CD40LG and dengue disease: Seroconversion by PRNT50 was not detected in the following eight patients: two DENV-1 infected cases (subjects 5 and 7) by RT-PCR and six (subjects 4, 30, 36, 39, 42, and 56) serologically-confirmed dengue cases (IgM and/or NS1Ag) presented with NAbs titers compatible with previous exposure without recognizing the infecting serotype.