新生儿梅毒螺旋体IgM抗体检测的方法研究与临床应用

目的研究新生儿梅毒螺旋体(TP)-IgM抗体的检测方法,及其在先天性梅毒早期诊断中的价值。方法采用甲苯胺红不加热血清试验(TRUST)和TP酶联免疫吸附试验(TP-ELISA)检测梅毒新生儿及其母亲血清TP-IgM抗体,同时检测血清TRUST滴度。以德国欧蒙试剂为对照,评估去除血清中IgG抗体和IgG型类风湿因子(IgG/RF)、酶标抗IgM抗体和酶标TP抗原等方法对IgM抗体检测效能的影响。结果 108例梅毒新生儿及其母亲TP-ELISA阳性率差异无统计学意义(P>0.05),梅毒母亲的TRUST阳性率显著高于其新生儿(P<0.05),而且梅毒母亲TRUST抗体滴度普遍高于新生儿(P<0.05)。与对照方法相比,IgM抗体检测时去除血清中IgG抗体可获得更好的相关性和一致性(Kappa>0.75),而使用酶标抗人IgM抗体(间接法,Kappa=0.956)比使用酶标TP抗原(双抗原夹心法,Kappa=0.817)的检测结果与对照方法更相近。结论 TRUST和TP-ELISA检测对新生儿先天性梅毒的早期诊断意义较小,而TP-IgM抗体检测方法在先天性梅毒的早期诊断中有较好应用前景。     

IgM antibody response to antigens prepared from vegetative and coccoid forms of Helicobacter pylori

This report describes the utility of antigens prepared from different coccoid and spiral forms of Helicobacter pylori in a serological method. The presence of IgM antibody to H. pylori was determined in 22 human sera on antigens prepared from 24 strains of H. pylori. Antigens prepared from spiral form of certain strains of H. pylori detected IgM in all confirmed positive sera. Antigens obtained from the coccoid cells of the same strains could not completely detect IgM in the same sera. Testing sera on boosted antigens of the coccoid cells showed reduction in the number of false negative, indicating that the coccoid cells do not have one or more antigenic fractions essential for accurate detection of antibody. Our data suggest that H. pylori may lose CagA during the coccoid conversion process and regain it in the spiral form. In conclusion, we suggest that the antigen used for the detection of antibodies to H. pylori in serological methods should contain a broad spectrum of antigenic fractions and should be prepared from certain strains and culturable cells of H. pylori.     

Effect of rat kidney fraction 3 (rKF3) antigen and specific IgM antibody against rKF3 on the progression of slowly progressive Heymann nephritis

The aim of the present study was to find out if specific IgM (M) antibody (directed against rat kidney fraction 3 (rKF3)) or rKF3 antigen were able to influence disease progression in an experimental autoimmune kidney disease called slowly progressive Heymann nephritis (SPHN). The level of circulating autoantibodies (aabs) and the morphological and functional changes to the kidney were studied in six groups of rats. All of the treatment components (except post-treatment with M) used in the SPHN pre- and post-treated rats and post-treated-only rats had measurable beneficial effects (even during restimulation with the chemically modified renal antigen, 22 weeks after the induction of the disease) as demonstrated by diminished pathogenic IgG aab production, less severe kidney lesions, and proteinuria reductions. The injected rKF3 minimized progression best in this experiment, especially when administered in a pre- and post-treatment regimen. It is thought that the effect of rKF3 in the reduced progression of SPHN was due to increased production of specific IgM aabs, which in turn limited pathogenic aab production and continuous buildup of immune complexes in the glomeruli by facilitating removal or blockage of nephritogenic autoantigens from the circulation.     

