Singh S, Gilman-Sachs A, Chang K P, Reed S G
Department of Microbiology/Immunology, University of Health Sciences/Chicago Medical School, Illinois 60064, USA.
J Parasitol. 1995 Dec;81(6):1000-3.
The recombinant product (rK39) of the 39 amino acid repeats encoded by a kinesin-like gene of visceral Leishmania spp. was further evaluated by enzyme-linked immunosorbent assay (ELISA) for its diagnostic potential in Indian kala-azar (VL) and post kala-azar dermal leishmaniasis (PKDL). Anti-rK39 antibodies were highly positive in 20 symptomatic cases, including 6 resistant to single or double chemotherapy, but became negligible or absent in 9 recently cured patients. Endpoint titration of samples from the 20 active cases showed that the anti-rK39 IgG titers fell within a wide range of 10(-2) to > 10(-6), and that their mean was > 1 order of magnitude higher than in VL reported previously. The anti-rK39 IgG titers were correlated with parasite burden found in the patients and remained undiminished in those refractory to chemotherapy. These results indicate that: (1) the K39 epitope is conserved in Indian strains of Leishmania donovani, (2) the extremely high levels of K39 antibodies in both VL and PKDL suggest the application of rK39 for sensitive and specific serodiagnosis, and (3) rK39 ELISA is also valuable for prognostic evaluation of both diseases.
内脏利什曼原虫属中一种类驱动蛋白基因编码的39个氨基酸重复序列的重组产物（rK39），通过酶联免疫吸附测定（ELISA）进一步评估其在印度黑热病（VL）和黑热病后皮肤利什曼病（PKDL）中的诊断潜力。在20例有症状的病例中，抗rK39抗体呈高度阳性，其中包括6例对单药或联合化疗耐药的病例，但在9例近期治愈的患者中，抗体水平可忽略不计或消失。对20例活动期病例的样本进行终点滴定显示，抗rK39 IgG滴度范围很广，从10（-2）到>10（-6），其平均值比先前报道的VL患者高出1个数量级以上。抗rK39 IgG滴度与患者体内发现的寄生虫负荷相关，并且在化疗难治的患者中并未降低。这些结果表明：（1）K39表位在印度杜氏利什曼原虫菌株中是保守的；（2）VL和PKDL中极高水平的K39抗体表明rK39可用于敏感和特异的血清学诊断；（3）rK39 ELISA对这两种疾病的预后评估也有价值。
