6种非梅毒螺旋体抗原血清学试验试剂对梅毒患者随访的影响

目的探讨几种非梅毒螺旋体抗原血清学试验试剂对梅毒患者随访的影响。方法按照非梅毒螺旋体抗原血清学定量试验稀释样本的原则,充分稀释11份梅毒患者血清,每份连续稀释成12个浓度,用1种梅毒快速血浆反应素环状卡片试验(RPR)和5种梅毒甲苯胺红不加热血清试验(TRUST)试剂检测稀释好的血清,观察不同试剂对样本的反应性。结果 6种试剂对同一份样本的检测能力不尽相同,RPR试剂与5种TRUST试剂的检测结果基本不相同,两者无可比性。TRUST试剂之间只有2种试剂的结果相似,其他的差异较大,甚至同一份样本的最高滴度是最低滴度的16倍。对所有样本来说,某些试剂检测的滴度有总体偏低或偏高的趋势。结论不同方法或不同厂家的同一方法对梅毒患者个体的治疗随访有影响,相互间检测结果不能互认,因此临床实验室在梅毒的诊断、治疗和随访中,要注意使用相同的非梅毒螺旋体抗原血清学试验试剂。     

原发性肺隐球菌病的临床和乳胶凝集试验分析

目的分析肺隐球菌病的临床特点和乳胶凝集试验,以提高对该病诊断。方法回顾分析15例经病理证实的原发性肺隐球菌病的临床及相关检查资料表现,同时对所有肺隐球菌病人行乳胶凝集试验。结果15例病人中男11例（73.3％）,女4例（26.7％）,且经病理证实为肺隐球菌病人,这些病人乳胶凝集试验均为阳性,而该试验特异性的感性为100％,其中一例没有临床症状,14例病人有咳嗽发热等症状。结论肺隐球菌病的临床与影像表现不典型,乳胶凝集试验作为一种快速简易的试验方法能提高肺隐球菌病的检出率。     

虎红平板凝集试验确诊布鲁杆菌病截断值的探讨

目的 探讨虎红平板凝集试验确诊布鲁杆菌病凝集度的截断值.方法 内蒙古地方病防治研究中心门诊部选择2009年5月至2009年6月,进行布鲁杆菌病检查的398人,进行试管凝集试验和虎红平板凝集试验检测,以试管凝集试验为金标准,探讨虎红平板凝集试验诊断布鲁杆菌病的截断值,并对可靠性和真实性进行评价.结果 以阳性预测值100.0％作为筛选标准,虎红平板凝集试验快速确诊布鲁杆菌病的截断值为“++”,以该凝集度强度作为截断值进行布鲁杆菌病诊断,灵敏度为83.3％,特异度为100.0％,约登指数为0.823,符合率为89.9％.结论 以虎红平板凝集试验的“++”作为截断值诊断布鲁杆菌病,值得临床推广.     

Human platelet antigen genotyping by using sequence-specific primers and the particle gel agglutination assay

BACKGROUND AND OBJECTIVES: Polymerase chain reaction using sequence-specific primers (PCR-SSP) is currently the most widely used technique for human platelet antigen (HPA) genotyping. Here, we describe a novel particle gel-agglutination technique for simplified visualization of the amplified products. MATERIALS AND METHODS: Biotinylated primers were used to amplify HPA-1, -2, -3, -4, -5, -6, and -15, and the PCR products were incubated with streptavidin particles. Fluorescein isothiocyanate (FITC)-labelled primers [amplifying a fragment of the human growth hormone (HGH) gene] and anti-FITC-coated particles were used as internal controls. Agglutination of the particles in or on top of the gel indicated specific amplification. A total of 100 samples from blood donors was tested by using this new technique and a standard PCR-SSP protocol. RESULTS: The use of biotinylated sequence-specific primers resulted in PCR products that agglutinated streptavidin particles, and the FITC-labelled HGH primers led to agglutination of anti-FITC-coated particles. Negative reactions were clearly distinguishable from positive reactions. The results of the particle gel agglutination method were in concordance with those of the electrophoretic visualization in all cases tested. CONCLUSIONS: The new particle agglutination method is reliable and easy to use.     

