Mycoplasma pneumoniae 특이 항체 검사에서 입자 응집법과 효소 면역 측정법의 비교

Abstract

연구 배경: Mycoplasma pneumoniae (MP)는 비정형 폐렴의 가장 흔한 원인균이다. MP에 의한 폐렴은 경험적 항생제 반응하지 않으므로 조기에 정확한 감별진단이 필요하다. MP 검사를 위한 다양한 검사법이 있지만, 기준 검사법은 아직 없어 현재 검사실 대부분은 쉽고 간편한 혈청학적 검사에 주로 의존하고 있다. 혈청학적 검사로 국내에서 주로 사용되는 방법은 입자 응집법과 효소 면역 측정법을 이용한 IgM 또는 IgG 측정 검사법이다. 입자 응집법과 효소 면역 측정법은 각각의 검사의 장점과 한계점이 잘 알려져 있어 MP 특이 항체 검사에서의 입자 응집법과 효소 면역 측정법의 비교가 다수 시도된 바 있다. 그러나 입자 응집법과 효소 면역 측정법의 검사 간 일치율과 상관관계의 차이를 환자의 나이를 고려하여 비교한 연구는 아직 보고된 바 없다. 이에 저자는 성인과 소아 환자에서 입자 응집법과 효소 면역 측정법 간 검사 일치율과 상관관계를 비교하고 검사실에서 유용한 검사 방법을 제시하고자 한다. 대상 및 방법: 총 35명의 환자를 대상으로 MP 특이 항체 검사를 입자 응집법과 효소 면역 측정법을 사용해 시행하였다. 대상 환자 중 성인 환자는 18명이었고 소아 환자는 17명이었다. 효소 면역 측정법은 IgM과 IgG를 구분하여 검사하였다. 총 35명의 환자 중 26명은 IgM 및 IgG 검사를 모두 시행하였고 9명의 환자는 IgG 검사만을 시행하였다. 입자 응집법과 효소 면역 측정법의 검사 간 비교를 위해 두 검사 간 결과 일치율을 비교하였고 역가에 따른 결과 일치율을 조사하였다. 성인과 소아에서의 결과 및 일치율, 입자 응집법의 역가에 따른 검사 간 결과 일치율을 비교하였고 각각의 환자군에서 입자 응집법의 역가와 효소 면역 측정법의 측정값 간의 상관관계를 분석하였다. 연구 결과: 본 연구에서 전체 환자의 입자 응집법과 효소 면역 측정법의 IgM 및 IgG 간의 일치율은 각각 57.7% 와 65.7%였다. 입자 응집법과 IgM 간의 결과 일치율은 60%로 성인에서 더 높았고 입자 응집법과 IgG 간의 결과 일치율은 76.5%로 소아에서 더 높았다. 성인과 소아 모두에서 입자 응집법과 IgM 간의 결과 일치율은 입자 응집법의 역가가 증가할수록 증가하는 양상을 보였으나 입자 응집법과 IgG 간의 결과는 소아에서 매우 높은 항체가를 보일 때 일부 불일치하였다. 또한, 성인에서는 입자 응집법의 역가와 IgM 및 IgG 측정값 사이의 상관관계가 뚜렷하고 통계적으로 유의하였다. 반면, 소아 환자에서는 입자 응집법의 역가와 IgG 측정값 사이의 상관관계가 뚜렷하고 통계적으로 유의하였다. 결론: 결론적으로 본 연구에서 조사된 바로는 입자 응집법과 효소 면역 측정법 간의 결과 일치율은 성인, 소아 모두에서 낮았다. 그러나 전체 환자에서는 입자 응집법의 역가와 급성 감염의 지표인 IgM 측정값은 서로 상관관계가 높아 검사실에서 검사법을 택일해야 한다면 간편하면서도 저렴한 입자 응집법이 임상적으로 충분히 유용하며 특히 성인에서 더욱 그러할 것으로 생각된다.

