A comparison of Brucella IgG and IgM ELISA assays with agglutination methodology

Despite brucellosis having a low incidence rate in developed nations, it still remains the leading zoonotic disease in the world. Culturing of Brucella spp. provides good specificity but in cases where the fever is intermittent, sensitivity is problematic. This has led to the development of serological methods of detection. Brucella agglutination methods have been considered the serological gold‐standard since their inception, although commercial Brucella IgG and IgM enzyme‐linked immunosorbentassays are available to potentially aid in the diagnosis of the disease. In our study, anti‐Brucella IgG and IgM assays were compared with agglutination. Individually the IgG assay tested had an accuracy of 56% and the IgM assay had an accuracy of 77%. These poor accuracies reinforce Centers for Disease Control's conclusion that nonagglutination tests should not be used to confirm brucellosis. J. Clin. Lab. Anal. 24:160–162, 2010. © 2010 Wiley‐Liss, Inc.     

Comparison of six commercial tick-borne encephalitis IgM and IgG ELISA kits and the molecular characterization of their antigenic design

Tick-borne encephalitis virus (TBEV) diagnosis is mainly based on the detection of viral-specific antibodies in serum. Several commercial assays are available, but published data on their performance remain unclear. We assessed six IgM and six IgG commercial enzyme-linked immunosorbent assay (ELISA) kits (ELISA-1 through ELISA-6) using 94 samples, including precharacterized TBEV-positive samples (n=50) and -negative samples (n=44). The six manufacturers showed satisfactory sensitivity and specificity and high overall agreement for both IgM and IgG. Three manufacturers showed better reproducibility and were the most sensitive (100%) and specific (95.5–98.1%) for both IgM and IgG. Two of them were also in agreement with the clinical interpretation in more than 90% of the cases. All the assays use inactivated virus as antigen, with strains showing approximately 94% homology at the amino acid level. The antigenic format of the assays was discussed to further improve this TBEV diagnostic tool.     

布鲁氏菌血清 IgM,IgG 抗体胶体金免疫层析检测方法的建立及初步临床应用

目的　应用胶体金免疫层析技术建立一种快速检测布鲁氏菌 IgM,IgG 抗体的方法,并进行初步的性能验证。方法　采用枸椽酸三钠还原法制备胶体金颗粒,标记纯化的抗重组布鲁氏菌抗原,将鼠抗人 IgG 抗体、鼠抗人 IgM 抗体和兔抗布鲁氏菌抗体喷在硝酸纤维素膜上作为检测线和质控线,对 pH 值和抗体浓度等条件优化;评估试剂盒灵敏度、特异度、交叉反应、准确度、精密度和干扰实验;用该方法对临床的 400 份血清进行检测,试管凝集试验验证其准确性。结果　该试纸条最佳胶体金标记的 pH 值为 7.5,标记重组抗原质量浓度为 30?g/ml。方法的灵敏度和稳定性较好且与其他病原菌无交叉反应。血清总胆红素、血脂和血红蛋白浓度的增高会使试纸条显色结果减弱。对400份临床样本进行检测,其结果与试管凝集试验的符合率为 93.75%。结论　该试验建立的布鲁氏菌 IgM/IgG 抗体的胶体金免疫层析检测方法具有较好的特异度和稳定性,整个检测过程可在 15min 内完成,能够快速检测样品血清,适用于现场快速检测。     

Comparison of SARS-CoV-2 IgM and IgG seroconversion profiles among hospitalized patients in two US cities

