Recent infections that more commonly precede GBS were reasonably excluded by negative results for Cytomegalovirus IgM, Mycoplasma pneumoniae IgM, Campylobacter jejuni IgM/IgA, Epstein–Barr virus capsid antigen (VCA) IgM, and Haemophilus influenzae IgM. This evidence concerns the gene CD40LG and infection.