Evaluation of myofibroblasts and its association with TGF-β and IFN-γ in lesions of patients with American tegumentary leishmaniasis.
BACKGROUND
Leishmaniasis is caused by protozoa of Leishmania spp. genus. It is transmitted by the bite of the sand fly insect. It is believed that 12 million people are infected with this disease and that its annual incidence is 2 million; this number is increasing.


OBJECTIVE
The present study aimed to evaluate the expression of myofibroblasts through alpha smooth muscle actin labeling, and to analyze their relationship with the expression of the cytokines Interferon gama (IFN-γ) and Transforming growth factor beta (TGF-β1) in lesions of American tegumentary leishmaniasis (ATL).


METHODS
For this retrospective study, we gathered 28 patients diagnosed with ATL between 2002 and 2006. We verified α-SMA positivity and performed IFN-γ and TGF-β1 immunolabeling to identify the profile of these cytokines in both positive and negative cases for myofibroblasts, via immunohistochemistry, in order to assess the presence of myofibroblasts,.


RESULTS
We observed that out of the 28 cases, 17 (60.71%) were positive for alpha smooth muscle actin, while 11 (39.29%) were negative, and IFN-γ was more expressed than TGF-β1 (p=0.007). The mean percentages of expression of IFN-γ and TGF-β1 in the group negative for alpha smooth muscle actin were different, with an increased expression of IFN-γ (p=0.047). However, in the group positive for alpha smooth muscle actin, there was no difference in cytokine labeling (p>0.05).


CONCLUSIONS
We verified the presence of positive α-SMA stromal cells in the majority of the cases of ATL, indicating the presence of myofibroblasts. In cases negative for alpha smooth muscle actin, an increased expression of IFN-γ compared to TGF-β1 was observed, revealing an inflammatory phase progressing to a healing process.
Post Graduation Program in Health Sciences, Universidade Estadual de Montes Claros, Brazil.
Agostinho Gonçalves
AG
Viana
Carlos Alberto de Carvalho
CA
Fraga
Patrícia Luciana
PL
Batista Domingos
Paulo Rogério Ferreti
PR
Bonan
D000199:Actins / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007371:Interferon-gamma / Q000378:metabolism*; D016773:Leishmaniasis, Cutaneous / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D058628:Myofibroblasts / Q000378:metabolism* / Q000473:pathology*; D012189:Retrospective Studies; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*; D055815:Young Adult
D000199:Actins; D053773:Transforming Growth Factor beta1; D007371:Interferon-gamma