Association of Natural Killer Cell Ligand Polymorphism HLA–C Asn80Lys With the Development of Anti-SSA/Ro–Associated Congenital Heart Block

Fetal exposure to maternal anti-SSA/Ro antibodies is necessary but not sufficient for the development of autoimmune congenital heart block (CHB), suggesting that other factors, such as fetal genetic predisposition, are important. Given the previously described association between major histocompatibility complex alleles and CHB risk, we undertook the present study to test the hypothesis that a variant form of HLA-C Asn80Lys, which binds with high affinity to an inhibitory killer cell immunoglobulin-like receptor (KIR) and thus renders natural killer (NK) cells incapable of restricting inflammation, contributes to the development of CHB.