Donor screening for antibody to hepatitis B core antigen and hepatitis B virus infection in transfusion recipients

BACKGROUND: Testing for antibody to hepatitis B core antigen (anti-HBc) as a surrogate for hepatitis C viremia is no longer needed for blood donor screening. Currently, the important question is how much its use supplements hepatitis B surface antigen (HBsAg) donor screening in preventing transfusion-transmitted hepatitis B virus (HBV) infection. STUDY DESIGN AND METHODS: In a study conducted in the 1970s, 64 blood donors were associated with 15 cases of HBV (1.0%) in 1533 transfusion recipients. Sera from 61 donors at donation and 29 follow-up visits were available for present-day assays for HBsAg, HBV DNA, anti-HBc, and antibody to HBsAg (anti-HBs). RESULTS: HBsAg was found in four previously negative blood donors; HBV DNA was limited to three of these four. Anti-HBc was detected in six HBsAg-negative donors. Two other donors were negative in all assays at donation, but positive for anti- HBc and anti-HBs 2 to 4 months later. The remaining donors were negative for all HBV markers, which left five recipient cases unexplained. No HBV transmission was observed when anti-HBs sample-to- negative control values were > or = 10. CONCLUSION: Some 33 to 50 percent of cases of hepatitis B that could be transmitted by transfusion of blood from HBsAg-negative donors are prevented by anti- HBc screening. Anti-HBc-positive donors unequivocally positive for anti- HBs should be considered noninfectious for HBV and should be allowed to donate. Anti-HBc screening of paid plasmapheresis donors, supplemented by anti-HBs testing, would reduce the amount of HBV to be processed by virus inactivation and increase the content of anti-HBs in plasma pools.     

Carrier-directed anti-hapten responses by b-cell subsets

The capacity of the trinitrophenyl (TNP) haptenic group, coupled to a series of chemically dissimilar carriers, to cross-stimulate putative T- dependent and T-independent murine B-cell subpepulations was determined by using an in vitro limiting dilution technique to generate primary IgM responses. It was found that TNP-Ficoll and TNP-dextran, two T- independent antigens with little or no polyclonal mitogenicity, stimulate the same population of anti-TNP precursors, which is distinct from the precursor population activated by TNP-bacterial lipopolysaccharide (LPS), a T-independent polyclonal mitogen, or TNP-horse erythrocytes (HRBC), a T-dependent antigen. On the other hand, TNP-LPS and TNP-HRBC activate the same precursor population, indicating that LPS can substitute for the T- cell signal in T-dependent B-cell responses, whereas nonmitogenic T- independent antigens cannot. However, the cumulative evidence from this and other laboratories strongly indicates that LPS and T-dependent antigens activate B cells by different mechanisms. Of particular interest, LPS is incapable of activating B cells responsive to weakly- or nonmitogenic T-independent antigens. Based on clonal burst size, T-dependent antigens are capable of inducing greater antigen-specific B-cell proliferation than T-independent antigens. However, TNP conjugates of Ficoll and dextran, which are relatively poor inducers of polyclonal B-cell activation, induced larger anti-TNP clones than did TNP-LPS, a strong polyclonal mitogen. The findings reinforce the evidence favoring existence of multiple B- cell subpopulations with distinctive activation pathways. They also strengthen the proposition that a given B-cell subset can be activated by more than one mechanism.     

Adverse reactions in blood donors with a history of seizures or epilepsy

BACKGROUND: Individuals with epilepsy or seizure disorders are restricted from donating blood because of concern that they are prone to adverse donor reactions such as syncope and convulsions. A study evaluating whether that concern is warranted is reported. STUDY DESIGN AND METHODS: During a 2-year period beginning in 1987, blood donors in Maryland with a history of seizures were actively recruited by the American Red Cross. Adverse donor reactions were classified as "slight", indicating dizziness and nausea without loss of consciousness; "moderate," denoting syncope; and "severe," indicating convulsive syncope. RESULTS: There were 329,143 satisfactory blood donations; 613 individuals reporting a history of seizures donated blood a total of 723 times. Among donors with seizures, 186 (35.7%) were taking antiepileptic medication, and 61 (8.4%) had had one or more seizures in the preceding year. Individuals with seizures had a low incidence of adverse reactions (3.34%). Although this incidence was slightly higher than that in the entire population (2.24%), the difference was not significant. In particular, the risk of syncope with or without convulsive activity was low for people with seizures (0.21%) and not significantly greater than that in other donors (0.28%). CONCLUSION: Individuals with seizures or epilepsy are not at greater risk for adverse reactions after blood donation, and major restrictions on their participation as blood donors are not warranted.     

