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B Cell Immunoglobulin Heavy Chain Gene Rearrangement

P IGH BCELL

Test Synonym:

B cell leukemia, lymphoma

CPT Code:

83891 – Molecular isolation
83894 – Gel electrophoresis

83900 – Amplfication multiplex, first sequence
83901 x8 – Amplification multiplex, each additional sequence
83912 – Interpretation and report

Turnaround Time:

3 days

Methodology:

Polymerase Chain Reaction (PCR), capillary gel electrophoresis

Specimen Requirements:

  • 5.0ml (min. 3.0ml) whole blood EDTA
  • 3.0ml (min. 1.0ml) bone marrow EDTA
  • 5mm3 bone marrow core biopsy, fresh tissue or frozen tissue in MPLN RPMI
  • 3.0ml (min. 2.0ml) FNA in MPLN RPMI medium;
  • Formalin fixed paraffin-embedded tissue

    • Causes for Rejection:

    Insufficient volume; specimen at incorrect temperature, incorrect anticoagulant or fixative

    Specimen Stability:

  • EDTA whole blood or bone marrow stable at 18-25°C for 72 hours
  • Bone marrow biopsy, fresh tissue or FNA in MPLN RPMI at 2-8°C stable for 72 hours
  • Frozen tissue frozen at 20°C stable indefinitely
  • Paraffin-embedded tissue at 18-25°C stable indefinitely

    • Storage and Handling:

    EDTA whole blood, bone marrow, bone marrow biopsy, fresh tissue or FNA, ship in a styrofoam container with an ice pack (do not allow the ice pack to directly contact the sample
    Frozen tissue ship on dry ice, paraffin-embedded tissue ship ambient

    Reference Range:

    No rearrangement detected (germline)

    Indication:

    Evaluation of clonality is useful in differential diagnosis where flow cytometric immunophenotype analysis and morphology of a malignant lymphoma are inconclusive. A subset of Non-Hodgkin's lymphoma fall into this category and a definitive diagnosis cannot be established without the evaluation of clonality.

    Immunoglobulin heavy chain (IgH) genes are located on chromosome 14. Heavy chain gene rearrangement first involves a diversity region (D) gene, combining with a joining region (J). The DJ complex then fuses with a variable (V) gene and a constant (C) gene. This new sequence acts as a template for RNA transcription, which when spliced, generates mRNA. The mRNA is translated into an amino acid sequence to produce the IgH protein. Each mature B cell will thus contain a unique IgH gene rearrangement. J-region probes are superior to C-region probes, since the C regions are often deleted. IgH join (JH) probes are used in fluorescence in situ hybridization (FISH) methods for the detection of B cell clonality. PCR methods are preferable when small amounts of relatively low-quality DNA material are obtained, such as from fixed paraffin-embedded tissue.

    References:

    1. Meier (2001). Simultaneous evaluation of T- and B-cell clonality, t(11;14) and t(14;18), in a single reaction by a four-color multiplex polymerase chain reaction assay and automated high-resolution fragment analysis: a method for the rapid molecular diagnosis of lymphoproliferative disorders applicable to fresh frozen and formalin-fixed, paraffin-embedded tissues, blood, and bone marrow aspirates. AJP 159(6):2031
    2. Medeiros et al. (1999). Review. Overview of the role of molecular methods in the diagnosis of malignant lymphomas. Arch Pathol Lab Med 123(12):1189
    3. Rechavi et al. (1989). Immunoglobulin heavy chain gene rearrangements in chronic lymphocytic leukemia correlation with clinical stage. Br J Haematol 72(4):524