Single nucleotide polymorphisms in immune system genes and their association with clinical symptoms persistence in dengue-infected persons

This study was undertaken to determine the prevalence of dengue clinical symptom persistence during 60 days of disease follow up, in patients of Espírito Santo state (ES)-Brazil and to evaluate the relation of single nucleotide polymorphisms (SNPs) in FcγRIIa, CD209, VDR, TNF-α, IL-4, IL-6 and IFN-γ genes with symptom persistence. During 2012–2013, 96 blood samples from individuals diagnosed with symptomatic dengue were collected. Clinical symptom persistence in 60 days of follow-up was assessed by a clinical and epidemiological questionnaire filled in 4 interviews. SNP genotyping was performed by polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP). In two months of monitoring the dengue infection, we observed that symptoms persisted in 38.5% (37/96) of dengue patients at the end of the first month (D30) and in 11.5% (11/96) of dengue patients at the end of the second month (D60). Our results show an association between FcγRIIa, TNF-α and IL-6 gene SNPs and symptom persistence and an association trend with CD209, IL-4 and IFN-γ gene SNPs. Our findings may increase the knowledge on the pathophysiological mechanisms of persistent symptoms of infection with the dengue virus (DENV) and thus help the clinical management of patients.