ERP29 and rheumatoid arthritis: For example, SPR has been used to determine the affinity of CRT for several of these lectin-independent interactions, including rheumatoid arthritis shared epitope (11 μM) (91), complement C1q (0.5 μM) (92), glycosylated laminin (0.5 μM) (93), ERp29 (13 μM), and ERp57 (23 μM) (94).