Influence of Sickle Cell Gene on the Allelic Diversity at the MSP-1 Locus of Plasmodium Falciparum in Adult Patients With Severe Malaria

Abstract

Although several studies have supported that sickle cell trait (HbAS) protects against falciparum malaria, the exact mechanism by which sickle gene confers protection is unclear. Further, there is no information on the influence of the sickle gene on the parasitic diversity of P. falciparum population in severe symptomatic malaria. This study was undertaken to assess the effect of the sickle gene on the parasite densities and diversities in hospitalized adult patients with severe falciparum malaria. The study was carried out in 166 adults hospitalized subjects with severe falciparum malaria at Sickle Cell Clinic and Molecular Biology Laboratory, Veer Surendra Sai Institute of Medical Sciences and Research, Burla, Odisha, India. They were divided into three groups on the basis of hemoglobin variants HbAA (n=104), HbAS (n=30) and HbSS (n=32). The msp-1 loci were genotyped using a PCR-based methodology. The parasite densities were significantly high in HbAA compared to HbAS and HbSS. The multiplicity of infection (MOI) and multi-clonality for msp-1 were significantly low in HbSS and HbAS compared to HbAA. The prevalence of K1 (p<0 .0001) and MAD20 (p=0.0003) alleles were significantly high in HbAA. The RO33 allele was detected at a higher frequency in HbSS and HbAS, compared to K1 and MAD20. Sickle gene was found to reduce both the parasite densities and diversity of P. falciparum in adults with severe malaria.

Prevalence of Plasmodium falciparum and non-P. falciparum infections in a highland district in Ghana, and the influence of HIV and sickle cell disease

“…In this study neither HbSS nor HbAC showed any influence on malaria; other studies have also been unable to show a clear relationship between them [ 16 , 18 , 36 ]. Whilst certain studies have shown decreased risk for malaria in people with HbSS [ 37 , 38 ], others have shown no difference between HbSS allele and HbAA where malaria risk is concerned [ 16 , 18 , 36 ]. Also, heterozygous HbAC has not been found to influence malaria in some studies [ 16 ], yet some studies have shown malaria to be reduced in people with HbAC [ 23 ].…”

Relationship between human genetic factors and Plasmodium falciparum genetic diversity of msp1, msp2 and glurp in a malaria endemic area of Burkina Faso

“…Previous studies assessing influence of sickle cell gene on the multiplicity of infection (MOI) in asymptomatic malaria in Africa [30] presented reliable results. In addition, in G6PD deficiency group, factors as pre-hospital treatment status, age, transmission intensity, genotyping methods, and immune status can influence the parasite diversity [31]. The high MOI reported in our study contrast with the actions taken to control malaria such as the wide deployment of ACTs, the free distribution campaigns of Long-Lasting Impregnated Mosquito Nets (LLINs) organized since 2010 throughout the country and the ongoing implementation of the SMC.…”