IgG response to Mycoplasma pneumoniae in patients with community-acquired pneumonia determined by ELISA

In a prospective study of community-acquired, radiologically verified pneumonia, a solubilized mycoplasma antigen was used in an enzyme-linked immunosorbent assay (ELISA) for the detection of IgG-antibodies to Mycoplasma pneumoniae in paired sera from 60 patients. All of the 13 patients with a positive complement fixation (CF) test for M. pneumoniae were positive in the ELISA, and 46 out of 47 patients with a negative CF test were negative. The only false positive test was recorded from a patient with a positive CF test for Chlamydia. Specific IgG antibodies were also determined in paired sera from 50 pneumonia patients, all positive in the CF test for M. pneumoniae, and collected over a period of 10 years. Of these 50 patients, 45 were recorded as positive in the ELISA for IgG antibodies to M. pneumoniae. In the prospective as well as in the retrospective study, the time for admission to hospital after onset of disease showed considerable variation (1-14 days), with the consequence that high titers were recorded in the CF as well as in the ELISA in some of the first serum samples. A tendency to earlier detection of significant titers was noted in the CF test as compared to the ELISA.