Cutaneous Manifestations of Human and Murine Leishmaniasis

Abstract

The leishmaniases are diseases caused by pathogenic protozoan parasites of the genus Leishmania. Infections are initiated when a sand fly vector inoculates Leishmania parasites into the skin of a mammalian host. Leishmania causes a spectrum of inflammatory cutaneous disease manifestations. The type of cutaneous pathology is determined in part by the infecting Leishmania species, but also by a combination of inflammatory and anti-inflammatory host immune response factors resulting in different clinical outcomes. This review discusses the distinct cutaneous syndromes described in humans, and current knowledge of the inflammatory responses associated with divergent cutaneous pathologic responses to different Leishmania species. The contribution of key hematopoietic cells in experimental cutaneous leishmaniasis in mouse models are also reviewed and compared with those observed during human infection. We hypothesize that local skin events influence the ensuing adaptive immune response to Leishmania spp. infections, and that the balance between inflammatory and regulatory factors induced by infection are critical for determining cutaneous pathology and outcome of infection.

Leishmania species‐dependent functional duality of toll‐like receptor 2

“…By contrast, the production of interferon‐inducible T‐cell alpha chemokine 1 (iTAC), which reduces IL‐12 expression by DCs, is enhanced in L. major ‐infected susceptible mouse keratinocytes (Figure ). L. infantum up‐regulates, but L. major inhibits, the expression of pro‐inflammatory cytokines such as IL‐6, IL‐8, TNF‐α, and IL‐1β in keratinocytes (Figure ).…”

“…Other suppressive factors such as prostaglandin E2, TGF‐β, and Arginase‐I may also contribute to enhanced Leishmania infection in DCL. In L. amazonensis and L. panamensis infections, T‐reg cells reduce lesion development suggesting roles in controlling immuno‐pathological responses …”

Macrophage priming is dispensable for NLRP3 inflammasome activation and restriction of Leishmania amazonensis replication

“…Leishmaniasis is a multifactorial disease caused by parasites of the Leishmania genus, and it is estimated that around 12 million people worldwide are infected with these parasites . The disease may range from self‐healing cutaneous lesions to visceral disease, which can ultimately become fatal . The factors governing these different outcomes are mainly the parasite specie and the host's immune response .…”

“…18,19 The disease may range from self-healing cutaneous lesions to visceral disease, which can ultimately become fatal. [20][21][22] The factors governing these different outcomes are mainly the parasite specie and the host's immune response. 23 Although adaptive immunity has been shown to be important for host protection during the course of the disease, a recent work has demonstrated that NLRP3 contributes to pathology during Leishmaniasis.…”

Proteins involved in the biosynthesis of lipophosphoglycan in Leishmania: a comparative genomic and evolutionary analysis

“…Localized cutaneous leishmaniasis (LCL) is characterized by ulcers of different sizes at the site of inoculation, while mucocutaneous leishmaniasis (ML) affects the skin and mucosae. Visceral leishmaniasis (VL) is the most severe and life-threatening form, where the parasite diffuses through the bloodstream, reaching essential organs, such as the liver and spleen, and eventually bone marrow [7][8][9][10][11].…”