Improving the performance of virtual crossmatch results by correlating with nationally-performed physical crossmatches: Obtaining additional value from proficiency testing activities

Purpose

When donor specific HLA antibodies (DSA) are identified, the predictive value of whether a certain strength of reactivity (mean fluorescence intensity, MFI) leads to a positive crossmatch is uncertain. To determine this, we compared the DSA MFI results we generated locally for nationally distributed proficiency samples against the percentage of other laboratories reporting a positive crossmatch.

肾移植后人类白细胞抗原抗体检测的临床意义

目的：了解肾移植受者的抗人类白细胞抗原（HLA）IgG抗体水平及其对肾移植效果的影响。方法：应用莱姆德抗原板和混合抗原板通过微量酶联免疫吸附法检测685例患者的抗HLA特异性IgG 抗体。结果：685例肾移植受者中HLA－IgG抗体阳性者占12％，致敏受者移植后排斥反应发生率为50％，明显高于HLA－IgG抗体阴性受者（P＜0．01），而移植物存活率则显著低于HLA－IgG抗体阴性受者（P＜0．01），移植后HLA－IgG抗体水平升高组，其排斥发生率和移植物丢失率分别为82％和77％，均显著高于HLA－IgG抗体无变化组（P＜0．01），而排斥逆转率则显著低于后者（P＜0．01）。结论：HLA－IgG抗体是预测受者HLA免疫致敏的一个敏感指标；动态监测HLA－IgG抗体水平的变化对临床筛选合适供者，减少排斥反应，提高移植物存活率重要意义。     

Histopathological features of liver and its relation to serum transaminase levels in 91 cases of anti-HBe-positive chronic hepatitis B

For assessing the histopathological features and its relation to alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in anti-HBe-positive chronic hepatitis B in Babol, north of Iran, liver biopsy samples of 91 anti-HBe-positive chronic hepatitis B virus (HBV) infection with raised ALT were scored according to histological hepatitis activity index (HAI) from March 2000 to July 2003. Seventy-seven males and 14 females with a mean age of 32.24 (+/-11.92) years were studied. Mean ALT and AST levels were 112.5 (+/-98.9) and 69.57 (+/-60.6) IU/l, respectively. Minimal, mild, moderate and severe chronic hepatitis were seen in 35 (38.5%), 49 (53.8%), seven (7.7%) and 0 cases, respectively. There was not any significant difference between HAI and ALT levels of < 60, between 60-79 and > or = 80 IU/l (p = 0.299), but with regard to AST levels, this difference was significant (p = 0.005). This study showed that more than 90% of our cases are in the early stages of the liver disease. Although both serum ALT and AST levels are associated with the activity of hepatitis in HBV carriers, the AST is a better laboratory screening test for finding the severity of liver injury than ALT.     

血清人附睾蛋白、CA125、CA199联合检测诊断妇科恶性肿瘤的价值

[目的] 探讨血清人附睾蛋白(HE4)、糖类抗原125(CA125)、CA199联合检测诊断妇科恶性肿瘤的价值.[方法] 检测42例妇科恶性肿瘤患者(A组)及同期收治的42例妇科良性肿瘤者(B组)HE4、CA125、CA199水平,比较不同标志物及联合检测的阳性率和相关指标.[结果] A组HE4、CA125、CA199表达水平、三项标志物单项检测及联合检测阳性率均高于B组,且差异有显著性(P<0.05);A组不同标志物联合检测阳性率、ROC曲线下面积(AUC)、准确性、特异性、灵敏度均高于CA125、CA199单独检测(P<0.05),其阳性率、AUC、准确性、特异性与HE4单独检测时无明显差异(P<0.05),但灵敏度显著高于HE4单独检测(P<0.05).[结论] HE4诊断妇科恶性肿瘤的价值优于CA125、CA199,三者联合诊断可进一步提高良恶性肿瘤鉴别诊断率.     

