Clonal identities and multiple isotype transcripts in hematological diseases revealed by a single-strand conformation polymorphism analysis of the immunoglobulin heavy chain messenger signals

A single-strand conformation polymorphism (SSCP) analysis of polymerase cha in reaction (PCR)-amplified products of immunoglobulin (Ig) heavy chain rea rrangements can be used to analyze B cell clonalities and clonal identities of B cells from different samples. However, the usefulness of the PCR-SSCP analysis Is not fully assessed in B cell malignancies. For example, we did not know whether the PCR-SSCP method can be used to detect tumor-related c lones In peripheral blood of patients with multiple myeloma and Waldenstrom 's macroglobulinemia. In addition, because genomic DNA is used in the PCR-S SCP method, we could obtain no information about the isotype of the expande d B cell clone. In this study, we combined the reverse transcriptase (RT)-P CR of immunoglobulin heavy chain transcripts with an SSCP analysis and thus analyzed eight healthy individuals, five patients with B chronic lymphocyt ic leukemia, four patients with multiple myeloma and three patients with Wa ldenstrom's macroglobulinemia. Clonal B cell populations were detected as d iscrete bands in the RT-PCR-SSCP analysis that can he readily detected over the background of polyclonal rearrangements. Circulating tumor-related clo nes were detected in all but one peripheral blood sample from multiple myel oma and Waldenstrom's macroglobulinemia patients and B cell clones in perip heral blood and bone marrow from these patients showed a similar mobility o n SSCP gel. Because the transcripts of different Isotypes were separately a nalyzed, we could thus determine the Isotype of B cell clones as well. When monoclonal Igs of different isotypes were defected in the individual sampl es, we analyzed the relationship of each monoclonal band by excising the ba nd and then further analyzing it by a PCR-SSCP analysis. RT-PCR amplificati on in conjunction with the SSCP analysis is thus considered to be a useful method to detect and characterize the B cell clones in hematological diseas es. Am. J. Hematol. 62:74-81, 1999. (C) 1999 Wiley-Liss, Inc.