Design of PCR-based method for detection of a gene-encoding Mycoplasma arthritidis mitogen superantigen in synovial fluid of rheumatoid arthritis patients

Mycoplasma arthritidis mitogen (MAM) superantigen has been shown to induce chronic arthritis, which resembles human rheumatoid arthritis (RA) in a rodent model. However, its role as a causative agent in human RA is not well understood yet. The aim of this study was to investigate the presence of MAM superantigen gene in the synovial fluid (SF) of RA patients. The MAM superantigen gene a reference was synthesized based on GenBank Data base (Gene ID: 6418105). Specific primer pairs were designed and PCR amplification was performed for MAM superantigen gene detection. A total of 133 SF samples of RA patients were assayed. The PCR products were subjected to sequencing and were descriptively analyzed. The results of the PCR product sequencing showed the method has objective applicability and accuracy. The sensitivity of the PCR reaction for the reference DNA template was 1ng/ml. The PCR results assay of the 133 SF samples raveled that, 9.7% and 22.5% of them were positive for the MAM superantigen gene and Mycoplasma pneumoniae (M. pneumoniae), respectively. In this study, two Mycoplasma genomes were detected with increased frequency in RA SF patients’ samples. This finding appears to be a promising instrument in the etiological diagnostic of RA patients and could also lead to improved treatment selection. Further research on the other Mycoplasma species present in the SF of RA patients is essential.