哮喘患儿血小板活化因子乙酰水解酶活性的研究

目的　探讨哮喘患儿血小板活化因子乙酰水解酶 (PAF AH)活性与病情的关系 ,及其活性与基因型的关系。方法　应用酶水解底物显色法测定不同病情哮喘患儿和健康儿童PAF AH活性。应用等位基因特异性聚合酶链式反应 (AS PCR)技术检测PAF AH基因第 9外显子Val2 79Phe基因型。结果　重度哮喘组血浆PAF AH活性明显低于轻、中度哮喘组和对照组 ,酶活性缺失率重度组占 15.4% ,而轻、中度哮喘组和对照组酶活性缺失率占 2 %～ 3 %。哮喘组及对照组 3种基因型 (Val/Val、Val/Phe和Phe/Phe)血浆PAH AH活性间比较有显著性差异 (P均 <0 .0 1) ,同一种基因型PAH AH活性哮喘组与对照组相比无显著性差异 (P >0 .0 5)。结论　血浆PAF AH活性与哮喘严重程度相关联 ,重度哮喘组酶活性显著低于轻、中度哮喘组和对照组 ;血浆PAF AH活性与PAF AH(Val2 79Phe)基因突变相关联

The study on activity of platelet-activating factor acetylhydrolase in asthmatic children

Objective Platelet activating factor(PAF),which has been implicated in the pathophysiology of inflammation in asthma,is degraded and inactivated by PAF acetlhydrolase(PAF AH).To investigate the association of PAF AH activity with genotype in asthmatic children.Methods We studied 57 asthmatic children and 30 normal controls. The plasma PAF AH genotype was detected as representative case with 3 different genotypes (Val/Val,Val/Phe and Phe/Phe) by allele specific polymerase chain reaction(AS PCR).The PAF AH activity in plasam was examined by the changes of substrate assay.Results In severe asthmatic individuals plasma PAF AH activities were lower than those of mild or moderate groups and control group,and plasma PAF AH activition was absent 15.4 %.In another three groups plasma PAF AH activation were absent 2 %-3 %.There was significant difference of plasma PAF AH activity among 3 groups of genotype(Val/Val,Val/Phe and Phe/Phe).In the similar genotype, there was no significant difference of plasma PAF AH activity between the groups of control and asthma.Conclusions There was imbalace of PAF/PAF AH in asthmatic children. In severe asthmatic individuals plasma PAF AH activities were lower than those of mild or moderate groups and control group. PAF AH(Val279Phe) gene mutation was related with plasma PAF AH activity.