Viral DNA was detected using real-time polymerase chain reaction (RT-PCR) of bronchoalveolar lavage (BAL) fluid from 58 HCMV IgM+ with respiratory infections, of which 47 were positive by both IgM detection and RT-PCR whereas 11 cases were only IgM-positive (Table 4). The gene discussed is CD40LG; the disease is respiratory tract infectious disorder.