中国人类免疫缺陷病毒-1感染者细胞毒性T淋巴细胞特异性应答

目的 探讨中国人类免疫缺陷病毒（HIV）／艾滋病（AIDS）患者HIV特异性细胞毒性T淋巴细胞（CTL）应答的特征。方法 以HIV-1 B、C亚型构建的2个全基因组肽库作为抗原，通过酶联免疫斑点（ELISPOT）法检测HIV／AIDS患者HIV特异性CTL应答。结果 无论HIV-1 B亚型还是HIV-1 C亚型所构建肽库的应答效应和频率主要集中在Gag和Nef蛋白，其他蛋白也有不同程度的应答。HIV-1 B、C亚型间应答比较，整体范围大致相同，但单个肽段水平还存在着一定差异，B亚型应答频率最高的是Nef的GPKEPFRDYVDRFYKTLR（5／17，29．4％）和Gag的LWVYHTQGYFPDWQNY（5/17，29．4％），C亚型应答频率最高的是Gag的GPKEPFRDYVDRFFKTLR应答频率为35．29％。结论 中国人群CTL应答多集中在Gag和Nef蛋白，B、C亚型在单个肽段水平略有差异。提示中国人群的CTL应答研究对设计针对中国人群的HIV疫苗有较重要的意义。     

乙型肝炎患者外周血病毒特异性CD8阳性细胞毒性T淋巴细胞的数量和功能分析

目的 分析急性乙型肝炎(AHB)和慢性乙型肝炎(CHB)患者外周血中乙型肝炎病毒(HBV)特异性细胞毒性T淋巴细胞( CTL)的数量及功能.方法 36例HLA-A2阳性的乙型肝炎患者,其中AHB 12例,CHB 24例.分别用含HBV抗原C、S和P区的c18-27、s183-191和p575-583三个肽段的四聚体[Tetramer (Tc 18-27、Ts183-191、Tp 575-583)]检测患者外周血单核淋巴细胞(PBMCs)中HBV特异性CD8阳性CTL细胞的数量,同时用酶联免疫斑点法(EHSPOT)检测其分泌IFN-γ的功能.用SPSS 13.0进行统计学分析.结果 AHB和CHB患者外周血中Tc18-27特异性的CTL数量无明显不同;而Ts 183-191特异性CTL的平均值分别为0.24％±0.39％和0.03％±0.02％,阳性率分别为75％和33.3％;Tp575-583特异性CTL平均值分别为0.08％±0.09％和0.02％±0.01％,阳性率分别为50％和16.7％,AHB较CHB显著升高(P＜0.05).此外,AHB患者平均Tetramer阳性的个数为1.58个,而CHB患者平均为0.67个,AHB较CHB显著增多(P＜0.01).在9例AHB患者中,其外周血Ts183-191特异性的CTL细胞的数量为139～21 735个/106 PBMCs,用ELISPOT方法检测相对应的分泌IFN-γ的斑点形成细胞(SFC)为0～252个/106 PBMCs,AHB患者Tetramer细胞数和ELISPOT检测的IFN-γ斑点数有明显相关性(P＜0.01),而CHB患者则无此相关性.结论 AHB与CHB患者外周血中HBV特异性CTL的数量和分泌IFN-γ的差异提示CTL可能在清除病毒方面发挥着至关重要的作用,是今后慢性乙型肝炎免疫治疗的重要研究方向之一.     

酶联免疫斑点法检测肺结核患者特异性结核抗原多肽T细胞的应答

目的 评价我国酶联免疫斑点法(ELISPOT)用于诊断肺结核患者的应用价值.方法 结核特异性ELISPOT法检测76例诊断明确的肺结核患者外周血单核细胞.同时选择30例无结核接触史、胸部X线片无异常且PPI)皮试阴性的成年人作为对照.数据采用卡方检验和非参数Mann-Whitney检验.结果 76例患者总体阳性率为71.0%,健康对照组阳性率为6.7%.按照患者抗结核疗程分为治疗1个月内、治疗6个月内、治疗6个月以卜3组,阳性率分别为87.5%、74.1%和52.0%(X2=35.63,P=0.000).该技术在初治结核患者中的灵敏度为87.5%,特异度为93.3%,阳性预测值为91.3%,阴性预测值为90.3%.结论 结核特异性ELISPOT技术在我国初治(抗结核化疗疗程1个月内)的结核病患者中具有较高诊断价值.     

