igk and Multiple-Myeloma

The ability to rearrange the germ-line DNA to generate antibody diversity is an essential prerequisite for the production of a functional repertoire. While this is essential to prevent infections, it also represents the "Achilles heel" of the B-cell lineage, occasionally leading to malignant transformation of these cells by translocation of protooncogenes into the immunoglobulin (Ig) loci. However, in evolutionary terms this is a small price to pay for a functional immune system. The study of the configuration and rearrangements of the Ig gene loci has contributed extensively to our understanding of the natural history of development of myeloma. In addition to this, the analysis of Ig gene rearrangements in B-cell neoplasms provides information about the clonal origin of the disease, prognosis, as well as providing a clinical useful tool for clonality detection and minimal residual disease monitoring. Herein, we review the data currently available on both Ig gene rearrangements and protein patterns seen in myeloma with the aim of illustrating how this knowledge has contributed to our understanding of the pathobiology of myeloma.

Topics: Animals; Gene Expression Regulation; Gene Rearrangement; Gene Rearrangement, B-Lymphocyte, Heavy Chain; Gene Rearrangement, B-Lymphocyte, Light Chain; Genes, Immunoglobulin; Humans; Immunoglobulins; Models, Biological; Multiple Myeloma; Paraproteins; Recombination, Genetic; Somatic Hypermutation, Immunoglobulin; Translocation, Genetic

The clonoSEQ® Assay (Adaptive Biotechnologies Corporation, Seattle, USA) identifies and tracks unique disease-associated immunoglobulin (Ig) sequences by next-generation sequencing of IgH, IgK, and IgL rearrangements and IgH-BCL1/2 translocations in malignant B cells. Here, we describe studies to validate the analytical performance of the assay using patient samples and cell lines.. Sensitivity and specificity were established by defining the limit of detection (LoD), limit of quantitation (LoQ) and limit of blank (LoB) in genomic DNA (gDNA) from 66 patients with multiple myeloma (MM), acute lymphoblastic leukemia (ALL), or chronic lymphocytic leukemia (CLL), and three cell lines. Healthy donor gDNA was used as a diluent to contrive samples with specific DNA masses and malignant-cell frequencies. Precision was validated using a range of samples contrived from patient gDNA, healthy donor gDNA, and 9 cell lines to generate measurable residual disease (MRD) frequencies spanning clinically relevant thresholds. Linearity was determined using samples contrived from cell line gDNA spiked into healthy gDNA to generate 11 MRD frequencies for each DNA input, then confirmed using clinical samples. Quantitation accuracy was assessed by (1) comparing clonoSEQ and multiparametric flow cytometry (mpFC) measurements of ALL and MM cell lines diluted in healthy mononuclear cells, and (2) analyzing precision study data for bias between clonoSEQ MRD results in diluted gDNA and those expected from mpFC based on original, undiluted samples. Repeatability of nucleotide base calls was assessed via the assay's ability to recover malignant clonotype sequences across several replicates, process features, and MRD levels.. LoD and LoQ were estimated at 1.903 cells and 2.390 malignant cells, respectively. LoB was zero in healthy donor gDNA. Precision ranged from 18% CV (coefficient of variation) at higher DNA inputs to 68% CV near the LoD. Variance component analysis showed MRD results were robust, with expected laboratory process variations contributing ≤3% CV. Linearity and accuracy were demonstrated for each disease across orders of magnitude of clonal frequencies. Nucleotide sequence error rates were extremely low.. These studies validate the analytical performance of the clonoSEQ Assay and demonstrate its potential as a highly sensitive diagnostic tool for selected lymphoid malignancies.

Topics: Bone Marrow; Cyclin D1; Gene Rearrangement; High-Throughput Nucleotide Sequencing; Humans; Immunoglobulin Heavy Chains; Immunoglobulin lambda-Chains; Immunoglobulins; Leukemia, Lymphocytic, Chronic, B-Cell; Limit of Detection; Multiple Myeloma; Neoplasm, Residual; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Proto-Oncogene Proteins c-bcl-2; Reagent Kits, Diagnostic; Translocation, Genetic

Topics: Aged; Antineoplastic Agents; Bortezomib; Corneal Diseases; Dexamethasone; Drug Therapy, Combination; Glucocorticoids; Humans; Immunoglobulin G; Immunoglobulins; Immunosuppressive Agents; Male; Microscopy, Electron, Transmission; Multiple Myeloma; Paraproteinemias; Thalidomide; Vision Disorders; Visual Acuity

A 35-year-old man suffered simultaneously from nodular sclerosis Hodgkin's disease (HD), Langerhans' cell histiocytosis and multiple myeloma (MM). There was no prior history of irradiation or chemotherapy, and clinically the lymphoma was confined to cervical lymph nodes. Immunohistochemically, neoplastic lymphoma cells reacted with CD15 and CD30 markers. The patient's bone marrow exhibited a diffuse infiltration by rather atypical plasma cells showing kappa immunoglobulin light-chain restriction. At 14 months after the diagnosis, after autologous bone marrow transplantation, the clinical evolution is favourable with complete remission of the diseases. This is the first time that the coexistence of these three haematological disorders has been discussed, and only the fourth documented case of simultaneous HD and MM. Speculations about the significance of this finding are discussed.

Topics: Adult; Histiocytosis, Langerhans-Cell; Hodgkin Disease; Humans; Immunoglobulins; Lymph Nodes; Male; Multiple Myeloma; Plasma Cells