Clonality Detection of Expanded T-Cell Populations in Patients With Multiple Myeloma

Expanded T-cell clones in the peripheral blood of patients with multiple myeloma and smoldering myeloma are usually CD8 positive and persist over long periods, suggesting that they are the result of chronic antigenic stimulation. The presence of enlarged T-cell clones can be demonstrated as bands other than the germ-line bands on Southern blots probed for the T-cell receptor β gene (Vβ), or defined by anti-TCRVβ monoclonal antibody staining. However, the most sensitive way to demonstrate clonality within a population of T-cells is by analysis of the length of complementarity-determining region 3 of the rearranged TCR gene, followed by sequencing. Furthermore, my colleagues and I have previously shown that the CD57⁺ T-cells expressing the “expanded” TCRVβ are monoclonal or biclonal, whereas the CD57^- cells are usually polyclonal.