Risk of HIV infection in recipients of untested blood from donors now anti-HIV-positive

Recipients of untested blood from donors who at a subsequent donation were positive for HIV antibody by enzyme immunoassay (EIA) were evaluated, whether the result on Western blot (WB) assay was negative (EIA+/WB-) or positive (EIA+/WB+). For 109 EIA+/WB- donors, 78 recipients were tested for HIV antibody, and 3 (4%) were positive. Two of the three anti-HIV-positive recipients had clotting disorders, and the other had been massively transfused; in each of these three cases, subsequent test data exonerated the EIA+/WB- donor. For 101 current EIA+/WB+ donors, 35 recipients were tested for HIV antibody, and 13 (37%) were positive. For donors subsequently found to be EIA+/WB+, the rate of isolation of HIV was the same whether the recipients were anti-HIV-positive or anti-HIV-negative (each, 5/6). While recipients of blood from donors subsequently found to be EIA+/WB+ were at substantial risk for HIV infection, regardless of the donor's subsequent HIV culture result, risk of HIV infection was not demonstrated for recipients of blood from donors later found to be EIA+/WB-.     

Evaluation of a commercially developed indirect immunofluorescence system for the detection of antihuman immunodeficiency virus antibodies

A commercially developed IFA system (Electro Nucleonics, Inc.) was compared to EIA (Abbott Laboratories) and WB (Bio-Rad, Inc.) for detection of HIV-1 antibodies. Of 91 EIA negative sera tested, 76 (83.5%) were negative, and 15 (16.5%) were equivocal by IFA on initial testing. Of 156 EIA positive sera tested, 18 were equivocal by either IFA or WB and could not be directly compared. Of 138 EIA positive sera directly comparable, IFA and WB agreed 137 times (99.3% correlation). Based on these findings, the commercially developed IFA system appears to be most useful as a supplementary test, similar to WB, rather than as a screening test.     

人类免疫缺陷病毒/丙型肝炎病毒共感染对实验室诊断影响的研究

目的 研究人类免疫缺陷病毒（HIV）／丙型肝炎病毒（HCV）共感染对两种病毒感染实验室诊断的影响。方法 对300例经免疫印迹试验（WB）确认的HIV感染者，以酶免疫测定HCV抗体，测定CD4／CD8计数；其中197例测定病毒载量，逆转录聚合酶链反应检测HCV核酸，阳性样品限制性片段长度分析丙肝分型，比较共感染和非共感染组在各检测诊断指标的差别。结果 HCV诊断：HCV抗体阴性组中19．5％为核酸阳性。多元回归分析，HCV核酸阳性，1b＋2a混合感染，1b基因型的感染3个因素对HCV EIA检测的S／CO值的升高有独立的显著影响。HIV诊断：300例，共感染组和非共感染组HIV ELISA A〈3的样本比例分别为4／265，5／41，有P〈0．01的差异有统计学意义；A〉3的样品中CD4分组后按比例取77份比较WB条带，共感染组P55条带出现率显著高于非共感染组（16／30，12／47，P〈0．01）。结论 HIV免疫抑制可造成很高的HCV抗体假阴性率，该人群推荐HCV核酸定性检测。共感染对HIV ELISA检测的影响表现为强阳性比例的显著提高；对HIV WB各主要诊断条带未见影响，共感染组p55条带比例显著高可能提示病毒间免疫和分子水平相互作用。对HC VEIA-3的S／CO值有独立影响的因素包括HCV核酸阳性，1b＋2a混合感染，1b基因型。     

Comparative evaluation of an immunofluorescent antibody test, enzyme immunoassay and western blot for the detection of HIV-1 antibody

Screening blood and blood products for human immunodeficiency virus type 1 (HIV-1) antibody is predominantly performed by enzyme immunoassay (EIA), and results must be confirmed by the more immunospecific Western blot (WB) assay. This study evaluated an HIV immunofluorescent antibody (IFA) test relative to WB assay for use in confirming EIA designated HIV-1 antibody-positive sera. Specimens from seroconversion and CDC panels as well as clinical specimens obtained for routine EIA HIV-1 antibody screening were evaluated. Results with 209 specimens indicated that sensitivity and specificity of the Fluorognost-HIV assay were equivalent relative to WB. In addition, the Fluorognost-HIV IFA test was faster and easier to perform than the WB assay, and unlike the WB assay was not prone to indeterminate results.     

