Analysis of circulating CD8⁺ CD57⁺ T cells in PNH patients and in healthy controls. (A) Quantitation of CD8⁺ CD57⁺ T cells. Percentage of CD8⁺ CD57⁺ T cells within peripheral blood mononuclear cells (PBMNCs). Each circle represents 1 control subject or 1 PNH patient. Average and standard deviation are shown for the patient group and for the control group (P = .38). (B) Size distribution of the CDR3 region of the TCRB genes within the CD8⁺ CD57⁺ cell population of individual subjects. Each 4-lane panel displays the analysis, by electrophoresis on a denaturing polyacrylamide gel, of the products of 4 multiplex PCRs (lanes 1 to 4) designed to detect all possible TCRB gene rearrangements that can take place in T cells. After silver staining, each lane shows a ladder of bands differing from each other by 3 bp or a multiple of 3 bp. The 2 left lanes are for reference: lane m shows the product of the amplification, obtained with the appropriate primers, of the TCR-β CDR3 from a monoclonal population of T cells (from a patient with a T-cell leukemia); lane p shows the product of the amplification, with 1 of the 4 sets of primers, of the TCR-β CDR3 from a polyclonal T-cell population (from a healthy person). The panel labeled “control” shows, in a healthy subject, a gaussian distribution of CDR3 sizes in each of the 4 lanes. The next 2 panels illustrate the results in 2 PNH patients (Table 1). In patient PNH 7, one sees nongaussian distributions of CDR3 sizes in all 4 lanes, with 1 band predominating in each of the 4 lanes. In patient PNH 9, there is only 1 heavy band in lane 4, and in the other 3 lanes the distributions are also markedly skewed.