Serological cross-reactions between Bartonella and Chlamydia species: implications for diagnosis.
".....Western blot analysis confirmed the presence of cross-reacting antigens and showed antibody patterns in all sera to be compatible with a Bartonella infection. These patients were therefore probably suffering from Bartonella-induced rather than Chlamydia-induced endocarditis.
In contrast, sera from 10 patients presumed to be suffering from C. pneumoniae pneumonia did not display anti-B. quintana antibodies, although cross-reacting antigens were revealed by Western blotting. This work highlights the possibility that cases of infective Bartonella endocarditis are erroneously diagnosed as chlamydial infections. ....."