Some of the DMPs were located in genes earlier described to be differentially methylated in responders and non-responders to MTX in bulk T cells from RA patients before treatment (19), i.e. TRIM15 and SORCS2. In our study, we found that MTX treatment influenced the CpG for TRIM15 in CD4+ naïve T cells, while for SORCS2 in CD4+ memory T cells. Here, TRIM15 is linked to rheumatoid arthritis.