血小板抗体及淋巴细胞亚群检测在特发性血小板减少性紫癜中的诊断意义

目的 比较抗血小板特异性抗体、PAIgG及淋巴细胞亚群在特发性血小板减少性紫癜（ITP）及非免疫性血小板减少症中的水平,以评价其在ITP中的诊断价值.方法 用改良单克隆抗体特异性俘获血小板抗原法（MAIPA）检测患者血浆中抗血小板膜糖蛋白（GPⅡb/Ⅲa、GPⅠb和P-选择素）的特异性抗体.利用流式细胞术（FCM）检测患者外周血中PAIgG及淋巴细胞亚群.结果 ITP组MAIPA的阳性率为63.3%,非免疫性血小板减少组为阴性;PAIgG分别为73.3%、45%.淋巴细胞亚群中,ITP组CD3、CD4、CD4/CD8显著高于正常对照组,CD8、CD19则显著低于正常对照组.结论 抗血小板特异性自身抗体抗体对提高ITP的诊断有一定的实用价值,淋巴细胞亚群的变化能较好地反映ITP 的病理机制.     

直接MAIPA对免疫性和非免疫性血小板减少性紫癜的鉴别诊断

目的检测免疫性与非免疫性血小板减少患者血小板膜糖蛋白特异性自身抗体，评价该方法在免疫性和非免疫性血小板减少性紫癜鉴别诊断中的价值。方法应用改良直接单克隆抗体俘获血小板抗原技术(MAIPA)检测血小板膜糖蛋白(GPⅡh／Ⅲa、GP I b和GPI a／Ⅱa)特异性自身抗体。结果免疫性血小板减少患者自身抗体阳性率(76．4％)显著高于非免疫性血小板减少患者(3．6％)(P＜0．05)。直接MAIPA诊断免疫性血小板减少的敏感性为76．4％，特异性为96．4％，阳性预测值为97．1％。GPⅡh／Ⅲa特异性自身抗体阳性的免疫性血小板减少患者血小板计数与自身抗体吸光度比值呈显著负相关(r=-0．338，P＜0．05)。结论直接MAIPA检测血小板膜糖蛋白特异性自身抗体对于鉴别免疫性与非免疫性血小板减少有一定意义。     

自身免疫性血小、板减少性紫癜的特异性免疫学诊断的研究

目的 检测自身免疫性血小板减少性紫癜（AITP）患者及非免疫性血小板减少症患者的抗血小板特异性抗体,并与血小板相关抗体（PAIgG)相比较,评价其诊断及鉴别诊断价值。方法 用酶联免疫吸附竞争法检测PAIgG,改良单克隆抗体特异性俘获血小板抗原（MAIPA）技术检测抗血小板GPⅡb/Ⅲa、GPIb/Ⅸ的特异性抗体。结果 血小板特异性抗体较PAIgG的敏感性低,但特异性明显增强。结论 抗血小板特异性抗体对鉴别免疫性与非免疫性血小板减少具有重要临床意义。     

血小板特异性抗体对特发性血小板减少性紫癜诊断价值的研究

目的:检测特发性血小板减少性紫癜及非免疫性血小板减少症患者抗血小板特异性抗体与血小板相关抗体,评价其在特发性血小板减少性紫癜中的诊断价值。方法:用流式细胞仪检测血小板相关抗体PAIgG,PAIgA,PAIgM;用改良单克隆抗体特异性俘获血小板抗原技术检测抗血小板膜糖蛋白(GPⅡb/Ⅲa,GPⅠb/Ⅸ)特异性自身抗体。结果:血小板相关抗体在特发性血小板减少性紫癜组敏感度为80%,在非免疫性血小板减少症组为63.3%。改良单克隆抗体特异性俘获血小板抗原法检测抗GPⅡb/Ⅲa和GPⅠb/Ⅸ抗体,在特发性血小板减少性紫癜组中的敏感度分别为53.3%和30%;在非免疫性血小板减少症组中除1例GPⅠb/Ⅸ阳性外,其余均为阴性;2组检出率比较差异有统计学意义(P<0.05)。结论:血小板相关抗体敏感度较高,但特异度较低;抗血小板特异性抗体敏感度虽较低,但特异性较高,可鉴别特发性血小板减少性紫癜和非免疫性血小板减少症。可作为特发性血小板减少性紫癜的特异性诊断指标。     

