ABSTRACT
The hyperendemicity and co-circulation of different dengue serotypes in Brazil have increased the number of severe dengue cases and the rate of hospitalization for dengue. Virological and individual factors are associated with the complexity of the disease. Antigenemia levels of nonstructural glycoprotein-1 (NS1) have been associated with severe dengue. Aiming to identify a severity marker during the acute phase (days 0 to 5 of disease), the association of NS1 antigenemia with clinical presentation, sex, age range, immune response, number of days of disease, and serotype RNA levels was evaluated in serum samples of patients from the state of Rio de Janeiro clinically classified as having dengue without warning signs (DWWS) or dengue with warning signs/severe dengue (DWWS/SD). The immune response was classified by in-house enzyme-linked immunosorbent assay, antigenemia was determined by quantification of NS1, and viremia was quantified by real-time PCR. Of the total number of patients, 36.6% (74 of 202) presented warning signs/severe dengue and 72.3% (146 of 202) were classified with primary infection. DENV-2 presented an association between clinical presentation and antigenemia (P = 0.02). DENV-3 had higher levels of NS1 (P < 0.0001). This study has shown that the infecting serotype influences circulating NS1 levels in the host, as well as NS1 antigenemia may vary as to the clinical presentation of the patient infected with DENV-2. However, the criterion used to screen patients for clinical presentation, in DWWS and DWWS/SD patients, was not a good marker for dengue severity in our study.