[Histopathology of tegumentary leishmaniasis caused by Leishmania braziliensis braziliensis. 3. Cellular reactions in tissues]

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

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.

What makes mucosal and anergic diffuse cutaneous leishmaniases so clinically and immunopathogically different? A review in Brazil

American cutaneous leishmaniasis (ACL) is a parasitic protozoan disease caused by different Leishmania species widely distributed throughout Latin America. Fifteen Leishmania species belonging to the subgenera Viannia, Leishmania and Mundinia are known to cause ACL. Seven of these species are found in Brazil, of which Leishmania (Viannia) braziliensis and Leishmania (Leishmania) amazonensis have the highest potential to cause mucosal (ML) and anergic diffuse cutaneous leishmaniasis (DCL), respectively, the most severe forms of ACL. The clinical and immunopathological differences between these two clinical forms are reviewed here, taking into account their different physiopathogenic mechanisms of dissemination from cutaneous lesions to mucosal tissues in the case of ML and to almost all body surfaces in the case of anergic DCL. We also discuss some immunopathogenic mechanisms of species-specific Leishmania antigens (from the subgenera Viannia and Leishmania) that are most likely associated with the clinical and immunopathological differences between ML and anergic DCL. Those discussions emphasize the pivotal importance of some surface antigens of L. (V.) braziliensis and L. (L.) amazonensis, such as lipophosphoglycan, phosphatidylserine and CD200 (an immunoregulatory molecule that inhibits macrophage activation), that have been shown to exert strong influences on the clinical and immunopathological differences between ML and anergic DCL.

The immunomodulatory effect of plant lectins: a review with emphasis on ArtinM properties

Advances in the glycobiology and immunology fields have provided many insights into the role of carbohydrate-protein interactions in the immune system. We aim to present a comprehensive review of the effects that some plant lectins exert as immunomodulatory agents, showing that they are able to positively modify the immune response to certain pathological conditions, such as cancer and infections. The present review comprises four main themes: (1) an overview of plant lectins that exert immunomodulatory effects and the mechanisms accounting for these activities; (2) general characteristics of the immunomodulatory lectin ArtinM from the seeds of Artocarpus heterophyllus; (3) activation of innate immunity cells by ArtinM and consequent induction of Th1 immunity; (4) resistance conferred by ArtinM administration in infections with intracellular pathogens, such as Leishmania (Leishmania) major, Leishmania (Leishmania) amazonensis, and Paracoccidioides brasiliensis. We believe that this review will be a valuable resource for more studies in this relatively neglected area of research, which has the potential to reveal carbohydrate targets for novel prophylactic and therapeutic strategies.

Perfil histopatológico e imuno-histoquímico da leishmaniose tegumentar americana com ênfase nos dendrócitos dérmicos FXIIIa+

FUNDAMENTOS: Leishmaniose tegumentar é doença parasitária infecciosa que apresenta aspectos imunológicos relevantes. OBJETIVO: Estudar a histopatologia e aspectos imuno-histoquímicos de 21 biópsias de leishmaniose tegumentar. MÉTODOS: Anticorpo policlonal anti-Leishmania foi utilizado para identificação das leishmânias. A classificação histopatológica adotada foi em grupos padrões de I a V. Foram analisados os dendrócitos dérmicos FXIIIa+, células de Langerhans CD1a+, macrófagos CD68+, linfócitos B CD20+ e T CD3+. As células FXIIIa+ foram quantificadas na derme papilar e comparadas a peles normais obtidas de área não exposta à luz solar, sendo o número de células FXIIIa+ avaliado estatisticamente através do teste de Mann-Whitney. As demais células foram contadas semiquantitativamente. RESULTADOS: Entre os grupos histopatológicos, predominaram os I e II. Não houve diferença estatisticamente significante (p=0,157) entre o número de células FXIIIa+ na leishmaniose e na pele normal. Não foi observada diferença si ificante entre a presença das células CD1a+, CD68+, CD20+ e CD3+, quando comparadas entre si ou com as células FXIIIa+. CONCLUSÃO: Não houve diferença no número de células dendríticas FXIIIa+ entre a leishmaniose e pele normal. No entanto, sugere-se que mais estudos sejam necessários para se entender o papel dessas células na leishmaniose.

