Ramírez S. and colleagues explored the role of KIR genes in relation to anti-cyclic citrullinated peptide (anti-CCP) serodiagnosis in RA patients from western Mexico, revealing associations of KIR2DL2 with anti-CCP positivity and KIR2DL3 with protection against RA, particularly in anti-CCP negative patients [108]. The gene discussed is KIR2DL3; the disease is rheumatoid arthritis.