我国HIV-1感染者耐药突变的流行性研究

目的 掌握我国大规模用药前耐药突变在我国HIV-1感染者中流行情况的本底资料。方法 在第二次全国HIV流行病调查2002年样本中随机选取20％，对于蛋白酶(PR)基因区全长和逆转录酶(RT)20～230氨基酸位点进行PCR扩增、测序并使用HIVdb-Drug Resistance Algorithm软件进行分析，检测耐药相关突变。结果 分别得到164份PR基因区样本和138份RT基因区样本。PR基因区样本中发现1份(0．61％)样本存在蛋白酶抑制剂(PI)主要相关突变，163份(99．39％)样本存在P1次要耐药相关突变。RT基因区样本中发现8份(5．80％)具有核苷类逆转录酶抑制剂(NRTI)耐药相关突变，2份(1．45％)存在非核苷类逆转录酶抑制剂(NNRTI)耐药相关突变。结论 我国未用药HIV感染者中耐药相关突变尚处于低流行状态，应当在用药过程中定期监控以减少耐药突变的产生与传播。     

Neisseria meningitidis W-135 in the Basque Country, northern Spain

Neisseria meningitidis W-135 accounted for nine (1.6%) of 562 cases of invasive meningococcal disease and 17 (3.9%) of 430 meningococcal isolates from healthy carriers. There was no mortality associated with the invasive nine isolates, which belonged to subtype P1.6 and geno-subtype P1.18-1. All invasive isolates and 15 of the 17 isolates from healthy carriers belonged to sequence type 22 by multilocus sequence typing, and showed a similarity of > 85% by pulsed-field gel electrophoresis following digestion with NheI. These results demonstrate that W-135 isolates in the Basque region of northern Spain have a high degree of similarity and are almost clonal.     

HIV-1 drug resistance evolution among patients on potent combination antiretroviral therapy with detectable viremia

Many patients infected with HIV do not achieve or maintain virologic suppression below levels of detection while on potent combination antiretroviral therapy. The likelihood of emergence of incident mutations conferring reduced antiretroviral drug susceptibility was estimated among patients maintained on a stable regimen with ongoing detectable plasma HIV RNA levels. Ninety-eight HIV-infected patients were identified who had 2 genotypic antiretroviral resistance tests available. Poisson log-linear regression models were used to identify predictors and estimate incidence rates of number of acquired antiretroviral drug resistance mutations per person-year. At the 1st resistance test, 88% of patients had evidence of at least 1 mutation. Sixty percent of patients acquired at least 1 new mutation during a median of 9.3 months between consecutive resistance tests, with an incidence rate of 1.61 acquired mutations per person-year (95% CI: 1.36-1.90). Predictors of resistance evolution included average plasma HIV RNA level, HIV RNA slope, and number of mutations detected at the 1st resistance test. The likelihood of acquiring drug resistance mutations while remaining on potent combination antiretroviral therapy that does not confer complete suppression of HIV replication is relatively low and depends on the level of viral replication and prior resistance.     

慢性HIV感染者抗逆转录病毒治疗过程中树突状细胞亚群的变化特点

目的 了解慢性人免疫缺陷病毒(HIV)感染者抗逆转录病毒治疗(ART)过程中树突状细胞(DC)亚群的变化特点.方法 选取ART治疗的慢性HIV感染者17例,分别于治疗0,4,8,12,24,48,60周采集静脉血,同时选取健康者、长期不进展者(LTNPs)各15例为对照.常规进行CD4+/CD8+T细胞计数和病毒载量测定;用流式细胞术测定DC亚群,ELISA测定血浆IFN-α水平;采用SPSS16.0软件分析数据特点.结果 (1) ART治疗前HIV感染者髓样树突状细胞(mDC)百分比及绝对计数明显低于健康组和LTNP组(P＜0.001).ART治疗60周后,HIV感染者mDC明显增加,与健康组、LTNP组之间差异无统计学意义.(2) ART治疗过程中浆细胞样树突状细胞(pDC)数量和血浆IFN-α水平保持相对稳定,且接近健康组、LTNP组水平.(3) ART治疗前DC亚群细胞计数与CD4+T细胞计数正相关.ART治疗12、24、60周,mDC细胞计数与CD4+T细胞计数正相关,与病毒载量负相关.ART治疗8周mDC细胞计数增加值与治疗60周CD4+T细胞计数增加值正相关,与病毒载量下降值负相关.结论 HIV感染者mDC细胞数量明显减少,ART治疗后明显上升,与CD4+T细胞计数正相关,提示mDC在控制HIV感染方面可能具有重要作用.治疗早期mDC细胞数量可能是ART治疗后免疫重建的早期预测指标.     

