In RA-MTX patients, a significantly higher proportion of CD8+ Tcm cells expressed CD38 after the first vaccination, whereas a more dynamic recall response was observed after the second vaccination where a greater proportion of CD8+ Tcm cells exhibited expression of CD38, PD1, TIGIT, and CD40L (Figure 5d and Figure 5—figure supplement 1d). Here, CD38 is linked to rheumatoid arthritis.