Broadly neutralizing antibodies suppress HIV in the persistent viral reservoir

Several highly potent and broadly neutralizing monoclonal antibodies against HIV have recently been isolated from B cells of infected individuals. However, the effects of these antibodies on the persistent viral reservoirs in HIV-infected individuals receiving antiretroviral therapy (ART) are unknown. We show that several HIV-specific monoclonal antibodies—in particular, PGT121, VRC01, and VRC03—potently inhibited entry into CD4⁺ T cells of HIV isolated from the latent viral reservoir of infected individuals whose plasma viremia was well controlled by ART. In addition, we demonstrate that HIV replication in autologous CD4⁺ T cells derived from infected individuals receiving ART was profoundly suppressed by three aforementioned and other HIV-specific monoclonal antibodies. These findings have implications for passive immunotherapy as an approach toward controlling plasma viral rebound in patients whose ART is withdrawn.The sustained suppression of HIV replication by antiretroviral therapy (ART) has dramatically improved the clinical outcome of infected individuals (1). In addition, research directed at potential pathways toward the development of an effective preventive HIV vaccine has provided insights into the nature of the immune response to HIV infection (2, 3). In this regard, recent advances in antibody-cloning technologies have led to the discovery of several highly potent and broadly neutralizing monoclonal antibodies against HIV from B cells of HIV-infected individuals (4–7). Of interest, several studies have demonstrated that certain broadly neutralizing HIV-specific monoclonal antibodies can prevent acquisition of the virus, suppress viral replication, delay and/or prevent plasma viral rebound following treatment interruption in infected animals (8–14), and block cell-to-cell transmission of laboratory-adapted HIV in vitro (15). However, it is unclear what in vivo effects these antibodies might have on HIV in humans and, in particular, what effects they may have on the virus contained in the persistently infected CD4⁺ T cells of individuals whose plasma viremia is controlled by ART. These infected CD4⁺ T cells are considered to be the major obstacle to viral eradication (16–18) as well as a potential source of plasma viral rebound following discontinuation of ART in patients whose viremia had been well controlled in therapy (1). In this regard, considerable efforts in current HIV therapeutic research have been focused on developing strategies aimed at achieving sustained virologic remission in the absence of ART (1). This focus is especially important given that viral rebound and sustained HIV replication has been observed in almost all infected individuals whose plasma viremia had been well controlled while receiving ART and whose ART was subsequently withdrawn (19). Therefore, it is important to determine which, if any, of the many recently characterized HIV-specific monoclonal antibodies can inhibit viral entry into CD4⁺ T cells of HIV isolated from the latent viral reservoir as well as replication of reservoir virus in autologous CD4⁺ T cells derived from infected individuals whose plasma viremia was well-controlled on ART. Such knowledge is critical to establishing novel opportunities for passive immunotherapy to prevent plasma viral rebound following discontinuation of antiretroviral drugs. We conducted the present study to address this issue.     

Epidemiological study of kala-azar by direct agglutination test in two rural communities of eastern Nepal

We conducted a sero-epidemiological study of kala-azar in two endemic communities (Kasaini and Gidhaniya) situated in the Terai (plain) of eastern Nepal. Direct agglutination test (DAT) was used as a serological test for screening. Capillary blood samples were collected by filter paper method from 601 (96%) people of a total population of 628 in Kasaini and from 482 (94%) people of 515 in Gidhaniya. Positive DAT titres (1:2000) were found in 66 (6.09%) of 1083 sera tested. The male-female sero-prevalence ratio was 1.44:1 and the age group of 15 years and above was most affected. Among the bone marrow aspirates collected from 66 DAT seropositive cases, only 19 were positive for Leishmania donovani (LD bodies). Of the 47 DAT seropositive but LD bodies' negative cases, three were clinically active cases of kala-azar. Another nine developed clinical symptoms of kala-azar during 6 months follow-up and 23 were cases that had received prior treatment for kala-azar (within 1 year). The results of this study show the potential of the DAT on filter paper as a screening test for the surveillance of kala-azar at a community level.     

