Serviço de Imunologia, Complexo Hospitalar Universitário Prof. Edgard Santos, Universidade Federal da Bahia, Salvador, Brazil.
PLoS Negl Trop Dis. 2012;6(12):e1947. doi: 10.1371/journal.pntd.0001947. Epub 2012 Dec 20.
Cutaneous leishmaniasis due to L. braziliensis (CL) is characterized by a positive delayed type hypersensitivity test (DTH) leishmania skin test (LST) and high IFN-γ production to soluble leishmania antigen (SLA). The LST is used for diagnosis of CL and for identification of individuals exposed to leishmania infection but without disease. The main aim of the present study was to identify markers of exposure to L. braziliensis infection. METHODOLGY/PRINCIPAL FINDINGS: This cohort study enrolled 308 household contacts (HC) of 76 CL index cases. HC had no active or past history of leishmaniasis. For the present cross-sectional study cytokines and chemokines were determined in supernatants of whole blood culture stimulated with SLA. Of the 308 HC, 36 (11.7%) had a positive LST but in these IFN-γ was only detected in 22 (61.1%). Moreover of the 40 HC with evidence of IFN-γ production only 22 (55%) had a positive LST. A total of 54 (17.5%) of 308 HC had specific immune response to SLA. Only a moderate agreement (Kappa = 0.52; 95% CI: 0.36-0.66) was found between LST and IFN-γ production. Moreover while enhancement of CXCL10 in cultures stimulated with SLA was observed in HC with DTH+ and IFN-γ+ and in patients with IFN-γ(+) and DTH(-), no enhancement of this chemokine was observed in supernatants of cells of HC with DTH(+) and IFN-γ(-).
CONCLUSIONS/SIGNIFICANCE: This study shows that in addition of LST, the evaluation of antigen specific IFN-γ production should be performed to determine evidence of exposure to leishmania infection. Moreover it suggests that in some HC production of IFN-γ and CXCL10 are performed by cells not involved with DTH reaction.
巴西利什曼原虫（L. braziliensis）引起的皮肤利什曼病的特征是迟发型超敏反应试验（DTH）利什曼原虫皮肤试验（LST）阳性和对可溶性利什曼抗原（SLA）产生高 IFN-γ。LST 用于诊断 CL 和识别暴露于利什曼原虫感染但无疾病的个体。本研究的主要目的是确定暴露于 L. braziliensis 感染的标志物。
方法/主要发现：这项队列研究纳入了 76 例 CL 索引病例的 308 名家庭接触者（HC）。HC 无活动性或既往利什曼病病史。在本横断面研究中，用 SLA 刺激全血培养上清液中细胞因子和趋化因子。在 308 名 HC 中，36 名（11.7%）LST 阳性，但其中仅 22 名（61.1%）检测到 IFN-γ。此外，在有 IFN-γ 产生证据的 40 名 HC 中，只有 22 名（55%）LST 阳性。308 名 HC 中共有 54 名（17.5%）对 SLA 具有特异性免疫反应。LST 和 IFN-γ 产生之间仅发现中度一致性（Kappa=0.52；95%CI：0.36-0.66）。此外，在 DTH+和 IFN-γ+的 HC 和 IFN-γ+和 DTH-的患者中观察到 SLA 刺激培养物中 CXCL10 的增强，但在 DTH+和 IFN-γ-的 HC 的细胞上清液中未观察到这种趋化因子的增强。
结论/意义：本研究表明，除了 LST 之外，还应评估抗原特异性 IFN-γ 产生以确定暴露于利什曼原虫感染的证据。此外，它表明在一些 HC 中，IFN-γ 和 CXCL10 的产生是由不参与 DTH 反应的细胞进行的。
