妊娠合并地中海贫血的产科管理

妊娠合并地中海贫血（thalassemia）是一种发生在妊娠期的单基因组遗传的溶血性疾病。由于血液中血红蛋白的组成比例失衡,妊娠合并地中海贫血患者血液系统发生了改变,可能会影响母体的心脏功能,增加血栓形成风险,损害免疫系统,使内分泌系统紊乱等。以往研究关注妊娠合并地中海贫血的流行病学及发病机制,缺乏对其所带来的并发症的妊娠期管理、遗传咨询及产前诊断的系统性阐述。从病变类型和发病机制入手,深度剖析地中海贫血在妊娠期的特有并发症及相应的处理方式,以期能取得更好的妊娠结局及围生儿结局。     

1例中间型β-地中海贫血的临床诊断和基因检测

目的通过回顾性分析1例中间型β-地中海贫血（地贫）的诊断及基因检测流程,总结中间型地贫的诊断策略。方法分析1例β-地贫合并α-地贫基因型患儿的临床表现,通过地贫基因多重PCR检测及DNA序列测定明确诊断,结合相关文献复习,探讨影响β-地贫表现型的基因因素。结果该地贫患儿基因型为B珠蛋白基因41／42突变的杂合予合并仅仅仅anti3.7基因杂合子。结论中间型地贫的诊断,需要临床表现与基因病变相一致,多重PCR结合DNA序列测定等方法可确诊罕见型基因突变。     

Erythrocytic phosphatidylserine exposure and hemostatic alterations in β-thalassemia intermediate patients

Introduction

Hypercoagulable state is one of the common findings in beta-thalassemia intermedia (β-TI), particularly in splenectomized patients, with infrequent blood transfusion. Abnormality of the red blood cells (RBC) membrane due to oxidative damage is suggestive of possible etiologies. Membrane lipid peroxidation increases the exposure of phosphatidylserine (PS) that plays a role in the activation of coagulation factors V and X, subsequently initiating thrombosis. Our aim of this study was to find the probable correlation of the alteration of the PS on the RBC outer membrane with the hypercoagulable state in the β-TI patients.

Materials and methods

Our cross-sectional study was conducted on 39 splenectomized β-TI patients and 38 age-matched healthy controls. The mean age was 37 years. Analysis of the PS exposure on the RBCs was performed by fluorescein isothiocyanate (FITC) conjugated AV protein .Measurement of the coagulation factors X, V and antithrombin III (AT-III) was performed. We also checked the D-dimer levels .Analysis was performed by SPSS16.

Results

Fluorescence of FITC-Annexin V labeling on patients RBCs were higher than healthy controls; (2.8 ± 2.2%) of the patients versus (0.4 ± 0.18%) in the control group and was statistically significant (P < 0.05). Mean levels of factor X and AT-III of the patients as compared with the control group decreased and showed significant difference (P < 0.05).

Conclusions

Circulation of thalassemic RBCs, which abnormally possess PS on RBC membrane outer surface, suggests the possibility of the gradual consumption of the coagulation factors in the presence of a chronic coagulability state.     

Clinical outcome of transfusions with extended red blood cell matching in β-thalassemia patients: A single-center experience

Background

The development of alloantibodies may complicate the management of patients with β-thalassemia. An extended antigenic matching may reduce the risk of alloimmunization. Our previous study showed that the introduction of molecular red blood cell (RBC) typing allows finding suitable blood units for multi-transfused patients. The aim of this study was to evaluate the benefit of RBC transfusion with extended antigenic match.

深圳地区12960例地中海贫血筛查受检者的地中海贫血基因型分析

目的 探讨深圳地区地中海贫血基因型特征,及其罕见基因型碱基突变位点.方法 选择2014年5月至2015年10月于广东省深圳市第二人民医院拟行地中海贫血筛查的12 960例受检者为研究对象.研究对象纳入标准:①红细胞平均体积(MCV)＜80 fl的门诊及住院患者;②于本院行产前筛查的孕妇.排除标准:①不愿意参加本试验者;②已被确诊为其他血液系统疾病者.受试者先进行血常规MCV、血红蛋白(Hb)电泳和红细胞脆性检测的地中海贫血筛查试验,对筛查试验阳性(红细胞脆性＜70％)的患者,采用跨越断裂点PCR及反向斑点杂交(RDB)技术进行地中海贫血基因常见缺失型和点突变的基因型检测.对常见基因型检测不能确诊的患者,采用巢式PCR和PCR-直接测序(SBT)技术进行罕见基因型分析.本研究遵循的程序符合深圳市第二人民医院制定的伦理学标准,得到该委员会批准,并征得受试对象本人的知情同意,与之签署临床研究知情同意书.结果 12 960例受检者中,地中海贫血筛查试验阳性患者为2 194例,通过常见基因型检测,确诊1 019例为地中海贫血,检出率为46.4％.537例α地中海贫血患者中,以东南亚缺失型(--SEA/αα)比例最高,占66.1％(355/537),其次为α地中海贫血2(-α 3.7/αα)占15.6％(84/537),而基因型(αCS α/αCSα、αQS α/αQS α、αWS α/αWSα)和4种HbH病基因型(-α3.7/αQS ααQS、--SEA /αCS αCS、--SEA/αQS αQS、--SEA/αWS αWS)较为少见.α地中海贫血罕见基因型检出率为0.1％(3/2 194),包括2例HKαα/--SEA及1例HKαα/αα.在456例β地中海贫血患者中,β41-42(-TCTT)/β和β654(C＞T) /βA基因型检出率最高,分别为33.8％(154/456)和30.3％(138/456).在26例β复合α地中海贫血患者中,以β复合α地中海贫血1(--SEA/αα)基因型检出率最高(34.6％,9/26).β地中海贫血罕见基因型检出率为0.2％(4/2 194),包括2例β37G＞A),突变点为413 G＞A或405 G＞A,1例β88-93(-AGTG),突变点为557处出现杂合峰,1例β-88(C＞T),突变点为-88 C＞T.结论 深圳地区地中海贫血基因型有独特的分布特征,巢式PCR技术有助于发现HKαα/--SEA及HKαα/αα基因型.采用PCR-SBT技术能鉴定罕见地中海贫血基因型并发现新突变点.本研究结果为在深圳地区开展遗传咨询和产前诊断提供了参考数据.     

