Using existing flow-cytometric data from medical records that were obtained at the time of the CLL diagnosis (available for 25 patients), we compared patterns of light-chain restriction at diagnosis with those observed in the prediagnostic samples and found all to be identical (Table 2). In particular, both the prediagnostic clone and the clone at CLL diagnosis showed kappa light-chain restriction in 19 patients and lambda light-chain restriction in 4 patients. For Patients 19 and 38, we found evidence of two detectable clones (i.e., biclonal light-chain restriction) in the prediagnostic sample, and at the time of CLL diagnosis, the clone was defined as kappa.
