免疫抑制法测定线粒体型天门冬氨酸氨基转移酶的影响因素分析

Analysis on the influence factors of determining mitochondrial aspartate aminotransferase by immune suppression method

目的探讨免疫抑制法测定血清线粒体型天门冬氨酸氨基转移酶(m-AST)的影响因素。方法应用免疫抑制法和酶水解法分别测定60例肝炎患者和48名肝功能基本正常者(AST≤50 U/L,对照组)的m-AST和天门冬氨酸氨基转移酶(AST),计算m-AST/AST比值;通过外加胞浆型天门冬氨酸氨基转移酶(c-AST)抗体试验,分析免疫抑制法试剂中存在的抗c-AST抗体不足问题。结果对照组免疫抑制法m-AST测定结果明显高于酶水解法(P<0.01);肝炎组则明显低于酶水解法(P<0.01)。由免疫抑制法得出的m-AST/AST比值在对照组和肝炎组之间差异无统计学意义(P=0.094);由酶水解法得出的m-AST/AST比值肝炎组明显高于对照组(P<0.01)。肝炎组免疫抑制法m-AST和AST的相关性(r=0.969)高于对照组(r=0.878);而酶水解法二者的相关性(r=0.856)则低于对照组(r=0.902)。在免疫抑制法外加抗c-AST抗体试验中,m-AST测定值随抗c-AST抗体加入量的增加而下降。结论免疫抑制法试剂中抗体不足导致c-AST抑制不完全,m-AST项目特异性下降。使用m-AST/AST比值可以分析肝病的严重程度。规范免疫抑制法m-AST试剂中的抗体浓度、抗体稳定剂等因素有利于质量控制工作,提高m-AST的临床应用价值。

Objective To investigate the influence factors of determining serum mitochondrial aspartate aminotransferase （m-AST） by immune suppression method. Methods The determinations of m-AST and aspartate aminotransferase （AST） in a control group （48 cases with AST≤50 U/L） and a hepatitis group （60 patients with hepatitis） were performed by immune suppression method and enzyme hydrolysis method respectively, and then the m-AST/AST ratios were calculated. The deficiency of cytosolic aspartate aminotransferase （c-AST） antibody in the immune suppression method reagents was confirmed through the complementary c-AST antibody test. Results In the control group, the m-AST value by immune suppression method was significantly higher than that by enzyme hydrolysis method （ P 〈 0.01 ） , while in the hepatitis group, the m-AST value by immune suppression method was significantly lower than that by enzyme hydrolysis method （ P 〈 0.01 ）. By the immune suppression method, the m-AST/AST ratio had no significant difference between the control group and the hepatitis group （ P = 0. 094）. By the enzyme hydrolysis method ,the m-AST/AST ratio in the hepatitis group was significantly higher than that in the control group （P 〈 0.01 ）. The correlation of m-AST and AST in the hepatitis group （ r = 0. 969 ） was higher than that in the control group by immune suppression method （ r = 0. 878 ）, while by the enzyme hydrolysis method, the correlation in the hepatitis group （ r = 0. 856） was lower than that in the control group （ r = 0. 902）. In the complementary c-AST antibody test of immune suppression method, the values of m-AST decreased with the increase of c-AST antibody being added. Conclusions If the c-AST antibody is not enough in the immune suppression method reagents, c-AST could not be inhibited completely, which would cause the decline of the specificity of m-AST test. Using the m-AST/AST ratio, the severity of the liver disease can be analyzed. The antibody concentration of m-AST reagent, the antibody stabilizers and so on should be standardized in order to contribute to the quality control work and improve the clinical application significance of m-AST.