CCL17 and thromboangiitis obliterans: In the TAO group, CCL17(rs223828) CC (16.7% vs. 39.4%, OR = 0.3, Pc = 0.030) had lower frequency, whereas CCR2(rs1799864) AA (16.7% vs. 4.9%, OR = 3.9, Pc = 0.026) had higher frequency than the control group.