Eosinophils of patients with localized and diffuse cutaneous leishmaniasis: Differential response to Leishmania mexicana, with insights into mechanisms of damage inflicted upon the parasites by eosinophils.

Eosinophils are mainly associated with parasitic infections and allergic manifestations. They produce many biologically active substances that contribute to the destruction of pathogens through the degranulation of microbicidal components and inflammatory tissue effects. In leishmaniasis, eosinophils have been found within inflammatory infiltrate with protective immunity against the parasite. We analyzed the responses of eosinophils from patients with localized (LCL) and diffuse (DCL) cutaneous leishmaniasis, as well as from healthy subjects, when exposed to Leishmania mexicana. All DCL patients exhibited blood eosinophilia, along with elevated eosinophil counts in non-ulcerated nodules. In contrast, only LCL patients with prolonged disease progression showed eosinophils in their blood and cutaneous ulcers. Eosinophils from DCL patients secreted significantly higher levels of IL-6, IL-8, and IL-13, compared to eosinophils from LCL patients. Additionally, DCL patients displayed higher serum levels of anti-Leishmania IgG antibodies. We also demonstrated that eosinophils from both LCL and DCL patients responded to L. mexicana promastigotes with a robust oxidative burst, which was equally intense in both patient groups and significantly higher than in healthy subjects. Coincubation of eosinophils (from donors with eosinophilia) with L. mexicana promastigotes in vitro revealed various mechanisms of parasite damage associated with different patterns of granule exocytosis: 1) localized degranulation on the parasite surface, 2) the release of cytoplasmic membrane-bound "degranulation sacs" containing granules, 3) release of eosinophil extracellular traps containing DNA and granules with major basic protein. In conclusion, eosinophils damage L. mexicana parasites through the release of granules via diverse mechanisms. However, despite DCL patients having abundant eosinophils in their blood and tissues, their apparent inability to provide protection may be linked to the release of cytokines and chemokines that promote a Th2 immune response and disease progression in these patients.

[Transmission of cutaneous leishmaniasis associated with cacao (Theobroma cacao) plantations in Tabasco]. / Transmisión de leishmaniasis cutánea asociada con plantaciones de cacao (Theobroma cacao) en Tabasco.

INTRODUCTION: Tabasco is the Mexican state that reported the highest number (37.4%) of patients with leishmaniasis during 1990-2011. Close to 90% of these patients lived in Chontalpa, where the municipality of Cunduacán accounted for the majority of the cases. One of the characteristics of this region is that houses are located within cacao plantations. OBJECTIVE: To determine if cacao plantations are a risk factor for leishmaniasis transmission in locations of Cunduacán, Tabasco. MATERIAL AND METHODS: We performed an analytical and retrospective study of 115 locations in Cunduacán, analyzing the number of localities with or without patients with leishmaniasis registered between 2000-2011 and, additionally, if they had cacao plantations, using a map where different crops were georeferenced. We measured the magnitude of the association (odds ratio, 95% CI). RESULTS: During the period 2000-2011, cases of leishmaniasis were reported in 77 (67.0%) Cunduacán locations, of these, 55 (71.4%) had cocoa plantations, five (6.5%) of banana, five (6.5%) of cane, and 12 (15.6%) had no crops georeferenced. We found that cocoa crops are a risk factor for the transmission of leishmaniasis (OR: 3.438; 95% CI: 1,526-7,742). CONCLUSIONS: The probability of transmission of leishmaniasis in areas with cocoa crops is greater than in communities without this crop.