A strong interferon response correlates with a milder dengue clinical condition

a b s t r a c t Background: Type 1 interferon (IFN/) has a significant role in establishing protection against virus infections. It has been well documented by in vitro studies that dengue virus (DENV) activates a robust IFN/ response. However, DENV also induces a down-regulation of the JAK/STAT pathway, inhibiting the induction of interferon regulated genes. As a consequence, the role played by the IFN type 1 response in the protection of dengue patients is not fully understood. Objective: To compare IFN- levels in dengue patients with dengue fever (DF) or dengue hemorrhagic fever (DHF) undergoing primary or secondary infections. Study design: Two hundred and four serum samples were analyzed for IFN- level by cytometric bead array. Patients' clinical condition was assigned following the WHO 1997 criteria and specific IgG and IgM antibodies were measured using commercial assays to determine primary and secondary infections. The infecting serotype was determined by qRT-PCR. Results and conclusion: The IFN- levels were found significantly higher in DF than DHF patients irrespec- tive of the infecting serotype (DENV1 or 2), and were found to decline rapidly at day 3 after fever onset. For DENV2 infections, higher IFN- level was found during primary than secondary infections. These results suggest that an early strong interferon response correlates with a better clinical condition.