title: Heterogeneity in junctional regions of immunoglobulin kappa deleting element rearrangements in B cell leukemias: a new molecular target for detection of minimal residual disease.
abstract: Virtually all immunoglobulin kappa (IGK) gene deletions are mediated via rearrangements of the so-called kappa deleting element (Kde). Kde rearrangements occur either to Vkappa gene segments (Vkappa-Kde rearrangements) or to the heptamer recombination signal sequence in the Jkappa-Ckappa intron. Kde rearrangements were analyzed by the polymerase chain reaction (PCR) and heteroduplex analysis in 130 B-lineage leukemias: 63 precursor-B-acute lymphoblastic leukemias (ALL) and 67 chronic B cell leukemias. To obtain detailed information about Kde rearrangements, we sequenced 109 of the 189 detected junctional regions. Vkappa gene family usage in the Vkappa-Kde rearrangements in our series of B-lineage leukemias was comparable to Vkappa gene family usage in functional Vkappa-Jkappa rearrangements in normal and malignant mature B cells, except for a higher frequency of VkappaII family usage in precursor-B-ALL. Junctional region sequencing of the Kde rearrangements in precursor-B-ALL revealed a mean insertion of 4.7 nucleotides and a mean deletion of 9.5 nucleotides, resulting in an extensive junctional diversity, whereas in chronic B cell leukemias the insertion (1.9) and deletion (6.0) were significantly lower. The relatively extensive junctional diversity of the Kde rearrangements in precursor-B-ALL allowed us to design leukemia/patient-specific oligonucleotide probes, which were proven to be useful for detection of minimal residual disease (MRD) with sensitivities of 10(-4) to 10(-5). Kde rearrangements occur in approximately 50% of precursor-B-ALL cases and are likely to remain stable during the disease course, because Kde rearrangements are assumed to be 'end-stage' rearrangements, which cannot easily be replaced by continuing rearrangement processes. These findings indicate that junctional regions of Kde rearrangements in precursor-B-ALL represent new valuable patient-specific PCR targets for detection of MRD.
authors.affiliation: Department of Immunology, University Hospital Rotterdam/Erasmus University Rotterdam, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Beishuizen
authors.forename: M A
authors.initials: MA
authors.lastname: de Bruijn
authors.forename: M J
authors.initials: MJ
authors.lastname: Pongers-Willemse
authors.forename: M A
authors.initials: MA
authors.lastname: Verhoeven
authors.forename: E R
authors.initials: ER
authors.lastname: van Wering
authors.forename: K
authors.initials: K
authors.lastname: Hählen
authors.forename: T M
authors.initials: TM
authors.lastname: Breit
authors.forename: S
authors.initials: S
authors.lastname: de Bruin-Versteeg
authors.forename: H
authors.initials: H
authors.lastname: Hooijkaas
authors.forename: J J
authors.initials: JJ
authors.lastname: van Dongen
mesh_terms: D017353:Gene Deletion; D015321:Gene Rearrangement; D006801:Humans; D007133:Immunoglobulin Joining Region / Q000235:genetics*; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D015448:Leukemia, B-Cell / Q000175:diagnosis*; D018365:Neoplasm, Residual; D015345:Oligonucleotide Probes; D016133:Polymerase Chain Reaction
chemical_list: D007133:Immunoglobulin Joining Region; D007145:Immunoglobulin kappa-Chains; D015345:Oligonucleotide Probes