β珠蛋白生成障碍性贫血的诊断

β珠蛋白生成障碍性贫血的诊断（武汉市儿童医院４３００１６）张纪平，韩玉兰，周玲β珠蛋白生成障碍性贫血（β地贫），是一组多类型、分布广的常染色体遗传性、溶血性疾病。现将我们所见的２２例小儿β地贫报告如下。临床资料一、一般资料男１６例，女６例。～６月５例...     

再生障碍性贫血与细胞因子

某些细胞因子对造血具有负调控作用，它们对于再生障碍性贫血（简称再障）的发生发展起来着重要作用，这是近年免疫发病机制研究中取得的较大进展。再障病理表现为骨髓造血细胞增殖低下或衰竭，是多种造血负调失因子协同引起的结果，此与化疗或骨髓损害所改造血你处和血细胞减少显然不同。造血生长因子是一种新的治疗ＡＡ药物。     

药物基因调控治疗β珠蛋白生成障碍性贫血研究进展

β珠蛋白生成障碍性贫血(地贫)是一种常见的常染色体单基因缺陷所致的遗传性慢性溶血性贫血。人们一直期望其能成为第1个通过基因矫正而治愈疾病。但种种原因导致该疗法离临床应用尚远。目前药物基因调控治疗此病经过20多年研究,在重新激活已近乎关闭的γ珠蛋白基因高表达方面取得较大进展,尤其是中药的研发具有良好前景,本文从药物基因调控治疗的理论基础、激活γ珠蛋白基因的国内外进展及目前存在问题和展望作一综述。     

桂林地区少见β-珠蛋白生成障碍性贫血基因突变分析

目的 分析桂林地区少见的β-珠蛋白生成障碍性贫血(β-地贫)的基因突变类型.方法 收集2005年5月- 2010年12月桂林地区11 941份检测血标本.男2 066例,女9 875例;年龄2个月～ 74岁.采用血细胞学检测红细胞平均容积和红细胞平均血红蛋白、血红蛋白电泳定量HbF、HbA2,初筛出β-地贫,PCR-反向斑点杂交同时检测17种中国人常见的β-地贫基因突变确定其基因型,对于常规基因检测不能确诊的基因突变,采用DNA直接测序法.结果 982例确诊为β-地贫的标本中,911例为轻型,71例为重型,共1 053条11号染色体携带了β珠蛋白缺陷基因,检出了 24例6种少见的β-地贫基因突变,其中IVS-Ⅰ-1(G→T)10例,CD43(G→T)6例,CD27-28(+C)、CD37( TGG→TAG)各3例,CD31(-C)、- 73 (A→T)各1例.结论 桂林地区β-地贫基因突变类型丰富,有明显的地域性,在地贫的诊断和产前诊断中应加以重视.     

贵阳地区重症β-地中海贫血患儿及双亲基因突变型的分析

目的 对15例贵阳地区重症β－地中海贫血患儿及其双亲进行基因突变分析，以探讨其突变基因的类型和频率的特点，为诊断和预防重症胎儿的出生提供线索。方法 采用一管法进行红细胞渗透休克实验测定红细胞渗透脆性、一分钟碱变性法测定抗碱血红蛋白（HbF）和醋酸纤维薄膜电泳洗脱比色法测定血红蛋白A2（HbA2）、氰化高铁血红蛋白法测定Hb等进行β－地中海贫血血液学检查。用常规法抽提外周血白细胞DNA，用聚合酶链反应－反向点杂交法（PCR－RDB）扩增目的的基因片段和 分析其基因类型。结果 15例重症β－地中海贫血患儿及其双亲共45例标本中检出中国人常见的11种突变中的5种：CD41－42（－TTCT）、IVSⅡnt654（C→T）、CD17（A→T）、β^E（G→A）和Nt-28（A→G）的基因突变类型，前3种占总数的89．99％。结论 采用PCR－RDB法进行基因诊断，具有操作简单、快速准确，仅需一次杂交就可确定样品中是否存在11种中国人常见的β－地中海贫血突变基因型，提高了基因诊断率，这对防止重症β－地中海贫血患儿的出生、提高人口素质具有重要意义。     

