assay of blood and synovial fluid of patients with rheumatoid arthritis for staphylococcus aureus enterotoxin d: absence of bacteria but presence of its toxin

Background: rheumatoid arthritis (ra) is the most common chronic inflammatory disease. the staphylococcal superantigens are considered as the causative agent of ra disease.objectives: this study aimed to assess the presence of staphylococcal enterotoxin d in synovial fluid and blood of patients with ra.patients and methods: a total of 120 blood and sf samples of patients with ra were studied. bacterial culture, primer pairs design, polymerase chain reaction (pcr), and enzyme-linked immunosorbent assay (elisa) methods have been used to assess of the staphylococcal enterotoxin d. the data were analyzed through descriptive statistics.results: during this study and after sequential subcultures, only 5 bacterial strains were isolated. the results of pcr showed the presence of staphylococcal enterotoxin d gene in almost 50% of sf and also in 48.4% of blood samples of patients with ra. similarly, the elisa method detected staphylococcal enterotoxin d in 36.16% of sf and in 33.33% of blood of patients with ra.conclusions: the result of this study showed that a high percentage of patients with ra have shown staphylococcal enterotoxin d (superantigen d) or entd gene in sf and in blood. however, the origin of this superantigen was not clarified and no staphylococcus aureus enterotoxin d producer was isolated. this finding indicates other role of this superantigen besides its intoxication. therefore, staphylococcal enterotoxin d as a biomarker may provide a good model for the diagnosis and treatment of patients with ra.