血小板特异性抗体联合检测在免疫性血小板减少症鉴别诊断中的价值

目的通过检测血小板减少症患者外周血B淋巴细胞血小板膜糖蛋白特异性抗体的变化,探讨其表达水平变化对血小板减少症鉴别诊断的临床意义。方法应用流式微球技术检测血小板减少症患者及健康对照者外周血GPⅡb/Ⅲa、GPⅠb/ⅠX的表达水平。结果原发ITP与继发ITP患者血小板特异性抗体GPⅡb/Ⅲa、GPⅠb/ⅠX与对照组比较差异有统计学意义(P0.05);血小板特异性抗体GPⅠb/ⅠX诊断原发ITP的敏感度43%,特异度89%;GPⅡb/Ⅲa诊断原发ITP的敏感度86%,特异度83%。两者联合诊断敏感度90%,特异度83%。结论联合检测两种血小板抗体,提高原发ITP和SLE的诊断阳性率;GPⅠb/ⅠX在ITP中的诊断优势不如GPⅡb/Ⅲa。     

前瞻性评价单克隆抗体俘获血小板抗原技术对免疫性血小板减少症的诊断价值

目的 评价单克隆抗体俘获血小板抗原技术(MAIPA)对免疫性血小板减少症(ITP)的诊断价值,以及对免疫性和非免疫性血小板减少的鉴别诊断价值.方法 以来自14家医院的321例血小板减少患者为研究对象,男118例,女203例,应用改良MAIPA试验双盲法检测患者血小板膜糖蛋白特异性自身抗体(抗-GPⅡb/Ⅲa和抗-GP Ⅰ b/Ⅸ),客观评价该试验在ITP诊断中的敏感性和特异性,了解ITP患者血小板特异性抗体浓度与血小板数量的相关性以及地塞米松治疗后抗体浓度的变化.结果 抗-GPⅡb/Ⅲa、抗-GP Ⅰ b/Ⅸ、抗-GPⅡb/Ⅲa联合抗-GP Ⅰ b/Ⅸ诊断ITP的敏感性分别为39.75%、32.64%、55.23%,特异性分别为97.56%、93.94%、92.68%,阳性预测值分别为97.94%、93.98%、95.65%,阴性预测值分别为35.71%、32.35%、41.53%,总有效率分别为54.51%、48.29%、64.80%;ITP患者血小板特异性抗体阳性率显著高于非免疫性血小板减少患者;抗体阳性患者的血小板数量显著低于阴性患者,ITP患者血小板特异性抗体水平[吸光度(A)值]与血小板数量呈负相关;激素治疗有效的ITP患者抗-GPⅡb/Ⅲa或(和)抗-GP Ⅰ b/Ⅸ转阴或抗体水平降低.结论 MAIPA试验对ITP具有较高的诊断价值,对ITP患者的疗效也具有指导意义,可作为IFP和非免疫性血小板减少的鉴别诊断依据.     

南宁地区成人及儿童ITP患者体内血小板自身抗体特异性分布的研究

目的：研究血小板膜糖蛋白特异性自身抗体在成人及儿童原发免疫性血小板减少症（ITP）患者中分布的异同。方法应用酶联免疫吸附试验（PAKAUTO 试剂盒）检测 ITP 组（83例）及非 ITP 组（58例）患者血小板自身抗体,并分析成人组ITP（46例）,儿童组 ITP（37例）的抗 GP Ⅱ b／Ⅲ a 、抗 GP Ⅰ b／Ⅸ及抗 GP Ⅰ a／Ⅱ a 自身抗体特异性分布规律。结果 ITP 组血小板自身抗体阳性率为66．27％,高于非 ITP 组的6．90％,差异有统计学意义差异有统计学意义（P＜0．05）。成人组女性 ITP 患者占60．87％,儿童组女性 ITP 患儿占64．86％,差异无统计学意义（P ＞0．05）,但两组女性发病率均高于男性,差异有统计学意义（P＜0．05）。成人组 ITP 患者血小板自身抗体阳性率为63．04％,儿童组 ITP 患儿抗体阳性率为70．27％,差异无统计学意义（P＞0．05）;且成人组与儿童组 ITP 患者血小板自身抗体特异性分布差异无统计学意义（P ＞0．05）,均以抗 GP Ⅱ b／Ⅲ a 和抗 GPⅠ b／Ⅸ抗体多见。结论血小板自身抗体检测对 ITP 诊断、鉴别诊断及治疗均有重要的参考价值,GP Ⅰ a／Ⅱ a 抗体介导的 ITP很值得深入研究。     

