Ballas S K, Burka E R, Gill F M
J Lab Clin Med. 1982 Feb;99(2):263-74.
A 63-year-old man of italian origin with severe heterozygous beta-thalassemia whose clinical condition deteriorated after splenectomy is described. The alpha/beta synthesis ration in the peripheral blood was 3.02 +/- 0.56 and in the bone marrow 1.43. The free alpha-chain pool comprised 73% of the total radioactive alpha-globin in the peripheral blood and 68% in the bone marrow. RBC membranes isolated from erythrocytes incubated in the presence of 14C-leucine were practically devoid of nascent beta-chains with an alpha/beta ratio of 5.12 +/- 1.47, significantly higher than that present in the corresponding hemolysate. RBC membranes from this patient, compared to control membrane preparations, showed increased proteolytic activity directed against tetrameric hemoglobin and beta-hemoglobin chains, with concomitant decreased catabolism of alpha-hemoglobin chains. RBC membranes from individuals with mild beta-thalassemia trait and from transfused patients with homozygous beta-thalassemia degraded alpha-hemoglobin chains more efficiently than those from the patient described. The data suggest that decreased degradation of the alpha-chain by RBC membranes from this patient might lead to progressive accumulation of this polypeptide and expansion of the free alpha-chain pool, which, in turn, may be responsible for the severity of the clinical picture.
本文描述了一名63岁具有意大利血统的男性，患有严重的杂合子β地中海贫血，脾切除术后临床状况恶化。外周血中α/β合成比为3.02±0.56，骨髓中为1.43。游离α链池在外周血中占总放射性α珠蛋白的73%，在骨髓中占68%。从在14C-亮氨酸存在下孵育的红细胞中分离出的红细胞膜几乎没有新生的β链，α/β比为5.12±1.47，显著高于相应溶血产物中的比例。与对照膜制剂相比，该患者的红细胞膜显示出针对四聚体血红蛋白和β血红蛋白链的蛋白水解活性增加，同时α血红蛋白链的分解代谢减少。轻度β地中海贫血特征个体和输血的纯合子β地中海贫血患者的红细胞膜比所述患者的红细胞膜更有效地降解α血红蛋白链。数据表明，该患者红细胞膜对α链的降解减少可能导致该多肽的逐渐积累和游离α链池的扩大，进而可能是临床症状严重程度的原因。
