Aguiar Bruno Guedes Alcoforado, Coelho Daniela Lemos, Costa Dorcas Lamounier, Drumond Betânia Paiva, Coelho Luiz Felipe Leomil, Figueiredo Lívio Carvalho, Zacarias Danielle Alves, Silva Jailthon Carlos da, Alonso Diego Peres, Ribolla Paulo Eduardo Martins, Ishikawa Edna Aoba Yassui, Gaído Samara Belchior, Costa Carlos Henrique Nery
Laboratório de Leishmanioses, Instituto de Doenças Tropicais Natan Portella, Universidade Federal do Piauí, Teresina, PI, Brasil.
Laboratório de Virologia, Universidade Federal de Juiz de Fora, Juiz de Fora, MG, Brasil.
Rev Soc Bras Med Trop. 2014 Sep-Oct;47(5):593-8. doi: 10.1590/0037-8682-0183-2014.
Kala-azar is a disease resulting from infection by Leishmania donovani and Leishmania infantum. Most patients with the disease exhibit prolonged fever, wasting, anemia and hepatosplenomegaly without complications. However, some patients develop severe disease with hemorrhagic manifestations, bacterial infections, jaundice, and edema dyspnea, among other symptoms, followed by death. Among the parasite molecules that might influence the disease severity are the macrophage migration inhibitory factor-like proteins (MIF1 and MIF2) and N-acetylglucosamine-1-phosphotransferase (NAGT), which act in the first step of protein N-glycosylation. This study aimed to determine whether MIF1, MIF2 and NAGT are virulence factors for severe kala-azar.
To determine the parasite genotype in kala-azar patients from Northeastern Brazil, we sequenced the NAGT genes of L. infantum from 68 patients as well as the MIF1 and MIF2 genes from 76 different subjects with diverse clinical manifestations. After polymerase chain reaction (PCR), the fragments were sequenced, followed by polymorphism identification.
The nucleotide sequencing of the 144 amplicons revealed the absence of genetic variability of the NAGT, MIF1 and MIF2 genes between the isolates. The conservation of these genes suggests that the clinical variability of kala-azar does not depend upon these genes. Additionally, this conservation suggests that these genes may be critical for parasite survival.
NAGT, MIF1 and MIF2 do not alter the severity of kala-azar. NAGT, MIF1 and MIF2 are highly conserved among different isolates of identical species and exhibit potential for use in phylogenetic inferences or molecular diagnosis.
黑热病是由杜氏利什曼原虫和婴儿利什曼原虫感染引起的疾病。大多数该病患者表现为长期发热、消瘦、贫血和肝脾肿大且无并发症。然而，一些患者会发展为严重疾病，出现出血表现、细菌感染、黄疸和水肿性呼吸困难等症状，随后死亡。在可能影响疾病严重程度的寄生虫分子中，有巨噬细胞迁移抑制因子样蛋白（MIF1和MIF2）以及N - 乙酰葡糖胺 - 1 - 磷酸转移酶（NAGT），它们在蛋白质N - 糖基化的第一步起作用。本研究旨在确定MIF1、MIF2和NAGT是否为严重黑热病的毒力因子。
为确定巴西东北部黑热病患者的寄生虫基因型，我们对68例患者的婴儿利什曼原虫的NAGT基因以及76例具有不同临床表现的不同受试者的MIF1和MIF2基因进行了测序。经过聚合酶链反应（PCR）后，对片段进行测序，随后进行多态性鉴定。
144个扩增子的核苷酸测序显示，分离株之间的NAGT、MIF1和MIF2基因不存在遗传变异性。这些基因的保守性表明，黑热病的临床变异性不取决于这些基因。此外，这种保守性表明这些基因可能对寄生虫的生存至关重要。
NAGT、MIF1和MIF2不会改变黑热病的严重程度。NAGT、MIF1和MIF2在相同物种的不同分离株中高度保守，并具有用于系统发育推断或分子诊断的潜力。
