[B27-positive diseases. A new concept in rheumatology (author's transl)].

In a large number of rheumatoid factor-negative arthritic conditions there is a number of diseases which are characterized by common clinical manifestations and the genetic property of the presence of B27. The term "B27-positive diseases" is based on a concept arising from intensive nosological studies and provides important suggestions for the study of the pathogenesis of a group of rheumatic diseases in that it emphasizes the significance of a genetic predisposition and makes an infectious etiology probable.