AIM2 inflammasome is associated with disease severity in tegumentary leishmaniasis caused by Leishmania (V.) braziliensis.

The inflammasome is a multiprotein signalling platform involved in the pathogenesis of various inflammatory skin diseases. Herein, we investigated gene and protein expression of the inflammasome molecules AIM2 and NLRP3 in active lesions from patients with L. (V.) braziliensis-associated tegumentary leishmaniasis (TL) and correlated these findings with the clinical presentations and responses to therapy. Real-time PCR assays showed a significantly higher AIM2 gene expression in mucosal leishmaniasis (ML) compared with that in cutaneous leishmaniasis (CL). Additionally, AIM2 mRNA expression was significantly higher in lesions from poor responders than in lesions from good responders. In situ protein quantification analyses revealed greater AIM2 expression in ML lesions than in CL lesions. The percentage of AIM2-producing cells was higher in poor responders than in good responders. Although not quite significant, IL-1ß+ cells were slightly more prominent in poor responders than in good responders. Similar results were observed when patients were evaluated according to clinical form. GP63 immunostaining was identified in all samples, but no significant variation between mucosal and cutaneous lesions was observed. GP63 could be associated with reduced NLRP3 inflammasome expression in CL and ML patients. Taken together, these data demonstrate that AIM2 is an important component of the inflammasome in TL patients and is directly associated with the severity of lesions.

Effector memory CD4(+) T cells differentially express activation associated molecules depending on the duration of American cutaneous leishmaniasis lesions.

A high number of Leishmania-responder T cells is found in cutaneous leishmaniasis lesions, suggesting that important immunological events occur at the site of infection. Although activated, cytotoxic and regulatory T cells infiltrating into lesions may influence disease pathogenesis, the role of the T cell differentiation pattern of lymphocytes in lesions is unknown. Our aim was to investigate whether the phase of lesion development (early or late) is influenced by the functional status of cells present in inflammatory infiltrate. Activation, cytotoxity and T cell differentiation molecules were evaluated in lesion mononuclear cells by flow cytometry. The frequency of T cells was correlated with the lesion area (r = 0·68; P = 0·020). CD4(+) CD25(+) T cells predominated over CD4(+) CD69(+) T cells in early lesions (less than 30 days), whereas late lesions (more than 60 days) exhibited more CD4(+) CD69(+) T cells than CD4(+) CD25(+) T cells. The duration of illness was correlated positively with CD4(+) CD69(+) (r = 0·68; P = 0·005) and negatively with CD4(+) CD25(+) T cells (r = -0·45; P = 0·046). Most CD8(+) T cells expressed cytotoxic-associated molecules (CD244(+) ), and the percentages were correlated with the lesion area (r = 0·52; P = 0·04). Both CD4(+) and CD8(+) effector memory T cells (TEM -CD45RO(+) CCR7(-) ) predominated in CL lesions and were significantly higher than central memory (TCM -CD45RO(+) CCR7(+) ) or naive T cells (CD45RO(-) CCR7(+) ). An enrichment of TEM cells and contraction of naive T cells were observed in lesions in comparison to blood (P = 0·006) for both CD4(+) and CD8(+) T cells. Lesion chronicity is associated with a shift in activation phenotype. The enrichment of TEM and activated cytotoxic cells can contribute to immune-mediated tissue damage.

Therapeutic failure in American cutaneous leishmaniasis is associated with gelatinase activity and cytokine expression.

Cutaneous lesions caused by Leishmania braziliensis infection occasionally heal spontaneously, but with antimonials therapy heal rapidly in approximately 3 weeks. However, about 15% of the cases require several courses of therapy. Matrix metalloproteinase-2 (MMP-2) and MMP-9 are gelatinases that have been implicated in other chronic cutaneous diseases and skin re-epithelialization. These enzymes are controlled by their natural inhibitors [tissue inhibitors of metalloproteinase (TIMPs)] and by some cytokines. Uncontrolled gelatinase activity may result in intense tissue degradation and, consequently, poorly healing wounds. The present study correlates gelatinase activity to therapeutic failure of cutaneous leishmaniasis (CL) lesions. Our results demonstrate an association between gelatinase activity and increased numbers of cells making interferon (IFN)-γ, interleukin (IL)-10 and transforming growth factor (TGF)-ß in lesions from poor responders. Conversely, high levels of MMP-2 mRNA and enhanced MMP-2 : TIMP-2 ratios were associated with a satisfactory response to antimonials treatment. Additionally, high gelatinolytic activity was found in the wound beds, necrotic areas in the dermis and within some granulomatous infiltrates. These results indicate the importance of gelatinase activity in the skin lesions caused by CL. Thus, we hypothesize that the immune response profile may be responsible for the gelatinase activity pattern and may ultimately influence the persistence or cure of CL lesions.

