CD40LG and infection: A two-tier test approach for active disease and previous infection with the demonstration of a significant change in IgM or IgG antibody response to B. burgdorferi in paired acute- and convalescent-phase serum samples, examination of diagnostic levels of IgM and IgG antibodies to the spirochete in CSF, and isolation of B. burgdorferi from CSF are recommended to improve the diagnostic accuracy of serological testing in Lyme disease [4, 5], including LNB.