In a prospective clinical study in New Halfa Teaching Hospital, the possible association between
FcgammaRIIa-R/H131 polymorphism and
anti-malarial antibody responses with clinical outcome of
Plasmodium falciparum malaria among Sudanese patients was investigated. A total of 256 individuals were consecutively enrolled, comprising 115 patients with severe
malaria, 85 with mild
malaria and 56
malaria-free controls. Genotyping of
FcgammaRIIa-R/H131 dimorphism was performed using gene-specific polymerase chain reaction (PCR) amplification with allele-specific restriction
enzyme digestion of the PCR product. The antibody responses to asexual blood-stage
antigens were assessed by an
enzyme-linked
immunosorbent assay. The frequency of the
FcgammaRIIa-R/R131 genotype was significantly higher in those with severe
malaria when compared with patients with mild
malaria, while the
FcgammaRIIa-H/H131 genotype showed a significant association with mild
malaria. A reduced risk of severe
malaria with
IgG3 antibodies in combination with the H/H131 genotype was observed. Furthermore, low levels of
IgG2 antibodies reactive with the Pf332-C231
antigen were also associated with lower risk of severe
malaria in individuals carrying the H131 allele. The levels of
IgG1 and
IgG3 antibodies were statistically significantly higher in the mild
malaria patients when compared with the severe
malaria patients. Taken together, our study revealed that the
FcgammaRIIa-R/R131 genotype is associated with the development of severe
malaria, while the H/H131 genotype is more likely to be associated with mild
malaria. Our results also revealed that the natural acquisition of immunity against clinical
malaria appeared to be more associated with
IgG1 and
IgG3 antibodies, signifying their roles in parasite-neutralizing immune mechanisms.