Transcriptional alterations of virulence factors in Leishmania major clinical isolates harboring Leishmania RNA virus 2 (LRV2)

Background Leishmaniasis is a parasitic disease caused by an intracellular protozoan, Leishmania. Various factors, including host immunity and the Leishmania species, influence the manifestation and severity of the disease. Recent investigations have shed light on the potentially significant role of Leishmania RNA virus (LRV) in the clinical prognosis of leishmaniasis. This study aims to investigate the influence of LRV2 + on various pathogenic genes of Leishmania. Materials and methods In this study, 35 Leishmania isolates were obtained from patients diagnosed with cutaneous leishmaniasis (CL). Leishmania species and the presence of LRV2 + were identified with the PCR-RFLP and semi-nested PCR methods, respectively. Additionally, the RNA expression levels of cysteine protease (CP), heat shock protein 70 (HSP70), heat shock protein 83 (HSP83), glycoprotein 63 (GP63), and mannose phosphate isomerase (MPI) were assessed in LRV2 + and LRV2- Leishmania clinical isolates using RT-qPCR. Results Out of the 35 isolates, 20 were selected from CL patients, all confirmed as Leishmania major. These isolates were divided into two groups, LRV2 + and LRV2-, with 10 isolates in each group. RT-qPCR analysis revealed that HSP83, MPI, and GP63 gene expression levels were statistically upregulated in LRV2 + isolates compared to LRV2- isolates (P < 0.05). Although HSP70 and CP genes showed slight up-regulation in LRV2 + isolates, it was not statistically significant compared to LRV2- isolates. Conclusion The notable increase in gene expression levels, particularly for GP63, HSP83, and MPI genes, suggests that the presence of LRV2 + may significantly influence the expression of these factors in L. major clinical isolates.