Modification of disease outcome in Salmonella-infected patients by HLA-B27

Objective, To study whether HLA-B27 modifies the outcome of Salmonella infe ction in vivo, Methods. The frequency of HLA-B27 was determined in 198 Salmonella-infected patients and 100 healthy controls by immunofluorescence and polymerase cha in reaction. The excretion of Salmonella was monitored at monthly intervals , The symptoms of acute infection and possible joint involvement were evalu ated using questionnaires. Results, Thirty-eight of 198 Salmonella-infected patients (19.2%) and 13 of 100 healthy controls (13.0%) were HLA-B27 positive, The excretion of Salmo nella did not differ significantly between HLA-B27-positive and -negative p atients, or for patients with versus those without joint symptoms. As many as 35 patients (17.7%) reported Salmonella-triggered joint symptoms. Three of 14 patients (21.4%) with arthralgia, 5 of 13 patients (38.5%) with proba ble reactive arthritis (ReA), and 6 of 8 patients (75%) with confirmed ReA were HLA-B27 positive. The duration and severity of joint symptoms directly correlated with HLA-B27 positivity. Women reported Salmonella-induced pain and swelling of joints more frequently than men (P = 0.07 and P = 0.03, re spectively), Patients with Salmonella-triggered joint symptoms reported abd ominal pain and headache more frequently than patients without joint sympto ms (P = 0.05 and P = 0.004, respectively). Conclusion, HLA-B27 did not (at least, not strongly) confer susceptibility to Salmonella infection. Salmonella excretion correlated neither with HLA-B 27 positivity nor with the occurrence of joint symptoms. Joint symptoms wer e surprisingly common during or after Salmonella infection. HLA-B27-positiv e patients had a significantly increased risk of developing joint and tendo n symptoms. Moreover, HLA-B27 positivity correlated with the development of more severe and prolonged joint symptoms.