PDPN and rheumatoid arthritis: The positive index of CD21 per GC in FTH‐RA group was significantly higher than that in FTH‐MG group (Figure 3a,b); similarly, the positive indices of l‐caldesmon and D2‐40 per GC in FTH‐RA group were significantly higher than those in FTH‐MG group (Table 2).