Jones J W, Su S, Jones M B, Heniford B T, McIntyre K, Granger D K
Department of Surgery, University of Louisville School of Medicine, Louisville, Kentucky, 40292, USA.
J Surg Res. 1999 Jun 15;84(2):134-7. doi: 10.1006/jsre.1999.5628.
The presentation of infection in immunocompromised patients can be subtle. Patients often undergo extensive testing and empiric treatment for rejection and infection while awaiting the results of the biopsy and culture results. Delay in diagnosis of either entity can result in a worse clinical outcome. Lysozyme activity has been found to be both a sensitive and a specific marker for infection in laboratory animals and trauma patients. Our goal was to determine whether lysozyme activity could serve as a reliable marker for infection in immunocompromised organ transplant recipients.
Transplant recipients from three clinical categories were enrolled in this study. Group 1 (n = 16) were patients hospitalized for sepsis (culture-positive), and Group 2 (n = 13) for biopsy-proven rejection. Group 3 (n = 51) were recipients who had routine blood sampling in the clinic. In Groups 1 and 2, blood was collected within 24 h of hospital admission and centrifuged, and serum samples were stored at 80 degrees C until processing. Lysozyme activity was assayed by turbidimetric measurement on a sample of a standard suspension (0.15 mg/ml) of Micrococcus lysodeikticus in buffer using a spectrophotometer to read the optical density at 450 nm. The lysozyme activity level was then determined by the measuring activity at 1 min subtracted from activity at 4 min. White blood cell count was determined by using a flow cytometer. Statistical comparisons between groups were made using paired Student's t test.
Serum lysozyme was found to be significantly elevated in Group 1; the mean level of activity was 60.1 +/- 13 (P < 0.05) compared to the level of activity in Group 2, mean 41.1 +/- 11, and Group 3, mean 40.8 +/- 13. A level of 45 units of activity/ml of serum or above indicated infection and not rejection in the patients admitted to the hospital.
These findings indicate that the lysozyme activity assay appears to be useful in differentiating infection from rejection in transplant recipients.
免疫功能低下患者的感染表现可能不明显。患者在等待活检和培养结果期间，通常会接受广泛的检查以及针对排斥反应和感染的经验性治疗。对这两种情况中任何一种的诊断延迟都可能导致更差的临床结果。在实验动物和创伤患者中，溶菌酶活性已被发现是感染的一种敏感且特异的标志物。我们的目标是确定溶菌酶活性是否可作为免疫功能低下器官移植受者感染的可靠标志物。
本研究纳入了来自三个临床类别的移植受者。第1组（n = 16）为因败血症住院（培养阳性）的患者，第2组（n = 13）为经活检证实有排斥反应的患者。第3组（n = 51）为在诊所进行常规血液采样的受者。在第1组和第2组中，入院后24小时内采集血液并离心，血清样本在80摄氏度下保存直至处理。使用分光光度计在450纳米处读取光密度，通过比浊法对缓冲液中溶壁微球菌标准悬浮液（0.15毫克/毫升）的样本进行溶菌酶活性测定。然后通过从4分钟时的活性中减去1分钟时的活性来确定溶菌酶活性水平。使用流式细胞仪测定白细胞计数。组间的统计比较采用配对学生t检验。
发现第1组血清溶菌酶显著升高；与第2组（平均活性水平为41.1±11）和第3组（平均活性水平为40.8±13）相比，第1组的平均活性水平为60.1±13（P < 0.05）。血清活性水平达到45单位/毫升及以上表明入院患者发生了感染而非排斥反应。
这些发现表明，溶菌酶活性测定似乎有助于区分移植受者的感染与排斥反应。