Transmission of HIV-1 drug resistance.

BACKGROUND: The use of highly-active anti-retroviral therapy (HAART) for treating HIV infections is increasing. Recent studies have demonstrated that HAART is improving both the length and quality of life in HIV-infected patients. Resistant strains of HIV arise when drug adherence is poor. This can lead to the transmission of drug-resistant strains of HIV to susceptible individuals. This can lead to suboptimal first-line therapy, if the resistance profile of the transmitted virus is unknown. OBJECTIVES: To review the mechanisms of how drug resistance arises; the methods used to characterise drug resistance; the problems arising with compliance leading to the development of drug-resistant HIV strains; the evidence for the incidence, prevalence and trends in the transmission of resistant HIV strains in different risk groups; and the evidence of suboptimal response to first-line therapy where transmission of a resistant HIV strain has occurred. On the basis of this, a case is presented for the routine resistance testing of all newly diagnosed HIV-infected individuals. STUDY DESIGN: Literature review. RESULTS AND CONCLUSIONS: There is evidence, though limited at present, that transmission of drug-resistant HIV strains can lead to suboptimal response to first-line therapy in newly diagnosed HIV-infected individuals. As the use of HAART can only increase in the future, and compliance will always be a problem in such HAART-treated patients, baseline resistance testing should become a routine part of their management.     

Structured therapeutic interruption in patients infected with HIV-1 experiencing a block in their antiretroviral treatment: preliminary results

Structured therapeutic interruption (STI) has been offered to HIV-1 infected patients with virological failure (viral load > 1500 copies/mL) of potent antiretroviral therapy (ART) (three or four drugs for at least one year). CD4 lymphocyte count, HIV-1 viral load, clinical status, were assessed every month during STI and after ART reintroduction. Genotype analysis by plasma virus sequencing was done before and after treatment interruption. The results of 14 patients who resumed ART for at least two months are presented. Median duration of STI was 7.5 months (range: 2-13 months). Median CD4 count was low (45/mm3) when treatment was stopped, and decreased during STI (-37/mm3 after six months). Several patients exhibited important CD4 diminutions. Viral load slightly increased (+0.83 log at M6). Few clinical events occurred: one: severe HIV-related prurigo and one CMV viremia. Reversion of resistance mutations was only seen in 2/13 (15: 4%) patients (who had previously a major CD4 deficiency, and a long treatment history), a partial reversion occurred in 5/13 (38.5%) subjects, and the mutations didn't change in the other cases (genotyping non interpretable in the last patient). ART reintroduction induced a good immune response: CD4/mm3 after six months, with significant increases in 10/14 subjects. There was an initial viral response (median viral load: -2.34 log at M1), but a quick rebound most often occurred. However, viral load remained < 50 copies/mL in four patients. In conclusion, a rapid and important decline in CD4 cell count can occur when treatment is discontinued, in patients with virological failure of ART, but the clinical risk appears to be limited. Treatment re-initiation induces a good response, but virologically transient in most cases. Patients with a shift to wild-type virus seem to have a better response.     

Genotypic drug resistance interpretation systems--the cutting edge of antiretroviral therapy

The technical quality of genotypic and phenotypic drug resistance testing has considerably improved, and therefore the major challenge now lies in the interpretation of drug resistance. This is due to several facts: (i) in times of combination therapy, the effect of drug resistance-associated mutations cannot be considered independently, (ii) many additive and subtractive interactions between mutations exist, and resistant strains may exhibit varying degrees of cross-resistance, (iii) the phenotype cannot adequately determine slight, but clinically relevant, differences for those drugs with a narrow range of resistance, and (iv) pharmacokinetic interactions may shift relevant levels of drug resistance. Genotypic drug resistance interpretation systems are designed to solve these problems. Rule-based systems incorporate current knowledge about correlations between genotype, phenotype and clinical response. Database-driven systems use the information provided by paired geno- and phenotypic data, applying database matching search or bioinformatic approaches. For detailed comparison, 11 interpretation systems were selected which present a comprehensive system for most of the available drugs, can easily be accessed via the Internet and are regularly updated. The systems were characterized for the source data, access, input, output, and availability of clinical studies. For further comparison, existing clinical databases should be merged into one large database to allow competition between the systems. This may also solve the burning problem of clinically relevant cut-offs. Head-to-head comparisons of interpretation systems require large prospective randomized trials in which only the interpretation system is different between groups, before a consensus can be achieved for the best antiretroviral therapy of the individual patient.     