PSNAV2.0-TNFα重组质粒的构建及其在体外的表达

目的:在前期微囊化基因工程细胞制备平台的基础上,构建分泌型人肿瘤坏死因子α的真核表达载体PSNAV2.0-TNFα重组质粒,并鉴定其蛋白的体外瞬时表达,为进一步利用该基因进行微囊化细胞移植治疗和改善疾病奠定基础。方法:实验于2006-06/2007-05在解放军总医院老年医学研究所细胞生物学实验室完成。①以含有人肿瘤坏死因子αcDNA序列的质粒为模板,通过PCR扩增获得人肿瘤坏死因子α基因片段;将其定向插入真核表达载体PSNAV2.0中,获得重组质粒PSNAV2.0-TNFα。采用SalⅠ和EcoRⅠ双酶切法、PCR法及插入片段序列测定法鉴定该质粒。②利用阳离子脂质体介导法,将其转染到人胚胎肾细胞HEK-293细胞中,构建可持续分泌人肿瘤坏死因子α的基因工程细胞,采用RT-PCR法和Western blot法检测转染细胞培养上清液中人肿瘤坏死因子蛋白的体外瞬时表达。结果:①通过SalⅠ和EcoRⅠ双酶切、PCR及测序鉴定证明:在HEK-293中插入片段正确。②采用RT-PCR和Western blot法检测表明HEK-293细胞培养上清中有人肿瘤坏死因子α蛋白,Mr17000。结论:成功构建了重组质粒PSNAV2.0-TNFα真核表达载体,转染HEK-293细胞后可有效分泌人肿瘤坏死因子α蛋白,并能分泌到细胞外。     

The use of a recombinant immunoblot assay in the interpretation of anti- hepatitis C virus reactivity among prospectively followed patients, implicated donors, and random donors

Samples from prospectively followed recipients, their respective donors, and a cohort of random donors were used to evaluate the specificity and efficacy of a recombinant immunoblot assay (RIBA) as an adjunct to anti-hepatitis C virus (HCV) testing by enzyme immunoassay (EIA). RIBA reacted (RIBA+) in 100 percent of patients who developed hepatitis associated with anti-HCV seroconversion documented by EIA and in 100 percent of the EIA-positive (EIA+) donors implicated in these cases. In contrast, RIBA reacted in none of 10 recipients who were EIA+ but did not develop hepatitis, in none of 7 EIA+ patients with hepatitis B or cytomegalovirus infection, in 33 percent of EIA+ donors who were not implicated in hepatitis transmission, and in 37 percent of EIA+ random donors. Hence, the vast majority of EIA+ individuals who have ancillary evidence of HCV infection react on RIBA, whereas the majority of EIA+ individuals in low-risk settings do not react (RIBA-negative, or RIBA-). There was a strong association between RIBA reactivity and the presence of a surrogate marker (elevated alanine aminotransferase [ALT] and/or antibody to hepatitis B core antigen); 43 percent of RIBA+ implicated donors had a surrogate marker as compared to none of 14 EIA+, RIBA- donors. Among EIA+ random donors, 77 percent of those with a surrogate marker were RIBA+, as compared with 29 percent of those without a surrogate marker. In addition, in EIA+ donors, RIBA reactivity correlated with the extent of ALT elevation; 86 percent of those with an ALT greater than 135 IU per L were RIBA+ compared with 18 percent of those with an ALT less than 30 IU per L.(ABSTRACT TRUNCATED AT 250 WORDS)     

壳聚糖载体介导关节内基因转移：转染效率与基因产品的关系

目的:分析壳聚糖-DNA超微颗粒在关节内的转基因效应。方法:实验于2005-09/2006-06在上海交通大学医学院健康科学研究所骨科细胞与分子生物学实验室完成。实验材料:①模型制备:采用切断内侧副韧带,切除内侧半月板的方法制备骨关节炎兔模型。②基因产品:白细胞介素(interleukin,IL)1Ra基因、IL-10基因。实验分组:15只新西兰兔按随机数字表法分为3组:①空载体对照组(n=3),造模后5d两侧膝关节关节腔注射400μL壳聚糖-PcDNA3.1溶液,共3次,每48h1次。②IL-1Ra基因治疗组和IL-10基因治疗组,每组6只,造模后5d对照侧膝关节关节腔分别注射20μg裸DNA(PcDNA3.1-IL-1Ra或PcDNA3.1-IL-10),实验侧膝关节关节腔注射400μL壳聚糖-DNA超微颗粒(含20μgIL-1Ra或IL-10),注射次数及间隔时间同空载体对照组。实验评估:①采用酶联免疫吸附分析及免疫组织化学检测IL-1Ra和IL-10基因的表达和分布。②苏木精-伊红染色和甲苯胺蓝染色观察骨关节炎软骨组织学变化。结果:纳入新西兰兔15只,均进入结果分析。①IL-1Ra和IL-10基因在关节滑液中的表达:空载体对照组及IL-1Ra基因治疗组对照侧膝关节滑液中未检测到IL-1Ra表达,实验侧于第1次基因注射后7,14d检测到IL-1Ra表达。IL-10基因治疗组对照侧和实验侧均未检测到IL-10表达。②IL-1Ra基因在兔膝关节的分布:IL-1Ra基因治疗组兔软骨表层和中间层部分细胞内表达IL-1Ra,至少持续到第1次基因注射后14d。在滑膜组织中未观察到明显的IL-1Ra表达。③兔骨关节炎软骨组织学变化:空载体对照组呈早期骨性关节炎的典型性改变。苏木精-伊红染色显示软骨细胞坏死,蛋白多糖甲苯胺蓝染色不均一,软骨表层和中间层大部分区域失染,软骨细胞簇聚区域其周围深染。IL-1Ra基因治疗组在软骨损坏方面明显减轻,甲苯胺蓝部分失染。结论:①壳聚糖-DNA超微颗粒的转染效率与基因产品有关。②将IL-1Ra用关节腔直接注射壳聚糖-DNA超微颗粒的方法直接转移入关节腔能一定程度上减轻骨性关节炎的进程。     

