Immunoglobulin light chain kappa deletion rearrangement as a marker of clonality in mantle cell lymphoma

Mantle cell lymphoma (MCL) express immunoglobulin Light chain lambda (IgL-l ambda) more frequently than other non-Hodgkin's lymphomas, and IgL-lambda p roducing B-cells usually delete one or both alleles of their IgL-kappa gene s. This inactivation is mediated by a rearrangement between the kappa delet ion element (kappa de) and the Recombinant Signal Sequence (RSS) in the reg ion between the Joining genes and the Constant region, or the RSS at the 3' -site of a Variable (V kappa) segment. This deletion appears as a feasible tool for detecting monoclonality and minimal residual, disease by polymeras e chain reaction (PCR). Among twelve MCL patients studied, ten presented Ig L-lambda expression, and all but one among these revealed a monoclonal kapp a de rearrangement by PCR analysis. Six of the nine cases showed a fusion b etween the kappa de and the intron RSS, whilst three with a V kappa segment . Since MCL has the worst prognosis of all B-cell lymphomas and high-dose c hemotherapy regimens have been proposed, PCR for the kappa de rearrangement might be a useful molecular tool to evaluate the ability of the different treatment modalities to eradicate the malignant clones.