Primary HIV-1 drug resistance in Spain before and after the introduction of protease inhibitors

The prevalence of genotypic resistance to nucleoside analogues was examined in 150 naive individuals with chronic HIV-1 infection acquired before June 1996, when protease inhibitors began to be used in Spain, and in a group of 52 recent seroconverters infected since 1997. Overall, the prevalence of subjects carrying nucleoside-resistant genotypes was similar in both groups (12.6% and 15.4%, respectively). A polymorphism at codon 70 accounted for more than half of cases (63.1%) in naive individuals infected before protease inhibitors became available, in contrast most recent seroconverters carried genotypes with one or more key nucleoside resistance mutations, mainly associated with lack of sensitivity to zidovudine or lamivudine (prevalence 9.6% and 5.9%, respectively). When only key mutations were considered in each of the two periods, the prevalence of nucleoside-resistant genotypes was increased significantly among recent seroconverters (13.5% vs. 4.7%; P<0.05). The relatively high rate of resistance to nucleosides in Spain justifies the introduction of drug resistance testing in naive recent seroconverters before beginning antiretroviral therapy.     

Strategies for overcoming resistance in HIV-1 infected patients receiving HAART

Highly active antiretroviral therapy (HAART) has fundamentally changed the clinical outcome of HIV infection and AIDS. However, the emergence of drug-resistant HIV variants is a barrier to successful use of HAART, with resistance to one drug often resulting in cross-resistance to many, if not all, others in the same class. The rise in the incidence of drug-resistant variants among newly infected patients also represents a formidable challenge for clinicians. Failure of the current HAART regimen due to drug resistance can severely limit second-line, third-line, and salvage treatment options. Although inadequate exposure of the virus to antiretroviral agents is a prime reason for the emergence of HIV drug-resistant variants, poor adherence to complicated regimens and variability in drug pharmacokinetics (PK), both within and between HIV-infected individuals, can also affect the overall efficacy of antiretroviral agents, promoting emergence of resistant HIV variants. Recent strategies to optimize antiretroviral drug regimens, including assessment of HIV genotype and/or phenotype, the use of protease inhibitor regimens that incorporate PK boosting, and scheduled treatment interruptions, have been explored. Additionally, several newer antiretroviral agents that produce rapid and sustained virologic and immunologic responses as well as novel resistance profiles (e.g. atazanavir and tenofovir) have become available. These characteristics thus increase the likelihood of durable viral suppression.     

Significant differences between plasma HIV-1 RNA assays in HIV-1 subtype E infected patients treated with antiretroviral therapy

A total of 72 HIV-1 infected Thai patients treated with didanosine (ddI) or stavudine (d4T) plus ddI at the time of interim analysis were analyzed. Sixty patients (83%) carried subtype E documented by HIV-1 V3 serotyping. HIV-1 RNA levels were measured using three commercial viral load assays. At baseline (n = 57), Quantiplex 2.0 and NucliSens 2.0 showed mean log10 HIV-1 RNA of 0.7 log10 or 5 fold lower than Amplicor 1.5 (mean 4.29 versus 5.0 log10, respectively, p < 0.001). At week 20 of treatment (n = 29), HIV-1 RNA levels were detected in 55.2%, 31%, and 33.5% of subjects tested by Amplicor 1.5, Quantiplex 2.0, and NucliSens 2.0, respectively. In conclusion: plasma HIV-1 RNA analyses showed comparable values with Quantiplex 2.0 and NucliSens 2.0 assays. In contrast, Amplicor 1.5 resulted in approximately 5 folds higher HIV-1 RNA levels and a 25% higher rate of detection of plasma HIV-1 RNA as compared to the other two assays. As the current goal of therapy is to suppress plasma viral load below the detection limit of the assays, the significant differences between the assays may influence antiretroviral efficacy evaluation and management.