Anti-RBC antibodies in patients with CLL. IELAT measurements of serum antibodies specific for human RBCs in healthy control donors (n = 10; ○), patients with primary AIHA (n = 10; •), patients with CLL with AIHA (n = 7; ▴), and patients with CLL with no clinical AIHA (n = 10). ▪ indicates Patients with CLL with no clinical AIHA whose PBMCs responded to purified RhD protein, RhD peptides, or both (n = 7); □, patients in this group with no such responses (n = 2). Horizontal bars indicate mean antibody level in each group. Significant differences are marked (Mann-Whitney U test).