Non-ulcerated or atypical cutaneous leishmaniasis caused by L. (L.) infantum chagasi in Amapala municipality, Valle, Honduras: immunohistopathological characterization of the skin lesions with emphasis to the involvement of the antigen presentation cells

Author(s)

Carmen Maria Sandoval Pacheco

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD)
• Defense date: 2022-03-15

Examining board members

Marcia Dalastra Laurenti; Claudia Maria de Castro Gomes; Fernando Tobias Silveira; Mirian Nacagami Sotto

• Advisor: Marcia Dalastra Laurenti

Abstract

In America, especially in South America, infection by L. (L.) infantum chagasi causes subclinical infection and visceral leishmaniasis, which, if non-treated, is potentially fatal. In Honduras, has been reported that infection by L. (L.) infantum chagasi causes visceral leishmaniasis and non-ulcerated or atypical cutaneous leishmaniasis (NUCL). However, little is known about the profile of human infection by L. (L.) infantum chagasi in Honduras. Thus, to deepen the knowledge regarding the pathophysiology of the infection caused by this species of parasite, this work aimed to evaluate the participation of subpopulations of antigen-presenting cells in skin lesions of patients affected by the atypical cutaneous form through cellular and intracellular markers by double-staining immunohistochemistry. In this study, we used twenty-three skin biopsies from patients with a positive direct parasitological diagnosis which was confirmed and characterized by hsp70 PCR-RFLP. Histological sections of non-ulcerated skin lesions were used for histopathological study. For immunohistochemistry reaction, we use primary antibodies to Langerhans cell (CD1a and CD207), dermal dendritic cells (CD11c and CD303), macrophages (CD68 and CD163), T lymphocytes (CD4 and CD8), and cytokines IL-12, IFN-, TNF-, iNOS, IL-10, and IL-4. Double-staining immunohistochemistry was used to evaluate subpopulations of macrophages (M1 and M2), Langerhans cells, dermal dendritic cells, and T lymphocytes. The hsp70 PCR-RFLP using the restriction enzyme HaeIII characterized the parasites in the biopsies of non-ulcerated skin lesions as L. (L.) infantum chagasi. Microscopically, the lesions were characterized by slight morphological changes in the epidermis. On the other hand, the changes in the dermis were more significant. Characterized by an inflammatory infiltrate, predominantly lymphohistiocytic of variable intensity (moderate to intense) with a diffuse arrangement and associated with epithelioid granulomas and discreet parasitism. Immunohistochemical analysis of skin lesions of non-ulcerated leishmaniasis showed the presence of all markers used in this study. The analysis of double-staining immunohistochemistry showed higher participation of M1 macrophages subpopulation than M2. Regarding the subpopulations of dendritic cells (Langerhans and dermal dendritic cells), we observed higher participation of CD1a, CD207, and CD11c producing the pro-inflammatory cytokine IL-12 in the skin lesions of patients with NUCL in relation to the other evaluated cytokines. Activation of the cellular immune response was marked by a higher density of CD8 Tc1 lymphocytes followed by CD4 Th1 lymphocytes producing mainly IFN-. In our study, the data obtained suggest that, in NUCL, antigen-presenting cells play an important role in the in situ immune response, through the production of pro-inflammatory cytokines, directing the cellular immune response preferentially to the Th1 and/or Tc1 type, in this atypical clinical form of cutaneous leishmaniasis caused by L. (L.) infantum chagasi (AU)

• FAPESP's process: 18/04698-6 - Non-ulcerated or atipycal Cutaneous Leishmaniasis caused by Leishmania (L.) infantum chagasi in the municipality of Amapala, Valle, Honduras: immunohistopathological characterization of skin lesions with emphasis in the participation of antigen presenting cells
• Grantee: Carmen Maria Sandoval Pacheco
• Support Opportunities: Scholarships in Brazil - Doctorate