Granulocytes in the inflammatory process of BALB/c mice infected by Leishmania amazonensis. A quantitative approach

We used previously immunized (partially resistant) and naive (highly susceptible) BALB/c mice infected with Leishmania amazonensis for evaluating the role of granulocytes in the course of murine leishmaniasis. The animals were examined at different times post-infection and granulocytes counted in lesion tissues examined ultra-structurally. Polymorphonuclear granulocytes predominated during the early phase of infection and their number decreased with progression of infection; their number was similar in both groups during the early and intermediate phases of infection, though slightly higher in immunized animals during the late phase. Eosinophils represented approximately 10% of cells in the inflammatory infiltrate, being higher during the intermediate phase, and not differing between the groups. Another approach was the evaluation of granulocyte migration to the peritoneal cavity of susceptible BALB/c mice or resistant C57BL/6 mice under several stimuli. There was no statistically significant difference between resistant and susceptible animals in any of the treatments. Despite the influx of granulocytes to the lesion and its possible role in the initial destruction of injected Leishmania, this aspect does not seem to have an important effect on the outcome of the leishmanial infection.

[Experimental cutaneous leishmaniasis. III. Histopathological aspects of the developmental behavior of the cutaneous lesion induced in Cebus apella (Primates: Cebidae) by Leishmania (Viannia) lainsoni, L. (V.) braziliensis and L. (Leishmania) amazonensis]

We have studied the histopathological aspects related to the evolution of cutaneous lesions experimentally produced in the monkey Cebus apella (Primates: Cebidae) by Leishmania (V.) lainsoni, L. (V.) braziliensis and L. (L.) amazonensis. Microscopical examination of a series of biopsies obtained from these animals showed the kinetics of the cutaneous lesions regarding three species of Leishmania inoculated, as follows: 1) an initial non-specific chronic inflammatory infiltrate; 2) macrophagic nodules; 3) necrosis of parasitized phagocytic cells; 4) epitheliode granuloma; 5) absorption of the necrotic area (sometimes forming "foreign-body granuloma"); 6) a non-specific residual inflammatory infiltration; and 7) cicatrization. These pathological processes are, of course, responsible for both development and resolution of the leishmaniotic lesion. We also discuss some immunopathological mechanisms probably related with the sequential events, and that could be also responsible for the different clinical aspects found in man.

[Spontaneous healing of leishmaniasis caused by Leishmania viannia braziliensis in cutaneous lesions]

In field clinics in the communities of Três Braços and Corte de Pedra, Bahia, we have attended 1.416 patients with tegumentary leishmaniasis in fourteen years, the predominant species in transmission is Leishmania Viannia brasi liensis (LVB). Because of the danger of metastasis with this infection treatment was routinely recommended with Glucan-time. However sixteen patients refused injection therapy and six women were pregnant when seen and not treated. All patients were followed up in our clinic. All these patients closed their skin ulcers although one subsequently relapsed. Patients were followed up for variable periods (four to twelve years), after the diagnosis. In nine patients (40.9%) of the cohort, the time to healing after initiation of the lesion was calculated as six months of evolution. At twelve months, nineteen patients (86.3%) had complete healing of their lesions. In three patients an active lesion was present for longer than one year. The determinants of this variable natural evolution of human LVB lesion remains completely unknown. It is difficult for us to understand and compare the effects of therapeutic agents in mucocutaneous leishmaniasis.