The clinical and public health utility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serologic testing requires a better understanding of the dynamics of the humoral response to infection. To track seroconversion of IgG and IgM antibodies in patients with SARS-CoV-2 infection and its association with patient and clinical factors and outcomes. Residual patient specimens were analyzed on the Abbott ARCHITECT i2000 instrument using the Abbott SARS-CoV-2 IgG assay and prototype SARS-CoV-2 IgM assay. Age, sex, comorbidities, symptom onset date, mortality, and specimen collection date were obtained from electronic medical records. Three hundred fifty-nine longitudinal samples were collected from 89 hospitalized patients 0 to 82 days postsymptom onset. Of all, 51.7% of the patients developed IgG and IgM antibodies simultaneously; 32.8% seroconverted for IgM before IgG. On average, patients seroconverted for IgG by 8 days and for IgM by 7 days postsymptom onset. All patients achieved IgG seropositivity by 19 days and IgM seropositivity by 17 days. Median time to IgG and IgM seroconversion was prolonged and initial levels of IgG were lower in immunocompromised patients and patients <65 years of age compared to immune competent patients and those ≥65 years of age. Immunocompromised patients also had persistently lower levels of IgM that peaked on day 17.6 and decreased thereafter compared to immune competent patients. IgM seroconversion in patients who died reached significantly higher levels later after symptom onset than in those who recovered. SARS-CoV-2 infected patients have similar time to seroconversion for IgG and IgM. However, differences in immune status and age alter time to seroconversion. These results may help guide serologic testing application in COVID-19 management.     

胶体金法与ELISA检测新型冠状病毒IgM和IgG抗体的临床诊断价值比较

目的 通过胶体金法与酶联免疫吸附测定(ELISA)检测新型冠状病毒(SARS-CoV-2)特异性抗体免疫球蛋白(Ig)M和IgG,评价2种方法在检测SARS-CoV-2特异性抗体中的诊断价值.方法 收集2020年1-2月在该院住院的患者81例,根据相关标准分为新型冠状病毒肺炎(COVID-19)确诊患者组38例,疑似患...     

SARS患者免疫球蛋白抗体动态监测及意义

目的 :动态监测严重急性呼吸综合征 (SARS)患者抗 SARS病毒免疫球蛋白 Ig G和 Ig M抗体并探讨其意义。方法 :采用间接酶联免疫吸附法 ,检测早期、恢复期 SARS患者以及出院后 SARS随访者、急诊一线未患 SARS健康医务人员、健康体检者血清中抗 SARS病毒 Ig G和 Ig M抗体的动态变化。结果 :SARS不同时期和不同人群 SARS病毒特异性 Ig G和 Ig M抗体阳性数有显著性差异 (P均 <0 .0 0 5 )。在疾病早期 ,Ig G抗体阳性率明显高于 Ig M抗体 ,而且在疾病恢复期和出院后随访时以及急诊一线未患病人群中 ,Ig G抗体的阳性率始终高于 Ig M抗体。结论 :SARS病毒抗体变化规律与一般传染病抗体产生规律不同 ,可用于流行病学调查和血清学诊断。     

A repA-based ELISA for discriminating cattle vaccinated with Brucella suis 2 from those naturally infected with Brucella abortus and Brucella melitensis

The commonest ways of diagnosing brucellosis in animals include the Rose-Bengal plate agglutination test, the buffered plate agglutination test (BPA), the slide agglutination test, the complement fixation test, and the indirect enzyme linked immunosorbent assay (I-ELISA). However, these methods cannot discriminate the Brucella vaccine strain (Brucella suis strain 2; B. suis S2) from naturally acquired virulent strains. Of the six common Brucella species, Brucella melitensis, Brucella abortus, and B. suis are the commonest species occurring in China. To develop an ELISA assay that can differentiate between cows inoculated with B. suis S2 and naturally infected with B. abortus and B. melitensis, genomic sequences from six Brucella spp. (B. melitensis, B. abortus, B. suis, Brucella canis, Brucella neotomae and Brucella ovis) were compared using Basic Local Alignment Search Tool software. One particular gene, the repA-related gene, was found to be a marker that can differentiate B. suis from B. abortus and B. melitensis. The repA-related gene of B. suis was PCR amplified and subcloned into the pET-32a vector. Expressed repA-related protein was purified and used as an antigen. The repA-based ELISA was optimized and used as specific tests. In the present study, serum from animals inoculated with the B. suis S2 vaccine strain had positive repA-based ELISA results. In contrast, the test-positive reference sera against B. abortus and B. melitensis had negative repA-based ELISA results. The concordance rate between B. abortus antibody-negative (based on the repA-based ELISA) and the Brucella gene-positive (based on the ‘Bruce ladder’ multiplex PCR) was 100%. Therefore, the findings suggest that the repA-based ELISA is a useful tool for differentiating cows vaccinated with the B. suis S2 and naturally infected with B. abortus and B. melitensis.     