β-珠蛋白生成障碍性贫血患儿血常规参数和基因检测结果分析

目的检验泸州地区β-珠蛋白生成障碍性贫血(β-地贫)患儿血常规参数和基因突变类型分布,探讨血常规参数在β-地贫筛查中的应用价值。方法 50例β-地贫患儿,根据临床表现和实验室检查分为重型组(18例)和轻型组(32例),提取外周血DNA,采用反向斑点杂交法进行β-地贫基因突变位点分析。选择同期儿保门诊健康儿童20例作为正常对照组,采用全自动血细胞分析仪分别检测三组儿童血常规红细胞数(RBC)、血红蛋白量(Hb)、平均红细胞体积(MCV)、平均血红蛋白含量(MCH)、平均血红蛋白浓度(MCHC)、红细胞分布宽度(RDW)和网织红细胞比率(RET)等指标,并进行统计学分析。结果 50例患儿共检测出7种基因突变类型,其中以CD17(A→T)、CD41/42(-TTCT)和IVS-Ⅱ-654(C→T)最多见。轻型组和重型组β-地贫患儿RBC、Hb、MCV和MCH均较正常对照组明显降低,RET明显升高,差异有统计学意义;而MCHC和RDW与正常对照组比较差异无显著性。结论 MCV、MCH和RET等血常规参数可作为β-地贫的联合筛查指标。     

重型β-珠蛋白生成障碍性贫血患儿hTERT基因表达的研究

目的：骨髓人类端粒酶催化亚单位（hTERT）是控制人细胞端粒酶活性的限速成分,决定了细胞寿命。该研究初步探讨重型β-珠蛋白生成障碍性贫血hTERT表达的变化及其与外周血红蛋白水平的关系。方法：多重等位基因特异聚合酶链反应(MASPCR)分析重型β-珠蛋白生成障碍性贫血患儿的基因类型,半定量逆转录-聚合酶链反应(RT-PCR)检测重型β-珠蛋白生成障碍性贫血和粒细胞减少症患儿骨髓和阳性对照K562细胞株的hTERT相对表达水平,常规检测患儿外周血血红蛋白水平。Spearman直线相关分析hTERT表达与外周血血红蛋白水平的关系。结果：重型β-珠蛋白生成障碍性贫血患儿组骨髓hTERT相对表达水平高于粒细胞减少症患儿组（0.2928±0.0838 vs 0.0993±0.0336, P<0.01）,但明显低于K562细胞株(0.8291±0.0908, P<0.01)。重型β-珠蛋白生成障碍性贫血患儿组骨髓hTERT表达与其外周血血红蛋白水平呈负相关（r=-0.841,P<0.01）。结论：重型β-珠蛋白生成障碍性贫血患儿慢性溶血时,低水平血红蛋白可能在一定范围内上调骨髓hTERT基因表达水平。［中国当代儿科杂志,2009,11（6）：449-452］     

再生障碍性贫血患儿免疫功能的研究

再生障碍性贫血患儿免疫功能的研究余素明，郭桂荣，孙书明为了探讨小儿再生障碍性贫血（简称再障）的发病机理、免疫功能及其相互关系，我们对１４例患儿外周血白细胞介素２（ＩＬ－２）生成量，２０例Ｔ细胞亚群及血清免疫球蛋白以及部分患儿治疗前后动态变化进行了研究...     

珠蛋白生成障碍性贫血伴缺铁的发生率及意义

目的 了解珠蛋白生成障碍性贫血（简称地贫）患儿伴缺铁的发生率，探讨其临床意义。方法 对127例确诊地贫儿进行铁指标（SF、SI、TIBC、FEP）的检测。结果 127例中缺铁者28例(22 %)，其中α型占19 %(4/21)，β型占22.6 %(24/106)，两者无显著差异 (P＞0.5)。β型地贫并缺铁者HbF＜30 %组占38.8 %(19/49)， HbF≥30 %组占8.8 %(5/57)，差异显著 (P＜0.005)。HbF＜30 %组＜3 a者的缺铁率明显高于＞3 a者(53.3 %vs 15.8 %, P＜0.01)。结论 地贫儿可能伴发铁缺乏，尤其是低HbF的婴幼儿缺铁率更高，有必要对其进行适当补铁治疗。     

不同剂量铁螯合剂治疗高量输血重型β珠蛋白生成障碍贫血患儿血清铁蛋白的变化

目的探讨采用不同剂量铁螯合剂治疗高量输血重型β珠蛋白生成障碍贫血(地贫)患儿1年后的血清铁蛋白(SF)的变化。方法以美国Beckman-Access化学发光仪分别于2005年4月和2006年3月每月定期检测68例高量输血维持血红蛋白100 g/L以上的重型β地贫患儿血SF水平。男41例,女27例;年龄4~15岁。每月使用铁螯合剂(去铁胺或去铁酮)≥20 d 6例(A组),10~15 d 13例(B组),5~9 d 24例(C组),≤3 d 25例(D组),健康对照组(E组)20例。男女各10例。结果2005年4月和2006年3月检测血SF水平分别为A组(2205.02±707.82)μg/L和(2285.29±693.14)μg/L,B组(4028.24±752.11)μg/L和(4736.69±841.50)μg/L,C组(2462.81±937.16)μg/L和(3356.79±994.85)μg/L,D组(2390.42±730.94)μg/L和(3286.12±641.12)μg/L,E组(213.10±42.88)μg/L和(217.25±57.42)μg/L。2006年3月的SF均高于2005年4月,除A组及E组外差异均有统计学意义(P均<0.01)。结论高量输血重型β地贫患儿应长期坚持足量应用铁螯合剂,每月按体质量计算足量使用20 d以上才能使SF增高不明显,SF已明显增高才开始用铁螯合剂患儿应增加每日用量。     