Histological analysis and the pathogenesis of mucocutaneous leishmaniasis

A series of over 400 well-documented biopsies of mucocutaneous leishmaniasis was evaluated to elucidate the histological processes associated with the elimination of parasites, and their correlation with the course of the disease. Non-specific inflammation was the most frequent and least effective response; its onset might be delayed, and in this event particularly the incidence of metastasis from skin to mucosa was high. Lysis of parasite-laden macrophages appeared to be the basic mechanism of parasite reduction, even when it was not overt. When it was acute the onset was usually rapid, and though it resulted in much tissue destruction the prognosis was generally better and mucosal metastasis rare. Lysis and non-specific inflammation both led to the formation of a post-necrotic type of granuloma, but reversion of the process was almost as common as progression. Ultimately a tuberculoid granuloma evolved and proceeded to resolution. In about 5 per cent of cases, macrophage activation appeared to bring about early resolution; neither reversion nor mucosal metastasis was seen.

[Leishmaniasis caused by Leishmania viannia braziliensis (Lvb). A case of atypical course]

Os autores relatam o caso de uma criança portadora de Leishmaniose Tegumentar Americana causada por Leishmania braziliensis braziliensis que foi infectada durante a amamentação, desenvolvendo lesão infiltrativa e nodular nos lábios, com posterior disseminação para os seios da face, fossas nasais e pavilhão auricular e cuja evolução clinica pós-terapêutica caracterizou-se por períodos sucessivos de regressão e de reativação da lesão. Enfatizam a gravidade do caso, e as dificuldades terapêuticas com a utilização dos antimoniais pentavalentes, antimoniato-N-metil glucamina (Glucantime) e o stibogluconato de sódio(Pentostam).

[Histopathology of cutaneous leishmaniasis caused by Leishmania braziliensis braziliensis. 4. Histopathological classification]

Os A A. analisaram as alterações histológicas encontradas em 162 casos de Leishmaniose Tegumentar da localidade de Três Braços, Estado da Bahia, dos quais 131 (80,9%) eram de portadores de lesões cutâneas e 31 (19,1%) de portadores de lesões mucosas. Analisaram, também, o comportamento clínico dos cinco padrões histopatológicos, já antes descritos, em relação à terapêutica. O melhor prognóstico esteve sempre ligado ao padrão de Reação Exsudativa e Granulomatosa, ou seja, a uma fase na qual o organismo, tendo lançado mão de um mecanismo endógeno de lise parasitária, já circunscreveu a área de necrose por uma reação granulomatosa, e esta é agora apenas o elemento residual. A ação terapêutica nessa fase somente acelera a resolução natural do caso. O grupo seguinte é amplo, e compreende os casos em que a lesão pertence aos padrões de Reação Exsudativa Celular (formas cutâneas), Reação Exsudativa e Necrótica e Reação Exsudativa e Necrótico-Granulomatosa. Nesses casos, o mecanismo de auto-controle da lesão encontra-se ainda em curso, e a ação terapêutica encurta o período de evolução natural. Os f.asos do padrão de Reação Exsudativa e Tuberculóide tiveram um prognóstico variável. Houve boa resposta à terapêutica quando o granuloma tuberculóide característico desse padrão surgiu em pacientes jovens, com curto tempo de evolução da doença e intradermorreação não exacerbada. Nos demais casos tuberculóides —. principalmente em pacientes adultos, com longo tempo de evolução da doença e intradermorreação exacerbada —, a resposta foi menos satisfatória. Em último lugar, com prognóstico reservado, ficaram os casos da forma mucosa que apresentaram o padrão de Reação Exsudativa Celular, onde o infiltrado pode estar desempenhando papel de auto-agressão. O presente estudo evoluiu para a proposição de uma classificação da Leishmaniose Tegumentar, baseada nos padrões histopatológicos observados. Esta classificação, estritamente morfológica, deverá ser de fácil aplicação para o Patologista e, como apresenta também uma correspondência clínico-evolutiva poderá constituir auxílio valioso ao médico envolvido no diagnóstico e tratamento da Leishmaniose Tegumentar.