The cutting edge of spondylarthropathy research in the millennium

In the last few years, with advances in technology and concept, research on the spondylarthropathies (SpA) has moved from random harvesting of piecemeal data to systematic evaluations of core puzzles. In the Second International Congress of Spondylarthropathies, held in Ghent, Belgium, on October 4–7, 2000, the most recent data were presented and these core puzzles were defined. The factors that are unique to SpA are 1) the site of inflammation is not only the synovium, but also the enthesis; 2) the essential predisposing gene is HLA– B27; 3) a number of other genes are required for development of ankylosing spondylitis (AS), a prototype of SpA; and 4) certain facultative intracellular Gramnegative bacteria can induce reactive arthritis (ReA), a form of SpA.