Immunoglobulin light chain–restricted CD27⁺ALDH^high B cells circulate in newly diagnosed HL patients. CD19⁺ cells were isolated from newly diagnosed HL patients and stained with Aldefluor and monoclonal antibodies against CD27 and kappa and lambda light chains. Expression of CD27 and kappa light chain in the (A) CD19⁺ and (B) CD19⁺ALDH^high peripheral blood cells from a HL patient. Expression of CD27 and (C) kappa or (D) lambda light chain in the CD19⁺ALDH^high peripheral blood cells from another HL patient.