地中海贫血患者心肌、肝脏铁沉积与血清铁蛋白相关性研究

目的定量评价地中海贫血患者心脏和肝脏铁过载,探讨心脏、肝脏铁沉积与血清铁蛋白(SF)相关性。材料与方法应用3.0 T磁共振扫描基因确诊地中海贫血患者134例(包括中间型73例和重型61例),扫描包括:肝脏冠状面T2WI及横断面T1WI、T2WI、12回波梯度回波(T2*)序列;心脏标准横断面T2WI及两腔位、四腔位及短轴面电影和8回波梯度回波(T2*)成像。测量心肌、肝脏T2*值,所有受试者MRI扫描前1周完成SF检测。采用Spearman秩相关分析心肌、肝脏铁沉积和SF三者间相关性。结果 134例地中海贫血患者心肌T2*、肝脏T2*、SF中位数分别为23.35(1.88~36.17)ms、1.33(0.36~16.39)ms、1235.3(105.1~14673.0)μg/L,心肌-肝脏T2*(r_s=0.324,P=0.000)、心肌T2*-SF(r_s=-0.491,P=0.000)、肝脏T2*-SF(r_s=-0.697,P=0.000)具有一定相关性。73例中间型地中海贫血患者心肌T2*、肝脏T2*、SF中位数分别为26.18(7.09~36.17)ms、1.81(0.37~16.39)ms、622.8(105.1~10807.0)μg/L,心肌-肝脏T2*(r_s=0.059,P=0.619)、心肌T2*-SF(rs=-0.166,P=0.161)无明显相关,但肝脏T2*-SF间中度负相关(r_s=-0.583,P=0.000)。61例重型地中海贫血患者心肌T2*、肝脏T2*、SF中位数分别为18.80(1.88~33.11)ms、0.72(0.36~10.36)ms、3310.0(313.0~14673.0)μg/L,心肌-肝脏T2*(r_s=0.365,P=0.004)、心肌T2*-SF(r_s=-0.359,P=0.004)、肝脏T2*-SF(r_s=-0.707,P=0.000)具有轻中度相关性。结论在一定范围内,地中海贫血患者心铁沉积与肝铁含量、SF具有较低或无相关性,其间相关性可能随病情加重而增加,而肝铁过载则与SF中度负相关。     

血常规及Hb电泳在孕期筛查地中海贫血的临床价值分析

目的：：探讨产前筛查地中海贫血的临床意义。方法：通过回顾性分析,对就诊的2284例中孕期孕妇进行血常规、血红蛋白电泳检查进行地中海贫血筛查分析,对表型阳性的样本进一步行地中海贫血基因检测。结果：2284例孕妇中,地中海贫血筛查阳性的有139例(6.09%),经基因检测确诊为地中海贫血的125例(5.60%),地中海贫血筛查的诊断符合率较高89.93%(125/139)。结论：地中海贫血基因检测要求高,方法繁琐,地中海贫血筛查方法简单,诊断符合率较高,可用于基层医院筛查地中海贫血。     

Myocardial T2* mapping: influence of noise on accuracy and precision

Background

Pixel-wise, parametric T2* mapping is emerging as a means of automatic measurement of iron content in tissues. It enables quick, intuitive interpretation and provides the potential benefit of spatial context between tissues. However, pixel-wise mapping uses much lower SNR data to estimate T2* when compared to region-based mapping thereby decreasing both its accuracy and precision. In this study, the effects that noise has on the precision and accuracy of pixel-wise T2* mapping were investigated and techniques to mitigate those effects are proposed.

Methods

To study precision across T2* mapping techniques, a pipeline to estimate the pixel-wise standard deviation (SD) of the T2* based on the fit residuals is proposed. For validation, a Monte-Carlo analysis was performed in which T2* phantoms were scanned N = 64 times, the true SD was measured and compared to the estimated SD. To improve accuracy and precision, the automatic truncation method for mitigating noise bias was extended to pixel-wise fitting by using an SNR scaled image reconstruction and truncating low SNR measurements. Finally, the precision and accuracy of non-linear regression with and without automatic truncation, were investigated using Monte-Carlo simulations.

Results

Measured and estimated SD’s were >99.9% correlated for non-linear regression with and without truncation. Non-linear regression with automatic truncation was shown to be the best mapping technique for improving accuracy and precision in low T2* and low SNR measurements.

Conclusions

A method for applying an automatic truncation method to pixel-wise T2* mapping that reduces T2* overestimation due to noise bias was proposed. A formulation for estimating pixel-wise standard deviation (SD) maps for T2* that can serve as a quality map for interpreting images and for comparison of imaging protocols was also proposed and validated.

Electronic supplementary material

The online version of this article (doi:10.1186/s12968-015-0115-3) contains supplementary material, which is available to authorized users.