Identification and isolation of murine antigen-reactive T cells according to CD154 expression

T helper (Th) cells are central regulators of adaptive immune responses. However, the detection of the small number of Th cells specific for a particular antigen or pathogen is still a major challenge. CD154 was recently introduced as a marker for antigen-specific Th cells. To date, this technology was not applicable for mice - arguably the most important immunological model system. CD154 is difficult to detect due to its rapid removal from the cell surface upon binding to CD40 during antigen-specific activation by APC. We present an efficient strategy to block the degradation of murine CD154 by combined use of antibodies against CD40 and CD154. This strategy makes CD154 easily accessible for surface staining, which allows isolation and expansion of rare antigen specific T cells. Importantly, CD154 identified all specific T cells in strongly Th1- or Th2-polarized immune responses against pathogens like Salmonella typhimurium and Heligmosomoides polygyrus, independent of their potential to produce cytokines. We demonstrate that CD154 can in fact be used as a reliable marker for antigen-specific CD4 T cells in mice, offering a unique option to analyze, isolate and rapidly expand the entire pool of Th-cells generated during a physiological T cell response in vivo.     

Hsp110 and Grp170, members of the Hsp70 superfamily, bind to scavenger receptor-A and scavenger receptor expressed by endothelial cells-I

Heat shock protein 110 (hsp110) and glucose-regulated protein (grp170) act as anti-cancer vaccines when complexed to tumor antigens by heat shock. It has been proposed that receptors on antigen-presenting cells contribute to HSP-mediated immune responses. Here, we show that hsp110 binds in a receptor-mediated manner to RAW264.7 macrophages, as does grp170. This hsp110/grp170 binding is inhibited by scavenger receptor ligands, suggesting a role for scavenger receptors as binding structures. We examined scavenger receptor class A (SR-A) and scavenger receptor expressed by endothelial cells-I (SREC-I). We show that hsp110/grp170 binds to both SR-A- and SREC-I-expressing CHO cells in a saturable manner and scavenger receptor ligands inhibit binding. Hsp110 also saturably binds mouse bone marrow-derived dendritic cells (bmDC) and is inhibited by scavenger receptor ligands. When an hsp110-rat neu (intracellular domain) heat shock complex vaccine is used to pulse mouse bmDC in vitro, an induction of IFN-gamma secretion is observed by CD8+ T lymphocytes isolated from vaccine-immunized mice. This immune response is inhibited by the application of scavenger receptor ligands to bmDC. Thus, SR-A and SREC-I appear to contribute to the binding of hsp110 and grp170 on APC. Scavenger receptors, in general, contribute to the cross-presentation of hsp110-chaperoned protein antigen.     

Prediction of supertype-specific HLA class I binding peptides using support vector machines

Experimental approaches for identifying T-cell epitopes are time-consuming, costly and not applicable to the large scale screening. Computer modeling methods can help to minimize the number of experiments required, enable a systematic scanning for candidate major histocompatibility complex (MHC) binding peptides and thus speed up vaccine development. We developed a prediction system based on a novel data representation of peptide/MHC interaction and support vector machines (SVM) for prediction of peptides that promiscuously bind to multiple Human Leukocyte Antigen (HLA, human MHC) alleles belonging to a HLA supertype. Ten-fold cross-validation results showed that the overall performance of SVM models is improved in comparison to our previously published methods based on hidden Markov models (HMM) and artificial neural networks (ANN), also confirmed by blind testing. At specificity 0.90, sensitivity values of SVM models were 0.90 and 0.92 for HLA-A2 and -A3 dataset respectively. Average area under the receiver operating curve (A_ROC) of SVM models in blind testing are 0.89 and 0.92 for HLA-A2 and -A3 datasets. A_ROC of HLA-A2 and -A3 SVM models were 0.94 and 0.95, validated using a full overlapping study of 9-mer peptides from human papillomavirus type 16 E6 and E7 proteins. In addition, a large-scale experimental dataset has been used to validate HLA-A2 and -A3 SVM models. The SVM prediction models were integrated into a web-based computational system MULTIPRED1, accessible at antigen.i2r.a-star.edu.sg/multipred1/.     

