de Gouvêa Viana Luciana, de Assis Tália Santana Machado, Orsini Marcela, da Silva Alexandre Rotondo, de Souza Guenael Freire, Caligiorne Rachel, da Silva Aline Christiane Louredo, Peruhype-Magalhães Vanessa, Marciano Ana Paula Vieira, Martins-Filho Olindo Assis, Rabello Ana
Laboratório de Pesquisas Clinicas, Instituto René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, MG, Brazil.
Trans R Soc Trop Med Hyg. 2008 Jun;102(6):548-55. doi: 10.1016/j.trstmh.2008.02.007. Epub 2008 Mar 25.
Peripheral blood samples of 138 co-habitants from 25 families with recently diagnosed cases of visceral leishmaniasis in the Metropolitan Region of Belo Horizonte, Minas Gerais, Brazil, were analyzed by indirect fluorescent antibody test (IFAT), rK39 and Leishmania chagasi Enzyme Linked Immunosorbent Assay (ELISA), intradermal skin-test and Polymerase Chain Reaction (PCR) over a 12-month period. The cumulative positivity was significantly higher by PCR (29.7%) than by IFAT, rK39 ELISA, L. chagasi ELISA and intradermal skin-test (5.1%, 6.5%, 14.5% and 2.9%, respectively). In addition, the cytokine profile was measured in 16 of the 138 volunteers, of whom eight were asymptomatic carriers and eight were non-infected co-habitants. The innate immunity cells from asymptomatic carriers displayed, upon in vitro antigenic stimulation, a modulated increase in cytokine synthesis that was distinct from that observed in non-infected volunteers. This study suggests that the identification of a large proportion of asymptomatic carriers is facilitated when more than one diagnostic method is applied and that a mixed pattern of immune response is correlated with clinical status of asymptomatic individuals. These observations suggest also that asymptomatic infection by L. chagasi is a frequent event and that control programs could benefit by including this indicator in their interventions.
在巴西米纳斯吉拉斯州贝洛奥里藏特市都会区，对来自25个家庭的138名与近期确诊的内脏利什曼病患者共同居住者的外周血样本，在12个月的时间里采用间接荧光抗体试验（IFAT）、rK39和恰加斯利什曼原虫酶联免疫吸附测定（ELISA）、皮内皮肤试验和聚合酶链反应（PCR）进行了分析。PCR检测的累积阳性率（29.7%）显著高于IFAT、rK39 ELISA、恰加斯利什曼原虫ELISA和皮内皮肤试验（分别为5.1%、6.5%、14.5%和2.9%）。此外，在138名志愿者中的16人检测了细胞因子谱，其中8人为无症状携带者，8人为未感染的共同居住者。无症状携带者的先天免疫细胞在体外抗原刺激后，细胞因子合成呈现出一种调节性增加，这与未感染志愿者中观察到的情况不同。这项研究表明，应用多种诊断方法有助于识别出很大比例的无症状携带者，并且免疫反应的混合模式与无症状个体的临床状态相关。这些观察结果还表明，恰加斯利什曼原虫的无症状感染是一个常见事件，控制项目将这一指标纳入干预措施可能会受益。
