Polymorphism of the FcÃÂ³ receptor IIA and malaria morbidity
- *Corresponding Author:
- Marcelo Urbano Ferreira
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Received date: 10 June 2005; Revised date: 11 July 2005; Accepted date: 11 July 2005; Available online 28 July 2005; Published date: 19 August 2005
Copyright: Érika Martins Braga et al.
Fc receptors (FcRs) are expressed on the surface of all types of cells of the immune system. They bind the Fc portion of immunoglobulin (Ig), thereby bridging specific antigen recognition by antibodies with cellular effector mechanisms. FcγRIIA, one of the three receptors for human IgG, is a low-affinity receptor for monomeric IgG, but binds IgG immune complexes efficiently. FcγRIIA is believed to play a major role in eliciting monocyte- and macrophage-mediated effector responses against blood-stage malaria parasites. A G → A single nucleotide polymorphism, which causes an arginine (R) to be replaced with histidine (H) at position 131, defines two allotypes which difer in their avidity for complexed human IgG2 and IgG3. Because FcγRIIA-H131 is the only FcγR allotype which interacts efficiently with human IgG2, this polymorphism may determine whether parasite-specific IgG2 may or may not elicit cooperation with cellular imune responses during blood-stage malaria infection. Here, we review data from four published case-control studies describing associations between FcγRIIA R/H131 polymorphism and malaria-related outcomes and discuss possible reasons for some incongruities found in these available results.