Serological testing confirmed a past EBV infection (VCA-IgM− (<10 U/mL), VCA-IgG+ (459 U/mL), and EBNA1-IgG+ (>600 U/mL) (Liaison EBV IgM, VCA IgG, and EBNA IgG, DiaSorin) with no virus reactivation (<8 U/mL; EBV EA IgG ELISA, Tecan). Here, CD40LG is linked to Epstein-Barr virus infection.