Infection with T. crassiceps increased expression of PDL-2 and MR which are markers of AAM in the Tc + RA compared to the RA non-infected group; it has been showed that infection with this parasite increased expression of PDL-1 and PDL-2 on AAM [14]; these ligands are involved in the PDL's pathway which is responsible for the inhibition of proliferative response of T cells in a contact-dependent manner. This evidence concerns the gene CD274 and rheumatoid arthritis.