In the ELISA results, the average levels of anti-TCP1 antibody were significantly higher in patients with SLE (50.1 ± 17.3 arbitrary unit (AU)) compared to those of RA (35 ± 8.7 AU), BD (37.5 ± 11.6 AU), SSc (43 ± 11.9 AU), and NCs (33.9 ± 9.3 AU) (Figure 6). Here, TCP1 is linked to rheumatoid arthritis.