Wide range of F cell levels in healthy Thai adults: Influence of Swiss-type hereditary persistence of foetal haemoglobin & ?-haemoglobinopathy

Background & objectives: Swiss-type hereditary persistence of foetal haemoglobin (HPFH) has been shown to be responsible for the wide range of F cell levels in healthy Thai adults. However, a survey for F cells in healthy Thai adults has not been performed. This study was conducted to determine the F cell distribution in adult Thai blood donors and to assess the possible involvement of ?-thalassaemia and haemoglobin E (HbE) carriers in increased HbF levels. Methods: Thai blood donors (n=375, 205 males and 170 females) were included in the study. Blood samples were collected for measuring haemoglobin (Hb) concentration and haematocrit (Hct) and F cell levels. Hb and Hct levels were determined by automated blood counter, while F cells were quantified by flow cytometric analysis of F cells stained by fluorescein isothiocyanate-conjugated anti ?-globin monoclonal antibody. Finally, F cell levels were compared between blood samples having mean corpuscular volume (MCV ) <80 fl and ?80 fl as well as between ?-haemoglobinopathies (HbE and ?-thalassaemia carriers) and normal adults. Results: F cell levels varied markedly spanning 0.80-39.2 per cent with a positively skewed distribution. Thirty two per cent of these individuals had F cell levels more than the 4.5 per cent cut-off point. F cell levels in females were significantly higher than those in males (P<0.05). F cell levels in individuals having MCV <80 fl were significantly higher than those having MCV ?80 fl (P<0.05). ?-haemoglobinopathy (HbE and ?-thalassaemia carriers) had significantly higher F cell levels than normal individuals (P<0.05). Interpretation & conclusions: The present results showed that besides Swiss-type HPFH, the ?-haemoglobinopathy was expected to be involved in increased F cell levels in adult Thais. Thus, influence of ?-haemoglobinopathy must be considered in interpreting F cell levels in area endemic of this globin disorder.

Zinc and copper status of thalassemic children.

We investigated the amount of both zinc and copper in plasma, erythrocytes and hair in 11 patients with hemoglobin H disease, 59 patients with beta-thalassemia/HbE disease and 20 patients with homozygous beta-thalassemia. Plasma and hair zinc levels were found to be much lower, but erythrocyte zinc levels were higher, in thalassemic patients than in controls. The levels of copper in both plasma and erythrocytes were higher in the patients than in the controls. The mechanism with respect to the increase of the amount of both zinc and copper in erythrocytes was not clear; this result may reflect the impairment of zinc and copper utilization in tissues in the pathogenesis of these thalassemic patients.

Hemoglobin typing by high performance liquid chromatography.

To evaluate the potential application of high performance liquid chromatography or HPLC in performing hemoglobin typing, comparison between this technique and routine methods was carried out. Blood specimens from Pediatric Hematology Unit, Research Center, Faculty of Medicine, Ramathibodi Hospital were examined by these methods. The level of Hb A2, Hb E and Hb F were compared. Hb A2 level determined by HPLC and electrophoresis was statistically significantly different but correlated well. Good correlation was found between Hb A2 level from HPLC compared with microcolumn chromatography although there was a statistical difference. No difference but very good correlation was found between the level of Hb E from HPLC compared with electrophoresis. Statistical difference was encountered when Hb F level determined by HPLC was compared to that determined by Betke alkaline denaturation test. However, good correlation was observed when the level of Hb F was greater than 2.0%. In conclusion, HPLC could be an alternative way of performing hemoglobin typing provided that Hb F is 10% or more, by calculating from the equation: Alk F = (0.83 x Hb F by HPLC) - 0.98.