Immunoglobulin Light Chain Kappa Deletion Rearrangement as a Marker of Clonality in Mantle Cell Lymphoma

Abstract

Mantle cell lymphoma (MCL) express immunoglobulin light chain h (IgL-h) more frequently than other non-Hodgkin's lymphomas, and IgL-h producing B-cells usually delete one or both alleles of their IgL-K genes. This inactivation is mediated by a rearrangement between the k deletion element (Kde) and the Recombinant Signal Sequence (RSS) in the region between the Joining genes and the Constant region, or the RSS at the 3′-site of a Variable (Vk) segment. This deletion appears as a feasible tool for detecting monoclonality and minimal residual disease by polymerase chain reaction (PCR). Among twelve MCL patients studied, ten presented IgL-K expression, and all but one among these revealed a monoclonal Kde rearrangement by PCR analysis. Six of the nine cases showed a fusion between the Kde and the intron RSS, whilst three with a Vk segment. Since MCL has the worst prognosis of all B-cell lymphomas and high-dose chemotherapy regimens have been proposed, PCR for the Kde rearrangement might be a useful molecular tool to evaluate the ability of the different treatment modalities to eradicate the malignant clones.

Key Words:

• mantle cell lymphoma
• immunoglobulin light chain genes
• lambda
• kappa deletion element
• PCR