Download B-Cell Gene Rearrangement

Laboratory Shipping Address: 2525 SW 3rd. Avenue
Suite 350 Portland, OR 97201
Correspondence Address: 3181 SW Sam Jackson Park Road
Mailstop MP-350 Portland, OR 97239
Phone: 855-KDL-1LAB (535-1522) - Fax: 855-KDL-1FAX (535-1329)
KNIGHT DIAGNOSTIC LABORATORIES
B-Cell Gene Rearrangement
Test Code: 4070
Department: Molecular Oncology
Test Synonyms:
Immunoglobulin (IgH) Gene Rearrangement
Immunoglobulin (IgH) Clonality
Immunoglobulin light chain clonality
Kappa gene rearrangement
Kappa gene clonality
Gene rearrangements for B-cell lymphoma;
B cell gene rearrangement for clonality
CPT Code(s):
83891
83892
83898 x 3
83909 x 3
Background:
B-cell lymphomas account for greater than 90% of non-Hodgkin lymphomas and may pose a diagnostic
challenge on the basis of histopathology alone. During normal B-cell maturation, the immunoglobulin heavy
chain gene is rearranged such that each mature B-cell and plasma cell has a unique rearranged heavy chain
gene profile. This process is vital to the function of B-cells in normal immune function, but can be exploited
to aid in the distinction between reactive (benign; polyclonal) versus neoplastic (clonal) processes of B-cell
proliferation. A reactive, benign B-cell proliferation is characterized by a polyclonal expansion of B-cells
whereas a malignant process is usually characterized by a clonal expansion of a predominant B-cell
population with a clone-specific immunoglobulin heavy (and/or light) chain gene rearrangement. In
conjunction with histopathology, flow, and immunohistochemistry,
the detection of a clonal
immunoglobulin heavy (and/or light) chain gene rearrangements by polymerase chain reaction (PCR) is
intended as an aid in the diagnosis of malignant B-cell lymphoma.
Clinical Utility:
PCR-based detection of rearranged immunoglobulin heavy (and/or light) chain genes can be used as an aid
to establish a diagnosis of a B-cell lymphoma, plasma cell malignancy, monitor treatment response, and/or
measure minimal residual disease (MRD).
Methodology:
Genomic DNA is extracted from blood, lymph node, bone marrow, or other tissue types (formalin-fixed or
fresh) and the rearranged immunoglobulin heavy (and/or light) chain genes are amplified by PCR using a
multiplex primer method based on the BIOMED-2 strategy (1,2). Precise fragment sizing of the amplicons is
accomplished using capillary gel electrophoresis. The presence or absence of a monoclonal B cell population
is determined based on the overall analysis of the electrophoretic pattern.
Sensitivity:
> 95% for the detection of clonality in most tissue types.
False negative results could be due to:
•
Rare clone-specific gene rearrangements that do not bind to any of the primers in BIOMED-2 multiplex
mixture.
•
Somatic hypermutation
•
Clonal B cells present at low abundance in polyclonal background, below the analytical sensitivity of the
assay (~1-10%, depending on the loci).
Molecular Diagnostics CLIA #38D0881787 |Translational Research Lab CLIA #38D2018256
Q11-TSD-100.01
KNIGHT DIAGNOSTIC LABORATORIES
Laboratory Shipping Address: 2525 SW 3rd. Avenue
Suite 350 Portland, OR 97201
Correspondence Address: 3181 SW Sam Jackson Park Road
Mailstop MP-350 Portland, OR 97239
Phone: 855-KDL-1LAB (535-1522) - Fax: 855-KDL-1FAX (535-1329)
B-Cell Gene Rearrangement
The presence of a clonal immunoglobulin cell gene rearrangement does not always equate to the presence
of B cell malignancy.
Specificity:
As cross-lineage immunoglobulin heavy chain gene rearrangements have been reported in certain T-cell
malignancies, interpretation of this test requires clinical, morphologic, and immunophenotypic correlation.
False positive gene rearrangement results are rare but could result from the inadvertent sampling of a
predominant B cell clone from within a polyclonal population.
Specimen Requirements:
• 5-10 mL of blood or bone marrow — yellow (ACD) or purple (EDTA) tube; or
• Formalin-fixed paraffin-embedded (FFPE) tissue blocks or 10 slides (5 micron)
• Refrigerate or keep at room temperature.
A REQUISITION FORM MUST ACCOMPANY ALL SAMPLES. Please include detailed clinical information.
Test Performed (Days):
Monday, Wednesday, Friday
Turnaround Time:
5-7 days
Shipment Sensitivity Requirements:
Keep specimen cold during transit, but do not ship on dry ice. Please use the cold pack provided in the KDL
shipping kit. Ship the specimen overnight express, using the FE priority overnight label provided. The
specimen must arrive at the lab no more than 24 hours after collection.
References:
1) Van Dongen JJ, Langerak AW, Bruggemann M, et al. Design and standardization of PCR primers
and protocols for detection of clonal immunoglobulin and T-cell receptor gene recombinations
in suspect lymphoproliferations: report of the BIOMED-2 Concerted Action BMH4-CT98-3936.
Leukemia 2003; 17(12):2257-2317.
2) Langerak AW, Molina TJ, Lavender FL, et al. Polymerase chain reaction-based clonality testing in
tissue samples with reactive lymphoproliferations: usefulness and pitfalls. Report of the
BIOMED-2 Concerted Action BMH4-CT98-3936. Leukemia 2007; 21:222-229.
Molecular Diagnostics CLIA #38D0881787 |Translational Research Lab CLIA #38D2018256
Q11-TSD-100.01