In RA patients, the serum levels of anti-citBiP antibodies were strongly correlated with those of anti-CCP antibodies (R2 = 0.59), whereas the levels of anti-BiP antibodies were less correlated with those of anti-CCP antibodies (R2 = 0.38) (Figure 1D). The gene discussed is HSPA5; the disease is rheumatoid arthritis.