Identification of A 2‐Md plasmid from shigella flexneri associated with reactive arthritis

Abstract

The development of reactive arthritis, a sterile inflammatory polyarthropathy that primarily affects HLA–B27 positive individuals, has been associated with previous enteric infections caused by various gram-negative bacteria. The possibility that a common bacterial epitope triggers the disease was investigated by screening a panel of documented arthritogenic Shigella strains as well as 2 epidemic-associated nonarthritogenic Shigella controls. A 2-Md plasmid specific to the arthritogenic strains was identified and sequenced. The plasmid encodes a number of small peptides that could be related to the development of reactive arthritis. Within 1 of these is a stretch of 5 consecutive amino acids, inferred from the DNA sequence and contained within an open reading frame, that is homologous to amino acid residues 71–75 of the polymorphic region of the α1 domain of HLA–B27. The data indicate that there is a bacterial plasmid common to arthritogenic Shigella strains that may play a role in triggering reactive arthritis. The finding that this plasmid encodes an epitope shared with HLA–B27 suggests that molecular mimicry may play a role in the induction of this disease.