Intralesional plasma cells and serological responses in human cutaneous leishmaniasis.

Intralesional plasma cells and serological responses were investigated in 20 Brazilian cases of cutaneous leishmaniasis. Plasma cell numbers varied from less than 10% to more than 50% of cells in inflammatory infiltrates, in general with greater numbers of such cells present in lesions of longer duration. Direct fluorescence examination with anti-IgG, -IgA and -IgM sera of trypsin-treated sections of formalin-fixed biopsy tissue revealed that most intralesional plasma cells contained IgG. Russell bodies were detected in eight cases, in seven of which these bodies fluoresced only with anti-IgM serum. There was no correlation between serum levels of total IgG, IgA and IgM (detected by radial immunodiffusion) or antileishmanial antibodies (detected by class-specific indirect immunofluorescence and by direct agglutination with and without 2-mercaptoethanol) and numbers of intralesional plasma cells of the same globulin class. No striking or consistent alterations in complement components were noted in the serum of these patients.

American tegumentary leishmaniasis (ATL) in Rio de Janeiro State, Brazil: main clinical and epidemiologic characteristics.

BACKGROUND: Rio de Janeiro State in Brazil is an endemic area of American tegumentary leishmaniasis (ATL) induced by Leishmania (Viannia) braziliensis. Objective Our purpose was to describe the main clinical and epidemiologic characteristics of the disease in Rio de Janeiro State. METHODS: Patients from endemic areas of Rio de Janeiro State attending the Evandro Chagas Hospital were included in the study. A general physical, dermatologic, and otorhinolaryngologic examination was performed in all patients, as well as a Leishmanin skin test. Skin biopsy specimens were obtained and utilized for touch preparations (stained with Leishman dye), culture in special media (Nicolle, Nevy and McNeal; NNN), and histopathologic examination after hematoxylin and eosin stain. Positive cultures were identified with regard to species by the isoenzyme technique. Therapy with pentavalent antimonial compounds was employed in all cases. Eco-epidemiologic characteristics were studied through regular field visits to endemic foci. RESULTS: Cutaneous disease was present in 87.2% of patients, and mucosal disease in only 12.7%. A single ulcerative cutaneous lesion was the most common clinical presentation. Demonstration of the parasite was always difficult and culture in special media gave the best results for diagnosis. The species involved in transmission was Leishmania (Viannia) braziliensis. Vectors included phlebotomine sand flies (Diptera: Psychodidae) of the genus Lutzomyia, and the most common species was Lutzomyia intermedia, captured mainly on the external walls of houses. CONCLUSIONS: ATL in Rio de Janeiro is mostly a cutaneous disease. In general, the cases showed great sensitivity to antimony. A pattern of peridomestic transmission seems to be the rule.

Leishmanial antigens in the diagnosis of active lesions and ancient scars of American tegumentary leishmaniasis patients.

Cutaneous biopsies (n = 94) obtained from 88 patients with American tegumentary leishmaniasis were studied by conventional and immunohistochemical techniques. Specimens were distributed as active lesions of cutaneous leishmaniasis (n = 53) (Group I), cicatricial lesions of cutaneous leishmaniasis (n = 35) (Group II) and suggestive scars of healed mucosal leishmaniasis patients (n = 6) (Group III). In addition, active cutaneous lesions of other etiology (n = 24) (Group C1) and cutaneous scars not related to leishmaniasis (n = 10) (Group C2) were also included in the protocol. Amastigotes in Group I biopsies were detected by routine histopathological exam (30.2%), imprint (28.2%), culture (43.4%), immunofluorescence (41.4%) and immunoperoxidase (58.5%) techniques; and by the five methods together (79.3%). In Group II, 5.7% of cultures were positive. Leishmanial antigen was also seen in the cytoplasm of macrophages and giant cells (cellular pattern), vessel walls (vascular pattern) and dermal nerves (neural pattern). Positive reaction was detected in 49 (92.5%), 20 (57%) and 4 (67%) biopsies of Groups I, II and III, respectively. Antigen persistency in cicatricial tissue may be related to immunoprotection or, on the contrary, to the development of late lesions. We suggest that the cellular, vascular and neural patterns could be applied in the immunodiagnosis of active and cicatricial lesions in which leishmaniasis is suspected.