Th1 and Th2-like protein balance in human inflammatory radicular cysts and periapical granulomas.

INTRODUCTION: Chronic dental periapical lesions result from chronic inflammation of periapical tissues caused by continuous antigenic stimulation from infected root canals. Recent findings have suggested that T helper (Th) 1 and Th2-like cytokines are important in the pathogenesis of chronic periapical inflammatory diseases. However, the mechanisms regulating these immunoinflammatory pathways have not been fully elucidated. Thus, the aim of this study was to evaluate interleukin (IL)-4, IL-12, and interferon γ (IFN-γ) protein levels in human radicular cysts and periapical granulomas. METHODS: Archived samples of cysts (n = 52) and granulomas (n = 27) were sectioned and submitted to immunohistochemistry to evaluate the tissue expression of IL-4, IL-12, and IFN-γ. The data were analyzed using the Mann-Whitney U test (P < .05). RESULTS: An increased expression of IFN-γ was observed in radicular cysts. IL-4 expression was stronger in periapical granulomas than in radicular cysts. IL-12 was not detected in any of the samples. CONCLUSIONS: Our study showed that IFN-γ protein levels are increased in radicular cysts, whereas IL-4 expression is stronger in samples of periapical granulomas. Further studies are necessary to elucidate the signaling pathways mediated by these cytokines and to facilitate the development of more effective periapical disease management strategies.

Evaluation of myofibroblasts and its association with TGF-ß 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. OBJECTIVES: 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-ß1) 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-ß1 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-ß1 (p=0.007). The mean percentages of expression of IFN-γ and TGF-ß1 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). CONCLUSION: 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-ß1 was observed, revealing an inflammatory phase progressing to a healing process.