For example, Wegdam-Blans et al. (2012) reported that IFAT detected IgM phase II antibodies in a significantly higher proportion of acute-phase sera from PCR-confirmed Q fever cases (31.8%) than ELISA (19.7%), and IFAT also demonstrated longer persistence of IgM antibodies up to 12 months post-infection. This evidence concerns the gene CD40LG and Q fever.