Histopathological features of skin lesions in patients affected by non‐ulcerated or atypical cutaneous leishmaniasis in Honduras, Central America

Abstract

Summary In Honduras visceral leishmaniasis and non‐ulcerated or atypical cutaneous leishmaniasis (NUCL) are caused by the species Leishmania (L.) infantum chagasi. NUCL is the most common clinical form in the southern regions of the country, mainly affecting the young. In view of the lack of knowledge about the pathogenesis of the disease pattern caused by L. (L) infantum chagasi in individuals affected by NUCL, the aim of the present study was to describe in detail the histopathological features of the skin lesion caused by the parasite. Biopsies from human NUCL lesions with a positive parasitological diagnosis were collected and processed using standard histological techniques. Paraffin sections stained by haematoxylin and eosin were used to examine the histopathological alterations seen in the skin. The lesions varied between 3 and 5 mm, and the majority of the patients (60%) had a single lesion. Lesions were more frequently seen in females (65%), with an average age of 33.4 years. Microscopically, the skin lesions were characterized by mononuclear inflammatory infiltrate in the dermis composed of lymphocytes, macrophages and a few plasma cells. The intensity of the infiltration varied from discrete to intense. In both cases, the parasitic infection was discrete. Granulomas were present in 60% of cases and were associated with intense inflammation. The data revealed by the histopathological alterations in the skin of individuals affected by NUCL suggest activation of a cellular immune response that potentially controls parasite spreading.

Clinical and Immunological Features of Human Leishmania (L.) infantum-Infection, Novel Insights Honduras, Central America

“…Another point that deserves to be highlighted regarding the ESI profile is its high frequency (25%) among the symptomatic infection profiles, being surpassed only by the frequency (30.8%) of the FSI profile, which denotes that, among the clinical-immunological profiles of symptomatic infection (NUCL), the ESI profile may also signal a state of adaptation of the parasite on the host skin, possibly seeking to produce an immune-inflammatory response of moderate intensity with the objective of using the host as a source of infection for the sand fly vector (Lutzomyia longipalpis). In this sense, there is already evidence obtained by our group pointing to the moderate presence of inflammatory response [13] as well as mediators of the immune-inflammatory response in the skin lesions of patients with NUCL [14].…”

American Cutaneous Leishmaniasis: A Pleomorphic Disease with Unusual Clinical Presentations - Report of Three Cases

“…and association with other systemic diseases, with HIV co-infection and diabetes being the main associated diseases. [12,13] Coinfection with HIV causes the emergence of unusual clinical forms and this fact is due to the sy-nergy present in the infectious mechanisms of both diseases, since leishmanias tend to infect especially myeloid cells, favoring the proliferation of HIV. On the other hand, lymphocyte depletion promoted by HIV favors the invasion of macrophages by leishmanias, creating a positive feedback loop of both diseases.…”

Laboratory Diagnosis of Cutaneous and Visceral Leishmaniasis: Current and Future Methods

“…The microscopic exam is the most widely available test for the diagnosis of leishmaniasis, but it does not allow the identification of Leishmania species [ 23 ]. For CL, the direct examination of stained material removed from the lesion (obtained by biopsy, punch, scraping, smear or imprinting) using light microscopy, has a 50–70% sensitivity for Leishmania species from Africa, Asia and Europe, and 15–30% for species from the Americas ( Table 1 ) [ 16 , 25 , 26 , 29 , 30 ]. For samples from CL patients, a combination of different methods is recommended, given the limited sensitivity of these methods, particularly for samples of ML that have a low parasite load.…”