Red cell parameters in alpha-thalassemia with and without beta-thalassemia trait or hemoglobin E trait

Abstract

Eighty-five patients who attended at Ramathibodi Hospital during November 1994 to June 1996 were investigated for thalassemia genotype. hemoglobin (Hb) typing and blood cell parameters All patients were screened primarily for complete blood count using the Technicon H *3 automated hematology analyzer and Hb typing using the automated HPLC. Their genotypes were evaluated by in vitro gene amplification using primers for detection of common α-thalassemic genes found in the Thai population. We found 45 cases out of 85 were α-thalassemia trait with A2A typing, 10 were normal, 7 were α-thalassemia trait complicated by β-thalassemia trait or HbE trait, 18 were HbH disease or HbH with Hb Constant Spring (HbH/CS), and 5 were AE Bart's disease. The α-thalassemia 1 trait had heterogeneity in red cell population as shown by increased red cell distribution width (RDW), the increased percent microcytic red cell (%Micro) and decreased mean cell volume (MCV). Red cell parameters in α-thalassemia 2 trait and HbCS trait were not significantly different from normal. The cases with coinheritance of α-thalassemia trait with β-thalassemia trait or with HbE trait showed variation in their red cell parameters: one case showed less abnormal red cell parameters than those of uncomplicated α-thalassemia but the other two cases showed unimproved values. The homozygous α-thalassemia 2 showed similar red cell parameters to the α-thalassemia 1 trait. In conclusion, we can screen the α-thalassemia 1 trait and homozygous α-thalassemia 2 by using the simple red cell parameters such as the MCV and RDW; however, they must be confirmed for α-thalassemic genes. Unfortunately, red cell parameters of α-thalassemia 2 trait or HbCS trait were not different from those of normal subjects.