Delta-globin gene expression improves sickle cell disease in a humanised mouse model.

Sickle cell disease (SCD) is a widespread genetic disease associated with severe disability and multi-organ damage, resulting in a reduced life expectancy. None of the existing clinical treatments provide a solution for all patients. Gene therapy and fetal haemoglobin (HbF) reactivation through genetic approaches have obtained promising, but early, results in patients. Furthermore, the search for active molecules to increase HbF is still ongoing. The delta-globin gene produces the delta-globin of haemoglobin A2 (HbA2). Although expressed at a low level, HbA2 is fully functional and could be a valid anti-sickling agent in SCD. To evaluate the therapeutic potential of a strategy aimed to over-express the delta-globin gene in vivo, we crossed transgenic mice carrying a single copy of the delta-globin gene, genetically modified to be expressed at a higher level (activated), with a humanised mouse model of SCD. The activated delta-globin gene gives rise to a consistent production of HbA2, effectively improving the SCD phenotype. For the first time in vivo, these results demonstrate the therapeutic potential of delta-globin, which could lead to novel approaches to the cure of SCD.

Analytical evaluation of the Tosoh HLC-723 G7 automated HPLC analyzer for hemoglobin A2 and F determination.

OBJECTIVES: The analytical performance of a new automated HPLC system (Tosoh HLV-723 G7) for Hb A(2) and Hb F quantification in blood was studied. DESIGN AND METHODS: Hb A(2) and Hb F measurements were studied for imprecision, linearity, carry-over, interferences and sample concentration effect. Method comparison study was performed with the Bio-Rad Variant II HPLC system. Hb F results were also compared with those obtained by the alkaline denaturation test. The detection of some common Hb variants was also studied. RESULTS: Hb A(2) within-run and between-run CVs were found between 0.8-2.2% and 2.9-7.2%, respectively, while CVs for Hb F were up to 10.0% in normal and between 1.9-5.3% at more clinically relevant Hb F concentrations (>1.5%). Comparison study with Bio-Rad Variant II for Hb A(2) determination showed good correlation but highlighted calibration differences. The following results were obtained in two different laboratories: y = 1.163x - 0.52, r = 0.9918, n = 144 (Lab A); y = 1.060x - 0.40, r = 0.9920, n = 93 (Lab B). With regard to the determination of Hb F, the measurements performed by the tested method was found to correlate well with the alkaline denaturation test (y = 1.0138x - 0.36, r = 0.9842, n = 20) and with the Variant II HPLC system (y = 0.812x + 0.52, r = 0.9835, n = 110). An excellent linearity (r = 0.999) was found for both Hb A(2) and Hb F in the range 0.8-19%. Hb S, Hb C and Hb D can be presumptively identified by the assigned retention time windows. CONCLUSION: The new analyzer Tosoh HLV-723 G7 was found to be a reliable method for Hb A(2) and Hb F quantification and for the presumptive identification of some common Hb variants.