ELISA与HI法检测麻疹抗体的比较

对人群的麻疹抗体水平监测,目前都采用血凝抑制法,此法虽简便快速,但许多地区因购买猴血球困难无法开展此项工作。本文通过对麻苗免疫前后和健康人群麻疹抗体的测定,比较酶联吸附法(ELISA)和血凝抑制法(HI)敏感性和特异性,结果表明ELISA法可以代替HI法进行麻疹的抗体水平监测。 1 材料与方法法 1.1 ELISA-IgG法 ELISA间接法,以OD值≥2.1的血清最高稀释度为其效价。麻疹人群抗体水平测定血清稀释度<1:200为阴     

麻疹中和试验对酶联免疫吸附试验的质量控制探讨

目的探讨酶联免疫吸附试验(ELISA)检测麻疹IgG抗体的质量控制方法。方法2003年对3个年龄组的294份ELISA法检测麻疹IgG抗体后的血清,用中和试验加以证实。结果两种方法相关,但差异较大,相关系数0.423~0.684,阳性符合率64.76%~98.24%。结论排除两种试验方法本身敏感性的差异,麻疹ELISA-IgG试剂盒质量的稳定性、操作方法的精确性等问题值得关注,必须确保血清学检测方法标准化。     

麻疹血凝抑制试验试剂盒的研制与应用

为了解决麻疹血凝抑制(HI)试验中猴红细胞的保存与人血清中非特异性凝集物质吸收的难点,推广麻疹HI试验方法,研制了麻疹HI试验试剂盒,并用该试剂盒与经典HI试验方法平行检测353份待检血清,结果有322份血清两法检测的效价完全一致(91.2%),其余31份两法检测效价的差异为±2倍,即在HI试验允许误差范围内.两法检测效价的差异无显著的统计学意义 (P＞0.05).而且试剂盒不必用猴红细胞去吸收血清中的非特异性凝集物质,还可在4℃保存4个月以上.该试剂盒的研制与使用,可大大方便与促进麻疹血清流行病学工作的开展.     

SARS-CoV特异性抗体产生规律的初步研究

目的 研究严重急性呼吸综合征(SARS)患者感染后体内病毒特异性抗体产生规律。方法 收集临床确诊为SARS患者的血清和非SARS人群血清标本,用IgM捕获法、间接法和抗原夹心法三种不同方法检测抗SARS病毒特异性IgM、IgG和总抗体。结果 检测146份临床诊断为SARS的患者不同发病时间血清标本,三种抗体阳性率分别为61.64％、53.43％和69.86％;SARS病毒特异性IgM、IgG抗体的最早检出时间分别在发病第7天和第12天,特异性IgM抗体最短在发病后42天消失。三种方法检测70份甲型肝炎患者血清时,均有2份非特异阳性反应,检测127份其他病种血清均阴性,1例密切接触SARS患者的医务人员SARS特异性IgG抗体和总抗体均阳性,三种检测方法均不受类风湿因子影响。结论 与其他病毒感染相比,SARS病毒感染者的特异性IgM抗体检出时间较晚,且持续时间较短;三种检测方法均有较好的特异性和敏感性,可用于SARS的流行病学调查和临床诊断的确认和补充,但不适用于SARS的早期诊断。     

1204例麻疹疑似病例血清学检测结果分析

目的分析芜湖市麻疹疑似病例血清抗体水平,提高麻疹和风疹诊断水平。方法采集2010~2015年疑似麻疹病例1 204份血清,采用酶联免疫吸附法(ELISA)对血清标本进行Ig M抗体检测。结果 6年共检测标本1204份,其中麻疹Ig M抗体阳性267份,总阳性率为22.18%;风疹Ig M抗体258份,总阳性率检为21.43%。不同年份麻疹、风疹抗体阳性率差异有统计学意义(P0.05);麻疹抗体阳性率男女差异有统计学意义(P0.05);不同月份麻疹、风疹病例构成差异有统计学意义(P0.05);麻疹发病高峰主要在3~6月份,0~1岁婴幼儿与16岁及以上人群是主要感染者;风疹发病高峰集中在4~6月份,6~25岁人群为主要发病人群。结论 16岁以上人群已成为本地区麻疹发病主要人群,风疹发病以青少年为主。     

