Parra G, Rodríguez-Iturbe B, Batsford S, Vogt A, Mezzano S, Olavarría F, Exeni R, Laso M, Orta N
Renal Service and Laboratory Hospital Universitario de Maracaibo, Venezuela.
Kidney Int. 1998 Aug;54(2):509-17. doi: 10.1046/j.1523-1755.1998.00012.x.
Cationic streptococcal proteinase (erythrotoxin B) and its precursor, zymogen, are putative nephritogenic antigens. The present study was designed to test whether serum titers to these antigens were good markers of streptococcal infection associated with glomerulonephritis.
We studied 153 patients (male/female = 104/49, age range, 2 to 23 years old) with acute poststreptococcal glomerulonephritis (APSGN) from three countries (Venezuela, Chile and Argentina). The site of the initial infection was the skin in 84 patients, the throat in 55 patients and was unknown in 14 patients. In addition, we studied 23 patients (1 to 24 years old) with streptococcal infection not associated with glomerulonephritis (14 patients with impetigo and 9 patients with pharyngitis). As control group, 93 healthy individuals (54 males, 2 to 19 years old) were studied. Anti-zymogen and anti-proteinase titers were determined in a single laboratory by ELISA, and the intra- and interassay coefficients of variation were 5.3% and 8.5%, respectively. ASO titers and anti-DNAse B titers were also done.
Anti-zymogen titers of 1:800 to 1:3200 had likelihood ratios (sensitivity/1-specificity) for detection of streptococcal infection in APSGN patients ranging from 2.00 to 44.2 in Argentina, Chile and Venezuela. Anti-zymogen titers decreased one to two months after APSGN and they were 1 to 3 log2 dilutions higher that anti-proteinase titers. Receiver operating characteristic (ROC) curves showed that anti-zymogen titers were consistently superior to anti-streptolysin O and anti-DNAse B titers as markers for streptococcal infection in APSGN.
These results suggest that increased anti-zymogen antibody titers are the best available marker for streptococcal infection associated with acute glomerulonephritis.
阳离子链球菌蛋白酶（红疹毒素B）及其前体酶原是假定的致肾炎抗原。本研究旨在测试针对这些抗原的血清滴度是否是与肾小球肾炎相关的链球菌感染的良好标志物。
我们研究了来自三个国家（委内瑞拉、智利和阿根廷）的153例急性链球菌感染后肾小球肾炎（APSGN）患者（男/女=104/49，年龄范围2至23岁）。初始感染部位为皮肤的患者有84例，咽喉部的患者有55例，14例患者感染部位不明。此外，我们研究了23例与肾小球肾炎无关的链球菌感染患者（14例脓疱病患者和9例咽炎患者）。作为对照组，研究了93名健康个体（54名男性，年龄2至19岁）。在单个实验室通过ELISA测定抗酶原和抗蛋白酶滴度，批内和批间变异系数分别为5.3%和8.5%。还检测了抗链球菌溶血素O滴度和抗DNA酶B滴度。
在阿根廷、智利和委内瑞拉，APSGN患者中抗酶原滴度为1:800至1:3200时，检测链球菌感染的似然比（敏感性/1-特异性）为2.00至44.2。APSGN发病后1至2个月抗酶原滴度下降，且比抗蛋白酶滴度高1至3个log2稀释度。受试者工作特征（ROC）曲线显示，作为APSGN中链球菌感染的标志物，抗酶原滴度始终优于抗链球菌溶血素O和抗DNA酶B滴度。
这些结果表明，抗酶原抗体滴度升高是与急性肾小球肾炎相关的链球菌感染的最佳可用标志物。
