Relationship between CTLA-4 gene promoter region-318 site C/T polymorphism and the leukopenia caused by antithyroid drug

This study aimed to investigate the relationship between the C/T polymorphism in the CTLA-4 promoter region-318 site and the leukopenia caused by ATD.This study recruited 159 patients with Graves disease(GD) including 73 patients with leukopenia caused by antithyroid drug(ATD) and 86 patients without ATD-caused leukopenia,52 GD patients with leukopenia before use ATD,74 patients with leukopenia but without GD,and 85 healthy controls.The genotype and allele frequencies of all subjects were assayed by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP).We found no significant differences in genotype frequencies and allele frequencies of CTLA-4 gene between GD group and control group(χ2 = 0.60,P = 0.74;χ2 = 0.062,P = 0.80).But significant differences in CTLA-4 gene were observed between the ATD-caused leukopenia group and no leukopenia GD group(χ2 = 7.28,P = 0.03;χ2 = 4.05,P = 0.04).Furthermore,the CT+TT genotype frequency was significantly higher in ATDcaused leukopenia group than that in no leukopenia GD group(26.0% vs 11.6%);The T allele frequency was significantly higher in ATD-caused leukopenia group than that in no leukopenia GD group(13.0% vs 6.4%).No significant differences in CTLA-4 gene was observed between ATD-caused leukopenia group and leukopenia before use ATD group(χ2 = 2.91,P = 0.09;χ2 = 2.57,P = 0.11).The results indicated that the polymorphism of T allele in CTLA-4 gene promoter region-318 site in Shandong Qingdao Han population is associated with the leukopenia caused by ATD,although is not associated with the susceptibility to the development of GD.