酶联免疫斑点法及其在自身免疫性糖尿病研究中的应用

酶联免疫斑点法（ELISPOT）是一种可在单细胞水平上检测抗原特异性T细胞频率的高敏感、高特异性、高通量的检测方法,广泛应用于各种与T细胞免疫相关疾病的研究,是体外直接检测糖尿病β细胞抗原特异性T细胞的最理想工具,对阐明自身免疫性糖尿病发生机制,以及疾病预测、预防、诊断与治疗效果的评价等方面有着重大的意义。现在面临的最大障碍是ELISPOT检测的国际标准化。     

结核杆菌特异性酶联免疫斑点技术在HIV感染人群中的应用

我国艾滋病病毒(HIV)感染人群中结核病的发病率高,造成了严重的疾病负担。提高潜伏结核和活动性结核的诊断准确性,对控制HIV病人中结核病的治疗和控制至关重要。该文总结了近年来出现、发展并完善的一种新的结核诊断技术,即结核杆菌特异性酶联免疫斑点技术,及其在HIV人群中的相关研究结果,并着重对该技术在潜伏结核和活动性结核的诊断、治疗效果监测以及结核相关性免疫重建炎症反应综合征中的应用进行了评价。     

T细胞酶联免疫斑点法对风湿性疾病患者潜伏性结核感染诊断价值的初步研究

目的 探讨T细胞酶联免疫斑点法(TSPOT)对风湿性疾病患者潜伏结核感染的诊断价值.方法 应用TSPOT-TB试剂盒对126例明确诊断的风湿性疾病患者血液标本进行结核分枝杆菌(Mtb)特异性T细胞应答的检测,同时对所有病例做结核菌素纯蛋白衍生物(PPD)试验进行联合分析.结果 TSPOT检测阳性率23.8%,PPD试验阳性率为34.9%,两者一致率为71.4%.其中PPD(-)者中11例TSPOT(+),占13.4%;PPD(+)中有25例TSPOT(-),占56.8%.有卡介苗接种史的患者PPD试验的阳性率显著高于无卡介苗接种史的患者(4l%与19%,P＜0.05),但有无卡介苗接种史的两组患者在TSPOT检测的阳性率上差异无统计学意义(22%与27%,P＞0.05).结论 卡介苗接种影响风湿性疾病患者PPD试验的结果,但对TSPOT检测结果未造成影响.TSPOT技术检测显示本研究风湿性疾病患者中的结核潜伏感染率为23.8%.     

酶联免疫斑点法在结核性脑膜炎诊断中的应用

近年来发展起来的酶联免疫斑点法（ELISPOT）作为一种新型的免疫酶技术为早期发现结核病（TB）提供了新的方向。ELISPOT法是全球首次利用探测结核感染者的特异性T细胞，而不是利用抗体来诊断TB的一种新方法，比皮肤试验更可靠，比培养方法更敏感。在TB患者中，尤以结核性脑膜炎诊断最为困难，如果用这种新型的ELISPOT法诊断可能会给防治结核性脑膜炎带来较大的进展，在欧美已经被批准用于临床，国内尚未见报道。我们首次尝试将该技术用于诊断结核性脑膜炎病例，现报道如下。     

乙型肝炎病毒特异性细胞毒性T淋巴细胞应答与不同临床感染状态的关系

目的 分析人类白细胞抗原(HLA)-A0201限制性的特异性CTL,研究急性肝炎急性期和慢性乙型肝炎活动期患者T淋巴细胞对特异性抗原表位免疫应答的差异.方法 收集HLA-A0201阳性的5例急性肝炎急性期和6例慢性乙型肝炎活动期患者的外周血单个核细胞(PBMC),酶联免疫斑点技术(ELISPOT)测定针对HBV聚合酶区(Pol575-583)、包膜区(Env348-357)和核心区(Core18-27)3个CD8+T淋巴细胞表位肽特异性CTL的数量和功能.数据采用t检验.结果 经Pol575-583、Env348-357和Core18-27三条抗原肽刺激,急性乙型肝炎急性期患者组斑点形成细胞数(SFC)分别为110±13、165±17和185±20;慢性乙型肝炎活动期患者组SFC分别为22±4、23±5和30±5,两组差异有统计学意义(t值分别为10.9、15.2和8.0,均P<0.05).急性乙型肝炎急性期患者各抗原肽特异性CTL的应答能力Pol575-5830.05).非特异性HLA-2402限制性Core117-125刺激也出现SFC增加,但与阴性对照组比较,差异无统计学意义(P>0.05).结论 急性感染者HBV特异性CTL应答水平显著高于慢性HBV感染者,慢性乙型肝炎患者体内的多克隆CTL数量和功能低下.     

