow-up related to hepatitis B and hepatitis C and traced sources. For cases reported to a hospital, hospital staff often did not trace HIV sources or follow up patients for hepatitis B and hepatitis C. KEY MEASURES FOR IMPROVEMENT: Providing adequate treatment for HIV, hepatitis B and hepatitis C after exposure for all reported exposures outside hospital. STRATEGIES FOR CHANGE: On 1 January 2000, a new protocol was introduced in which three Amsterdam hospitals and the municipal health service collaborated in the treatment and follow-up of exposures outside hospital. Both municipal health service and hospitals can decide whether HIV prophylaxis is necessary and prescribe accordingly. All people exposed in the community who report to hospitals are subsequently referred to the municipal health service for further treatment and follow-up. EFFECTS OF CHANGE: The protocol is effective in that most people comply with treatment and follow-up. When indicated, HIV prophylaxis is started soon after exposure. In nearly two thirds of cases the municipal health service traced and tested the source. LESSONS LEARNT: Provision of treatment and follow-up in one place enables treatment, tracing and testing sources, and follow-up, including counselling and registration of all reported exposures in Amsterdam, which allows for swift identification of emerging epidemiological trends. Since May 2004 all Amsterdam hospitals have participated in the protocol.

Anti-HIV Agents↗
PubMed2005

Safety of long-term interruption of successful antiretroviral therapy: the ATHENA cohort study.

We studied the dynamics of CD4 cell counts after the interruption of virologically successful highly active antiretroviral therapy (HAART) in 139 patients. Changes in CD4 cell counts during HAART interruption followed a biphasic pattern: an initial rapid decline during the first month followed by a slow decrease. During 48 weeks of follow-up mean CD4 cell counts remained just above the mean pre-HAART level. This limits the feasibility of structured treatment interruptions for patients with low nadir CD4 cell counts.

Adult↗
PubMed2004

Mitochondrial dysfunction in AIDS and its treatment.

Advances in anti-retroviral therapy (ART) has led to improved survival of patients infected with the human immunodeficiency virus (HIV). ART for HIV patients is composed of a combination of nucleoside reverse transcriptase inhibitors (NRTI) and/or a non-nucleoside reverse transcriptase inhibitor (NNRTI), and/or a protease inhibitor (PI). The long-term exposure to ART and HIV are causing mitochondrial toxicities, such as myopathies, neuropathy, myelopoiesis, pancreatitis, lactic acidosis, hepatic steatosis, and lipodystrophy. The mitochondrial pathogenesis has been believed to be due exclusively to NRTI-induced inhibition of DNA polymerase-gamma; it is now apparent that the etiology is far more complex, involving multiple mechanisms as well as an effect by HIV per se. Current therapy for patients includes interruption or change in medications and mitochondrial co-factors.

Journal Article↗
PubMed2004

Pharmacokinetics of indinavir/ritonavir (800/100 mg twice a day) combined with efavirenz in HIV-infected patients.

A pharmacokinetics study was performed in HIV-infected patients who used indinavir/ritonavir (800/100 mg twice a day) plus efavirenz in the European and South American Study of Indinavir, Efavirenz and Ritonavir. Indinavir plasma concentrations were similar to values previously obtained in healthy volunteers who used the same combination. Efavirenz concentrations were higher than reported before. The pharmacokinetic data suggest that indinavir/ritonavir plus efavirenz (without dose modifications) should be effective in treatment-naive patients, and this was supported by the treatment response of the participants.

Adult↗
PubMed2004

Prevalence of lipoatrophy and mitochondrial DNA content of blood and subcutaneous fat in HIV-1-infected patients randomly allocated to zidovudine- or stavudine-based therapy.

