GSTM1 and rheumatoid arthritis: Antibodies against bacterial pathogens: IgG and IgA antibody levels of P. gingivalis-LPS, E. coli-LPS and Streptococcus pyogenes-peptidoglycan polysaccharide;RA clinical assessment: DAS28-ESR, TJC, SJC, VAS, mTSS, the presence of osteitis and precise osteitis area;laboratory variables: CCP, ESR, CRP, MMP3, IgM-RF, lymphocytes, WBC, RBC, Hb, TNF-α, IL-6