检测麻疹IgM抗体对诊断麻疹的意义和麻疹IgM阳性病例的临床表现

分析了 1993～ 1998年 45 6例采集血标本的麻疹确诊病例和 83例采集双份血标本的麻疹确诊病例的麻疹IgM抗体阳性率。发病后 4～ 2 1天阳性率分别为 92 86%和 95 0 6% ,而发病后 1～ 3天和 2 2～ 42天的麻疹IgM阳性率显著较低。病例的同一份血清检测麻疹和风疹两种IgM抗体 ,说明麻疹阳性和风疹阳性互不干扰 ,各具特异性。分析 2 70份麻疹IgM阳性的病例临床表现 ,不同年龄组和有无免疫史的表现有极显著差别。检测麻疹IgM抗体具有高度特异性、敏感性和早期诊断的意义     

2009年池州市麻疹疑似病例麻疹IgM抗体检测结果分析

目的了解池州市2009年麻疹疑似病例的麻疹IgM抗体水平,为麻疹预防和临床诊断提供可靠依据。方法采用酶联免疫吸附试验（ELISA法）对2009年池州市的麻疹疑似病例血清进行IgM检测。结果共检测血清324份,其中麻疹IgM抗体阳性81份,阳性率25.00%。实验室病例年龄以20～30年龄段最多。发病时间主要集中在3月份到5月份。结论加强麻疹预防知识的健康教育,加强对重点人群麻疹疫苗的强化免疫。     

用ELISA法评定麻疹的免疫状态

本文报告了应用ELISA法和HI法检测麻疹流行前后85对血清的结果。表明:流行前抗体滴度HI<1:2、ELISA<1:100的22例儿童全部发病。另两例,一例HI<1:2、ELISA1:100。一例HI1:2、ELISA<1:100的儿童也发病。5例流行前抗体滴度HI1:2~1:8,ELISA1:100~1:400者,3人发病,2人隐性惑染。流行前抗体滴度HI≥1:16、ELISA≥1:400的56例接触者既未发病,也无抗体升高。两种方法比较表明:当ELISA<1:200为抗体阴性时,ELISA法的灵敏度为100%,特异度为95.2%。ELISA法可以代替HI法进行麻疹的免疫状态监测。     

麻疹被动血凝法和血凝抑制试验法的比较

麻疹抗体测定以往多用血凝抑制试验(HI),但由于该方法需猴血球,使其使用受到一定的限制。近年来推出的麻疹被动血凝试验(PHA)具有特异,敏感、快速和不需猴血球的优点,是替代HI法的方法之一,我们对307份血清用麻疹被动血凝法和常规HI法作了比较,现将结果报导如下:     

乳胶凝集法检测麻疹IgM抗体的应用

为了筛选敏感、特异、快速和经济的麻疹IgM抗体检测方法 ,比较了IgM抗体捕捉乳胶凝集法 (IgM PA)、IgM抗体捕捉酶联免疫吸附试验 (ELISA)法和IgM抗体间接ELISA法检测麻疹血清IgM抗体的优越性。用IgM PA法和两种ELISA法共检测 12 5份麻疹可疑病例和 30份正常儿童血清。结果表明 :三种方法检测 30名健康儿童血清均为阴性。检测 12 5份麻疹可疑病例血清 ,IgM PA检出阳性 80份 ,阳性检出率 6 4%;两种ELISA法检出阳性 75份 ,阳性检出率 6 0 %;两者差异无显著的统计学意义。IgM PA法检测可疑麻疹病人的敏感性为 10 0 %,特异性为 90 %。此方法操作简便 ,成本较低 ,适宜于地区和县级疾病预防控制机构应用。     

捕获-EIA法用于麻疹疫苗免疫效果监测的初步探讨

用捕获-EIA法和血凝抑制试验同时检测72名麻疹疫苗初免者的特异性IgM抗体和血凝抑制抗体。结果表明,72份免疫前及7份未免疫成功者血清,两种方法检测结果完全相符(均为阴性)。65名血凝抑制抗体阳转者,捕获-EIA法检测结果的符合率为83~100%。特异性IgM抗体水平和动态与接种的疫苗病毒量相关。由此,我们认为捕获-EIA法完全可用于麻疹疫苗初免后的效果监测。     

Development of a simple indirect enzyme-linked immunosorbent assay for the detection of immunoglobulin M antibody in serum from patients following an outbreak of chikungunya virus infection in Yangon, Myanmar.

