The seropositive rates of M. pneumoniae IgM in acute Q fever were much higher than the acute infection rates of M. pneumoniae as determined by serological studies in healthy adolescents (6.0%) [22], adults with respiratory symptoms (3.3%) [23], and community-acquired pneumonia (CAP) (14.3%-20.0%) [24,25] in Taiwan. The gene discussed is CD40LG; the disease is Q fever.