Study patients with LD were not systematically screened for tick-borne co-infections; we now know that human granulocytic anaplasmosis (HGA) can lead to cross-reacting IgM antibodies to B. burgdorferi [76], and Borrelia miyamotoi infection can cause false-positive reactions to the C6 peptide and whole-cell EIAs [77]. This evidence concerns the gene CD40LG and human granulocytic anaplasmosis.