抗血小板膜糖蛋白Ⅱb/Ⅲa单克隆抗体对原发性血小板减少性紫癜诊断价值的研究

目的 旨在探讨血小板膜糖蛋白Ⅱb/Ⅲa单克隆抗体（Ⅱb/Ⅲa McAb）检测对原发性血小板减少性紫癜（ITP）的诊断价值。方法 共检测成人慢性ITP114例，应用Ⅱb/Ⅲa McAb(SZ-21 SZ-22)与ITP患者的血小板共同孵育，用吸光度计检测其吸光度值并与正常值相比较（做为结合值），如此值＜0．5为阳性，即判定患者血小板膜上原已结合有抗Ⅱb/Ⅲa的自身抗体。同时用竞争性酶联免疫吸附法检测患者的血小板相关IgG(PA IgG)。以非ITP性血小板减少患者做为对照组。结果 114例成人慢性ITP中，GPⅡb/Ⅲa检测阳性率为49％；非ITP组无1例假阳性。ITP组PAIgG阳性率为64％；非ITP组假阳性率为26．6％。结论 实验证实本检测法特异性好，操作简单技术稳定，对ITP的诊断、疗效观察及发病机理研究具有实用价值。     

GPⅡb/Ⅲa在免疫性血小板减少症中的诊疗意义

目的:采用流式细胞术(FCM)联合酶联免疫吸附法(ELISA)分析血小板膜糖蛋白(GPⅡb/Ⅲa)在免疫性血小板减少症中的表达情况及识别作用,探讨其对ITP的诊疗意义。方法:选择2014年10月-2018年10月期间本院血液科收治的免疫性血小板减少症患者52例作为ITP组,同时选取体检中心的30例健康人作为对照组,通过FCM测定血小板膜糖蛋白阳性表达率以及全自动分析仪检测外周血小板计数,ELISA检测血浆膜糖蛋白水平;比较免疫性血小板减少症患者治疗前、后血小板膜糖蛋白水平;分析免疫性血小板减少症患者血小板膜糖蛋白阳性表达率和血浆膜糖蛋白水平与血小板数的相关性。结果:免疫性血小板减少症患者GPⅡb/Ⅲa+(即CD41+/CD61+)表达率以及血浆GPⅡb/Ⅲa水平显著低于对照组(P 0. 001);免疫性血小板减少症患者在接受治疗后,血小板GPⅡb/Ⅲa+表达率较治疗前明显升高(P 0. 001);血小板GPⅡb/Ⅲa+表达率、GPⅡb/Ⅲa水平均与其血小板计数呈正相关(r=0. 772,r=0. 966)。血小板GPⅡb/Ⅲa水平联合血小板数诊断免疫性血小板减少症灵敏度为90. 38%,特异度为93. 33%,阳性似然比为13. 57,阳性预测值为95. 92%。结论:在临床上运用血小板膜糖蛋白作为免疫性血小板减少症初步筛查方式简单方便,灵敏快捷,具有临床意义,可考虑作为临床诊断的新方法。     

血小板相关抗体检测及其临床研究

目的：探讨血小板相关抗体（PAIg)检测的临床意义。方法：对54例血小板减少症患者采用ELISA法作PAIgG,PAIgA,PAIgM联合检测，并作动态观察。结果：原发性血小板减少性紫癜（ITP）患者的PAIg,PAIgM含量均明显高于继发性血小板减少症组及正常对照组（P＜0．01），PAIg增高患者采用泼尼松治疗，其疗效无显著性差异（P＞0．05），PAIg含量与血小板计数呈负相关，结论：PAIg检测有助于ITP的诊断，选择最佳治疗方案并判断疗效。     

Enzymes of lysosomal origin in human plasma and serum: assay conditions and parameters influencing the assay

The condition for maximal activity (pH, buffer, saturating substrate concentration, range of linear relationships between enzyme activity versus incubation time, and versus enzyme concentration) in the fluorimetric assay of several glycohydrolases of lysosomal origin in human plasma and serum have been established. The following enzymes were studied: alpha-galactosidase, beta-galactosidase, beta-N-acetylglucosaminidase, beta-glucosidase, beta-glucuronidase, alpha-mannosidase, alpha-fucosidase. All examined enzymes turned out to be more or less unstable upon storage at 37 degrees C, 4 degrees c, and -20 degrees C in both serum and plasma. The only exceptions were beta-glucuronidase, which was stable in plasma and serum, and alpha-fucosidase which was stable only in plasma. Generally the degree of instability was greater in serum than in plasma. The levels of some enzymes (alpha-galactosidase, beta-galactosidase, beta-N-acetyl glucosaminidase, beta=glucuronidase) were markedly higher in serum than in plasma; conversely the levels of the same enzymes in "platelet free" serum equalled those in plasma. This stresses the necessity to use freshly prepared plasma for lysosomal glycohydrolase assay. Under the procedural conditions recommended for the assay the methods for the determination of lysosomal glycohydrolases in plasma appeared to be simple, sensitive and reproducible.     