During 1984, 1548 children were admitted to the Yangon [Rangoon] Children's Hospital in Myanmar [Burma] with haemorrhagic fever. No evidence of recent dengue infection was found in 577 of the 803 children from whom paired sera were obtained, raising the possibility of reappearance of Chikungunya virus infection in Myanmar. An enzyme-linked immunosorbent assay (ELISA) for the detection of anti-Chikungunya virus immunoglobulin M (IgM) antibody was prepared and standardized using only reagents which are commercially available or which could be prepared without the use of sophisticated equipment. While there was 90% agreement between haemagglutination inhibition (HI) tests and the IgM ELISA in the diagnosis of acute Chikungunya virus infections, 12 additional patients with stationary anti-Chikungunya virus HI antibody titres could be identified as having acute Chikungunya infections using the ELISA. Furthermore, the ELISA could identify twice as many patients (31/103) at the time of admission to hospital as the HI test (15/103). There was no false positive IgM reaction with the ELISA which could be attributed to the presence of rheumatoid factor. Using the test, 103 of a sample of 163 children who presented to the Yangon Children's Hospital with fever/haemorrhagic fever were diagnosed as Chikungunya patients, 4 had possible dual Chikungunya and dengue infections, 16 had dengue, 30 had neither Chikungunya nor dengue infections, and a definitive diagnosis could not be made for 10 patients. Routine use of the ELISA would alert authorities to future outbreaks of Chikungunya virus infection and avoid admission to hospital of patients with a non-life-threatening viral disease.     

Are many women immunized against rubella unnecessarily?

Radial haemolysis (RH) was used to test sera for immunity to rubella from 1317 patients attending a general practice. One hundred and forty-one (10.7%) were treated as susceptible and offered an attenuated virus vaccine (RA 27/3). Pre-immunization sera from 43% of these patients were reactive at low levels in RH (less than 15 international units rubella antibody per ml). Pre- (S1) and post- (S2) immunization sera from 66 vaccinees were studied in detail. Antibody was detected by RH, haemagglutination inhibition (HI) and enzyme-linked immunosorbent assay (ELISA), and the specific IgM response was measured by a solid-phase M-antibody capture radioimmunoassay (MACRIA). The vaccine-induced IgM response was only detected if the S1 serum was non-reactive by all tests for rubella antibody. It was weaker than that seen following wild virus infection. It could be detected reliably for six weeks, and in most cases for nine weeks, after immunization. In contrast, patients with S1 specimens reactive by RH, HI or ELISA never showed an IgM response in the S2 specimen despite "significant'' antibody rises often being present. It was considered that an IgM response to RA 27/3 was the best indicator of pre-immunization susceptibility to rubella. The failure of many vaccinees to make an IgM response implied that a significant proportion were already immune. It is suggested that the threshold for a report of immunity to rubella could be lowered from 15 i.u. antibody per ml and so fewer women immunized without vaccine being withheld from those who need it.     

Evaluation of serological diagnostic indices for mucocutaneous leishmaniasis: immunofluorescence tests and enzyme-linked immunoassays for IgG, IgM and IgA antibodies

The sensitivity, specificity, positive predictive value, negative predictive value, and efficiency of immunofluorescence (IF) and enzyme-linked immunoassays (ELISA) for IgG, IgM and IgA antibodies were assessed on sera from mucocutaneous leishmaniasis patients and controls. The sensitivity of the IgG-ELISA test was 93.3% with 95% confidence interval higher than what could be due to a random test not associated with the disease. The specificity of all tests, except the IgM-ELISA, gave indices that could not have been due to chance. The IgG-ELISA and IgG-IF had the highest positive predictive value and the kappa statistic showed that the strength of agreement between the disease and the test was strongest for IgG-ELISA. The IgG-ELISA had a negative predictive value with 95% confidence limits that were not due to chance alone. Efficiency was highest for IgG-ELISA and IgG-IF. These results were obtained using sera from patients with severe or long-standing disease and from controls in whom the disease was ruled out by a negative Montenegro skin test. In field surveys where the differences between cases and controls are less easy to define the diagnostic indices of these tests may vary with the disease prevalence.     

