Pereira-Chioccola Vera Lucia, Fragata-Filho Abilio Augusto, Levy Antonio Marcos de Apparecida, Rodrigues Mauricio M, Schenkman Sergio
Laboratório de Parasitologia, Instituto Adolfo Lutz, São Paulo, SP, Brazil.
Clin Diagn Lab Immunol. 2003 Sep;10(5):826-30. doi: 10.1128/cdli.10.5.826-830.2003.
trans-Sialidase is an enzyme present on the surface of Trypanosoma cruzi and is an important antigen recognized by sera from patients with Chagas' disease. In the present study we investigated whether the benznidazole treatment of patients with Chagas' disease induced changes in the reactivity of serum toward a recombinant form of trans-sialidase in order to develop an assay for monitoring of patients after treatment for Chagas' disease, which is needed at Chagas' disease control centers. By using an enzyme-linked immunosorbent assay containing a recombinant protein corresponding to the catalytic domain of trans-sialidase, we found that the antigen had a high specificity for sera from untreated patients with Chagas' disease. Sera from healthy individuals or patients with active visceral leishmaniasis minimally cross-reacted with the antigen. Anti-trans-sialidase immunoglobulin was detected in 98% of 151 untreated patients with Chagas' disease. Of these, 124 patients were treated for 60 days with benznidazole (5 mg/kg of body weight/day), and their sera were assayed for reactivity with the recombinant trans-sialidase. By using this methodology, three groups of patients could be established. The first group (60 patients), which was considered to have been successfully treated, showed no reactivity after treatment. The second group (46 patients) still showed signs of infection, and after treatment their sera recognized trans-sialidase, but with reduced titers. The third group (18 patients) was considered to be resistant to drug treatment, and their sera presented identical reactivities before and after treatment. These results suggest that determination of the absence of antibodies to recombinant trans-sialidase in treated patients by the present assay is indicative of treatment success, while the presence of antibodies may indicate the persistence of infection. Therefore, this method may be useful for the diagnosis and monitoring of patients undergoing benznidazole treatment.
转唾液酸酶是克氏锥虫表面存在的一种酶，是恰加斯病患者血清识别的重要抗原。在本研究中，我们调查了恰加斯病患者接受苯硝唑治疗后，其血清对重组转唾液酸酶的反应性是否发生变化，以便开发一种用于监测恰加斯病治疗后患者的检测方法，这是恰加斯病控制中心所需要的。通过使用一种含有与转唾液酸酶催化结构域相对应的重组蛋白的酶联免疫吸附测定法，我们发现该抗原对未经治疗的恰加斯病患者的血清具有高度特异性。健康个体或活动性内脏利什曼病患者的血清与该抗原的交叉反应极小。在151例未经治疗的恰加斯病患者中，98%检测到抗转唾液酸酶免疫球蛋白。其中，124例患者接受了60天的苯硝唑治疗（5毫克/千克体重/天），并检测了他们的血清与重组转唾液酸酶的反应性。通过使用这种方法，可以将患者分为三组。第一组（60例患者）被认为治疗成功，治疗后无反应。第二组（46例患者）仍显示感染迹象，治疗后其血清可识别转唾液酸酶，但滴度降低。第三组（18例患者）被认为对药物治疗耐药，其血清在治疗前后的反应性相同。这些结果表明，通过本检测方法测定治疗患者中重组转唾液酸酶抗体的缺失表明治疗成功，而抗体的存在可能表明感染持续存在。因此，该方法可能有助于恰加斯病患者接受苯硝唑治疗的诊断和监测。
