Cationic Yersinia antigen-induced chronic allergic arthritis in rats. A model for reactive arthritis in humans.

Cationic antigens are known to have considerable arthritogenic potential in experimental systems. During a systematic search for suitable, naturally occurring candidates an intracellular protein was isolated from the ribosomal pellet of Yersinia enterocolitica 0:3, a bacterial strain associated with reactive arthritis in humans. The protein is highly cationic, contains two 19-kD polypeptide chains linked by a disulfide bond, and reveals a strong tendency for spontaneous aggregation. It is suggested to be a nucleic acid binding protein. We tested this antigen for its ability to induce arthritis after intra-articular challenge in preimmunized rats. An acute inflammatory phase followed by transition to chronicity was observed both by technetium-99m scintigraphy and from histology. Massive polymorphonuclear leucocyte infiltration of the synovium was seen early on and fibrosis and thickening of the joint capsule occurred in later stages. Control groups showed no evidence of inflammation. Western blot and ELISA analysis of unselected sera from Yersinia enterocolitica 0:3-infected patients revealed antibodies to the antigen in the majority of cases, whereas healthy individuals rarely reacted. This is the first report of a naturally occurring cationic antigen capable of inducing immunologic tissue injury; it justifies the speculation that cationic antigens from prokaryotic cells could trigger reactive arthritis in humans.

Serovar specific risk factors and clinical features of Salmonella enterica ssp. enterica serovar Enteritidis: a study in South-West Germany.

Human salmonellosis in Germany has been an increasing problem since the 1980s, with a peak of 195,000 reported cases in 1992. During the peak years, isolates of Salmonella Enteritidis (SE) predominated by far over other salmonella serovars (NSE) (80 vs. 20%). In a comparison of the clinical characteristics of 790 persons infected with SE to 175 persons infected with NSE, watery diarrhoea (OR 1.7) and high grade (> 39 degrees C) fever (OR 1.8) were independently associated with SE infection. When comparing possible risk factors for acquiring salmonella infection among patients with SE compared to those with NSE, consumption of raw eggs (OR 4.4; P = 0.0006) was the most significant alimentary risk factor for SE infection, while travel outside Europe was negatively associated with SE infection (OR 0.08; P = 0.0001). When comparing all patients with salmonella infection, regardless of serovar, with healthy controls, consumption of raw eggs (OR 30.3; P = 0.001), of raw or undercooked eggs (OR 1.9; P = 0.003), or having puppies, kittens or turtles (OR 6.8; P = 0.002), were risk factors for salmonellosis.