CD40LG and infection: Detection of IgM and IgG antibodies separately is an established procedure in the serological diagnosis of LD that is expected to provide information on temporal characteristics of infection [3,29,34], however, our findings in TBRF patients show that IgM and IgG antibody formation against BipA, GlpQ, fHbp, and FlaB is variable, for example, only IgM antibodies may be detected against one antigen and only IgG antibodies against another in a particular serum, and that this pattern may change with a subsequent serum sample obtained several weeks later.