Spontaneous cytokine production by macrophages expressing BRAFV600E. (A) Immunohistochemistry staining of an ECD biopsy specimen (lung lesion) showing IL-6 expression by infiltrating macrophages. Original magnification ×400. (B) Spontaneous production of IL-6 by circulating monocytes of patients with ECD compared with healthy controls. Bars indicate mean ± SEM; biological duplicates were performed for each condition. (C-D) Spontaneous production of IL-6 (C) and TNFα (D) by nontransduced macrophages (UT) or macrophages expressing wtBRAF (WT) and BRAFV600E (VE). Data are shown as the mean ± SEM (n = 4); biological duplicates were performed for each condition. (E) Representative smFISH images using probes targeted to IL6 mRNA; IL6 RNAs appear as scattered dots in the cell cytosol, whereas nascent mRNAs appear as 1 to 2 bright dots in the cell nucleus. Scale bar, 5 µm. (F) Quantification of cells with visible nascent IL6 mRNAs. *P < .05, Student t test (B-D).