INTRODUCTION: Mitochondrial toxicity resulting from mitochondrial DNA (mtDNA) depletion is suggested to be involved in the pathogenesis of lipodystrophy. METHODS: We cross-sectionally assessed lipodystrophy both clinically and radiographically in patients who, 4 years before, had been enrolled in a randomized comparative trial of stavudine- or zidovudine-based therapy. mtDNA content was measured in peripheral blood mononuclear cells (PBMCs) and subcutaneous adipose tissue from the thigh and back. RESULTS: Twenty-eight of the 45 patients enrolled in the original trial were included. Despite comparable exposure to stavudine or zidovudine (51 and 50 months, respectively), lipoatrophy prevalence by intent-to-treat analysis was significantly greater in stavudine recipients (82 vs 9%, P=0.0001). Likewise, those allocated to stavudine had significantly less peripheral fat. In an analysis restricted to patients who had remained on randomly allocated nucleoside reverse transcriptase inhibitors (NRTIs), mtDNA in PBMCs decreased after the start of treatment in both groups (P<0.0001) (-73% for stavudine and -67% for zidovudine, P=0.11), resulting in significantly lower levels in patients with lipoatrophy (P=0.007). The mtDNA content in subcutaneous adipose tissue from the thigh, but not from the back, was significantly lower in patients allocated to stavudine compared to zidovudine (P=0.01). mtDNA in adipose tissue from either location did not differ significantly between those with or without lipoatrophy. DISCUSSION: This study objectively confirms that regimens containing stavudine are associated with a greater risk of lipoatrophy than those containing zidovudine. mtDNA in PBMCs markedly declined with both treatments and was lowest in patients with lipoatrophy. The lack of difference in mtDNA in adipose tissue from patients with as opposed to without lipoatrophy may have been masked by a relative preponderance of stromal and vascular tissue in the subcutaneous tissue samples from these patients, combined with compensatory mitochondrial proliferation in remaining adipocytes. However, our findings may also suggest that the different risk of lipoatrophy observed between NRTIs cannot solely be explained by differences in mtDNA depletion directly at the level of peripheral adipose tissue.

Adipose Tissue↗
PubMed2003

Mortality and progression to AIDS after starting highly active antiretroviral therapy.

OBJECTIVES: To examine survival and progression to AIDS among HIV-infected patients after starting highly active antiretroviral therapy (HAART). METHODS: The study population consisted of 3724 patients from the ATHENA observational cohort who initiated HAART. We considered progression to either an AIDS-defining disease or death, distinguishing HIV-related and non-related (including therapy-related) deaths. A time-dependent multivariate hazards model was fitted to the patient data and 5-year survival probabilities under various therapy scenarios estimated. RESULTS: A total of 459 patients developed AIDS and 346 died during 12 503 person-years of follow-up. HIV-related mortality decreased from 3.8 to 0.7 per 100 person-years between 1996 and 2000 whereas non-HIV-related mortality did not change (0.4 and 0.9, respectively, P = 0.25). For asymptomatic and symptomatic therapy naive patients younger than 50 years with CD4 counts above 10 x 10(6) and 150 x 10(6) cells/l, respectively, predicted 5-year survival probabilities were above 90% when HAART was used continuously. This limit was 450 x 10(6) cells/l when HAART was used during 20 weeks in each 24 week-period of follow-up, and 110 x 10(6) cells/l when patients delayed initiation of HAART for 1 year after becoming eligible for treatment. CONCLUSIONS: Survival probabilities were high among HIV-infected patients initiating HAART at an early stage of infection. The best therapy strategy is therefore to start HAART at this stage of infection. However, deferring HAART in patients with high CD4 cell counts may be clinically more appropriate given toxicity and adherence problems. The lack of any change in non-HIV-related mortality suggests that toxicity has not yet become a major risk factor for death.

Acquired Immunodeficiency Syndrome↗
PubMed2003

Therapeutic drug monitoring of nelfinavir and indinavir in treatment-naive HIV-1-infected individuals.

