Circulating light chain–restricted CD27⁺ALDH^high B cells show identical immunoglobulin rearrangements to HRS cells. Capillary electrophoretic profiles of (A) immunoglobuin heavy chain CDR3 amplification products and (B) immunoglobulin kappa light chain CDR3 amplification products obtained by PCR of circulating light chain–restricted CD27⁺ALDH^high B cells from 2 respective patients. Capillary electrophoretic profiles of HRS cells isolated from a diagnostic lymph node (C) from the first patient by CD30 microbeads and (D) from the second patient by microdissection. PCR products are shown in blue lines, and red lines are size markers. ↓show identical-sized PCR products in the circulating clonotypic B cells and HRS cells from (A,C) patient 1 (at 76 and 94 bp) and (B,D) patient 2 (at 146 and 150 bp). indicates control PCR reaction product.