Assessment of Thyroid Function in Children Aged 1-13 Years with Beta-Thalassemia Major

Objective

Hypothyroidism usually appears in the second decade of life and is thought to be associated with iron overload in patients with thalassemia major. This study aimed to evaluate thyroid dysfunctions in patients with beta-thalassemia major and to see if they appear in the earlier period of life.

Methods

Thyroid function and iron load status were evaluated in 90 children with a mean age of 7.17±3.78 years with beta-thalassemia major by measuring serum free thyroxin (FT4), serum free triiodothyronine (FT3), total thyroxin (T3), serum total triiodothyronine (T4), thyroid-stimulating hormone (TSH) and ferritin levels from serum of patients admitted to the Pediatric Department, Faculty of Medicine University of Dicle between March 2005 and July 2009. A control group formed from an age-sex matched healthy children with a mean age of 6.98±3.66 years was also included. A standard thyrotropin releasing hormone test was applied to 3 patients who had high TSH levels and were classified as subclinical primer hypothyroidism. The study was designed according to the Declaration of Helsinki and informed consent was obtained from the parents of all participants.

Findings

All thyroid parameters in patients were in the normal ranges compared with the controls except three of them which had high TSH levels. Serum ferritin level (2703±1649 ng/mL) in patients was significantly higher than in controls (81.5±15.5 ng/mL).

Conclusion

The work implies that hypothyroidism could be even seen in the first decade of life in patients with beta-thalassemia major in spite of improved hematological cares.     

Usefulness of Pulsed Wave Tissue Doppler Imaging in Assessment of Left Ventricular Functions in Children with Beta-Thalassemia Major

Objective

To evaluate the changes in the LV systolic and diastolic function in children with beta-thalassemia major (β-TM) using pulsed wave tissue doppler (TD) echocardiography.

Methods

Clinical, conventional echo doppler and pulsed wave tissue doppler imaging parameters were compared in 40 beta-thalassemia major patients (mean age, 6.52?±?3.5 y) and 25 age and sex matched normal subjects (mean age, 6.5?±?2.7 y).

Results

There were no significant statistical differences between mean fractional shortening (FS) and ejection fraction (EF) of left ventricle (LV) of the patients and control group. Children with beta-thalassemia had significantly lower E′ wave velocities measured at the left ventricular septal annulus (8.1?±?3.3 vs. 13?±?2.5, P?<?0.001), lateral margin of the mitral annulus (9.1?±?5.4 vs. 13.3?±?2.5, P?<?0.001) and lateral margin of the tricuspid annulus (9.3?±?3.9 vs. 13.3?±?2.5, P?<?0.001) when compared to the control group. Furthermore children with beta-thalassemia had significantly lower E′/A′ wave ratio at the left ventricular septal annulus (0.76?±?0.34 vs. 1.36?±?0.23), lateral margin of the mitral annulus (0.83?±?0.17 vs. 1.28?±?0.22), and lateral margin of the tricuspid annulus ((0.90?±?0.27 vs. 1.26?±?0.23, (P?<?0.05) when compared to the control group.

Conclusions

This study showed that patients with beta-thalassemia major and normal conventional echo doppler parameters had statistically significant changes detected by pulsed wave tissue doppler imaging.     

Zinc and Copper Status in Children with Beta-Thalassemia Major

Objective

There are some reports in which a condition of zinc deficiency and its associated outcomes with a change in concentration of serum copper among the thalassemic patients has been highlighted. The aim of this prospective study was to determine the serum zinc and copper levels in children with beta-thalassemia major.

Methods

In this cross sectional study all children under 12 years affected by beta thalassemia major (40 patients) were evaluated for serum zinc and copper levels in Qazvin thalassemia center (Qazvin, Iran) in 2007. Serum measurements for zinc and copper were performed by atomic absorption spectrophotometer.

Findings

The mean concentrations of serum zinc and copper levels were 67.35±20.38 and 152.42±24.17 µg/dl respectively. Twenty-six (65%) of thalassemic patients had zinc concentration under 70 µg/dl (hypozincemia). None of the thalassemic children had copper deficiency. No significant correlation between serum zinc level with age, weight, height, body mass index, duration of blood transfusion, desferrioxamine dose and ferritin level was observed in thalassemic patients (P=0.3).

