A strategic conflict between two sides: host immune cells vs. viral symbiont of Leishmania spp. in cutaneous Leishmaniasis

Leishmaniasis comprises a group of neglected tropical diseases that primarily affect regions in the Americas, the Mediterranean basin, the Middle East and central Asia, according to the World Health Organization (WHO). Although treatment options are available, leishmaniasis remains far from being considered a controlled disease. It has a complex immunological profile, involving components that act at different stages of disease progression. These include immune cells, skin (integumentary) cells, cytokines, and chemokines, each contributing to the pathology to varying degrees. The immune response is the primary mechanism for combating Leishmania parasites and plays a fundamental role in disease control. Moreover, the symbiotic relationship between the etiological agent of leishmaniasis and the Leishmania RNA virus (LRV) represents an additional risk factor for disease exacerbation. This relationship introduces yet another challenge for the host immune system, increasing susceptibility during the course of infection. The impact of LRV on the immune response in leishmaniasis is still not completely understood, as its role in modulating immune cell functions and soluble mediators are still under investigation. In this review, we aim to consolidate current knowledge and identify possible targets for future research. We will focus specifically on the immunological aspects of cutaneous leishmaniasis, with an emphasis on adaptive immune cells that are crucial in responding to reinfection.