Evaluation of the direct agglutination test based on freeze-dried Leishmania donovani promastigotes for the serodiagnosis of visceral leishmaniasis in Sudanese patients

The direct agglutination test (DAT) based on freeze-dried (FD) Leishmania donovani antigen was evaluated for the serodiagnosis of kala-azar in a rural setting in eastern Sudan. The performance of the FD-DAT was compared with standard liquid antigen (LQ) by testing serum samples and blood samples collected on filter paper of microscopically and PCR-confirmed VL patients, apparently healthy endemic controls and patients with other relevant infectious diseases for the region. In the present study, the FD-DAT had a sensitivity of 96.8% and a specificity of 96.2%. The LQ-DAT had a sensitivity of 91.0% and a specificity of 96.6%. A high degree of agreement (97.3%; r-value 0.94) was observed between the FD-DAT and the LQ-DAT, as well as between the FD-DAT performed on serum samples and corresponding blood samples collected on filter paper (agreement 97.8%; r-value 0.79). The FD-DAT is very suitable as diagnostic test for kala-azar in remote rural conditions as it is sensitive, specific and stable. The antigen is affordable, reproducible and available, which contributes to the sustainability of the DAT as a diagnostic test for VL.     

Increased sensitivity of the card agglutination test CATT/Trypanosoma brucei gambiense by inhibition of complement

CATT/Trypanosoma brucei (T.b.) gambiense is an antibody detection test currently used in field surveys on Gambian sleeping sickness. The screening test is usually performed on a drop of freshly collected heparinized blood, followed by a more specific confirmation test on diluted blood, plasma or serum. This approach may be biased by the occurrence of a complement-mediated prozone phenomenon causing lower test sensitivity at lower sample dilutions. A simple remedy is by addition of a Ca²⁺ chelating agent such as EDTA.     

湖南省2008-2012年HIV抗体不确定结果分析

目的分析湖南省近5年艾滋病病毒(HIV)抗体不确定结果产生的原因和特点,为改进检测策略提供依据。方法收集2008-2012年HIV抗体不确定结果资料,结合流行病学随访、CD+4T淋巴细胞计数和病毒载量,分析不确定人群转归与蛋白免疫印迹试验(WB)带型分布的关系。结果 2008-2012年共有2995份标本进行了WB确证试验,其中不确定433例,不确定的比例为14.5%。HIV抗体不确定结果的比例逐年增长,从2008年的4.4%(21/477)上升至2012年的23.0%(182/791);其中阳性感染者比例逐年增高,尤其是晚期感染者增长迅速,分别由2009年的10.3%(3/29)和6.9%(2/29)上升到2012年的51.4%(91/177)和35.0%(62/177)。不确定结果中阴性受检者带型分布以p24或gp160为主,一般不超过两条条带;早期感染者带型分布以p24和p24+gp160为主,其中p24出现比例为100%;晚期感染者条带数目较多,显色较弱且组合更多元化,主要为p24、p31、gp120和gp160。结论随着HIV感染者增多,尤其是晚期感染比例增加,对不确定结果应予以重视,及时调整检测策略,避免漏诊。     

HIV抗体快速检测在自愿咨询检测中的应用

目的在AIDS自愿咨询检测(voluntary counselling and testing,VCT)中应用快速检测,并与免疫印迹试验(western blotting,WB)结果比较,探讨进一步缩短确证时间及提高HIV感染者CD4+T淋巴细胞检测率的措施。方法用2种快速试剂进行筛查,对一阴一阳或双阳性样本进行WB确证检测,并比较和评价检测结果,同时采集患者血样行CD4+T淋巴细胞检测。结果 1435份样本中,1种或2种快速试剂检测结果为阳性有398份,经WB检测确证377份阳性,符合率94.7%;2种快速试剂检测结果均为阳性的有379份,WB检测确证376份阳性,符合率99.2%;2种快速试剂检测结果为阴性的有1037份,经PCR检测未发现HIV RNA阳性样本。结论在VCT及各种应急检测时,可用快速试剂进行筛查,然后WB确证,以缩短等待时间,提高CD4+T淋巴细胞检测率。同时为保证检测质量,以防漏检,推荐使用2种质量优良的快速试剂同时筛查。