[Relationship between clopidogrel resistance and genetic variability in Kawasaki disease children with coronary artery lesions].

<b>Objective:</b> To analyze the distribution of clopidogrel metabolism-related gene variability in Kawasaki disease (KD) children with coronary artery lesions (CAL) across different age groups and the impact of genetic variability on the efficacy of clopidogrel antiplatelet therapy. <b>Methods:</b> A retrospective cohort study was conducted. Clinical data were collected from 46 KD children with CAL who were hospitalized in the Cardiovascular Center of Children's Hospital of Fudan University between January 2021 and August 2022 and were treated with clopidogrel, including gender, age, body mass index, course of KD, CAL severity grade, and baseline platelet count. According to their age, the children were divided into ≥2-year-old group and <2-year-old group. Their platelet responsiveness was assessed by adenosine diphosphate-induced platelet inhibition rate (ADPi) calculated via thromboelastography, and children were categorized into high on-treatment platelet reactivity (HTPR) and normal on-treatment platelet reactivity (NTPR) groups. Genotypes of CYP2C19, PON1 and ABCB1 were detected. The <i>t</i> test, one-way analysis of variance and Chi-square test were used for intergroup comparison. <b>Results:</b> Among the 46 KD children with CAL, 34 were male and 12 were female; 37 were ≥2-year-old and 9 were <2-year-old; 25 cases were in the HTPR group and 21 cases were in the NTPR group, with 19 HTPR and 18 NTPR in the ≥2-year-old group, and 6 HTPR and 3 NTPR in the <2-year-old group. Genetic analysis showed that 92 alleles among the 46 children, with frequencies of CYP2C19*1, CYP2C19*2, CYP2C19*3, CYP2C19*17, PON1 192Q, PON1 192R, ABCB1 3435C, ABCB1 3435T at 59% (54/92), 32% (29/92), 9% (8/92), 1% (1/92), 36% (36/92), 64% (59/92), 63% (58/92) and 37% (34/92), respectively. Analysis of the impact of genotype on ADPi revealed that in children aged ≥2 years, those with CYP2C19*1/*3 genotype had significantly lower ADPi than those with CYP2C19*1/*1 genotype ((34±15)% <i>vs.</i> (61±29)%, <i>t</i>=2.18, <i>P</i>=0.036). There were also no significant difference in ADPi among children with PON1 192Q homozygous, PON1 192R heterozygote and PON1 192R homozygous genotypes ((40±22)% <i>vs.</i> (52±33)% <i>vs.</i> (65±27)%, <i>F</i>=2.17, <i>P</i>=0.130), or among those with ABCB1 3435C homozygous, ABCB1 3435T heterozygote and ABCB1 3435T homozygous genotypes ((55±34)% <i>vs.</i> (60±27)% <i>vs.</i> (49±24)%, <i>F</i>=0.33, <i>P</i>=0.719). In <2-year-old group, there were no significant differences in ADPi across CYP2C19*1/*1, CYP2C19*1/*2 and CYP2C19*2*2 genotypes ((40±20)% <i>vs.</i> (53±37)% <i>vs.</i> (34±16)%, <i>F</i>=0.37, <i>P</i>>0.05). There were no significant differences in ADPi across CYP2C19*1/*1 and CYP2C19*1/*3 genotypes ((44±27)% <i>vs.</i> (42±20)%, <i>t</i>=0.08, <i>P</i>>0.05). There were no significant differences in ADPi across PON1 192Q homozygous, PON1 192R heterozygote and PON1 192R homozygous genotypes (45% <i>vs.</i> (55±27)% <i>vs.</i> (24±5)%, <i>F</i>=1.83, <i>P</i>>0.05). There were no significant differences in ADPi across ABCB1 3435C homozygous, ABCB1 3435T heterozygote and ABCB1 3435T homozygous genotypes ((36±16)% <i>vs.</i> (50±35)% <i>vs.</i> 45%, <i>F</i>=0.29, <i>P</i>>0.05). The risk analysis of HTPR in different genotypes revealed that in children aged ≥2 years, carrying at least 1 or 2 loss-of-function alleles of CYP2C19 was a risk factor for HTPR (<i>OR</i>=4.69, 10.00, 95%<i>CI</i> 1.11-19.83, 0.84-119.32, <i>P</i>=0.033, 0.046, respectively), and PON1 192R homozygosity and carrying at least one PON1 192R allele were protective factors against HTPR (<i>OR</i>=0.08, 0.13, 95%<i>CI</i> 0.01-0.86, 0.01-1.19, <i>P</i>=0.019, 0.043, respectively). <b>Conclusion:</b> KD children aged ≥2 years carrying CYP2C19 loss-of-function alleles and PON1 192Q are more likely to develop HTPR.