CD40LG and Lyme disease: Case 3 had a positive Lyme two-tier serology result at the initial visit, with three positive IgM bands and an EIA >5.00. This is consistent with a more established immune response associated with disseminated infection; per the Centers for Disease Control and Prevention (CDC) clinical and diagnostic criteria, serologic testing has a 99% specificity and >87% sensitivity for disseminated Lyme disease cases [18].