B-Cell Clones Appear Years Before CLL Diagnosis

Virtually all diagnosed cases of chronic lymphocytic leukemia (CLL) had certain B-cell clones in their blood up to six years after sampling.

Monoclonal B-cell lymphocytosis (MBL) appears in otherwise healthy people. It is characterized by a small number of B-cell clones circulating in the peripheral blood. Hospital studies indicated that MBL is a high risk factor for the development of CLL.

Investigators tested the hypothesis that CLL is always preceded by MBL. They identified 45 patients in whom CLL was subsequently diagnosed (up to 6.4 years later) from among 77,469 healthy adults who were enrolled in a cancer screening trial. Peripheral-blood samples were examined by six-color flow cytometry (with antibodies CD45, CD19, CD5, CD10, kappa, and lambda) and immunoglobulin heavy-chain gene rearrangement by the reverse-transcriptase-polymerase-chain-reaction assay. The association between MBL and subsequent CLL was determined and characterized the immunoglobulin gene repertoire of the prediagnostic B-cell clones.

Among the 45 patients in the prospective cohort study who eventually developed CLL, 44 had monoclonal B cells with a surface phenotype similar to leukemic cells in baseline blood samples, reported C. Ola Landgren, M.D., Ph.D., of the National Cancer Institute (Bethesda, MD, USA) and colleagues in the February 12, 2009 issue of The New England Journal of Medicine.

In an accompanying editorial, Robert Vogt Jr., Ph.D., of the CDC, and Robert A. Kyle, M.D., of the Mayo Clinic (Rochester, MN, USA) said the study should help "open new doors to the detection, assessment, treatment, and prevention of B-cell lymphoid cancers."

Related Links:
National Cancer Institute
Mayo Clinic