Cross-reacting antibodies to Micropolyspora faeni in Mycoplasma pneumoniae infection


  • Presented in part at the European Academy of Allergology and Clinical Immunology, 9th European Congress, London, September 1974.

Dr J. H. Edwards, MRC Pneumoconiosis Unit, Llandough Hospital, Penarth, Glamorgan.


Two cases are described of severe Mycoplasma pneumoniae infection in whom cross-reacting antibodies developed to a glycopeptide antigen of Micropolyspora faeni. The antibodies were predominantly IgG, although some IgM was detected. Precipitin responses to M. faeni were detected for 4 months after the initial illness in one case, and 1 month in the second case. The cross-reacting antibodies were closely related to the antibodies responsible for the complement fixation reaction to M. pneumoniae. It is suggested that a common potysaccharide antigen may exist on the surface membranes of M. pneumoniae and M. faeni. Initial studies of the frequency of the development of cross-reacting antibodies in M. pneumoniae infection suggest it is uncommon. Atypical cases of farmer's lung should be investigated to exclude M. pneumoniae infection.