Based on ELISAs and Western blots (aka immunoblots), antibody, mostly of the IgM class, can be detected within a few weeks after the initial appearance of a solitary EM; thereafter, as the infection progresses in the absence of antibiotic treatment, a gradual increase in overall titer along with development of an IgG antibody response occurs for the duration of an untreated infection (24). Here, CD40LG is linked to infection.