Conclusion

This study revealed that hypozincemia is common in thalassemic patients, but in contrast, there is no copper deficiency. Further evaluation in this regard is recommended.     

The Effect of HFE Polymorphisms on Cardiac Iron Overload in Patients with Beta-Thalassemia Major

Objective: We aimed to investigate the effect of human hemochromatosis protein (HFE) polymorphisms on cardiac iron overload in patients with beta-thalassemia major. Methods: Our study included 33 patients diagnosed with beta-thalassemia major who were treated with regular transfusions and chelation therapy. M-mode, tissue Doppler, and pulsed wave Doppler echocardiography were performed on all patients. T2* magnetic resonance imaging (MRI) scans were also performed. The HFE polymorphisms (H63D, C282Y, S65C, Q283P, E168Q, E168X, W169X, P160delC, Q127H, H63H, V59M, and V53M) were studied using polymerase chain reaction. Results: The H63D polymorphism was detected in six patients with beta-thalassemia major. Five patients were heterozygous for the H63D polymorphism, while one was homozygous. There were no other polymorphisms. There was no relationship between the HFE polymorphisms and either the serum ferritin levels or the T2-weighted MRI values (P > .05). Moreover, conventional echo and tissue Doppler echo findings were not correlated with the HFE polymorphisms. Pulmonary vein atrial reversal flow velocity, which is a manifestation of diastolic dysfunction measured with pulse wave echo, was higher in the patients with HFE polymorphisms (P = .036). Conclusions: The HFE polymorphisms had no effect on cardiac iron overload. However, pulmonary vein atrial reversal flow velocity measurements can provide important information for detecting diastolic dysfunction during cardiac follow-up of patients with HFE polymorphisms. Studies with more patients are needed to provide more information regarding this matter.     

Serum Immunoglobulin Levels in Splenectomized and Non- Splenectomized Patients with Major Beta-Thalassemia

Objective

Thalassemia is a common disease in many countries, in which several complications such as infections can occur. Although aberration in the function of the immune system could be a reason for such complication, a little is known about the status of humoral immune system in major beta thalassemia. In this study we measured serum immunoglobulins level in a group of patients with major beta thalassemia.

Methods

Ninety nine patients with major beta thalassemia were enrolled in this study divided into two groups of splenctomized and not splenctomized patients. Serum IgG, IgM and IgA levels of these patients were measured and analyzed.

Findings

Serum mean levels of IgG and IgM in patients of all ages in both groups were normal. The mean serum IgA level in the group of not splenectomized patients aged less than five years as well as in the splenectomized patients aged more than twenty years was increased. However, it was normal in other age groups.

Conclusion

Although this study could not show any defect in the humoral immune system, evaluation of immunoglobulins could be useful to understand the relmarkable high rate of infection in the patients with major beta thalassemia.     

Determination of Hepatitis C Genotypes and the Viral Titer Distribution in Children and Adolescents with Major Thalassemia

Objective

Hepatitis C virus (HCV) is an etiological agent responsible for occurrence of post-transfusion hepatitis in thalassemic patients. This study identified hepatitis C genotypes in pediatric and adolescent thalassemic patients and their correlation with age, blood transfusion, HCV RNA viral titer and liver function.

Methods

This study considers cross-sectional data from the Center for Thalassemia in Zahedan (Iran) carried out between August 2005 and September 2007. Twenty multitransfused patients suffering from β-thalassemia major and chronic HCV infection (13 males, 7 females) were included in the study. Patients were considered eligible for the study if they were seropositive for HCV RNA polymerase chain reaction (PCR) before initiation of evaluation. Blood sample was taken for HCV genotype and viral titer as well as biochemical markers. Type specific primer and real-time RT-PCR HCV were used for determination of viral genotype and HCV-RNA titer.

Findings

There was a significant positive correlation between serum HCV RNA titer and genotypes (P<0001). Serum HCV RNA levels were found higher in genotype 3a than in others. The most prevalent genotype in thalassemic patients was genotype 3a (40%) followed by 1b (25%), unclassified (20%) and la (15%). There was no meaningful relationship between genotype, Alanine aminotranferease, ferritin and alkaline phosphatase. Age, serum HCV RNA titer and number of transfusions were the only significant factors associated with genotypes (P<015, P<0.0001 and P<0.001 respectively).

Conclusion

This study showed that HCV genotype and viral titer are related to the number of blood transfusions received by thalassemic patients. Screening donated blood in blood banks would prevent the occurrence of hepatitis C in this high-risk group.