Examples of comparative heteroduplex PCR analysis.

(A) Comparative heteroduplex analysis of IGH gene rearrangements. Monoclonal homoduplexes (ho) in patients 5766, 6335, and 6124 found at diagnosis and at relapse were of the same size. Mixing of the PCR products of these disease phases followed by heteroduplex PCR analysis demonstrated no heteroduplex (he) formation, proving that these gene rearrangements had identical junctional regions. In patient 5784, monoclonal homoduplexes found at diagnosis and at relapse slightly differed in size. Mixing of the VH4-JH PCR products followed by heteroduplex PCR analysis demonstrated clear heteroduplex formation, proving that these VH4-JHgene rearrangements had different junctional regions; (ss) indicates remaining single-strand fragments. (B) Comparative heteroduplex analysis of Kde rearrangements showed completely identical rearrangements at diagnosis and at relapse. (C) Comparative heteroduplex analysis of Vδ2-Dδ3 gene rearrangements. Patients 5373 and 5513 with monoallelic and biallelic rearrangements, respectively, had stable Vδ2-Dδ3 rearrangements. In contrast, Vδ2-Dδ3 joinings at diagnosis in patients 5171 and 5514 are oligoclonal, while in both cases 2 monoclonal Vδ2-Dδ3 rearrangements were found at relapse.