Evaluation of FcγRIIIB-NA1/NA2 Polymorphism in Visceral Leishmaniasis.

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.

The Cytotoxic T Lymphocyte Antigen-4 +49A/G Single Nucleotide Polymorphism Association With Visceral Leishmaniasis.

BACKGROUND: Several lines of evidence approve that innate and adaptive immunity play key roles in the defense against visceral leishmaniasis (VL). The polymorphism within the cytotoxic T lymphocyte antigen 4 (CTLA-4) gene alters its expression. OBJECTIVES: The main aim of this study was to evaluate the polymorphism within the +49 position of the CTLA-4 gene of Iranian patients with VL in comparison with healthy controls. MATERIALS AND METHODS: In this cross-sectional study, 88 patients with clinical presentations of VL, who were seropositive for Leishmania (group 1), 86 patients without clinical presentations but seropositive (group 2), and 115 healthy controls (group 3) were assessed with respect to the CTLA-4 +49A/G polymorphism, using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The anti-Leishmania antibody titration was evaluated using an immunofluorescence method. RESULTS: Our results indicated that both CTLA-4 +49A/G polymorphisms were significantly associated with VL. CONCLUSIONS: According to the results, the polymorphisms within the +49 position of CTLA-4 can be associated with VL and may be considered as risk factors for the disease.

Is the polymorphism at position -1082 of IL-10 gene associated with visceral leishmaniasis?

BACKGROUND: Immune responses play critical roles in the leishmaniasis eradication. IL-10 is a key regulator of immune responses, and the polymorphisms within its promoter region are associated with alteration in its expression. Therefore, this study was designed to examine the correlation between polymorphism at the -1082 position of the IL-10 gene and visceral leishmaniasis (VL). METHODS: The IL-10 -1082 polymorphism and anti-Leishmania antibody titration were examined in 110 patients with clinical presentation of VL and seropositive for the Leishmania (group 1), 74 seropositive patients but without clinical presentation (group 2) and 113 healthy controls (group 3) using the PCR-RFLP and immunofluorescence techniques, respectively. RESULTS: The polymorphism at IL-10 -1082 (A/G) position was significantly associated with VL and A/G genotype was significantly higher in VL patients when compared to the groups 2 and 3 (P< 0.001). However, the results demonstrated that the A and G alleles were not associated with VL (P= 0.263). CONCLUSIONS: Previous investigations have shown that the polymorphism at the -1082 position of the IL-10 gene can influence its expression and also it has been proved that IL-10 level was increased during VL. Our results suggest that the A/G genotype may be considered as a risk factor for VL.

Is the IL-10 -819 polymorphism associated with visceral leishmaniasis?

Previous investigations demonstrated that immune responses play critical roles in the defense against visceral leishmaniasis (VL). A key regulator of immune responses is the cytokine, IL-10 and polymorphisms within its promoter which could alter its expression. Thus, the aim of this study was to examine the correlation between polymorphism at the -819 position of the IL-10 gene and VL in a selected Iranian population. This cross-sectional study was performed on 100 patients with clinical presentation of VL and seropositive for the leishmania (group 1), 62 patients without clinical presentation but seropositive (group 2), and 128 healthy controls (group 3). The IL-10 -819 polymorphism was evaluated using the PCR-RFLP technique. The anti-leishmania antibody titration was assessed using an immunofluorescence assay. Our results showed that the polymorphism at IL-10 -819 (C/T) position was significantly associated with VL, and C/T genotype was significantly higher in VL patients when compared to groups 2 and 3 (p < 0.001). However, the results demonstrated that the C and T alleles were not associated with VL (p = 0.855). The data presented here confirm the results of previous reports that polymorphisms at the -819 position of the IL-10 gene can influence susceptibility to VL suggesting that the C/T genotype may be considered as a risk factor for the disease.