CD40LG and rheumatoid arthritis: Elevated levels of IgM, IgG and IgA Abs were detected in sera from RA patients reacting with P. mirabilis UreC, UreF, HpmA, HLA-DR1/4 and collagen type XI peptide epitopes (Christopoulos et al. 2017; Konieczna et al. 2012; Rashid and Ebringer 2007).