Quadri M I, Islam S I, Nasserullah Z
Department of Hematology, Regional Laboratory and Blood Bank, Dammam, Saudi Arabia.
Ann Saudi Med. 2000 Sep-Nov;20(5-6):367-70. doi: 10.5144/0256-4947.2000.367.
AA+/--thalassemia is known to be prevalent in the Eastern region of Saudi Arabia. There are no large scale reports regarding the effect of alpha-thalassemia on red cell indices of cord blood from Saudi Arabia. Similarly, there are no reports regarding the interaction of AA+/--thalassemia and the sickle cell gene in relation to red cell indices in cord blood. To address these issues, we undertook a study on neonatal cord blood samples.
In a prospective study, cord blood samples from 504 neonates from the Qatif area of the Eastern Province of Saudi Arabia were analyzed for complete blood counts (CBC) and cellulose acetate Hb electrophoresis. Hb S was confirmed by citrate agar Hb electrophoresis.
There were 243 case samples with normal Hb electrophoresis (Hb A 27.2+/-7% and Hb F 72.6+/-7.7%). Their mean Hb (g/dL), RBC (x10(12) /L), Hct (%), MCV (fl), MCH (pg), MCHC (g/dL), RDW-SD (fl) and RDWCV (%) were 15.05+/-1.6, 4.5+/-0.5, 47.4+/-5.3, 106+/-8, 33.6+/-2.3, 31.8+/-1.7, 69.2+/-9.5 and 17.9+/-1.7, respectively. There were 136 cases with alpha-thalassemia trait (alphaTT), 57 cases with sickle cell trait (SCT) and 50 cases of sickle cell trait with alpha-thalassemia trait (SCT/alphaTT). There were 10 cases of Hb H disease (6 definite), including one with sickle cell disease (SCD) and two with SCT, Hb Bart's 23.9%-43.6%; four probable with Hb Bart's 10.9%-16.1%, and one with SCT. The effect on red cell parameters in Hb H disease were most pronounced. In addition, there were seven cases of SCD, four of whom had coexistent AA+/--thalassemia trait (SCD/alphaTT).
The prevalence of alpha-thalassemia in this cohort of Saudi population was 39.99%. Hb H disease appeared as common as SCD. Sickle cell gene was seen in 23.4% of neonatal samples. alpha-Thalassemia gene significantly reduces MCH, MCV, RDW-SD, Hct, Hb, and increases RBC count in both normal or sickle cell trait neonates. Generally, the variation of red cell parameters is directly proportional to the amount of Hb Bart's in the cord blood. Sickle cell gene in itself produces low MCV, RDW-SD and MCH in cord blood. Further, normal reference values for red cell parameters of cord blood are established.
已知αα+/--地中海贫血在沙特阿拉伯东部地区较为普遍。目前尚无关于α地中海贫血对沙特阿拉伯脐带血红细胞指数影响的大规模报告。同样，也没有关于αα+/--地中海贫血与镰状细胞基因在脐带血红细胞指数方面相互作用的报告。为解决这些问题，我们对新生儿脐带血样本进行了一项研究。
在一项前瞻性研究中，对来自沙特阿拉伯东部省卡提夫地区的504名新生儿的脐带血样本进行了全血细胞计数（CBC）和醋酸纤维素血红蛋白电泳分析。通过柠檬酸盐琼脂血红蛋白电泳确认血红蛋白S。
有243例样本血红蛋白电泳正常（血红蛋白A 27.2±7%，血红蛋白F 72.6±7.7%）。其平均血红蛋白（g/dL）、红细胞（x10¹²/L）、血细胞比容（%）、平均红细胞体积（fl）、平均红细胞血红蛋白含量（pg）、平均红细胞血红蛋白浓度（g/dL）、红细胞分布宽度标准差（fl）和红细胞分布宽度变异系数（%）分别为15.05±1.6、4.5±0.5、47.4±5.3、106±8、33.6±2.3、31.8±1.7、69.2±9.5和17.9±1.7。有136例α地中海贫血特征（αTT）病例、57例镰状细胞特征（SCT）病例和50例同时具有镰状细胞特征和α地中海贫血特征（SCT/αTT）的病例。有10例血红蛋白H病（6例确诊），包括1例镰状细胞病（SCD）和2例SCT，血红蛋白Bart's为23.9%-43.6%；4例可能患有血红蛋白Bart's为10.9%-16.1%，1例患有SCT。血红蛋白H病对红细胞参数的影响最为明显。此外，有7例SCD，其中4例同时存在αα+/--地中海贫血特征（SCD/αTT）。
该沙特人群队列中α地中海贫血的患病率为39.99%。血红蛋白H病与SCD的发生率相当。在23.4%的新生儿样本中发现了镰状细胞基因。α地中海贫血基因在正常或镰状细胞特征的新生儿中均显著降低平均红细胞血红蛋白含量、平均红细胞体积、红细胞分布宽度标准差、血细胞比容、血红蛋白，并增加红细胞计数。一般来说，红细胞参数的变化与脐带血中血红蛋白Bart's的含量成正比。镰状细胞基因本身会使脐带血中的平均红细胞体积、红细胞分布宽度标准差和平均红细胞血红蛋白含量降低。此外，还建立了脐带血红细胞参数的正常参考值。
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