Reactive arthritis

Major histocompatibility complex class I peptide presentation after Salmonella enterica serovar typhimurium infection assessed via stable isotope tagging of the B27-presented peptide repertoire

Reactive arthritis (ReA) induced by infection with several gram-negative bacteria is strongly associated with expression of the major histocompatibility complex class I molecule HLA-B27. It is thought that due to the intracellular lifestyle of ReA-inducing bacteria, bacterial fragments can be presented by HLA-B27. Cytotoxic T cells recognizing such bacterial peptides or other induced host peptides could cross-react with self peptides presented in the joints, giving rise to disease. Studies to analyze the B27 peptide repertoire in relation to infection were severely hampered, as complex peptide profiles obtained from separate infected and noninfected cell preparations had to be compared. For this study, we applied a new approach to examine the effect of Salmonella enterica serovar Typhimurium infection on the B27 peptide repertoire presented by the HLA-B*2704 subtype associated with disease. Firstly, we showed that both host cell and S. enterica serovar Typhimurium proteins can be tagged metabolically with stable-isotope-labeled arginine. We then designed experiments so that either the tagged endogenous or tagged bacterial B*2704-presented peptide repertoires from infected cells could be analyzed by mass spectrometry from single peptide preparations that included uninfected controls. Using this new approach, we found no evidence for significant changes in endogenous B*2704 peptide presentation after infection or for any S. enterica serovar Typhimurium-derived B27-bound peptide. In conclusion, the hypothesis that S. enterica serovar Typhimurium induces changes in B27 peptide presentation could not be supported.

Reactive arthritis associated with prolonged cryptosporidial infection

In contrast to arthritic disease caused by different bacterial agents, reactive arthritis due to parasitic infection is rare. We report on an 8-year-old immunocompetent boy with a symptomatic intestinal cryptosporidiosis over a 13-months period. The protozoan infestation was accompanied by arthritic symptoms involving several joints at different times (migratory arthritis). Symptoms resolved spontaneously after 20 months in parallel with stool samples negative for cryptosporidia.

BPI-ANCA is found in reactive arthritis caused by Yersinia and Salmonella infection and recognise exclusively the C-terminal part of the BPI molecule

OBJECTIVE

To examine the prevalence, binding sites and functional interactions of antineutrophil cytoplasmic autoantibodies (ANCA) against the bactericidal/permeability increasing protein (BPI) in reactive arthritis (ReA).

METHODS

Sera were analysed for the occurrence of ANCA by indirect immunofluorescence microscopy (IIF) and ELISA. Binding sites were determined using BPI, lipopolysaccharid binding protein (LBP), and fusion proteins of both proteins in ELISA. In addition, the effect of antibodies on the antibiotic activity of BPI was examined.

RESULTS

BPI-ANCA was found in patients with Yersinia- and Salmonella-triggered ReA and directed against the C-terminal portion of BPI. Goat anti BPI antibodies recognising this part inhibited the antibiotic activity of BPI in vitro.

CONCLUSION

BPI-ANCA was associated with ReA triggered by Salmonella and Yersinia infection. Directed against the C-terminal part of BPI, it can potentially inhibit its antibiotic activity and might be useful to identify patients with infectious bowel disease prone to extraintestinal sequelae.

Antibiotics for the treatment of rheumatologic syndromes

Design of rational therapy depends on knowledge of the causes of the disease, which is knowledge often lacking in rheumatology. There have been theories of infectious causes of many rheumatologic diseases but no proof. The seductive possibility of an infectious etiology has led to the use of antibiotics for treating these diseases. This article reviews the effectiveness of antibiotics against rheumatologic syndromes, including rheumatoid arthritis and Lyme disease.

Differential diagnosis: a reasonable clinical approach

The reasonable clinical approach to the patient who has low back pain includes a search for any of the red flags that would prompt consideration of additional diagnostic testing for serious underlying disease. The common patterns of back pain would be explored in an effort to categorize the patient's symptoms and to begin formulation of a diagnostic impression. Re-evaluation of the patient in light of his response (or lack of response) to these measures is an essential component of the clinical assessment. Finally, some consideration must be given to the various biopsychosocial factors that may affect prognosis, particularly in patients who have more chronic pain and disability-related issues.