乙肝病毒感染患者HBcAg特异性细胞毒性T细胞检测及意义

应用四聚体技术结合流式细胞术检测人外周全血中HBcAg表位肽Tcl8-27特异性细胞毒T淋巴细胞（HBVsCTL）的比率,并分析其与外周血HBVDNA、ALT、HBeAg之间的关系。结果HLA-A2＋慢乙肝患者、无症状携带者和急性HBV感染者HBVsCTL比率均较健康对照者升高（P〈0．05）;且HLA-A2＋急性HBV感染者HB-VsCTL比率较慢性HBV感染者明显升高（P〈0．01）。HBVsCTLs比率与HBVDNA定量及ALT之间无显著相关性（P〉0．05）。HBeAg（＋）慢乙肝患者HBVsCTL比率与正常对照无统计学差异（P〉0．05）,但HBeAg（-）慢乙肝患者HBVsCTL比率较健康对照高（P〈0．05）。认为HBVsCTL与肝内病毒复制和肝细胞损伤之间无直接相关关系,但其水平高低在一定程度上反映了HBV特异性细胞免疫功能的高低,对发病及转归有一定影响。     

丙型肝炎病毒特异性细胞毒性T淋巴细胞功能的研究

目的 研究慢性丙型肝炎患者丙型肝炎病毒(HCV)特异性细胞毒性T淋巴细胞(CTL)的功能及其与临床疾病状态的关系.方法 表达HCV核心蛋白的真核表达质粒pcDNA3.1-core通过Lipofecta-mineTM基因转染法转染HepG2细胞,经G418筛选获得稳定转染HepG2细胞(Hep-core),经Western blot证实有HCV核心蛋白表达;分离患者外周血单个核细胞,经体外诱导扩增获得HCV特异性CTL(HCV-CTL),以Hep-Core细胞和HepG2细胞作靶细胞,乳酸脱氢酶释放法检测HCV-CTL活性,用酶联免疫吸附法检测培养上清液中干扰素-γ(IFN-γ)含量,以正常人作为对照.结果 慢性丙型肝炎患者组HCV-CTL活性值为(23.9±4.8)%,明显低于对照组(42.6±6.5)%(t=7.22,P=0.011).高病毒载量组HCV-CTL活性值(18.9±4.8)%,明显低于低病毒载量组的(33.7±3.2)%(t:8.22,P=0.003);基因1型患者HCV-CTL活性值(20.8±2.1)%明显低于基因2或3型的(32.4±2.5)%(t=11.7,P=0.001);ALT升高患者HCV-CTL活性值(29.3±3.1)%与ALT正常患者(25.7±3.4)%相比无统计学差异(t=0.93,P＞0.05).慢性丙型肝炎患者培养上清液中的IFN-γ量(957±241)pg/ml明显低于对照组的(3117±673)pg/ml(t=8.87,P=0.001).结论 慢性丙型肝炎患者HCV-CTL活性降低,CTL的免疫功能低下与病毒水平和基因型相关而与ALT水平无关.     

Hepatitis C virus infection among HIV-1 infected individuals from northern Mexico

Aims: The prevalence of hepatitis C virus (HCV) infection, risk factors and HCV genotypes in 140 HIV-1 infected individuals from northern Mexico was determined. Methods: Hepatitis C infection was confirmed by the detection of anti-HCV antibodies and HCV-RNA in sera, and genotyping was performed by the InnoLiPA-HCV genotype assay. Results: Seventeen (12.1%) out of 140 HIV-infected individuals were found to be HCV-positive. Coinfected individuals were more likely to be male (87%). The most frequent genotype was 1a (41%), followed by 1b (29.4%), 2a/c (17.6%), 2b (5.9%) and 3 (5.9%). Serum transaminase concentrations (AST and ALT) were higher in coinfected patients. Among the risk factors for coinfection: sexual transmission was the most frequently observed (men who have sex with men (MSM); 64.7% and bisexual behavior; 64.7%) followed by intravenous drug users (IVDU) (53%). There was no association of the HCV genotypes with the age and risk factors for HIV-1 and HCV infection observed in the studied patients. Conclusion: The results suggest that the prevalence of HIV-1/HCV coinfection in Mexico is lower than in other American countries.     