Radial haemolysis for the detection of rubella antibody in acute postnatal rubella.

One hundred and forty-eight sera from 101 cases of acute postnatal rubella were examined by the radial haemolysis (RH) technique currently recommended by the Public Health Laboratory Service of the United Kingdom. In 75 cases the date of onset of rash was known. No sera were RH positive until the third day after the onset of rash and one serum was still negative at 9 days. By 10 days all sera gave a zone of at least 10 mm. The antibody response detected by RH appears later than that detected by haemagglutination inhibition (HI). Thirty-nine of the 101 cases could be diagnosed by seroconversion or a significant rise in titre using the HI test (diagnosis of the remainder depending upon rubella-specific IgM tests). Using the RH test this figure rises to 48 but in ten of these cases reliance on RH would have meant a delay in diagnosis. The results also indicate that many more sera would need to be tested for rubella-specific IgM if the RH test was used instead of the HI test for evaluating possible cases and contacts of rubella.     

Long-term antibody response after measles vaccination in an isolated arctic society in Greenland

Scoresbysund is an isolated district on the east coast of Greenland with 500 inhabitants, mainly Polar Eskimos, which had never been exposed to natural measles. In 1968 more than 90% of the population were vaccinated with the Schwarz live further-attenuated measles vaccine and subsequently children born after 1968 likewise received the measles vaccination. Upon the initial measles vaccination no clinical cases of measles have been observed. The immunity status of the isolated population has been followed for 16 years after vaccination by IgM, IgA, and IgG ELISA tests and by HI test on a series of serum samples taken at intervals. Immunoblotting was performed on sera obtained 16 years after the vaccination. In general, antibody studies have demonstrated some decline in antibody titres after the initial measles vaccination. However, a temporary moderate increase in measles antibodies occurred in some individuals 2-4 years after vaccination, probably due to a reinfection of vaccinees. Most of these individuals did not have demonstrable IgA antibodies prior to the supposed reinfection.     

Serologic studies in 11,460 pregnant women during the 1972 rubella epidemic in Israel.

A total of 11,460 women in the first 4 months of pregnancy, either exposed to or with suspected clinical rubella were tested for rubella antibody during an extensive epidemic of this disease in 1972. The proportion of women who were seronegative decreased from 25% at the beginning of the epidemic to 16% toward the end. In 542 (79%) of 682 cases with suspected clinical rubella, the laboratory findings were consistent with recent rubella infection, while in the remaining 140 cases of suspected clinical rubella recent infection could be excluded by serologic tests. CF tests were more useful than HI for confirmation of clinical rubella, and especially for retrospective diagnosis, since elevated titers (larger than or equal to 1:16) were suggestive of recent infection. Paired sera were tested from 4203 patients exposed to rubella: 1126 of the subjects were seronegative and the remaining 3077 seropositive (HI larger than or equal to 1:16) on first testing. In the seronegative group, 278 seroconversions were detected (24.6%): 247 cases of clinical rubella (21.9%) and 31 seroconversions without clinical symptoms (2.7%). Among the seropositive subjects in 2306 instances (74.9%) recent subclinical rubella could be excluded by low and stable HI or CF antibody titers in paired sera. In 32 (1.1%) an antibody rise (HI or CF) without clinical symptoms was detected, and in the remaining 739 (24%) high CF titers were found in paired sera, and these were classified as suspected subclinical rubella.     

Study of acute trichinosis in Ghurkas: specificity and sensitivity of enzyme-linked immunosorbent assays for IgM and IgE antibodies to Trichinella larval antigens in diagnosis

The enzyme-linked immunosorbent assay (ELISA) was successfully applied to detect IgE antibodies against parasitic antigens by using an additional antibody layer to attain an amplification effect. The sera of 18 Gurkha patients with clinical manifestations of acute trichinosis and 35 Chinese with other parasitic infections were tested for antibodies to Trichinella spiralis by IgE-, IgM- and IgG-ELISA, IgG-radioimmunoassay (RIA) and indirect haemagglutination test (IHA). ELISAs for detection of IgE and IgM antibodies provided a 100% specific and sensitive diagnosis. Although IHA, IgG-RIA and IgG-ELISA detected antibodies in 94% of patients, non-specific reactions were also observed in the two last named methods. Muscle biopsies were positive in only 56% of patients.