Concurrent chronic lymphocytic leukemia and prolymphocytic leukemia derived from two separate B-cell clones

Chronic lymphocytic leukaemia and prolymphocytic leukaemia. Two coins or two sides of the same coin?

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Double productive immunoglobulin sequence rearrangements in patients with chronic lymphocytic leukemia

The immunoglobulin heavy chain variable (IGHV) gene mutational status represents a major prognostic marker in chronic lymphocytic leukemia (CLL). Usually, the prognostic implications of IGHV gene analysis can be reliably ascertained but, occasionally, double productive rearrangements have been detected. Clinical presentation and biological features of such cases are unknown. Sixty patients with morphologically and phenotypically monoclonal CLL but double productive IGHV rearrangements were retrospectively identified by mRNA analysis from three Hematology Institutions. Clinical and biological features and survival of these 60 patients were compared with a control group of patients with CLL and single IGHV rearrangement. A prospective registry was used to assess the epidemiology of double productive IGHV among incidental patients with CLL. Using standard criteria to define IGHV-mutated (M) or unmutated (U) cases, 39 of the 60 patients (65%) with double productive IGHV rearrangement had concordant status (23 MM, 16 UU), while 21 (35%) had discordant IGHV status. As compared with M patients, the MM ones had lower CD38 expression, more favorable cytogenetics and more indolent clinical behavior. Cases with UU had similar characteristics of U patients. Discordant cases presented with adverse prognostic features and had an aggressive clinical behavior requiring early treatment, similar to U patients. The prevalence of double IGHV was 3.1%. Patients with CLL with double concordant mutational status (MM or UU) have a clinical course similar to that of the corresponding single IGHV status, while those exhibiting discordant status represent a high risk population. This may help correct stratification within clinical trials.

Molecular characterization of neoplastic and normal "sister" lymphoblastoid B-cell lines from chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) B-cells resemble self-renewing CD5 + B-cells carrying auto/xeno-antigen-reactive B-cell receptors (BCRs) and multiple innate pattern-recognition receptors, such as Toll-like receptors and scavenger receptors. Integration of signals from BCRs with multiple surface membrane receptors determines whether the cells will be proliferating, anergic or apoptotic. To better understand the role of antigen in leukemogenesis, CLL cell lines producing monoclonal antibodies (mAbs) will facilitate structural analysis of antigens and supply DNA for genetic studies. We present here a comprehensive genotypic and phenotypic characterization of available CLL and normal B-cell-derived lymphoblastoid cell lines (LCLs) from the same individuals (n = 17). Authenticity and verification studies of CLL-patient origin were done by IGHV sequencing, fluorescence in situ hybridization (FISH) and DNA/short tandem repeat (STR) fingerprinting. Innate B-cell features, i.e. natural Ab production and CD5 receptors, were present in most CLL cell lines, but in none of the normal LCLs. This panel of immortalized CLL-derived cell lines is a valuable reference representing a renewable source of authentic Abs and DNA.