Detection and quantification of HIV-1 specific CD4 helper and CD8 cytotoxic cells: their role in HIV-1-infected individuals and vaccine recipients

There is a strong link between virus specific CD8 T-cell function and the efficiency of regulatory CD4 helper T cells. Controlling viraemia in HIV-1-infected individuals requires the maintenance of strong CD4 and CD8 T-cell responses. These responses should be elicited by prophylactic vaccination and by postexposure immunotherapy. This review will examine the methods that are available for the detection and quantification of HIV-1 specific CD4 and CD8 T-cell responses. We will also discuss the methods that should be used to identify these responses in HIV-1-infected individuals, seropositive recipients of immunotherapy and seronegative vaccinees. Finally, we will give examples of how responses observed in vitro relate to those known to occur in vivo .     

Cytokine detection by ELISPOT: relevance for immunological studies in type 1 diabetes

Diabetes mellitus type 1 is a chronic disease in which the insulin-secreting ss-cells are selectively destroyed by an immune-mediated process. Autoantibodies directed against several islet antigens are useful parameters to estimate the risk to develop diabetes, but cell-mediated immunity involving T lymphocytes plays a major part in causing the specific destruction of ss-cells. T cells are characterized by their antigen-specificity, phenotype and cytokine-secreting profile. T cells that secrete cytokines of the T helper 1 (Th1) type have been shown to transfer diabetes in animal studies, in contrast to T helper 2 (Th2) cytokine-secreting T cells that are thought to be rather nondestructive. In the absence of phenotypic markers for Th1 and Th2 cells, several different approaches have been taken to examine T cell responses in detail. Methods involve T-cell proliferation assays, Enzyme-Linked-Immuno-Sorbent-Assay (ELISA) analysis of secreted cytokines and phenotype analysis applying flow cytometry. A more recent development is ELISPOT analysis, which enables the investigator to determine the qualitative and quantitative antigen-specific immune response on a single-cell level with regard to cytokine secretion. This article aims to give an introduction to the advantages and limitations inherent in the different techniques and their potential relevance for immunological studies in diabetes mellitus type 1.     

Increase of hemoglobin A2 in human immunodeficiency virus-1-infected patients treated with zidovudine

We observed increased hemoglobin A₂ (HbA₂) levels in an asymptomatic human immunodeficiency virus-1 (HIV¹) patient with no previous history of β-thalassemia. He was treated only with zidovudine (AZT). In an attempt to understand this observation, a retrospective study was initiated to determine whether mean HbA₂ levels are higher in AZT-treated patients than in subjects not receiving this drug and to assess if other hematologic alterations are associated with elevated HbA₂. One hundred fifty-one HIV-positive cases were investigated; AZT was administered to 81 of them. The mean value of HbA₂ was 0.032 (SD ±0.005) for the treated group vs. 0.027 (SD ±0.004) for the controls. This difference was highly significant (P < 0.001). Twenty-four patients (31%) in the treated group had elevated HbA₂ levels vs. none in the controls. Bone marrow toxicity seemed to be more significant in patients with heightened HbA₂ values, and HbA₂ levels did not increase with CDC clinical stage. We conclude that AZT may be linked to high HbA₂ levels in some patients.     

Selective transduction of HIV-1-infected cells by the combination of HIV and MMLV vectors

Human immunodeficiency virus 1 (HIV-1)-infected cells are important targets of gene therapy for acquired immune deficiency syndrome. We have developed a novel strategy for targeted gene transfer into HIV-1-infected cells based on 2-step gene transfer. The first step involves the stable introduction of the HIV vector containing the ecotropic Moloney murine leukemia virus (MMLV) receptor gene (EcoRec) into human CD4+ T cells as a molecular switch. Because the HIV-long terminal repeat (HIV-LTR) is Tat inducible, it is expected that EcoRec is expressed only after HIV-1 infection. Northern blot analysis and a retrovirus binding assay confirmed that the HIV-LTR of the integrated vector was silent in transduced cells but strongly transactivated in HIV-1 infection. High levels of EcoRec expression were observed only in HIV-1-infected cells. These cells became highly susceptible to ecotropic MMLV infection and, therefore, in the second step, HIV-1-infected cells were selectively transduced with ecotropic MMLV vectors. More than 70% of HIV-1-infected cells were transduced by this strategy. These findings indicate that this 2-step method can be used for selective and stable gene transfer into HIV-1-infected cells.     

