Routinediagnosis of Flavivirus infections is usually made either throughantibody detection by ELISA (enzyme-linked immunosorbent assay) or RT-PCR (reversetranscription polymerase chain reaction), depending on the phase of the disease.RT-PCR is used in the acute phase of diseases and IgM antibodies are usuallydetected in patients’ serum collected in the convalescence phase (3). Here, CD40LG is linked to Flavivirus Infections.