Resumo

Introduction: Dengue fever is an infection caused by a flavivirus that remains as an important epidemiological problem in tropical countries as Brazil. It can cause a wild variety of symptoms since a self-limiting febrile disease to a significant plasma leakage leading to severe hemorrhagic symptoms. Several immunological and hematological factors are different expressed in those patients. Tissue Factor (TF) is a component of coagulation cascade that converts prothrombin to thrombin. The present work aims to analyze TF expression (CD142) in monocytes correlating to TF polymorphism in dengue infection patients compared to non-infected ones. Methods and Results: Blood samples were collected from volunteers in EDTA tubes. Clinical exams, Cell Blood Counts and IgM serology were done to confirm Dengue virus infection. TF expression was analyzed by flow cytometry (CD142 expression on CD14+ cells) and a polymorphism on tissue factor gene at promoter region was investigated by polymerase chain reaction (PCR). PCR products were visualized on 1% agarose gel, showing the following bands: Homozygotes for the insert with a 205bp band (II); homozygous for deletion showing an 187bp band (DD) and heterozygous presenting 187bp and 205bp bands (ID). Our results showed an increased CD142 expression on CD14+ cells from dengue patients (mean fluorescence intensity, MFI = 76,99) compared to individuals without dengue (MFI = 39,85). PCR data showed no correlation between clinical forms and TF genotypes. Discussion: Increased expression of CD142 suggests an important role for tissue factor during the acute phase of dengue virus infection. However, more studies are needed and a greater number of patients should be investigated to rule out an association between TF gene polymorphisms and development of DHF. Our work may contribute to understand mechanisms involved in immune response and DHF development.