不同病期HIV-1感染者的病毒学和免疫学研究

目的了解不同疾病阶段艾滋病病毒Ⅰ型(HIV-1)感染者体内的病毒载量和免疫学变化,探讨其在疾病发展过程中的作用。方法应用核酸序列扩增技术(NASBA)、流式细胞仪和定量酶联免疫吸附试验(ELISA)检测20例正常人、38例HIV无症状感染者、24例HIV有症状感染者和21例艾滋病(AIDS)病人的外周血浆病毒载量、T淋巴细胞亚群和Th1/Th2细胞因子浓度,并结合临床情况进行分析。结果处于不同疾病阶段的HIV无症状感染者、HIV有症状感染者和AIDS病人的血浆病毒载量不同,3组之间有显著性差异(P<0.01),艾滋病组的病毒载量为HIV-RNA 6.04±0.28 log/ml,远远高于HIV无症状组的3.84±0.26 log/ml。3组的CD4 细胞、CD4/CD8比值及IL-2浓度不断下降且明显低于正常人群(P<0.01),Th2细胞因子IL-4和IL-10则明显高于正常人群,且各组之间均有显著性差异(P<0.01)。各因素的相关性分析显示:HIV-RNA与CD4 、CD4/CD8、IL-2,IL-2与IL-4、IL-10,IL-4与IFN-γ、CD4 细胞之间有高度直线负相关关系(P<0.001);HIV-RNA与IL-4、IL-10,CD4 与CD8 、CD4/CD8、IL-2,IL-2与IFN-γ,IL-4与IL-10之间有高度直线正相关关系(P<0.001)。结论不同病期的HIV-1感染者其病毒载量水平、免疫学状况有明显不同。当HIV-RNA升高,CD4 细胞、CD4/CD8比值下降和细胞因子由Th1型为主转变为以Th2型为主时,提示疾病处于进展中。因此,检测这些指标变化可为HIV的临床分期、判断预后和治疗提供依据。     

Prevalence and correlates of insecticide-treated bednet use among HIV-1-infected adults in Kenya

HIV-1-infected adults are at increased risk for malaria. Insecticide-treated bednets protect individuals from malaria. Little is known about correlates of ownership and use of bednets among HIV-1-infected individuals. We conducted a cross-sectional survey of 388 HIV-1-infected adults recruited from three sites in Kenya (Kilifi, Kisii, and Kisumu) to determine factors associated with ownership and use of optimal bednets. We defined an optimal bednet as an untorn, insecticide-treated bednet. Of 388 participants, 134(34.5%) reported owning an optimal bednet. Of those that owned optimal bednets, most (76.9%) reported using it daily. In a multivariate model, higher socioeconomic status as defined as postsecondary education [OR = 2.8 (95% CI: 1.3–6.4), p = 0.01] and living in a permanent home [OR = 1.7(1.03–2.9), p = 0.04] were significantly associated with optimal bednet ownership. Among individuals who owned bednets, employed individuals were less likely [OR = 0.2(0.04–0.8), p = 0.01] and participants from Kilifi were more likely to use bednets [OR = 2.9 (95% CI 1.04–8.1), p = 0.04] in univariate analysis. Participants from Kilifi had the least education, lowest income, and lowest rate of employment. Our findings suggest that lower socioeconomic status is a barrier to ownership of an optimal bednet. However, consistent use is high once individuals are in possession of an optimal bednet. Increasing access to optimal bednets will lead to high uptake and use.     

