An Observational Study of the Effect of Hemoglobinopathy, Alpha Thalassemia and Hemoglobin E on Parasitemia.

BACKGROUND

The protective effect of α-thalassemia, a common hematological disorder in Southeast Asia, against malaria has been well established. However, there is much less understanding of the effect of α-thalassemia against . Here, we aimed to investigate the proportion of α-thalassemia including the impact of α-thalassemia and HbE on the parasitemia of in Southeast Asian malaria patients in Thailand.

METHODS

A total of 210 malaria patients, admitted to the Hospital for Tropical Diseases, Thailand during 2011-2012, consisting of 159 Myanmeses, 13 Karens, 26 Thais, 3 Mons, 3 Laotians, and 6 Cambodians were recruited. and parasite densities were determined. Group of deletion mutation (--, -α, -αdeletion) and substitution mutation (HbCS and HbE) were genotyped using multiplex gap-PCR and PCR-RFLP, respectively.

RESULTS

In our malaria patients, 17/210 homozygous and 74/210 heterozygous -α deletion were found. Only 3/210 heterozygous -α and 2/210 heterozygous-- deletion were detected. HbE is frequently found with 6/210 homozygotes and 35/210 heterozygotes. The most common thalassemia allele frequencies in Myanmar population were -α deletion (0.282), followed by HbE (0.101), HbCS (0.013), -α deletion (0.009), and -- deletion (0.003). Only density of in α-thalassemia trait patients (-α/-α, --/αα, -α/-α) but not in silent α-thalassemia (-α/αα, -α/αα, αα/αα) were significantly higher compared with non-α-thalassemia patients (=0.027). HbE did not affect parasitemia. The density of significantly increased in heterozygous HbE patients (=0.046).

CONCLUSIONS

Alpha-thalassemia trait is associated with high levels of parasitemia in malaria patients in Southeast Asia.