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

Abstract

BackgroundThe protective effect of α-thalassemia, a common hematological disorder in Southeast Asia, against Plasmodium falciparum malaria has been well established. However, there is much less understanding of the effect of α-thalassemia against P. vivax. Here, we aimed to investigate the proportion of α-thalassemia including the impact of α-thalassemia and HbE on the parasitemia of P. vivax in Southeast Asian malaria patients in Thailand.MethodsA 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. Plasmodium spp. and parasite densities were determined. Group of deletion mutation (--SEA, −α3.7, −α4.2deletion) and substitution mutation (HbCS and HbE) were genotyped using multiplex gap-PCR and PCR-RFLP, respectively.ResultsIn our malaria patients, 17/210 homozygous and 74/210 heterozygous −α3.7 deletion were found. Only 3/210 heterozygous −α4.2 and 2/210 heterozygous--SEA 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 −α3.7 deletion (0.282), followed by HbE (0.101), HbCS (0.013), −α4.2 deletion (0.009), and --SEA deletion (0.003). Only density of P. vivax in α-thalassemia trait patients (−α3.7/−α3.7, --SEA/αα, −α3.7/−α4.2) but not in silent α-thalassemia (−α3.7/αα, −α4.2/αα, ααCS/αα) were significantly higher compared with non-α-thalassemia patients (p=0.027). HbE did not affect P. vivax parasitemia. The density of P. falciparum significantly increased in heterozygous HbE patients (p=0.046).ConclusionsAlpha-thalassemia trait is associated with high levels of P. vivax parasitemia in malaria patients in Southeast Asia.

Haematological profile of malaria patients with G6PD and PKLR variants (erythrocytic enzymopathies): a cross-sectional study in Thailand

“…A total of malaria patients consisting of 189 individuals from Myanmar (74.1%), 35 Thais (13.7%), 16 Karen (6.3%), 8 Cambodians (3.1%), 4 Mons (1.6%), 2 Laotians (0.8%), and 1 unknown ethnicity (0.4%) are summarized in Table 1 . These patients were from malaria-endemic areas, including the Thailand-Myanmar border (N = 25), Thailand-Cambodia border (N = 5) and several provinces of Thailand (N = 225), as described in a previous report [ 16 ] (Fig. 1 ).…”

“…Plasmodium spp. were identified under a microscope by an independent parasitologist at the Hospital for Tropical Diseases and further confirmed by polymerase chain reaction (PCR)-based analysis [ 16 ].…”

“…The normal allele produced two fragments of 102 bp and 19 bp. For G6PD-deficient patients with unknown mutations by the PCR–RFLP method, the coding exons of G6PD (exons 3–12) were amplified using primers described previously [ 16 ]. The PCR products were sequenced (Macrogen, Korea).…”

Estimation of Malaria Parasite Densities by Different Formulas in Thailand

“…In this study, parasite density by assumed RBC count of 5.0 x10 6 /µL (for males) and 4.5 x10 6 /µL (for females) showed overestimation, possibly people living in Thailand including Thai and other ethnicities from Myanmar had underlying anemia due to hemoglobinopathy (which is commonly found) [13,14] and intestinal parasitic infection [15][16][17][18][19] causing lower exactly assumed RBC counts in these population in Thailand.…”

Plasmodium falciparumProtein Exported in Erythrocyte and Mechanism Resistance to Malaria

“…Following, with less able to adhere to endothelial cells. Of this mode, studies have suggested that altered cells maintain that membrane band 3 may be a target for enhanced antibody binding to parasitized a-thalassemic cells [90,91].…”