BACKGROUND: Both virological failure and the toxicity of HIV protease inhibitors have been related to interindividual variability of plasma drug concentrations. Therapeutic drug monitoring (TDM) offers the possibility to detect patients with drug concentrations outside therapeutic ranges, who can subsequently benefit from dose modifications. METHODS: ATHENA was a randomized controlled clinical trial. Subjects were randomly assigned to either a TDM group, in which the results of drug concentration measurements plus advice were reported to their treating physician, or to a control group for whom TDM results were not reported. This analysis refers to treatment-naive patients who started a regimen containing indinavir or nelfinavir before November 1999. FINDINGS: A total of 147 patients were randomly assigned: 92 to nelfinavir, 55 to indinavir. After one year of follow-up significantly fewer patients in the TDM group had discontinued nelfinavir or indinavir than in the control group: 17.4 versus 39.7%. This was mainly driven by a significantly lower rate of discontinuation because of virological failure in nelfinavir patients: 2.4% in the TDM group versus 17.6% in the control group, and by a non-significant difference in the rate of discontinuation because of toxicity in indinavir patients: 14.3% in the TDM group versus 29.6% in the control group. In a non-completer equals failure analysis of all randomized patients, the TDM group showed a significantly higher proportion of patients with a viral load below 500 copies after 12 months of treatment (78.2 versus 55.1%). INTERPRETATION: TDM of nelfinavir and indinavir in treatment-naive patients improves treatment response.

Adult↗
PubMed2003

Clinical, immunological and virological response to different antiretroviral regimens in a cohort of HIV-2-infected patients.

OBJECTIVE: To assess the clinical, immunological and virological response and the emergence of resistance towards antiretroviral therapy (ART) in a cohort of HIV-2-infected patients. DESIGN: Observational study. PATIENTS: HIV-2-infected patients residing in the Netherlands. RESULTS: From 1995 to 2001 seven patients failed various ART regimens. The resistance mutations were analysed retrospectively. Development of mutations proved to be similar to that observed in HIV-1-infected patients, with the exception of a higher occurrence of the Q151M mutation within the reverse transcriptase gene. In a prospective study, comprising 13 consecutive naive HIV-2-infected patients, all patients achieved plasma HIV-2-RNA suppression below the detection limit (500 copies/ml). The antiretroviral regimen consisted of two nucleoside reverse transcriptase inhibitors (NRTIs) and indinavir, with a boosting dose of ritonavir; the median follow-up was 91 weeks. Two patients experienced a temporary virological rebound, while at the same time therapeutic drug monitoring showed sub-therapeutic plasma levels of indinavir. CONCLUSION: Sustained viral suppression in HIV-2-infected patients can be achieved using an antiretroviral regimen of two NRTIs and boosted indinavir or lopinavir.

Adult↗
PubMed2002

Determinants of recurrent toxicity-driven switches of highly active antiretroviral therapy. The ATHENA cohort.

BACKGROUND: Toxicity is the most important reason for premature switching of highly active antiretroviral therapy (HAART). In order to optimize the benefit-risk ratio of HAART, guidelines for toxicity management are needed. OBJECTIVE: An observational cohort study to estimate the incidence and identify determinants of toxicity-driven switches on second-line HAART after having switched first-line HAART despite successful viral suppression. METHODS: Patients were selected from those in the ATHENA cohort (n = 2470) who switched the initial HIV protease inhibitor (PI)-containing HAART while plasma HIV-1 RNA was <or= 500 copies/ml (n = 775). One-year cumulative incidences of subsequent toxicity-driven switches and adjusted relative risks (RR) for potential determinants were calculated. RESULTS: The 1-year cumulative incidence of toxicity-driven switches of the second regimen was 24% [95% confidence interval (CI), 21-28], mostly because of gastrointestinal toxicity and neuropathy. Those who had switched from first HAART because of toxicity were at an increased risk of a recurrent toxicity-driven switch (RR, 2.5; 95% CI, 1.7-3.5). Switching from PI to nevirapine while continuing the other antiretroviral drugs was more protective against a subsequent switch because of further toxicity than changing to another PI-containing regimen (RR, 0.2; 95% CI, 0.1-0.6). CONCLUSIONS: As for first-line HAART, toxicity is responsible for the majority of switches during second-line HAART. Prior switching for toxicity increased the risk of having to switch the subsequent regimen for toxicity, but this risk is reduced when switching to nevirapine rather than to an alternative PI. The latter should be taken into account when designing toxicity-management guidelines.

Adult↗