A second kidney biopsy (day 128) revealed: (a) borderline TCMR, (b) moderate arteriolosclerosis, and (c) focal interstitial infiltration (10–20% total surface) by CLL-like B lymphocytes (PAX5+, CD5+, CD20+, CD23+, surface IgM-; cyclin D1 negative) (Figure 2B). This evidence concerns the gene PAX5 and B-cell chronic lymphocytic leukemia.