Comparison of two Cobas Core enzyme immunoassays with other test systems for the detection of cytomegalovirus-specific IgG and IgM antibodies

The new Cobas Core CMV IGM and IgG enzyme immunoassays (Roche Diagnostic Systems, Basle, Switzerland) were evaluated for their ability to detect cytomegalovirus (CMV)-specific IgM and IgG antibodies. Therefore, both were compared with some other commercially available and already established serological tests used in the laboratory diagnosis of CMV infection. These included the Abbott IMx CMV IgM and IgG assays, the Abbott CMV-M EIA, the Gull CMV IgM and IgG immunofluorescence tests, the medac CMV-IgM-ELA, and the Enzygnost anti-cytomegalovirus assay (Behringwerke). A total of 572 serum samples of various categories were examined and the results showed high concordances between all methods, ranging from 84.5% to 94.9%. In a follow-up on renal transplant patients, the times of first detection of seroconversions were compared. Since a high overall agreement between the Cobas Core CMV IgM and IgG enzyme immunoassays and the other test systems were observed, these new assays represent useful and reliable tools for clinical CMV diagnosis. © 1994 Wiley-Liss, Inc.     

IgG抗-E合并IgG+IgM抗-Mur致交叉配血不合分析

目的对输血前检测中发现抗-E、抗-Mur的患者进行血型血清学特异性鉴定,分析其在输血中的临床意义。方法采用微柱凝胶法检测患者血清与抗体筛查谱细胞的反应格局,鉴定抗体的种类及特异性。结果 2例患者血清中均存在IgG抗-E合并IgG+IgM抗-Mur 3种抗体。结论抗-E与抗-Mur都易引起溶血性输血反应,准确的抗体鉴定基础上挑选合适的供血者,可为输血安全提供保障。     

Pre- and postsurgical detection of IgG,IgM, and IgA specific to hydatidosis by ELISA with purified antigen enriched with the 5/B antigen complex

An enzyme-linked immunoassay (ELISA) using purified 5/B Echinococcus enriched antigen was used to follow IgG, IgM, and IgA antibody levels pre- and posttreatment or surgical removal of hydatid cysts. The sensitivity was 97%, 37.5%, and 54.5%, respectively, and the specificity was 95.7%, 100%, and 98.9%, respectively. All isotypes could be detected 3 years after surgical removal of cysts in patients showing no remaining cyst evidence. This was especially true for IgG, which persisted in 85.2% of the patients. The data indicate that antigen purification improves specificity without affecting sensitivity, although this new antigen offers no advantages in the postsurgical monitoring of the patients.     

