FACS analysis of intracytoplasmic tryptase expression by 2-week-old c-kit⁺/CD13⁺ (A) and c-kit⁺/CD13⁻ (B) progeny. Right panels show tryptase expression. Isotype controls are shown in left panels. Results shown are representative of 4 experiments separately performed, using either BM (n = 2) or PB (n = 2) cells.