Morphological and immunohistochemical characteristics of Blau granulomas. Brown colour denotes positive cytokine staining. A (top left). H & E staining showing prominent lymphocyte corona, emperipoletic lymphocytes, and multinucleated giant cell death with fragmented cytoplasm and pycnotic nuclei. Using immunohistochmistry dense staining was observed for IFN-γ (B, top right, low magnification showing several granulomas), IL-6 (C, bottom left, single granuloma showing predominant staining in corona) and IL-17 (D, bottom right, single granuloma with giant cell in center showing strong Il-17 staining).