Hemoglobin E protects against acute Plasmodium vivax infections in a Kachin population at the China–Myanmar border - 06/08/18

Doi : 10.1016/j.jinf.2018.06.005

Zeshuai Deng ^a,^{^{1
These authors contributed equally to this work.}}, Qing Li ^a,^{^{1
These authors contributed equally to this work.}}, Haoan Yi ^a,^{^{1
These authors contributed equally to this work.}}, Yanjie Zhang ^a, Fang Yang ^a, Hong Li ^a, Lan Luo ^a, Limei Ma ^b, Zhaoqing Yang ^c, Yongshu He ^a,^⁎ , Liwang Cui ^d,^⁎
^a Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
^b Department of Histology and Embryology, Kunming Medical University, Kunming, Yunnan Province, China
^c Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province, China
^d Department of Entomology, The Pennsylvania State University, Pennsylvania, United States of America

^⁎Corresponding authors.

Sous presse. Épreuves corrigées par l'auteur. Disponible en ligne depuis le Monday 06 August 2018

Highlights

•	Hemoglobin E (HbE) is highly prevalent in the Kachin population of eastern Myanmar
•	HbE was significantly less prevalent in P. vivax patients than in healthy villagers
•	HbEA heterozygotes had significantly lower P. vivax asexual parasite densities
•	HbE offers protection against occurrence and severity of acute P. vivax infections

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Summary

Objectives

Hemoglobin E (HbE, β^{26 Glu-Lys}) is the most prevalent hemoglobinopathy in Southeast Asia. This study aimed to determine whether HbE protects against clinical Plasmodium vivax malaria in Southeast Asia.

Methods

In a case-control study performed in villages along the China-Myanmar border, we determined the prevalence of HbE in 257 villagers who had acute P. vivax infections and in 157 control healthy villagers.

Results

HbE in P. vivax patients (17.4%) was significantly less prevalent than in the healthy villager population (36.3%). Moreover, there was a complete lack of HbEE homozygotes in the vivax patients as compared to 9.5% prevalence in the healthy villagers. Using the HbAA group as the reference, both the HbEA heterozygotes and HbEE homozygotes had significantly lower odds of presenting with acute P. vivax infections. Furthermore, HbEA heterozygotes also had significantly lower P. vivax asexual parasite densities. HbEA did not affect the proportion of P. vivax patients with gametocytemia nor the gametocyte densities.

Conclusions

HbE offers significant protection against the occurrence and parasite density of acute P. vivax infections and provides a renewed perspective on P. vivax malaria as a potentially strong driving force behind the high frequencies of HbE in the Kachin population.

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Keywords : Hemogloinopathy, Hemoglobin E, Plasmodium vivax, Malaria hypothesis, Protection