Lack of serologically defined arthritogenic Shigella flexneri cell envelope antigens in post-dysenteric arthritis

A review of serological tests to assist diagnosis of reactive arthritis: critical appraisal on methodologies

On a population-based level, the incidence of reactive arthritis (ReA) is 0.6–27/100,000. The definition of ReA varies and its pathogenesis is not yet clear. Attempts in basic immunology to suggest hypotheses for proliferation of forbidden B cell clones, molecular mimicry, and involvement of cross-reactive antibodies are helpful but not sufficient. Importantly, for the clinical diagnosis of the preceding infection, serology is widely used. Unfortunately, the accuracy of associations between serologic findings and clinical conclusions is plagued by poor standardization of methods. So far, few attempts have been done to examine the pitfalls of different approaches. Here, we review several serologic techniques, their performance and limitations. We will focus on serology for Yersinia, Campylobacter, Salmonella, Shigella, and Chlamydia trachomatis because these bacteria have a longer history of being associated with ReA. We also address controversies regarding the role of serology for some other bacteria linked to autoimmune disorders.

Prevalence and molecular diversity of pHS-2 plasmids, marker for arthritogenicity, among clinical Escherichia coli Shigella isolates

Reactive arthritis can occur after numerous bacterial infections, including bacillary dysentery caused by Escherichia coli Shigella. A major risk factor for the disease is the HLA B27 phenotype in the human host. By comparison between plasmid profiles of arthritogenic vs. nonarthritogenic Shigella strains, the pHS-2 plasmid has been previously associated with the arthritogenic capacity of Shigella isolates. However, the prevalence of this plasmid in the various Shigella biotypes and serotypes is largely unknown. On this background, 188 clinical isolates from intestinal disease representing all 46 Shigella serogroups were studied for the presence of the pHS-2 plasmid, using PCR, dot blot and Southern blot techniques and by analysis of restriction fragment length polymorphisms. The pHS-2 plasmid was found in nine of 14 E. coli Flexneri serogroups, in E. coli Dysenteriae 1 and in E. coli Boydii 16. In addition, we show marked variability of this plasmid in E. coli Flexneri 3A and 4A strains. Major biological diversity of the pHS-2 plasmid was found to be strictly related to Shigella serogroups. The prevalence pattern of the pHS-2 plasmid matches published data on arthritogenic Shigella isolates, providing additional indirect evidence for the potential validity of this plasmid as a marker for arthritogenicity.