血清SARS-CoV-2IgM和IgG抗体阳性患者血常规及肾功能参数分析

目的 了解新型冠状病毒(SARS-CoV-2)IgG抗体阳性患者的血常规及肾功能参数特点,鉴别诊断SARS-CoV-2感染患者及抗体阳性患者的血液指标,为早期临床诊断提供依据.方法 回顾性分析常州市第一人民医院2020年3月19-31日门诊检测SARS-CoV-2 IgG和IgM抗体阳性患者,体检中心健康成年人及传染病院核酸阳性确诊的SARS-CoV-2感染患者临床资料.所有患者均检测血常规、肾功能,以及影像学CT平扫胸部检查,选择有鉴别意义的标志物.结果 新型冠状病毒肺炎患者白细胞计数、淋巴细胞计数及嗜酸性粒细胞计数均明显低于健康成年人,差异均有统计学意义(P<0.05);肾功能参数中,新型冠状病毒肺炎患者的肌酐明显高于健康成年人,差异有统计学意义(P<0.05).SARS-CoV-2 IgM和IgG抗体阳性患者与健康成年人比较,白细胞计数差异无统计学意义(P>0.05);但淋巴细胞计数明显低于健康成年人,差异有统计学意义(P<0.05);肾功能参数中,两组肌酐水平比较,差异无统计学学意义(P>0.05).结论 SARS-CoV-2 IgM和Ig G抗体阳性提示为感染中后期或既往感染,抗体阳性核酸检测阴性是否为假阳性或无症状感染者自愈值得临床进一步观察研究.血常规及肾功能参数在鉴别诊断中存在一定意义,可为核酸及CT诊断提供补充.     

Clinical reliability of IgG, IgA, and IgM antibodies in detecting Epstein-Barr virus at different stages of infection with a commercial nonrecombinant polyantigenic ELISA

We studied the diagnostic reliability of a modification of the Enzygnost EBV test (Behringwerke, Germany) for the detection of IgG, IgA, and IgM antibodies (Abs) in the diagnosis of Epstein-Barr virus (EBV) disease. One hundred and twenty-three serum samples were studied: 14 asymptomatic subjects without EBV infection, 48 patients with primary infection, 46 subjects with past EBV infection (11 patients with other acute infections), 8 patients without EBV infection but with other viral infection, and 7 patients with probable acute clonal stimulation of B lymphocytes caused by different microorganisms. Enzygnost EBV is based on an ELISA test with a pool of viral antigens. In our series the reliability of IgM for the diagnosis of recent primary EBV infection was: sensitivity 100%, specificity 95%, positive predictive value 90.5%, and negative predictive value 100%. The IgG detection with Enzygnost was: sensitivity 98%, specificity 100%, positive predictive value 100%, and negative predictive value 91.7%. Only two subjects had positive IgA. The Enzygnost test is an efficient method for the diagnosis of EBV infection although a few IgM false positives can occur.     

SARS患者康复后血清抗SARS病毒特异性抗体IgM和IgG动态变化

目的:探讨SARS患者康复后4年内血清抗SARS病毒特异性抗体IgM(SARS-CoV-IgM)和IgG(SARS-CoV-IgG)的动态变化.方法:前瞻性跟踪50例SARS患者血清抗SARS-CoV-IgM和IgG的变化.用ELISA法检测该组患者患SARS后第0～10 d、11～20 d、21～30 d、31～40 d、41～50 d、51～60 d、61～70 d、71～80 d、81～90 d、91～120 d、121～150 d和第4年血清抗SARS-CoV-IgM和lgG的变化.结果:抗-SARS-CoY-IgM和IgG阳性率均在SARS发病10d后逐渐升高.并在发病后31～40d达100%,但抗-SARS-CoY-IgM阳性率在发病51～60d后逐渐下降,发病后第4年为0;抗SARS-CoV-Igc阳性率在发病81～90d后逐渐下降,发病后第4年为47%.在体内维持时间较短,而IgG下降缓慢,在体内维持时间较长.结论:根据SARS患者血清中抗-SARS-CoV-IgM在体内维持时间短和IgG在体内维持时间长的特点,抗-SARS-CoV抗体可用于SARS流行病学追踪调查.     

Serum IgA and IgG antibodies to α-gliadin: Comparison between two ELISA methods

Summary We have developed two ELISA methods, i.e., enzyme immunoassay (EIA) and fluorescence immunoassay (FIA), for the semiquantitative detection of specific IgA and IgG antibodies directed against α-gliadin. The tests differ only for the enzyme substrate and, when optimized, could be used in large routine screening of celiac disease. Several serum samples from patients with celiac disease and gastrointestinal disorders as well as from control subjects were tested. Both methods gave good correlation with clinical data, were easily performed and had same specificity features, while FIA proved to be more sensitive.