As the anti-rheumatic drug methotrexate (MTX) is reported to mediate the up-regulation of interleukin-10 and HLA-G [33], we additionally analyzed the LILRB1 recognition to sHLA-G molecules in treated (N = 58) and non-treated (N = 10) RA patients. Here, LILRB1 is linked to rheumatoid arthritis.