Immunofluorescence double staining identifies TrkA⁺, TrkB⁺, and TrkC⁺cells infiltrating the skin of patients with mastocytosis as MCs. (A-C) Representative immunofluorescence double staining of skin biopsy taken from a healthy control patient (CTR) and a patient with mastocytosis (MAST) with an anti-tryptase antibody labeled with Cy-2 (green) and anti-TrkA, anti-TrkB, and anti-TrkC antibodies labeled with Cy-3 (red) and the overlay pictures of both stainings are shown.