|Background: Mycoplasma pneumoniae (MP) is the most common cause of atypical pneumonia. Since the empirical antibiotic therapy does not treat MP pneumonia, it is important to make an accurate initial differential diagnosis. Various laboratory test methods are available for MP detection but there is no reference method yet. Hence many laboratories depend on serological tests which are easy and convenient to perform. The two serological test methods most commonly used in Korea are Particle agglutination assay (PA) and IgM and IgG measurement by Enzyme immunoassay (EIA). Both PA and EIA are well understood of their strengths and weaknesses in the detection of MP specific antibodies which is why in many studies, the comparisons between the two methods were already attempted previously. Yet, there was no attempt to compare the concordance rates and the correlation between PA and EIA in respect to the age difference of the patient groups. Thereby we are to compare the differences in concordance rate and the correlation between the two methods in adults and children to suggest a test method that is useful in the laboratory. Material and methods: A total of 35 patients performed MP specific antibody test by PA and EIA methods. They were 18 adult and 17 pediatric patients. IgM and IgG measurements were performed separately. 26 out of 35 patients performed PA and both IgM and IgG EIA and 9 patients performed PA and IgG-EIA only. We compared the differences in concordance rates, the differences in concordance rates according to PA titers and the differences in correlations between the two methods in both adults and children. Results: The rates of concordant results between PA and IgM-EIA and between IgG-EIA were 57.7% and 65.7% each. The concordance rate between PA and IgM-EIA was higher in adults (60%) than in children and the concordance rate between PA and IgG-EIA was higher in children (76.5%) than in adults. In both adults and children, the rate of concordance between PA and IgM-EIA increased as the PA titer increases whereas the concordance between PA and IgG-EIA was not prominent in the very high PA titer in children. In adults, the correlation between PA titer and IgM and IgG-EIA values were strong and statistically significant. However, in children, the correlation between PA titer and IgG-EIA value only was statistically significant. Conclusion: To conclude, the rates of concordance between PA and EIA methods in both adults and children were low. However the correlation between PA titer and IgM measure was reasonably high when adults and children were grouped together. Therefore, when laboratories are required to adopt one of the two methods they may consider adopting easy and less costly PA method since they are clinically useful enough to aid diagnosing acute infection especially in adult patients.; Background: Mycoplasma pneumoniae (MP) is the most common cause of atypical pneumonia. Since the empirical antibiotic therapy does not treat MP pneumonia, it is important to make an accurate initial differential diagnosis. Various laboratory test methods are available for MP detection but there is no reference method yet. Hence many laboratories depend on serological tests which are easy and convenient to perform. The two serological test methods most commonly used in Korea are Particle agglutination assay (PA) and IgM and IgG measurement by Enzyme immunoassay (EIA). Both PA and EIA are well understood of their strengths and weaknesses in the detection of MP specific antibodies which is why in many studies, the comparisons between the two methods were already attempted previously. Yet, there was no attempt to compare the concordance rates and the correlation between PA and EIA in respect to the age difference of the patient groups. Thereby we are to compare the differences in concordance rate and the correlation between the two methods in adults and children to suggest a test method that is useful in the laboratory. Material and methods: A total of 35 patients performed MP specific antibody test by PA and EIA methods. They were 18 adult and 17 pediatric patients. IgM and IgG measurements were performed separately. 26 out of 35 patients performed PA and both IgM and IgG EIA and 9 patients performed PA and IgG-EIA only. We compared the differences in concordance rates, the differences in concordance rates according to PA titers and the differences in correlations between the two methods in both adults and children. Results: The rates of concordant results between PA and IgM-EIA and between IgG-EIA were 57.7% and 65.7% each. The concordance rate between PA and IgM-EIA was higher in adults (60%) than in children and the concordance rate between PA and IgG-EIA was higher in children (76.5%) than in adults. In both adults and children, the rate of concordance between PA and IgM-EIA increased as the PA titer increases whereas the concordance between PA and IgG-EIA was not prominent in the very high PA titer in children. In adults, the correlation between PA titer and IgM and IgG-EIA values were strong and statistically significant. However, in children, the correlation between PA titer and IgG-EIA value only was statistically significant. Conclusion: To conclude, the rates of concordance between PA and EIA methods in both adults and children were low. However the correlation between PA titer and IgM measure was reasonably high when adults and children were grouped together. Therefore, when laboratories are required to adopt one of the two methods they may consider adopting easy and less costly PA method since they are clinically useful enough to aid diagnosing acute infection especially in adult patients.