Prevalence of α-thalassaemia genotypes in pregnant women in northern Thailand.

BACKGROUND & OBJECTIVES: Alpha-thalassaemias are genetic disorders with high prevalence in northern Thailand. However, common genotypes and current data on the prevalence of α-thalassaemias have not been reported in this region. Therefore, the objective of the present study was to determine the prevalence of α-thalassaemia genotypes in pregnant women in northern Thailand. METHODS: Genomic DNA was extracted from blood samples of pregnant women who came to Maharaj Nakorn Chiang Mai University Hospital during July 2009 to 2010. The common deletion and point mutation genotypes of α-thalassaemia were evaluated by gap- polymerase chain reaction (PCR) and PCR with restriction fragment length polymorphism (RFLP). RESULTS: Genotypes of 638 pregnant women were: 409 samples (64.11%) being normal subjects (αα/αα) and 229 samples (35.89%) with α-thalassaemias. these 229 samples could be classified into deletional HbH disease (--SEA/-α3.7) for 18 samples (2.82%); heterozygous α0-thalassaemia --SEA type (--SEA/αα)) for 78 (12.23%); heterozygous α+-thalassaemia - α3.7 type (-α3.7/αα) for 99 (15.52%); homozygous α+-thalassaemia - α3.7 type (-α3.7/- α3.7) for five (0.78%); heterozygous α+-thalassaemia - α4.2 type (-α4.2/αα) for two (0.31%); and heterozygous HbCS (αCSα/αα) for 27 (4.23%) cases. INTERPRETATION & CONCLUSIONS: The prevalence of α-thalassaemias in pregnant women in northern Thailand was high. This finding supports the implementation of the prevention and control of this common genetic disorder by screening for α-thalassaemia genotypes.

Production of a mouse hybridoma secreting monoclonal antibody highly specific to hemoglobin Bart's (gamma4).

Hemoglobin (Hb) Bart's (gamma4) was isolated and purified from Hb Bart's hydrops fetalis syndrome blood by CM-Sephadex C-50 chromatography. The isolated Hb Bart's was analyzed for its purity by high performance liquid chromatography. Balb/c mice were immunized intraperitoneally with Hb Bart's. The immunized mouse splenic cells were hybridized with mouse myeloma, X63-Ag8.653, by polyethylene glycol. There were 12 hybridoma clones, out of several thousand culture wells, secreting antibody against purified Hb Bart's. However, when those 12 monoclonal antibodies (mAb) were tested with Hb Bart's (gamma4), HbF (alpha2gamma12), HbH, HbE, and HbA2, there was only 1 hybridoma clone secreting mAb highly reactive to Hb Bart's with very low reactivity to HbF. A rabbit polyclonal antibody with relative high reactivity to Hb Bart's compared to HbF with the ratio of 2.4:1 was also produced by affinity column chromatography for the purpose of developing an enzyme-linked immunosorbent assay (ELISA) base for qualitative and quantitative determination of Hb Bart's in adult hemolysates. Preliminary results in quantitative determination of Hb Bart's in Hb solution of 3 alpha thalassemia families having at least 1 child with HbH disease and 6 normal subjects indicated that it was possible to quantify Hb Bart's by our developed ELISA with appropriate sensitivity and specificity.