title: Acute rheumatoid factor positive (IgM) polyarthritis associated with a Klebsiella pneumonitis.
abstract: 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.
mesh_terms: D000208:Acute Disease; D001170:Arthritis, Infectious / Q000150:complications* / Q000378:metabolism; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000378:metabolism*; D007710:Klebsiella Infections / Q000150:complications*; D007711:Klebsiella pneumoniae; D008875:Middle Aged; D011014:Pneumonia / Q000150:complications* / Q000378:metabolism; D012217:Rheumatoid Factor / Q000378:metabolism*
chemical_list: D007075:Immunoglobulin M; D012217:Rheumatoid Factor