Kutlu Selda Sayin, Celikbaş Aysel, Ergönül Onder, Kutlu Murat, Aksaray Sebahat, Güvener Engin, Dokuzoğuz Başak
Ankara Numune Eğitim ve Araştirma Hastanesi, Birinci Infeksiyon Hastaliklari ve Klinik Mikrobiyoloji Kliniği, Ankara.
Mikrobiyol Bul. 2003 Oct;37(4):261-7.
In order to investigate the value of immunoglobulin G (IgG) avidity test for the serological diagnosis of Brucella infections, a total of 118 patients (74 male, 44 female; mean age: 43 +/- 18.7 years) were included into the present study. The patients have been diagnosed with the characteristic clinical findings, > or = 1/160 antibody titers in standard tube agglutination (STA) test and/or blood culture positivities. Brucella spp. have been grown in blood cultures of 78 patients, and STA test results were found positive (> or = 1/160 titers) in 117 patients. The diagnosis of a patient with 1/80 STA titer was based on the blood culture positivity. By enzyme immunoassay (ELISA), 3 patients (2.5%) were found positive for IgM, 14 (11.9%) were positive for IgG, and 101 (85.6%) were positive for both IgM and IgG. The patients who were found IgG positive have been grouped according to their duration of complaints. Group 1 included 99 patients with the history of brucellosis < or = 6 months, and group 2 included 16 patients with the history of brucellosis > 6 months. IgG avidity test was performed by ELISA in 115 IgG positive serum samples, with the denaturation substance (8 M urea). The cut-off value for IgG avidity index (AI) was accepted as 40%, and the avidity maturation period was defined as 6 months. As a result, the rates of patients who had low IgG AI in group 1 and 2 were found as 91.9% and 43.7%, respectively, while these rates were 8.1% and 56.3% for the presence of high IgG AI, respectively. The rate of low AI in group 1 was an expected result, while the rate was more than expected in group 2, indicating that Brucella antibodies with low avidity indices would not be helpful for the diagnosis of a recent infection, while Brucella antibodies with high avidity indices would be useful for the elimination of a recent infection.
为了研究免疫球蛋白G（IgG）亲和力检测在布鲁氏菌感染血清学诊断中的价值，本研究共纳入118例患者（男性74例，女性44例；平均年龄：43±18.7岁）。这些患者具有特征性临床症状，标准试管凝集（STA）试验抗体效价≥1/160，和/或血培养呈阳性。78例患者的血培养中培养出布鲁氏菌属，117例患者的STA试验结果呈阳性（效价≥1/160）。1例STA效价为1/80的患者诊断基于血培养阳性。通过酶免疫测定法（ELISA），3例患者（2.5%）IgM呈阳性，14例（11.9%）IgG呈阳性，101例（85.6%）IgM和IgG均呈阳性。IgG呈阳性的患者根据其主诉持续时间分组。第1组包括99例布鲁氏菌病病史≤6个月的患者，第2组包括16例布鲁氏菌病病史>6个月的患者。采用ELISA法对115份IgG阳性血清样本与变性剂（8M尿素）进行IgG亲和力检测。IgG亲和力指数（AI）的临界值设定为40%，亲和力成熟期定义为6个月。结果显示，第1组和第2组中低IgG AI患者的比例分别为91.9%和43.7%，而高IgG AI患者的比例分别为8.1%和56.3%。第1组低AI比例是预期结果，而第2组该比例高于预期，表明低亲和力指数的布鲁氏菌抗体对近期感染的诊断无帮助，而高亲和力指数的布鲁氏菌抗体有助于排除近期感染。
