Comparing the RA patient cohort as a whole (n = 91) to the healthy subjects (n = 11), a slightly higher percentage of experienced (CD45R0+) cells, was observed (45.5 ±13.5 vs. 40.0 +/-8.8%) as well as a higher percentage of CD4+ CD26+ cells (77.0 ±11.7 vs. 70.4 ±8.6%) [15,18]. This evidence concerns the gene DPP4 and rheumatoid arthritis.