CD40LG and infection: In fact, Shankar et al. [40] found that culture was more reliable for diagnosing M. pneumoniae infections in HIV-positive individuals since it was able to identify infections in 31% (n = 31) of their adult HIV population, while IgM enzyme-linked immunosorbent assay only identified 21% (n = 21), highlighting that relying solely on serology could lead to a false negative.