A search for hepatitis C virus polymerase chain reaction-positive but seronegative subjects among blood donors with elevated alanine aminotransferase

BACKGROUND: Previous studies reported the existence of hepatitis C virus (HCV) polymerase chain reaction (PCR)-positive but seronegative sera. This is not surprising in the case of window-phase specimens, because PCR can detect HCV RNA many weeks before the appearance of antibody. To determine whether such sera can also be found in chronically infected subjects, a high-risk population of blood donors with elevated alanine aminotransferase was studied. STUDY DESIGN AND METHODS: Freshly frozen plasma from 301 donors with alanine aminotransferase > 100 IU per L was tested with PCR assays that were rigidly controlled for specificity and contamination, and with current and newer versions of assays for anti-HCV. Sera were classified as seropositive if positive in two screening assays and one supplemental assay or if positive in two screening assays and PCR. RESULTS: New versions of screening assays detected 100 percent of seropositive samples. A second-generation immunoblot assay detected 98 percent of seropositive sera, a second-generation recombinant immunoblot assay detected 96 percent, and an enzyme immunoassay for antibody to the envelope protein of HCV detected 98 percent. Fifty-one of 54 seropositive sera were PCR positive. None of the 247 seronegative samples was reproducibly positive on PCR. CONCLUSION: No PCR-positive but seronegative donors were found in this high-risk donor population. The possible benefit of PCR screening of blood donors can be determined only by large-scale comparative testing of donor populations and may be limited to the detection of window-phase infections.     

Characteristics of a donor population in western Venezuela

To determine the characteristics of blood donors in western Venezuela, we collected data from 1983 to 1985 on 31,320 volunteer donors at the Blood Bank of the State of Zulia in Maracaibo. Fifty-nine percent of the donors were blood group O, 30 percent were group A, 9 percent were group B, and 2 percent were group AB. Most of the donors (93%) were Rh positive. One percent of donors had positive reactions to hepatitis B surface antigen, 3.15 percent for syphilis, 1.43 percent for antibodies to Trypanosoma cruzi, and 0.32 percent to human immunodeficiency virus antibodies. About one-half of the donors were between 18 and 30 years old, and only 10 percent were women. To determine if iron deficiency anemia was a cause for the small size of the female donor pool, we measured serum ferritin in 50 first-time female donors. Ten of these (20%) had serum ferritin values below normal, and the distribution of serum ferritin levels of all 50 was very similar to that reported for frequent donors in Europe and the United States, with a clustering of ferritin values between 10 and 70 ng per ml. The data indicate that blood donors in western Venezuela are markedly different from those in the United States and that iron supplementation may be indicated for female Venezuelan donors.     

清开灵与利巴韦林治疗小儿呼吸道合胞病毒肺炎的比较：单盲、随机、平行对照试验

目的:比较清开灵与利巴韦林对呼吸道合胞病毒肺炎患儿治疗效果的差异。方法:选择2005-02/2006-04在北京儿童医院分中心治疗的小儿呼吸道合胞病毒肺炎97例,患儿法定监护人知情同意。采用单盲、随机、平行对照试验的原则,按区组随机化方法分为2组,清开灵注射液组49例,利巴韦林组48例。①清开灵注射液组:清开灵注射液静脉滴注加口服中成药。②利巴韦林组:利巴韦林注射液静脉滴注加口服复方愈创木酚磺酸钾口服液。两组疗程均为10d,比较两组患儿的疗效。结果:清开灵注射液组脱落3例,利巴韦林组脱落1例,进入结果分析清开灵注射液组46例,利巴韦林组47例。①清开灵注射液组发热患儿体温恢复正常时间比利巴韦林组短[(2.72±1.86)d,(6.29±2.41)d(P<0.01)]。②清开灵注射液组患儿咳嗽、痰壅、气促症状积分改善方面优于利巴韦林组(P<0.05～0.01)。③清开灵注射液组的呼吸道合胞病毒转阴时间明显优于利巴韦林组。④咳嗽、痰壅、病毒转阴时间、气促均进入Logistic模型,其中前两个症状的回归系数绝对值较大。结论:清开灵注射液治疗小儿呼吸道合胞病毒肺炎在退热、止咳平喘、呼吸道合胞病毒转阴时间等方面均具有明显优势,咳嗽、痰壅这两个症状更能反映清开灵注射液的疗效优于利巴韦林。