Sensitivity and specificity of immunoglobulin G titer for the diagnosis of mumps virus in infected patients depending on vaccination status

The aim of the study was to evaluate the usefulness of serological detection of mumps IgM and titration of IgG in patients with acute parotitis according to their vaccination status. The detection of mumps virus RNA in saliva by RT-PCR was used as reference. 116 patients (109 of them previously vaccinated) with mumps RT-PCR-negative results and 21 (19 vaccinated) with mumps RT-PCR-positive results were studied. Mumps-specific IgM and IgG were assayed by EIA (Enzygnost, Dade Behring, Germany). IgM results were expressed as positive or negative. For IgG, several cut-offs were calculated using receiver operating characteristic (ROC) curves. Seven RT-PCR-positive and five RT-PCR-negative patients showed IgM-positive results (sensitivity 33.3% and specificity 95.7%). Among vaccinated patients, the sensitivity and specificity of IgM were 26.3% (5/19) and 99.1% (108/109). For IgG, a titer of 5,000 in all the patients showed a sensitivity of 76.2% (16/21) and a specificity of 83.6% (97/116). In vaccinated patients, the corresponding figures for this cut-off were 84.2% (16/19) and 83.5% (91/109), respectively. Although IgM detection against mumps is highly specific, its sensitivity is very low in immunized subjects. In this group, the titration of IgG could serve as an additional diagnostic tool.     

Prevalence and estimated incidence of Toxoplasma infection among pregnant women in Poland: a decreasing trend in the younger population

This study investigated the prevalence of specific Toxoplasma gondii IgG in pregnancy, the incidence of congenital toxoplasmosis and the prevalence trend of T. gondii infection among pregnant Polish women between 1998 and 2003. The study population comprised 4916 women who were admitted to the Polish Mother's Memorial Hospital Research Institute in Łódź. Their sera were tested for specific IgG and IgM antibodies to T. gondii, and the incidence of T. gondii infection was calculated from the increase in prevalence rates of IgG antibodies in various age groups. Specific IgG antibody was found in 41.3% (95% CI 39.9–42.7) of pregnant women, and the prevalence of IgG increased with age. The linear trend was significant (p <0.001), with an annual seroconversion rate of 0.7% (95% CI 0.004–0.010). The risk of primary infection was estimated to be 0.5% for 9 months, i.e., an incidence of 5/1000 pregnancies. Assuming a 30% maternofetal transmission rate, 1.5/1000 neonates were infected in utero. Seroprevalence during the 6-year study period decreased from 45.4% in 1998 to 39.4% in 2003, with a yearly decline in prevalence of 1.0% (p 0.02). The most important contributory factor to this decline was the group of women aged 19–29 years, among whom seroprevalence decreased significantly (p 0.007). Specific IgM was found in 244 (4.9%) women.     

两种ELISA试剂检测麻疹病毒IgM抗体实验室对比与评估

目的：对海泰两种麻疹病毒IgM抗体诊断ELISA试剂的实验室现场应用效果进行对比和评估。方法：同时采用该两种ELISA试剂和参比试剂对疑似麻疹患者的血清标本42份进行检测,并通过标本阳性检出率、敏感性、重复性、稳定性进行对比。结果：过夜法试剂在标本检出率、敏感性和稳定性都优于快速法试剂。结论：应制备外部对照质控血清,以便控制试剂和检测质量。疑似麻疹患者的血清标本OD值接近Cottoff值时,应采集第二份血清进行确诊。     

