Evaluation of FcγRIIIB-NA1 NA2 polymorphism in visceral leishmaniasis

Abstract EN

Background : Several lines of evidence demonstrating that innate and adaptive immunity play important roles in the defense against visceral leishmaniasis (VL).

A polymorphism within the FcγRIIIB gene can lead to the expression of three variants of NA1, NA2, and the combined one (NA1 / NA2) which alters affinity of IgG to its receptor.

Objectives : The main aim of this study was to evaluate the FcγRIIIB-NA1/NA2 polymorphism in the FcγRIIIB gene of VL patients in comparison to healthy controls.

Patients and Methods : In this cross-sectional study, three groups ; 54 seropositive patients with clinical presentation of VL (group 1), 104 seropositive patients without clinical presentation (group 2), and 104 healthy controls (group 3) were evaluated with respect to the FcγRIIIB-NA1 / NA2 polymorphism using a PCR-SSP method.

The titration of anti-leishmania antibodies was analyzed using an immunoflorescence technique.

Results : Our results indicated that polymorphisms within the FcγRIIIB gene (that lead to the expression of the NA1 / NA2 isoforms) are significantly associated with VL.

The results demonstrated that the genotype heterozygotic for FcγRIIIB-NA1 / NA2 expression was significantly increased in VL patients, group 1 when compared to groups 2 and 3.

Conversely, there is a decrease in homozygous NA1 and NA2 genotypes in VL patients ; however, the overall frequency of NA1 and NA2 alleles appear similar across the three cohorts examined.

Conclusions : According to our results, it is likely that the increased frequency of the FcγRIIIB-NA1 / NA2 genotype is associated with impaired immune responses against VL and its subsequent clearance from the patient.