The authors report a case of a patient suffering from acute polyarthritis with a high rheumatoid factor titre, associated with a Klebsiella pneumonitis. A polyclonal B lymphocyte activation or a possible cross reaction between rheumatoid factor and an antigen related to Klebsiella may explain the elevated production of rheumatoid factor observed. © 1988 Acta Medica Belgica.
- Rheumatoid Factor
- Klebsiella Pneumoniae