Detection of Clonal Excess in Lymphoproliferative Disease by K/X Analysis: Correlation With Immunoglobulin Gene DNA Rearrangement

Previous studies have suggested that analysis of the distribution of surface immunoglobulin light chain isotypes by flow cytometry provides evidence for monoclonality of B cell tumors and may detect populations of circulating tumor cells in patients with lymphoproliferative disease. We have used simultaneous flow cytometry and DNA restriction enzyme analysis on 58 samples of tissue and blood to determine whether lymphocyte populations detected by “ic/X” analysis are indeed monoclonal. In >90% of cases. abnormalities detected by flow cytometry correlated with monoclonal rearrangements of immunoglobulin genes as detected by Southern blot analysis. By analyzing tissue and blood from the same patients. we have also demonstrated that monoclonal circulating cells