Clinical and laboratory manifestations in patients with serological evidence of Mycoplasma pneumoniae infection.

139 cases of Mycoplasma pneumoniae infection (serological diagnosis) were treated at Aurora Hospital, Helsinki, between January 1975 and August 1977. In 123 patients the main diagnosis was respiratory infection; 114 of these had pneumonia. The frequency of complications was high: 8 patients had neurologic, 6 cardiac and 5 joint symptoms. Although a significant rise in titre of complement-fixing antibodies to M. pneumoniae was required, the low titre level in some patients who had manifestations less frequently associated with M. pneumoniae infection may suggest nonspecific reactions. Nearly half of the patients in this study had plasmocytosis in the peripheral blood suggesting a strong antibody response. This might be connected with some serological reactions detected in association with M. pneumoniae infections.