The role of macrophages in the pathogenesis of mycosis fungoides

BACKGROUND: Macrophages are classified into classically activated (M1) and alternatively activated (M2) macrophages. Decrease in macrophage number in tumour tissue with treatment has been reported. AIM: The aim of this study was to determine whether treatment has an effect on the number of dermal M1 and M2 macrophages in patients with mycosis fungoides (MF). METHODS: In total, 21 patients (8 women, 13 men; age range 42-73 years) were included in this study. We determined markers for dermal M1 (inducible nitric oxide synthase and CD68) and M2 (markers: CD163 and CD206) macrophages using double immunohistochemistry to reduce the error rate, and then counted the cells. RESULTS: The number of dermal M1 cells was significantly lower pretreatment compared with post-treatment (P < 0.01). The numbers of dermal M2 cells were also numerically decreased by treatment. These results did not change significantly after exclusion of the patients who had recurrence (n = 2). There were no statistically significant differences between groups classified by stage, lesion type or treatment outcome. CONCLUSION: Macrophage numbers are decreased in MF after treatment of tumour tissue.