Detection of clonal immunoglobulin gene rearrangements by polymerase chain reaction amplification and single-strand...

Area of Science:

• Molecular Biology
• Oncology
• Immunogenetics

Background:

• Southern blotting is a standard method for detecting B cell malignancies via immunoglobulin gene rearrangements.
• This technique requires substantial intact DNA, limiting its use with small or fixed tissue samples.
• A need exists for sensitive methods applicable to limited and preserved biological specimens.

Purpose of the Study:

• To evaluate the utility of polymerase chain reaction (PCR) amplification combined with single-strand conformational polymorphism (SSCP) analysis for detecting clonal immunoglobulin heavy chain (IgH) gene rearrangements.
• To determine if this method can be applied to minute amounts of fresh, frozen, or formalin-fixed tissue.
• To assess the sensitivity of PCR-SSCP for identifying malignant B cells in mixed cell populations.

Main Methods:

• Immunoglobulin heavy chain (IgH) gene rearrangements were amplified from frozen and formalin-fixed B cell malignancy samples using PCR with consensus oligonucleotide primers.
• PCR products were analyzed using single-strand conformational polymorphism (SSCP) on nondenaturing polyacrylamide gels.
• The detection limit of SSCP for malignant cells in peripheral blood was assessed.

Main Results:

• Discrete SSCP patterns, indicative of clonal IgH gene rearrangements, were observed in malignant B cells.
• The PCR-SSCP method successfully detected these rearrangements in both fresh/frozen and formalin-fixed tissues.
• Clonal rearrangements were detectable even when malignant cells constituted as little as 0.2% of total mononuclear cells.

Conclusions:

• Polymerase chain reaction (PCR) amplification coupled with single-strand conformational polymorphism (SSCP) analysis is a sensitive and specific method for detecting clonal immunoglobulin heavy chain (IgH) gene rearrangements.
• This technique overcomes the limitations of Southern blotting, enabling analysis of minute amounts of DNA from various sample types, including fixed tissues.
• PCR-SSCP offers a valuable tool for the diagnosis and study of B cell malignancies, particularly when sample quantity or quality is restricted.