Pooled analysis of LAMP assay for the diagnosis of norovirus infection

BackgroundRapid laboratory detection is essential to diagnose norovirus infection. LAMP has many advantages compared with RT‐PCR for detecting norovirus, including high sensitivity, high specificity, rapidity, low cost, and intuitive results, which can be easily read with the naked eye with the help of color‐based reporters. In this study, we intend to analyze the accuracy of LAMP methods for the diagnosis of norovirus infection.MethodsTwo researchers independently retrieved relevant literature up to January 2021 (PubMed, Web of Science, Cochrane Library, Embase, CNKI, Wan Fang, and VIP). The researchers screened all articles and extracted their research data for meta‐analysis. QUADAS‐2 tool was used to evaluate the quality of the included studies by Review Manager 5.3. Forest plots were performed by Meta‐DiSc 1.4 to evaluate the accuracy of the test. Deeks’ funnel plot symmetry tests were conducted by Stata 15.0 to check the potential publication bias.ResultsEleven sets of data extracted from the eight included studies were included for meta‐analysis. For the detection of norovirus, the pooled sensitivity, specificity, positive LR, negative LR, diagnostic OR, and their 95% CI were 0.96 (0.95–0.97), 0.99 (0.99–1.00), 91.14 (31.88–260.56), 0.06 (0.04–0.09), and 1473.68 (562.96–3857.70), respectively. Besides, AUC in the SROC curve was 0.9920.ConclusionLAMP had high sensitivity and specificity in terms of the diagnosis of norovirus infection. However, further extension of this approach should be researched to ensure the accuracy and practicability of this hopeful test in the future.     

Value of an enzymatic assay for the determination of serum ceruloplasmin

The serum concentration of the copper protein ceruloplasmin has been an important diagnostic indicator of Wilson's disease (WD). It is widely quoted that 95% of people with WD have low serum ceruloplasmin concentrations. Current evidence suggests that a normal serum ceruloplasmin concentration is more common in patients with WD, particularly those with liver disease, perhaps in part because of the routine use of an immunologic assay. This assay might indicate a normal level of ceruloplasmin when the enzymatic activity is lower. Enzymatic activity is the biologically relevant parameter. We compared the immunologic measurement with the enzymatic assessment of oxidase activity in patients with liver or neurologic symptoms of unknown origin in whom WD was considered in the differential diagnosis. Although a strong correlation of ceruloplasmin protein concentration with oxidase activity was observed in controls, this was not the case for these patients. Twelve patients, presenting with various types of hepatic disease, demonstrated a weak correlation between ceruloplasmin protein concentration and oxidase activity. Ten percent of patients with neurologic symptoms ( n = 41) had low ceruloplasmin concentrations and oxidase activity, and another 8% had normal ceruloplasmin concentrations associated with low oxidase activity. Although the enzymatic method is preferred for its biologic relevance, ceruloplasmin analysis is not a reliable diagnostic parameter for the diagnosis of WD in patients with liver disease. An important use of the ceruloplasmin oxidase assay is in the follow-up of patients with WD. Ceruloplasmin oxidase activity was undetectable in sera from patients with WD who were undergoing long-term chelation therapy, suggesting an early sign of copper depletion and a need for subsequent monitoring for symptoms of copper deficiency.     

A one-step dipstick assay for the on-site detection of nucleic acid

Objectives

We have developed a one-step nucleic acid dipstick assay (NADA) for visually detecting polymerase chain reaction (PCR) products within 3 min. “One-step” means that there were no additional procedures between amplification and detection.

Methods

This method was achieved through the use of asymmetric PCR and specially designed probes with appropriate melting temperature values. We initially combined one-step NADA with asymmetric capillary convective PCR (ACCPCR), an easy and rapid nucleic acid amplification technique, to construct an on-site nucleic acid diagnostic platform.

Results

We developed a diagnostic assay for the hepatitis B virus based on the ACCPCR-NADA platform to verify its feasibility. It exhibited an analytical sensitivity of three copies per test and a broad detection spectrum including genotype A–I. It also showed 97.9% sensitivity and 100% specificity based on the results observed using 67 serum samples with the Roche COBAS AmpliPrep/COBAS TaqMan (COBAS) system as the standard for comparison.

Conclusion

The results provide evidence for the feasibility of using an ACCPCR-NADA platform in practical applications, especially in on-site test.     

