Open Access | IL4 gene polymorphism and previous malaria experiences manipulate anti-Plasmodium falciparum antibody isotype profiles in complicated and uncomplicated malaria

Background
The IL4-590 gene polymorphism has been shown to be associated with elevated levels of anti-Plasmodium falciparum IgG antibodies and parasite intensity in the malaria protected Fulani of West Africa. This study aimed to investigate the possible impact of IL4-590C/T polymorphism on anti-P. falciparum IgG subclasses and IgE antibodies levels and the alteration of malaria severity in complicated and uncomplicated malaria patients with or without previous malaria experiences.
Methods
Anti-P.falciparum IgG subclasses and IgE antibodies in plasma of complicated and uncomplicated malaria patients with or without previous malaria experiences were analysed using ELISA. IL4-590 polymorphisms were genotyped using RFLP-PCR. Statistical analyses of the IgG subclasses and IgE levels were done by Oneway ANOVA. Genotype differences were tested by Chi-squared test.
Results
The IL4-590T allele was significantly associated with anti-P. falciparum IgG3 antibody levels in patients with complicated (P=0.031), but not with uncomplicated malaria (P=0.622). Complicated malaria patients with previous malaria experiences carrying IL4-590TT genotype had significantly lower levels of anti-P. falciparum IgG3 (P=0.0156), while uncomplicated malaria patients with previous malaria experiences carrying the same genotype had significantly higher levels (P=0.0206) compared to their IL4-590 counterparts. The different anti-P. falciparum IgG1 and IgG3 levels among IL4-590 genotypes were observed. Complicated malaria patients with previous malaria experiences tended to have lower IgG3 levels in individuals carrying TT when compared to CT genotypes (P=0.075). In contrast, complicated malaria patients without previous malaria experiences carrying CC genotype had significantly higher anti-P. falciparum IgG1 than those carrying either CT or TT genotypes (P=0.004, P=0.002, respectively).
Conclusions
The results suggest that IL4-590C or T alleles participated differently in the regulation of anti-malarial antibody isotype profiles in primary and secondary malaria infection and, therefore, could play an important role in alteration of malaria severity.