Evaluation of a confidential method of excluding blood donors exposed to human immunodeficiency virus

A confidential self-administered questionnaire was given to all donors prior to blood donation (n = 95,917). The questionnaire describes acquired immunodeficiency syndrome (AIDS) high-risk groups and requires the donor to designate his blood for either laboratory purposes or for transfusion. Six-hundred and twenty-seven people (0.65%; 78% men) designated their blood for laboratory purposes. In addition to routine enzyme-linked immunoassay (EIA) screening for human immunodeficiency virus (HIV) antibody, all units from the latter group of donors were tested by Western blot (WB) irrespective of the EIA result. An equal number of donor units was selected from those designating their blood for transfusion (age, sex and clinic matched) and these too were tested by WB irrespective of the EIA result. We found that donors designating their blood for laboratory purposes had a 10 times (vs transfusion-designated controls) to 100 times (vs general donor population) greater exposure to HIV. In the laboratory-designated group, an EIA negative donor was WB positive, yielding an estimated EIA false-negative rate of 16 per million. A confidential questionnaire, as described, is a valuable adjunct in ascertaining high-risk blood donors.     

Immunoglobulin (Ig) M antibody against myelin associated glycoprotein (MAG): A comparison of methods

The presence of immunoglobulin (Ig)M antibody against myelin associated glycoprotein (MAG) has been associated with autoimmune demyelinating, sensorimotor neuropathies. Approximately 50% of patients with IgM paraproteinemia and associated peripheral neuropathy possess antibodies against MAG. These autoantibodies are thought to interfere with the process of myelination, myelin maintenance, or axon-Schwann cell interaction. The detection of these autoantibodies is useful to the clinician and is suggestive of active demyelination in a peripheral neuropathy. Our objective in this study was to compare the results obtained using three different methods (dual enzyme immunoassay [EIA], immunofluorescent antibody [IFA] and Western blot [WB]) for detecting IgM antibody against MAG in patients suspected of having autoimmune demyelinating neuropathies. Since the dual EIA utilized two different antigens, results from this assay were separated into two groups: MAG and sulfate-3-glucuronyl paragloboside (SGPG). When compared to WB (gold standard), percent agreement, sensitivity, and specificity for EIA and IFA are as follows: MAG EIA (68.3, 100.0, and 60.6); SGPG EIA (95.1, 100.0, and 93.9); and myelin IFA (97.6, 100.0, and 97.0). The authors conclude that the SGPG EIA and myelin IFA compared well with the standard WB method when detecting IgM antibody against MAG (100 kD). Many sera demonstrated reactivity on the MAG EIA that were negative by WB (100 kD glycoprotein). The authors recommend screening for MAG IgM in suspected patient sera by SGPG EIA or myelin IFA and utilizing these same methods to titer sera confirmed positive by WB.     

Effect of Heat Inactivation of Serum on Bordetella pertussis Antibody Determination by Enzyme-linked Immunosorbent Assay

The effect of heat inactivation on Bordetella pertussis antibodies determined by enzyme-linked immunosorbent assay (ELISA) was studied. Sera were heated at increasing temperatures (from 30 to 50°C at 5°C increments and from 52 to 70°C at 2°C increments). Between 30 and 50°C, no significant differences were observed in immunoglobulin G (IgG) antibodies to pertussis toxin (PT). From 50 to 56°C the antibody values were twofold higher than those of uninactivated sera; at 64°C the values were 3.6- to 9.1-fold higher. The increase in PT IgG antibody values was more pronounced in sera with low antibody values. ELISA antibody values of sera from a vaccine trial were determined in unheated and heat inactivated sera. The geometric mean value (GMV) of the heat inactivated samples was 3.2 times the geometric mean value of the uninactivated sera. ELISA IgG antibodies to filamentous hemagglutinin, fimbriae-2, and pertactin were studied, and the values of heat inactivated sera did not differ significantly from the values of the uninactivated sera. Our findings indicate that heat inactivation of sera leads to higher, variable, and false-positive PT IgG values.     