汉坦病毒N蛋白的重组表达及其用于IgM直接捕捉ELISA的建立和应用

目的克隆并表达汉坦病毒（HV）Z10株（HV—Z10）N蛋白（NP）编码基因，建立基于辣根过氧化酶（HRP）标记重组NP（rNP）的rNP—IgM直接捕捉ELISA，检测肾综合征出血热（HFRS）患者血清并评价其检测效果。方法PCR扩增HV—Z10株NP编码基因，基因工程方法构建NP编码基因原核表达系统pET28a—Z10N—E．coli BL21DE3。SDS-PAGE了解rNP表达情况，离子交换法和Ni—NTA亲和层析法提纯rNP。Western blot检测rNP的特异性免疫反应性。建立HRP标记rNP—IgM直接捕捉ELISA检测HFRS患者血清样品，并与常规HV—IgM间接捕捉ELISA进行比较。结果pET28a—Z10N—E．coli BL21DE3高效表达rNP。提纯rNPSDS-PAGE显示单一蛋白条带，HV-IgG能有效识别rNP并与之结合。94．73％（90／95）HFRS患者血清样品rNP—IgM直接捕捉ELISA检测结果阳性，HV—IgM间接捕捉ELISA阳性率为92．63％（88／95）。两种IgM捕捉ELISAs检测的HFRS患者血清样品A450值分布及对多份不同稀释度血清检测的A450，均值变化均相似。结论成功构建了HV—Z10株NP编码基因高效原核表达系统。所建立的rNP—IgM直接捕捉ELISA可作为HFRS简便、安全、敏感、特异的血清学诊断新方法。     

几种CMV相关物检测对诊断肾移植患者CMV感染的评价

目的 比较血中pp65抗原、DNA和IgM抗体检测对肾移植患者巨细胞病毒（CMV）活动性感染的诊断价值,为临床上对CMV感染的诊断和治疗提供参考.方法 收集83位肾移植患者的血标本（共302份）,分离血浆和多型核白细胞,血浆用于CMV-DNA（定性PCR）和IgM抗体（ELISA）检测,白细胞用于pp65抗原血症检测（荧光免疫法）.结果 CMV-DNA阳性率为36.1%,CMV IgM抗体阳性率20.2%,CMV pp65抗原阳性率为38.5%.pp65抗原阳性细胞数与病人的临床症状密切相关.结论 pp65抗原阳性细胞数能反应CMV的数量,可监测早期活动性CMV感染及疗效观察,检测方法特异,灵敏,操作简单,适合临床实验室应用.     

Clinicl Significance of Mesangial IgM Deposits in Minimal Change Nephrotic Syndrome

The clinicopathologic features and the response to corticosteroid therapy were compared in 9 patients with minimal change nephrotic syndrome (MCNS) and diffuse mesangial IgM deposits (Group I) and in 32 of those without IgM deposits (Group II). However, serum IgM levels in Group I in both relapse and remission were significantly higher than those of Group II and controls (p<0.001). In Group I mesangial IgM deposits were diffuse in 9 (100%), mesangial C_1q was present in 4, IgA and fibrinogen were each observed in 1, respectively. Electron dense deposits in the mesangium were also present in 2 to 5 patients in Group I. No significant differences were found between the two groups in age of onset, sex ratio, laboratory data except for serum IgM level, duration before biopsy, follow-up periods, outcome, and response to steroid therapy. Our data suggest that a more severe degree of either impairment of mesangial clearance of IgM or overproduction of IgM may be involved in patients with MCNS and mesangial IgM deposits but that these patients could not be considered a distinct group of patients.     

惠州市麻疹患者血清流行病学调查

目的 了解惠州市麻疹病例血清流行病学特征，探讨麻疹发病原因。方法 对2003～2005年收集的390例麻疹疑似病例血清标本，采用酶联免疫吸附实验（ELISA）检测麻疹IgM抗体，麻疹IgM抗体阳性病例再用ELISA法检测麻疹IgG抗体。结果麻疹IgM抗体阳性率为76．6％，合格标本采集率34．1％。麻疹IgM抗体阳性病例麻疹IgG抗体阳性率64．9％；出疹与采血间隔天数长，IgG抗体阳性率和GMT高，≤1岁组病例IgG抗体阳性率和GMT水平最低。结论 麻疹发病主要原因是未接种麻疹疫苗（MY）和接种后原发性免疫失败，提高血清样本采集率和开展风疹血清学鉴别诊断是惠州市加强麻疹实验室监测亟待解决的问题。