The in-house monoclonal antibody against γ-globin chain; Thal N/B, accurately measured F cells in SEA-α thalassemia 1 trait.

The monoclonal antibody (mAb) against γ-globin chain clone Thal N/B was produced. It was aimed at measuring the quantity of HbF (α2γ2)-containing red blood cells or F cells by flow cytometry. However, it may cross-react with Hb Bart's (γ4) which is present in the SEA-α thalassemia 1 trait. We measured FC levels by flow cytometry using this in-house mAb for 100 blood samples. Prevalence of high FC trait in this cohort was 51%. Ten of 12 SEA-α thalassemia 1 trait were included in the 51% high FC individuals. Comparing FC levels in the 51 high FC individuals having and not having the SEA-α thalassemia 1 trait showed no difference of FC levels. It was concluded that Hb Bart's did not interfere with FC measurement by flow cytometry using the in-house Thal N/B mAb. Therefore, it can be used for measuring F cell levels in regions having a high prevalence of the SEA-α thalassemia 1 trait. The findings of this research should apply to other clones of anti-γ-globin chain mAb that are aimed for HbF/FC quantification.

The Hb E (HBB: c.79G>A), Mean Corpuscular Volume, Mean Corpuscular Hemoglobin Cutoff Points in Double Heterozygous Hb E/- -SEA α-Thalassemia-1 Carriers are Dependent on Hemoglobin Levels.

Identifying double heterozygosities in Hb E (HBB: c.79 G>A)/- -SEA (Southeast Asian) (α-thalassemia-1) (α-thal-1) in patients first diagnosed as carrying Hb E is important in thalassemia control. Low Hb E, mean corpuscular volume (MCV) and mean corpuscular hemoglobin (Hb) (MCH) levels have been observed in this double heterozygosity. However, the cutoff points of these parameters have never been systematically established. Here, we analyzed Hb E and red blood cell (RBC) parameters in 372 Hb E patients grouped by Hb levels, by the status of - -SEA and -α3.7 (α-thal-2; rightward) deletions, to establish the cutoff points. Then, the established cutoff points were evaluated in 184 Hb E patients. It was found that the cutoff points of Hb E, MCV, MCH were significantly dependent on the Hb levels. In the group having Hb levels <10.0 g/dL, the cutoff points of Hb E, MCV and MCH were 21.2%, 64.9 fL and 21.0 pg, respectively, and were 25.6%, 72.8 fL and 23.9 pg, respectively, in the group having Hb levels 10.0-11.9 g/dL. Finally, in the group having Hb levels ≥12.0 g/dL, the cutoff points of Hb E, MCV and MCH were 27.1%, 76.7 fL and 25.3 pg, respectively. Thus, to screen for the double heterozygous Hb E/- -SEA anomaly in patients initially diagnosed as carrying Hb E, the Hb levels must be taken into account in choosing the suitable cutoff points of these three parameters.

Screening for co-existence of α-thalassemia in ß-thalassemia and in HbE heterozygotes via an enzyme-linked immunosorbent assay for Hb Bart's and embryonic ζ-globin chain.

We sought to demonstrate the ability of levels of Hb Bart's and ζ-globin chain quantified by enzyme-linked immunosorbent assay (ELISA) in detecting α-thalassemia in ß-thalassemia and HbE heterozygotes. We developed an in-house sandwich ELISA method using monoclonal antibodies (mAbs) to Hb Bart's and ζ-globin chain, and quantified levels of Hb Bart's and ζ-globin chain in 172 and 223 anonymous blood samples of ß-thalassemia and HbE heterozygotes, respectively. Genotypes of α-thalassemia 1, ß-thalassemia were identified, and HbE allele was confirmed using a newly developed multiplex allele-specific PCR. The in-house sandwich ELISA method detected Hb Bart's in 6.4% of ß-thalassemia heterozygotes, of which 5.2% showed detectable amounts of the ζ-globin chain. 15.2% of individuals heterozygous for HbE showed a detectable amount of Hb Bart's, and the ζ-globin chain was detected in 11.2% of this cohort. All samples having detectable amounts of Hb Bart's and the ζ-globin chain were verified to be SEA-type α-thalassemia 1. ELISA-quantified Hb Bart's and ζ-globin chain levels can be used to detect double heterozygosity of α- and ß-thalassemia and of α-thalassemia and HbE. This strategy may be useful in screening for co-existence of α-thalassemia in ß-thalassemia and in HbE heterozygotes, particularly in countries where α-, ß-thalassemia and HbE are endemic.