丙型肝炎病毒抗体筛查阳性结果确证方案的探讨

目的明确抗-HCV酶免检测结果与确证阳性结果之间的相互关系,以期建立简便、经济的血液筛查实验室抗-HCV确证试验方案。方法使用重组免疫印迹试验结合核酸检测方法对134份酶免抗-HCV阳性样本确证,初步探讨2或3种抗-HCV酶免试剂(Ortho、Murex和科华联合复检的S/Co值与阳性预期值的关系及不同试剂组合检测的阳性预期值。结果134份样本中,92份真阳性,5份可疑,其余均为阴性。Ortho和Murex试剂的S/Co与阳性预期值呈正相关,当S/Co≥3.8时,阳性预期值分别可达98.33%和97.78%。Murex联合科华、Ortho联合科华以及3种试剂同时检测为阳性时的阳性预期值为100%;Ortho联合Murex的阳性预期值为98.48%,与上述其它2或3种试剂组合比较,差异无统计学意义(P>0.05)。结论2种或3种酶免试剂联合复检的确证方案优于美国CDC推荐的S/Co≥3.8方案。在常规血液筛查实验室,可以选择3种抗-HCV试剂中的任2种同时复检,先行对抗-HCV阳性标本确证,对无法确证的样本再作重组免疫印迹试验分析。     

Effects of heat inactivation on HIV antibody screening and confirmatory test systems

In order to evaluate the effect of heat inactivation on serum undergoing testing for HIV antibody, 100 heat-inactivated and nonheat-inactivated serum samples were tested by two modifications of Abbott's screening assays for human T-cell lymphotropic virus type-III (lot numbers 1037 and 3036) and by two confirmatory assays (Cambridge BioScience CBre3-EIA; Damon Corporation Western blot). The samples consisted of 75 HIV antibody-negative and 25 HIV antibody-positive sera. The specimens were divided into two equal aliquots. One set was not subjected to heat inactivation, while the others were subjected to heat inactivation at 56 degrees C for 30 min. Heat inactivation had no significant effect on the HIV-position sera; however, heat-inactivated, negative sera evaluated by Abbott lot numbers 1037 and 3036 resulted in false-positive rates of 8% and 7%, respectively. No false positives were generated by the two confirmatory assays; however, the CBre3-EIA recombinant envelope protein assay had a significantly increased optical density reading following heat inactivation of the negative sera. The Western blot procedure used in the study was not affected by heat inactivation.     

Longitudinal follow-up of blood donors found to be reactive for antibody to human immunodeficiency virus (anti-HIV) by enzyme-linked immunoassay (EIA+) but negative by western blot (WB-)

Abstract: A cohort of 467 volunteer blood donors who were found to be EIA+/WB- was studied longitudinally for up to two years. EIA screening for anti-HIV and WB testing, regardless of the EIA result, was performed on all 769 subsequent donation events of this cohort to ascertain the consistency of test results over time. The following results were obtained: 1) 8.8% of subsequent donation events were EIA+; 2) Most donors who returned were found to be EIA-/WB-; 3) EIA-/WB? (indeterminate) was 14.5 times more common than EIA+/WB?; 4) EIA and WB results were generally inconsistent from donation to donation; 5) No donor was found to be WB+. These results suggest that, in a volunteer donor population, an EIA+/WB- result may have little value in predicting anti-HIV test results and AIDS infectivity in a future donation. The current practice of not using blood donated subsequently by EIA+/WB- donors unless a re-entry testing scheme is satisfactorily completed should be reconsidered.     

Delineation of false-positive HIV antibody response in patients with renal failure and history of multiple transfusions

Four patients with a history of multiple blood transfusions who awaited renal transplantation were tested for human immunodeficiency virus (HIV) infection and found to be positive on enzyme immunoassay (EIA) and negative on Western blot. None of these patients had any clinical evidence of HIV infection. Absorption of these patients' sera with B-lymphoblastoid cell lines (B-LCL) positive for the serologic specificities DR3, DR4 (Dw4, Dw10, Dw14), and DR5 resulted in EIAs that were negative for HIV. Treatment of the B-LCL with an anti-DR monoclonal antibody (L243) interfered with the absorption of the serum sample by B-LCL. This indicates that the initial false-positive EIA results may be due to HLA antibodies. Furthermore, it was shown that these HLA antibodies are not limited in specificity to the HLA type of the host cell used in the preparation of the EIA reagents, but can consist of other DR specificities.     

