[Association between polymorphisms of killer cell immunoglobulin-like receptor gene and the risk of essential hypertension: a case-control study].

OBJECTIVE:To assess the association between killer cell immunoglobulin-like receptor (KIR) gene polymorphisms and the risk of hypertension in autoimmune mechanism. METHODS:We conducted a case-control study including 205 hypertensives and 205 controls matched with sex and age, from a community-based population. KIR genes of all subjects were genotyped by polymerase chain reaction with sequence-specific primers (PCR-SSP). Conditional logistic regression model and generalized multifactor dimensionality reduction (GMDR) method were used to estimate the association among KIR gene polymorphisms and the risk of hypertension. RESULTS:The genotypic frequencies of KIRs were not significantly different between the hypertensives and the control groups (P > 0.05). Among all the models of GMDR concerning the association between interactions of KIR genes and essential hypertension, the testing accuracy of the interaction between KIR2DS2 and KIR2DS3 was the highest (55.13%), with cross-validation consistency as 10/10 (P = 0.054). Results from the conditional logistic regression showed that individuals with KIR2DS2+: KIR2DS3- were significantly associated with an increased risk on hypertension (OR = 2.555, 95% CI: 1.203-5.429, P = 0.015). However, individuals with KIR2DS2+: KIR2DS3+ were significantly associated with a reduced risk of hypertension (OR = 0.268, 95% CI: 0.088-0.815, P = 0.020). Individuals with KIR2DS2- KIR2DS3+ did not seem to be associated with the risk of hypertension (OR = 1.602, 95% CI: 0.785-3.266, P = 0.195), when compared to the KIR2DS2- KIR2DS3- group. Interactions between KIR2DS2 and KIR2DS3 were significantly associated with the risk of hypertension, after adjusted for BMI, smoking, drinking and family history of hypertension (OR = 0.065, 95% CI: 0.013-0.317, P = 0.001). CONCLUSION:Individuals with KIR2DS2 and no KIR2DS3 were associated with the increased risk of hypertension. KIR2DS2 that coexisted with KIR2DS3 were associated with the reduced risk of hypertension. Antagonism between KIR2DS2 and KIR2DS3 might serve as a protect factor for hypertension.