Testing for human immunodeficiency virus (HIV-1) antigens in haemophiliacs positive for HIV antibody

Summary Sera collected from 28 haemophiliacs during the 2 years from 1985 to 1987 were examined for the presence of human immunodeficiency virus (HIV-1) antigen by two different methods using commercially available test kits. Of 28 patients, 18 had been positive for HIV antibody since at least 1985 and their HIV infection by blood products went back 3–6 years. Of these 18 antibody-positive patients, 8 were positive for HIV antigen according to one or both antigen tests on one or more occasions. The longest period of antigen expression was 21 months in two patients, one being in perfect health, the other showing AIDS-related complex (ARC) for the last 9 months. The detection of antigen expression was highly variable between the two tests used. Both positive and negative antigen-test results must therefore be used with great caution in clinical practice.     

HIV-1耐药突变的研究进展

至2015年止,全球约有1 700万HIV/AIDS病例得到抗逆转录病毒治疗,使HIV-1死亡率和发病率迅速下降。随着抗逆转录病毒治疗向所有感染HIV者全面推进,HIV耐药突变问题对长期治疗也构成了威胁,并对全球2030年消除艾滋病这一重要公共卫生战略产生了负面影响。本综述试图从不同的经济和地理环境出发,从个体和群体水平上阐述了常用的抗逆转录病毒药物的遗传屏障、交互耐药程度、耐药突变的流行病学和耐药管理;同时本文汇总了高、中低两类国家的可传播性耐药(TDR)和获得性耐药(ADR)的流行方式,分析了两类具有重要的公共卫生意义HIV耐药突变问题,即治疗前耐药和暴露前预防性服药的耐药。此外,鉴于有效地对不同类国家的HIV病例的治疗和管理,分别分析了基因型耐药性检测和治疗实践方面的关联,这些内容对我国的艾滋病防治也具有一定的参考作用。     

Prevalence of hepatitis C in an ethnically diverse HIV-1-infected cohort in south London

OBJECTIVES: There is limited information on the prevalence of and risk factors for hepatitis C virus (HCV) infection among HIV-1-infected patients in the UK. Our objective was to determine the prevalence of HCV infection among an ethnically diverse cohort of HIV-infected patients in south London, and to extrapolate from these data the number of co-infected patients in the UK. METHODS: A total of 1017 HIV-1-infected patients who had attended King's College Hospital HIV clinic between September 2000 and August 2002 were screened for HCV antibody using a commercial enzyme-linked immunosorbent assay (ELISA). Positive results were confirmed by polymerase chain reaction (PCR) or recombinant immunoblot assay. Demographic, clinical and laboratory data were obtained from the local computerized database and medical records. We applied our HCV prevalence rates in the different HIV transmission groups to the estimated number of HIV-infected persons in these groups in the UK, to obtain a national estimate of the level of HIV-HCV co-infection. RESULTS: Of the 1017 HIV-1-infected patients, 407 (40%) were white men, 158 (15.5%) were black African men, 268 (26.3%) were black African women, and 61 (6%) and 26 (2.6%) were black Caribbean men and women, respectively. Heterosexual exposure was the most common route of HIV acquisition (53.5%), followed by men having sex with men (36.9%), and current or previous injecting drug use (IDU) (7.2%). The overall prevalence of HCV co-infection was 90/1017 (8.9%), but this varied substantially according to route of transmission, from 82.2% among those with a history of IDU (which accounted for 67% of all HCV infections), to 31.8% in those who had received blood products, to 3.5% and 1.8% in those with homosexually and heterosexually acquired infection, respectively. Multivariate logistic regression analysis identified several independent risk factors for HCV infection: a history of IDU [odds ratio (OR) = 107.2; 95% confidence interval (CI) = 38.5-298.4], having received blood products (OR = 16.5; 95% CI = 5.1-53.7), and either being from a white ethnic group (OR = 4.3; 95% CI = 1.5-12.0) or being born in Southern Europe (OR = 6.7; 95% CI = 1.5-30.7). Based on the 35,473 known HIV-1-infected persons in the UK and the 10 997 estimated to be unaware of their status, we projected that there are at least 4136 HIV-HCV co-infected individuals in the UK and 979 who are unaware of their status. CONCLUSIONS: Overall, 9% of our cohort was HIV-HCV co-infected. The prevalence was highest among intravenous drug users (82%), who accounted for most of our HCV cases, and lowest among heterosexual men and women from sub-Saharan Africa and the Caribbean [< 2%]. Our estimate that a significant number of co-infected persons may be unaware of their HIV and HCV status, highlights an urgent need to increase the uptake of HCV and HIV testing, particularly among injecting drug users, to reduce the risk of onward transmission.