The Presence of Leishmania braziliensis DNA in the Nasal Mucosa of Cutaneous Leishmaniasis Patients and the Search for Possible Clinical and Immunological Patterns of Disease Progression: A Cross Sectional Study

Abstract

Leishmania braziliensis is the most important causal agent of American tegumentary leishmaniasis (ATL), and 3 to 5% of patients develop mucosal lesions. The mechanisms related to parasite and host immune interactions and the parasite life cycle that lead to dissemination to the mucosa are poorly understood. We aimed to detect L. braziliensis DNA in the nasal mucosa of cutaneous leishmaniasis (CL) patients with early mucous dissemination and to relate those findings to specific inflammatory responses. Nasal swabs were collected from patients with the cutaneous form of ATL. L. braziliensis DNA was investigated using TaqMan-based real-time PCR. The levels of serum cytokines (IL-12, IL-6, TNF-α, IL-10, IL-1β and IL-8) were measured by a multiplex cytometric array. A Poisson regression model was used to test prevalence ratios (PRs) and multivariate interactions of clinical and laboratory characteristics. Of the 79 CL patients, 24 (30%) had L. braziliensis DNA in the nasal mucosa. In the multivariate model, parasite DNA presence in mucosa was associated with a reduction in IL-12 levels (PR = 0.440; p=0.034), increased IL-6 levels (PR = 1.001; p=0.002) and a higher number of affected body segments (PR = 1.65; p<0.001). In this study, we observed a higher rate of early dissemination to the nasal mucosa than what was previously described. We suggest that an enhanced Th1 profile characterized by higher IL-12 is important for preventing dissemination of L. braziliensis to the mucosa. Further evaluation of parasite-related interactions with the host immunological response is necessary to elucidate the dissemination mechanisms of Leishmania.

First Report of an Asymptomatic Leishmania (Viannia) shawi Infection Using a Nasal Swab in Amazon, Brazil

“…The findings of this study provide a warning for the possible association between L. (V.) shawi and mucous lesions, since L. (V.) braziliensis can be found both in normal mucosa and in injured mucosa [5]. Experimental studies showed that infection by L. (V.) shawi without symptoms in mice can occur through the activation of antigens capable of inducing a protective immune profile, which is important for the development of vaccines against TL [34,35].…”

“…L. (V.) braziliensis causes more frequently disseminated conditions, being the main species causing mucosal leishmaniasis [4]. L. (V.) braziliensis can be detected in the nasal mucosa of both sick and healthy people living in areas with endemic TL [5]. L. (V.) guyanensis, which is predominant in certain endemic areas of northern Brazil, notably in the states of Amazonas and Amapá [6], can also cause mucosal lesions [7] and is highly resistant to Glucantime, the first-line drug treatment for TL in Brazil [2].…”

Severe Inflammatory and Disseminated Cutaneous Leishmaniasis in a Pregnant Woman: A Case Report from Portoviejo, Ecuador

“…After a study of 26 well-registered cases, authors reached to the conclusion that pregnancy has influence on clinical manifestations when the causative parasite is L. (V.) braziliensis, because all studied women presented painless large lesions with an atypical exophytic appearance [28]. Machado et al [29] and Barroso et al [30] describe that disseminated leishmaniasis caused by L. (V.) braziliensis is associated with immunosuppression and specific inflammatory responses, in which there is a decrease in IL-12 cytokines in the peripheral blood and attraction of Th1 cells activated by the protozoan in the multiple skin lesions. However, they did not present any important inflammation signs, such as the pictures we present of our present patient in Ecuador, whose lesions were not atypical neither vegetative nor exophytic but larger than usual, strongly inflammatory, and painful, although there was no secondary infection.…”