海南地区α-地中海贫血筛查方法探讨

目的:探讨血液常规参数分析、zeta链蛋白检测及高效液相色谱分析法在海南α-地中海贫血筛查中的临床价值。方法:收集平均红细胞体积(MCV)<80 fl,平均红细胞血红蛋白含量(MCH)<26 pg,红细胞体积分布宽度(RDW)正常或稍高的EDTA-K2抗凝全血标本共139例,采用双抗体夹心酶联免疫吸附法检测zeta链蛋白和HPLC法测定血红蛋白亚型HbA2含量,然后提取全血DNA,经PCR扩增后,琼脂糖凝胶电泳检测常见α-地贫缺失类型--SEA、-α3.7、-α4.2。结果:139例全血标本中zeta链蛋白阳性49例,48例为东南亚缺失型α-地贫,其中2例同时合并有左缺失或右缺失;阴性90例,4例为东南亚缺失型。Zeta链蛋白检测东南亚缺失型α-地贫的灵敏度为92.31%,特异度为98.85%,假阳性率为2.04%,假阴性率为4.44%,阳性预测值为97.96%,阴性预测值为95.56%。经HPLC检测HbA2≤2.5%标本共92例,确诊为α-地贫患者62例,占67.39%;HbA2>2.5%标本47例,4例为α-地贫,占8.51%。HbA2≤2.5%标本和HbA2>2.5%标本中α-地贫所占百分率差异比较有统计学意义。139例小细胞低色素性贫血患者中证实为α-地贫者66例,α-地贫检出率为47.48%,以--SEA/αα基因型为主,占34.53%;3种α-地贫缺失突变的基因频率为0.575 7,其中-α3.7、-α4.2和--SEA的等位基因频率分别为0.068 2,0.113 6和0.393 9。结论:血液学参数分析、zeta链蛋白检测及HPLC法均可作为海南地区α-地贫筛查的有效方法。

Study on screening of α-thalassemia in Hainan

Objective: To evaluate the parameters of conventional blood test,zeta chain protein detection and high-performance liquid chromatography analysis in the screening of α-thalassemia in Hainan.Methods: One hundred and thirty-nine EDTA-K2 anticoagulant blood samples with erythrocyte mean corpuscular volume(MCV) <80 fl,mean corpuscular hemoglobin(MCH) <26 pg,red cell distribution width(RDW)was normal or slightly higher than normal value were collected.Zeta chain protein was determined using double-antibody enzyme-linked immunosorbent assay(ELISA),the content of subtype HbA2 of hemoglobin was detected by HPLC,and then the DNA of blood was extracted,after amplified by PCR,using agarose gel electrophoresis to detect the common loss type of α-thalassemia-SEA,——α3.7,-α4.2.Results: Of the 139 blood samples,zeta chain protein positive had 49 cases,among them,48 cases were Southeast Asia loss type of α-thalassemia,of which two cases combined with right loss or left loss together;negative 90 cases,four cases had Southeast Asia loss.The sensitivity and specificity of the detection of zeta chain protein for southeast asia deletion α-thalassemia were 92.31% and 98.85% respectively,the false positive rate was 2.04 %,the false negative rate was 4.44%,the positive predictive value was 97.96%,the negative predictive value was 95.56%.Detected by HPLC,92 cases HbA2 ≤2.5%,62 cases were diagnosed firmly as α-thalassemia,accounting for 67.39%;HbA2> 2.5% were 47 cases,4 cases were α-thalassemia,accounting for 8.51%.There was significant difference of the percentage of α-thalassemia between sample of HbA2 ≤ 2.5% and sample of HbA2> 2.5%.66 out of 139 cases microcytic and hypochromatic anemia were found to be α-thalassemia,the detection rate was 47.48%,dominated by——SEA/αα genotype,accounting for 34.53%;the frequency of gene deletion mutation in three types of α-thalassemia was 0.575 7,of which,the allele frequencies of-α3.7,-α4.2,——SEA were 0.068 2,0.113 6 and 0.393 9 respectively.Conclusion: Parameters of conventional blood test,zeta chain protein detection and high-performance liquid chromatography analysis are effective methods for the screening of α-thalassemia in Hainan.