First report of treatment failure in a patient with cutaneous leishmaniasis infected by Leishmania (Viannia) naiffi carrying Leishmania RNA virus: a fortuitous combination?

We report the case of a 32-year-old man from Rio de Janeiro, who was infected in the Amazon region of Brazil by Leishmania (Viannia) naiffi. Generally, patients with L. naiffi cutaneous leishmaniasis exhibit a good therapeutic response to either pentavalent antimonials or pentamidine. However, after pentamidine treatment, this patient's infection evolved to therapeutic failure. To understand this clinical outcome, we investigated the presence of the Leishmania RNA virus (LRV) in parasites isolated from the cutaneous lesion; herein, we discuss the possible association between a poor response to pentamidine therapy and the presence of the LRV.

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.

Clinical features of cutaneous and disseminated cutaneous leishmaniasis caused by Leishmania (Viannia) braziliensis in Paraty, Rio de Janeiro

BACKGROUND

American tegumentary leishmaniasis (ATL) caused by Leishmania (Viannia) braziliensis is endemic in Rio de Janeiro State (RJ), where the disease shows epidemiologic and clinical characteristics distinct from those of ATL in other Brazilian regions. Paraty is the second most important endemic area in RJ; however, reports on leishmaniasis in this region refer to the occurrence of the disease without describing its characteristics.

METHODS

The clinical features of 71 cases of ATL reported between 1991 and 1997 in Paraty are presented. Thirty patients were re-evaluated 10 years later.

RESULTS

Males and females were affected in similar proportions, and the disease was more prevalent in patients aged between 10 and 49 years (63.4%). Cutaneous leishmaniasis was the most prevalent clinical form observed. Unique lesions were present in 69% of cases, 91.6% of which displayed an ulcerated aspect. Although mucosal leishmaniasis was not observed, severe clinical manifestations, such as disseminated cutaneous lesions caused by L. braziliensis, were diagnosed in two patients. These patients presented skin lesions with different clinical aspects spread throughout the body, as well as low cellular immune responses. Montenegro skin test (92% positivity) and serology (8% IgM and 56% IgG anti-Leishmania positive results) were the most utilized tests for supporting the diagnosis of leishmaniasis. Parasites, detected in 27 of the 33 cases analyzed, were characterized as L. braziliensis.

CONCLUSION

ATL in Paraty shares the clinical and laboratory characteristics reported for ATL in other regions of RJ, probably because of the similar epidemiologic context related to the Atlantic rainforest region.

T-cell responses associated with resistance to Leishmania infection in individuals from endemic areas for Leishmania (Viannia) braziliensis

Subclinical or asymptomatic infection is documented in individuals living in endemic areas for leishmaniasis suggesting that the development of an appropriate immune response can control parasite replication and maintain tissue integrity. A low morbidity indicates that intrinsic factors could favor resistance to Leishmania infection. Herein, leishmanial T-cell responses induced in subjects with low susceptibility to leishmaniasis as asymptomatic subjects were compared to those observed in cured cutaneous leishmaniasis (CCL) patients, who controlled the disease after antimonial therapy. All of them have shown maintenance of specific long-term immune responses characterized by expansion of higher proportions of CD4+ as compared to CD8+ Leishmania reactive T-lymphocytes. Asymptomatic subjects had lower indexes of in vitro Leishmania induced lymphoproliferative responses and interferon-gamma (IFN-gamma) production in comparison to CCL patients. On the other hand, interleukin (IL-10) production was much higher in asymptomatics than in CCL, while no differences in IL-5 levels were found. In conclusion, long lived T-cell responses achieved by asymptomatic individuals differed from those who had developed symptomatic leishmaniasis in terms of intensity of lymphocyte activation (proliferation or IFN-gamma) and regulatory mechanisms (IL-10). The absence of the disease in asymptomatics could be explained by their intrinsic ability to create a balance between immunoregulatory (IL-10) and effector cytokines (IFN-gamma), leading to parasite destruction without producing skin tissue damage. The establishment of profiles of cell-mediated immune responses associated with resistance against Leishmania infection is likely to make new inroads into understanding the long-lived immune protection against the disease.