CD40LG and tick-borne encephalitis: The aims of the present study were (1) to test the quality of the reporting system by investigating the serological response of TBEV-specific IgM and IgG antibodies in stored serum and cerebrospinal fluid (CSF) samples in patients notified with TBE in Western Gotaland, Sweden, during 2004-2012, in order to confirm or reject the diagnosis, (2) to assess RT-PCR as a diagnostic tool for TBEV infection in these notified cases, and (3) to compare the compiled data with the ECDC criteria for TBE diagnosis.