Chlamydia pneumoniae specific IgG, IgA and IgM responses were dissociated in children with acute lower respiratory tract infection

Abstract

We examined 66 patients aged 10 months to 12 years with lower respiratory tract infection during January 1999-Decenber 2000. All of them were diagnosed as acute Chlamydia pneumoniae infection by presence of positive serum IgM to Chlamydia pneumoniae. Serum IgG, IgA and IgM antibodies to Chlamydia pneumoniae were determined by an enzyme-linked immunosorbent assey (ELISA) test employing a Chlamydia pneumoniae outer membrand complex protein. Serum specimens for serologic testing were obtained at least twice, the intervals were longer than two weeks. No patient met the criteria for acute Chlamydia pneumoniae infection. We might underestimate the number of infection associated with Chlamydia pneumoniae in children, if specific IgM were not tested.