Aberrant Rearrangements of the Immunoglobulin Heavy Chain Switch Region in Chronic B-Cell Leukemia

Abstract

Analysis of the organisation of the Cμ -switch region of the immunoglobulin heavy chain locus in B-lymphocytes from 80 patients with chronic B-cell leukemia revealed 25 patients with abnormal rearrangements that could not be explained by the normal recombination events that take place in B-lymphocytes. Detailed analysis with probes spanning the Cμ-switch region and various restriction digests localised the rearrangements in two thirds of the patients to a 1300 bp region at the 5″ end of the switch region while in the remaining patients the rearrangements occurred in the switch region. The consequences of these aberrant rearrangements remain to be determined, but their clustering to a defined region of the switch region suggests a “hot spot” that may be involved in the aetiology of the disease.

Key Words:

• Chronic B-cell leukemia
• Immunoglobulin genes
• Cu- switch
• abnormal rearrangements