Utilizing self-prepared ELISA plates for a cross-population study of different anti-HBe IgG subclass profiles

Fourteen serum samples obtained from hepatitis B virus (HBV) chronic carriers and patients recovered from hepatitis B infection were used with four sodium dodecyl sulfate-treated enzyme-linked immunosorbent assay (ELISA) plates available commercially, and one self-prepared HBcAg analog for evaluation of anti-HBe subclass pattern absorbance. The self-prepared plates had the best performance and were thus used for samples obtained from 104 (60 male and 44 female) HBV chronic carriers and 439 (247 male and 192 female) recovered individuals. Tests for aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were also carried out in 21 of the subjects (>25 IU/ml). Statistical comparison of these patients with elevated ALT/AST levels with other ALT/AST-normal chronic carriers revealed no significant differences in the anti-HBe OD, although the mean optical density (OD) of patients with elevated ALT/AST levels was higher. The results suggest that the anti-HBe IgG subclass profiles in the chronic carriers did not change with inflammation of the liver, and were independent of sex and age. In contrast to previous anti-HBc findings, the distribution pattern of anti-HBe subclasses in HBV chronic carriers was IgG1 > IgG4 > IgG3 while in the recovered individuals it was IgG1 > IgG3 > IgG4, for both males and females. Subclasses IgG1 and IgG2 were the most and least prevalent isotypes, respectively, in both study groups. The results of the study suggest that induction of IgG1 and/or IgG3 antibodies is important for effective virus neutralization, while IgG2 antibodies are of limited importance. Significantly higher OD values for anti-HBe IgG4 were observed when comparing samples from the chronic carriers and recovered individuals, which may reflect the effects of persistence. Further, in contrast to previous anti-HBs results, the concentrations of total IgG and IgG1 were higher in the samples from chronic carriers relative to those from recovered individuals.     

寡脱氧核糖核苷酸致敏树突状细胞对OVCAR-3卵巢癌细胞株杀伤作用的实验研究

目的探讨含有未甲基化“胞嘧啶-磷酸二酯键-鸟嘌呤（CpG）基序”的寡脱氧核糖核苷酸（CpGODN）致敏人外周血来源树突状细胞（DC）在卵巢癌免疫治疗中的作用。方法应用CpGODN2006联合肿瘤相关抗原CA125体外冲击致敏DCs,流式细胞技术检测DC膜表面CD1α、CD8、CD86和人白细胞DR抗原（HLA-DR）的表达,用EHSA测定DC培养上清液中白细胞介素（IL）-12的分泌水平;四唑盐（MTT）比色试验法检测活化DCs对细胞毒性T淋巴细胞（CTL）杀伤OVCAR-3卵巢癌细胞株作用的影响。结果CpG ODN2006联合CA125在体外可明显激活人外周血来源DCs,DC表面分子CD83、CD86和HLA-DR表达的阳性细胞百分率[（85±4）％、（87±12）％和（92±7）％]明显高于未致敏组[（19±4）％、（67±9）％和（63±6）％]（P＜0．01）;联合致敏后DCs培养上清液中白细胞介素（IL）-12分泌水平为（467±84）ng／L,与未致敏组[（60±9）ng／L]和单纯CA125致敏组[（97±16）ng／L]相比差异有统计学意义（P＜0．01）;联合刺激后的DCs可以促进T淋巴细胞的增殖,增殖活性显著高于未致敏组和单纯CA125致敏组（P＜0．01）,且相同效靶比下所诱导的CTLs对OVCAR-3卵巢癌细胞的杀伤活性显著强于未致敏组、单纯CA125致敏组和单纯CpGODN致敏组（P＜0．01）。结论CpGODN联合CA125体外致敏DC可诱导产生对OVCAR-3卵巢癌细胞的免疫杀伤作用,是一种临床应用前景良好的肿瘤免疫治疗方法。     

Cross-reactivity of non-Aspergillus fungal species in the Aspergillus galactomannan enzyme immunoassay

The Aspergillus galactomannan enzyme-linked immunosorbant assay (EIA) has been demonstrated to facilitate rapid and sensitive detection of invasive aspergillosis. However, test specificity has not been fully evaluated in non-Aspergillus fungal species. Of 53 fungal isolates, cross-reactivity was observed with 5 non-Aspergillus spp.: Blastomyces dermatitidis, Nigrospora oryzae, Paecilomyces lilacinus, Penicillium chrysogenum, and Trichothecium roseum.