ABSTRACT

American tegumentary leishmaniasis (TL) caused by Leishmania braziliensis is characterized by a spectrum of clinical presentations, ranging from localized cutaneous ulcers (CL), mucosal (ML), or disseminated (DL) disease, to a subclinical (SC) asymptomatic form. Current diagnosis based on parasite culture and/or microscopy lacks sensitivity and specificity. Previous studies showed that patients with CL and ML have very high levels of Leishmania-specific anti-α-Gal antibodies. However, the native parasite α-Gal glycotope(s) is(are) still elusive, thus they have not yet been explored for a more accurate TL diagnosis. Using a chemiluminescent immunoassay, we evaluated the seroreactivity of TL patients across its clinical spectrum, and of endemic (EC) and nonendemic healthy controls (NEC) against three synthetic neoglycoproteins (NGP29b, NGP30b, and NGP28b), respectively comprising the L. major-derived type-2 glycoinositolphospholipid (GIPL)-1 (Galfβ1,3Manα), GIPL-2 (Galα1,3Galfβ1,3Manα), and GIPL-3 (Galα1,6Galα1,3Galfβ) glycotopes. Contrary to NGP29b and NGP30b, NGP28b exhibited high sensitivity and specificity to a CL serum pool. More importantly, NGP28b reacted strongly and specifically with individual sera from distinct clinical forms of TL, especially with SC sera, with 94% sensitivity and 97% specificity, by post-two-graph receiver-operating characteristic curve analysis. Contrary to NGP29b, NGP28b showed low cross-reactivity with Chagas disease and control (NEC/EC) sera. Additionally, seroreactivity of CL patients against NGP28b was significantly decreased after successful chemotherapy, indicating that L. braziliensis-specific anti-α-Gal antibodies may serve as an early biomarker of cure in CL. Our data also points towards the applicability of L. major type-2 GIPL-3-derived Galα1,6Galα1,3Galfβ glycotope for the serological diagnosis of American TL, particularly of the subclinical form.

摘要

由巴西利什曼原虫引起的美国皮肤利什曼病 (TL)具有一系列临床表现，从局部皮肤溃疡 (CL)、粘膜 (ML) 或播散性 (DL) 疾病到亚临床 (SC) 无症状形式。目前基于寄生虫培养和/或显微镜检查的诊断缺乏敏感性和特异性。先前的研究表明，患有 CL 和 ML 的患者的利什曼原虫水平非常高-特异性抗α-Gal抗体。然而，天然寄生虫 α-Gal 糖位仍然难以捉摸，因此尚未探索它们以进行更准确的 TL 诊断。使用化学发光免疫测定法，我们评估了 TL 患者在其临床范围内的血清反应性，以及地方病 (EC) 和非地方病健康对照 (NEC) 对三种合成新糖蛋白（NGP29b、NGP30b 和 NGP28b）的血清反应性，分别包含 L. major-衍生的 2 型糖肌醇磷脂 (GIPL)-1 (Gal f β1,3Manα)、GIPL-2 (Galα1,3Gal f β1,3Manα) 和 GIPL-3 (Galα1,6Galα1,3Gal fβ) 糖表位。与 NGP29b 和 NGP30b 相反，NGP28b 对 CL 血清池表现出高灵敏度和特异性。更重要的是，通过后两图接受者操作特征曲线分析，NGP28b 与来自不同临床形式的 TL 的个体血清，尤其是 SC 血清，具有 94% 的敏感性和 97% 的特异性反应强烈且特异性。与 NGP29b 相反，NGP28b 与南美锥虫病和对照 (NEC/EC) 血清的交叉反应性较低。此外，化疗成功后，CL 患者针对 NGP28b 的血清反应性显着降低，表明巴西乳杆菌特异性抗 α-Gal 抗体可作为 CL 治愈的早期生物标志物。我们的数据还指向L. major type-2 GIPL-3 衍生的 Galα1,6Galα1,3Gal的适用性f β 糖表位用于美国 TL 的血清学诊断，特别是亚临床形式。