评估第4代HIV酶联免疫法诊断试剂对静脉吸毒者感染窗口期的检测能力

目的应用BBI公司血清抗体阳转盘评价第4代人类免疫缺陷病毒（HIV）酶联免疫法诊断试剂（以下简称第4代试剂）对窗口期感染的检测能力,并应用其从静脉吸毒人群样本中筛查窗口期感染者,从而分析第四代试剂检测临床样本的特异性和敏感性。方法首先应用第3代HIV酶联免疫法诊断试剂筛查BBI血清阳转盘和收集的吸毒人群样本,阳性样本进一步用免疫印迹法确认。再用第4代试剂分别检测阴性和阳性样本,阴性样本中出现阳性反应者,进行p24抗原和HIV RNA病毒载量检测,证实是否为窗口期样本。对证实为窗口期的感染者随访至抗体阳转。结果用第3代试剂检测BBI阳转血清盘,未发现阳性样本;检测静脉吸毒人群样本2629份,发现HIV抗体阳性样本77份,经免疫印迹法（WB）确认均为阳性,阴性样本2552份。第4代试剂可检出BBI阳转血清盘第14天的窗口期样本;在2552份静脉吸毒人群抗体阴性样本中检出2份窗口期样本,一例随访至血清阳转,一例失访。临床检测特异性为99.2％,假阳性率0.8％（95％可信区间0．4％～1．1％）。结论第4代试剂比第3代试剂能够更早地发现HIV感染者,降低窗口期漏检,减少HIV传播。     

Matrix effects in clinical immunoassays and the effect of preheating and cooling analytical samples.

Immunological reactions are influenced by various factors including antigens, antibodies and other variables. We focused on two items: i) matrix effects, especially of detergents and ii) temperature effects: preheating sera, especially effects on rheumatoid factor (RF) measurement and false-positive reactions in ELISAs, and cold storage of sera, especially effects on complement. Among various additives, detergents affected the agglutination reaction for fecal hemoglobin and hepatitis B surface (HBs) antigen. Some of the detergents examined abolished these antigenicities, however, polyethylenglycols enhanced the reactions. Heat-inactivation of sera at 56 degrees C for 30 min was employed in serological testing. However, in RF measurement, 10 min of preheating was sufficient to abolish C1q (subcomponent of C1), which could participate in the agglutination reaction. In ELISA for antibodies, false-positive reactions were caused by preheating sera. By the analyses of assays for antibodies to hepatitis C virus (HCV) and cardiolipin, it was found that they were induced by immunoglobulin G (IgG) modified by preheating. Cold storage induced activation of complement (cold activation) in anti-HCV antibody positive sera. CH50 titers in the sera were lowered by one cycle of freezing at -20 degrees C and thawing, and the decrease was affected by the containers.     

A comparison of polymerase chain reaction and an infectivity assay for human immunodeficiency virus type 1 titration during virus inactivation of blood components

Three examples of human plasma-derived concentrates, intermediate- purity factors VIII and IX, and fibrinogen were spiked with tissue culture-grown human immunodeficiency virus type 1 (HIV-1) strain RF. All examples were freeze-dried and heated at 80 degrees C for 72 hours by using validated production process models. HIV-1 infectivity was measured by a syncytial infectivity assay in C8166 cells and then compared with levels determined by nested HIV polymerase chain reaction (PCR). The infectivity assay demonstrated a reduction index of at least 4.5 log10, while PCR showed an average 1.7 log10. Large amounts of HIV- 1 RNA (10(5)) were still detectable by PCR in samples in which infectivity assays failed to detect any HIV-1. These data suggest that HIV-1 PCR levels do not parallel HIV-1 infectivity levels during virus- inactivation procedures involved in coagulation factor concentrate production. PCR was able to detect the RNA associated with inactivated HIV-1 particles in the factor concentrates, which allows the conclusion that PCR is not a useful test with which to monitor virus-inactivation procedures such as heating at 80 degrees C for 72 hours. This judgment contrasts with the more definite and sensitive role of PCR in diagnosing HIV-1 infection in patients in whom a positive HIV-1 PCR result correlates with active HIV-1 infection and with PCR's usefulness in monitoring virus removal.     

Analysis of false positive HIV-1 serologic testing in Kenya

Sera of 95 mothers and 129 children from Nairobi, Kenya, collected in 1976, and of 466 adults and 193 children of Embu District, Kenya, collected in 1984 and 1985, were analyzed for the presence of human immunodeficiency virus type 1 (HIV-1) antibodies. Although no HIV-1 seropositivity was demonstrated by western blot analysis in both study groups, 7% of Nairobi mothers and 10% of adult females from Embu District had false positive results by enzyme immunoassay (EIA) compared with less than 1% seroreactivity rates observed in adult males and children. False positive results were not due to simian T lymphotropic virus type III (STLV-IIIAGM)/human T lymphotropic virus type IV (HTLV-IV) seropositivity. Sixty-one percent of the HIV-1 EIA reactive sera could not be explained by cytotoxic activity to lymphocytes bearing the HLA-DR4 or HLA-DQw3 phenotype. We conclude that false positive HIV EIA tests are frequently encountered in East Africa. Seroprevalence rates in rural Africa must be interpreted with caution due to the decreased specificity of HIV EIAs.     