Investigation of age-adjusted D-dimer using an uncommon assay

BackgroundUse of an age-adjusted D-dimer for the evaluation of acute pulmonary embolus (PE) has been prospectively validated in the literature and has become a practice recommendation from major medical societies. Most research on this subject involves the most common D-dimer assays reporting in Fibrinogen Equivalent Units (FEU) with a non-age-adjusted manufacturer-recommended cutoff of 500 ng/ml FEU. Limited research to date has evaluated age-adjustment in assays that report in D-Dimer Units (D-DU), which use a manufacturer-recommended cutoff of 230 ng/ml D-DU. Despite scant evidence, an age-adjusted formula using D-DU has been recently endorsed by the American College of Emergency Physicians (ACEP). This formula seems arbitrary in its derivation and unnecessarily deviates from existing thresholds, thus prompting the creation of our novel-age adjustment formula. The goal of this study was to retrospectively evaluate the test characteristics of our novel age-adjusted D-dimer formula using the D-DU assay in comparison to existing traditional and age-adjusted D-dimer thresholds for the evaluation of acute PE in the ED.MethodsThis was a retrospective chart review at an academic quaternary health system with three EDs and 195,000 combined annual ED visits. Only patients with D-dimer testing and CT PE protocol (CTPE) imaging were included. Admission and discharge diagnosis codes were used to identify acute PE. Outcome measures were sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) of an unadjusted traditional threshold (230) compared with both novel and ACEP-endorsed age adjusted thresholds, (Age × 5) ? 20 and Age × 5 if >50, respectively. Estimates with their exact 95% threshold were performed.Results4846 adult patients were evaluated from January 2012 to July 2017. Group characteristics include a mean age of 52 and a frequency of acute PE diagnosis by CTPE of 8.25%. Traditional D-dimer cutoff demonstrated a sensitivity of 99.8% (95% CI 98.6–100), specificity of 16.7% (95% CI 15.6–17.8) and NPV of 99.9% (95% CI 99.3–100). Our novel age-adjusted D-dimer thresholds had a sensitivity of 97.0% (95% CI 94.8–98.4), specificity of 27.9% (95% CI 26.6–29.2) and NPV of 99.0% (95% CI 98.3–99.5) with the ACEP-endorsed formula demonstrating similar test characteristics.ConclusionUse of an age-adjusted D-dimer on appropriately selected patients being evaluated for acute PE in the ED with a D-DU assay increases specificity while maintaining a high sensitivity and NPV. Both our novel formula and the ACEP-endorsed age-adjusted formula performed well, with our novel formula showing a trend towards improved testing characteristics.     

Interference and blood sample preparation for a pyruvate enzymatic assay

BACKGROUND: To assess the severity of circulatory failure, a pyruvate enzymatic assay was performed on whole blood using lactate dehydrogenase to catalyze the conversion of pyruvate to lactate. We investigated factors related to blood sample collection and preparation that might influence the results, including the timing of blood deproteinization, temperature of sample storage, and hemolysis. METHOD: A total of 25 whole blood specimens were collected for this study. Each sample was divided into 2 parts: one stored at room temperature (RT) and another kept on ice. The samples were deproteinizied by using 8% perchloric acid (PCA) at varying times after collection; the first deproteinization was immediately after the blood was drawn (0 h), then at 1 h intervals for 6 h and also in samples kept overnight. The supernatant samples were analyzed soon after deproteinization using a COBAS Centrifugal Analyzer. In another set of samples, the blood was immediately deproteinized, and the supernatants were stored at RT and 4 degrees C and assayed for pyruvate at varying times, as above. Finally, the effect of hemolysis on the blood pyruvate enzymatic assay was also evaluated. RESULTS: When samples were stored at RT, pyruvate levels remained constant until the third h after deproteinization, when there was an approximately 13.3% increase in pyruvate concentration. When whole blood samples were kept at 4 degrees C before deproteinization, pyruvate levels were significantly reduced over time, ranging from 37.8% to 62.2% (paired t test showed a significant mean difference, P < 0.001). No significant differences in pyruvate concentration were observed in supernatant stored at either RT or 4 degrees C. Hemolysis caused a 33.7% increase in the pyruvate concentration, equivalent to 0.18 mg pyruvate per gram per deciliter of hemoglobin. CONCLUSIONS: For a pyruvate enzymatic assay, keeping a whole blood sample at RT will not cause a significant difference in the pyruvate level as long as the sample is immediately deproteinized. Whole blood samples should not be stored in an ice bath for transport, nor should hemolyzed samples be used for a blood pyruvate enzymatic assay.