Increased degranulation of mast cells in PCL. Degranulation of mast cells stained with anti-tryptase antibody was evaluated semiquantitatively at 200× magnification in skin biopsies from PCL patients, patients with inflammatory cutaneous diseases and control subjects and graded as (C) not degranulated, (D) moderately degranulated, and (E) extensively degranulated. (A) Extensively degranulated (ED) mast cells were counted in 3 high power fields at 200× magnification in skin biopsies from patients with PCL (All; n = 43) subdivided into patients with CTCL (n = 35) and CBCL (n = 8), from subjects with normal skin (Ctrl; n = 12) and from patients with inflammatory cutaneous diseases (All; n = 24), such as psoriasis (n = 8), atopic dermatitis (AD; n = 8), and pseudolymphoma (Pseudolym; n = 8). Results are presented as percentage of ED mast cells of all mast cells and expressed as mean ± SEM. Statistical significance was assessed by 2-tailed Student t test. (B) ND mast cells and ED mast cells were counted in skin biopsies from patients with stable PCL (n = 32) and progressive PCL (n = 11). Data represent the mean ± SEM. Statistical significance was assessed by 2-tailed Student t test.