Serologic markers for staging human immunodeficiency virus infections

In the present study, 80 serum specimens were tested for human immunodeficiency virus (HIV) antibody by enzyme immunoassay (EIA) and indirect fluorescent antibody tests, HIV (p24) antigen, and Western Blot analyses. A total of 40 specimens were HIV antigen-positive, 35 were antigen-negative and five were indeterminant. Among the 40 antigen-positive sera, 38 had positive antibodies by EIA with confirmation by Western Blot. Two cases were antigen-positive and were thought to be early stages where antibodies had not yet developed. Among the 38 sera, 30 (79%) had decreased or had no reactions by indirect fluorescent antibody tests. Among the 35 antigen-negative cases, all 35 had positive antibodies by EIA and all 35 had bands at gp41 by Western Blot. Among 84 HIV-infected patients, 30 had >400 CD4+ cells per cubic millimeter, 21 patients had 200–400 CD4+ cells and 33 had <200 CD4+ cells. A total of 28 (93%) of the HIV antigen-negative cases with full banding patterns by Western Blot had >400 CD4+ cells. In contrast 18 (55%) of the patients with antigen positivity and incomplete banding on Western Blot had <200 CD4+ cells.     

甲型肝炎病毒感染性灭活与抗原性破坏的比较

经比较，在３００μＷ／ｃｍ２紫外线照射下，ＨＡＶ颗粒感染性灭活速度远快于抗原性的破坏。经１％过氧化氢作用的ＨＡＶ颗粒，其感染性灭活速度与抗原性破坏速度基本呈平行关系，作用６０分钟，感染性消失，抗原性亦被破坏。     

无偿献血者HIV-1抗体蛋白印迹确认与核酸检测结果分析

目的对酶联免疫检测HIV抗体呈反应性标本进行蛋白印迹(WB法)确认和TMA-化学发光法对照检测,以探讨其应用特点。方法将本中心检验科ELISA法检测结果呈HIV抗体反应性的117份标本,重新进行ELISA法检测,结果为S/CO>0.8的标本做蛋白印迹(WB法)确认试验。同时,对117份标本采用TMA-化学发光法检测核酸作为对照试验。血清学检测参加国家CDC及澳大利亚(CITIC)室间质评;核酸检测参加卫生部临检中心和澳大利亚(CITIC)室间质评。结果 ELISA初筛试验:117份标本中,S/CO>1的为37份;0.8相似文献   

Detection of cytomegalovirus antibody in platelet concentrates by fluorescence immunoassay and latex agglutination

A passive latex agglutination (PLA) test for cytomegalovirus (CMV) antibody detection has been shown to be an acceptable method of screening both donor sera and plasma from units of red cells and platelets stored in CPDA-1. However, most plateletpheresis concentrates are collected in ACD, and CMV antibody testing of ACD-stored products has not been systematically evaluated by PLA. Sera and ACD-stored platelet concentrate bag segments from 104 donors were tested by PLA and by a solid-phase fluorescence immunoassay (FIAX) as a reference standard for CMV-IgM and CMV-IgG antibodies. Sera were stored at both 4 and 22 degrees C and were tested on Days 1 and 5 of storage; segments were tested daily for 5 days. Of 63 donor samples (61%) that tested negative for CMV-IgG by FIAX, there were two false-positive results in bag segments by PLA testing, one on Day 1 and the other on Day 2 of storage. PLA testing was consistently positive in sera and segments in the 40 donors (38%) who tested positive for CMV-IgG by FIAX. Potential false-negative PLA results occurred in five bag segments derived from one donor whose serum gave equivocal CMV-IgG results on FIAX. The sensitivity and specificity of the PLA assay were 100 percent for donor sera tested at both 4 and 22 degrees C and 91.5 and 98.4 percent, respectively, for platelet bag segment tests. Although no donors positive for CMV-IgM were identified, 15 (14.4%) had equivocal IgM anti-CMV test results.(ABSTRACT TRUNCATED AT 250 WORDS)