Clinical and immunological studies on neonatal infectious pneumonia

To explore etiology, clinical manifestation and immunological changes of infectious pneumonia of neonates in Chengdu area. Serum specimens were collected from 111 infants with infectious pneumonia. Eight viral and mycoplasmal specific serum IgM antibodies were detected by enzyme linked immunosorbent assay (ELISA); C reactive protein (CRP), total IgG and its subclasses, IgA and IgM were determined by rate scattered nephelometry; T lymphocyte subpopulations were detected by biotin-streptavidin-peroxidase method, and clinical and other laboratory data were analyzed. (1) Etiological agents: specific serum IgM antibodies were positive in 40 of 111 cases (36.0%) with pneumonias. All the 30 control infants were negative for the specific serum IgM antibodies. Among 111 infants with infectious pneumonia, 20.7% had single viral or mycoplasmal infection, 40.5% had bacterial infection, 15.3% had viral and mycoplasmal infection with bacterial infection; 23.4% had infection with unknown agents. (2) The most common clinical