p19ARF expression in the human Rag1^−/− CD34⁺CD19⁺ population. (A) FACS analysis of a Rag1-deficient patient after CD34⁺ cell sorting of BM-derived MNCs (1 of 6 representative experiments is shown here). (B) TaqMan analysis of p19ARF expression in the cell-sorted human RAG1^−/− CD34⁺CD19⁺ and CD34⁺CD19⁻ population indicated 26-fold higher p19ARF expression in the CD34⁺CD19⁺ population than in the CD34⁺CD19⁻ counterpart. One of 2 independent TaqMan analysis of a patient sample is shown here.