Change in expression pattern of TCR-CD3 complex in patients with multiple myeloma

In haematological malignancy, cell-mediated immunity has been shown to be suppressed in advanced disease. This immune dysfunction may be due, in part, to altered expression of the T cell receptor (TCR)-CD3 complex. The distribution and clonality of the TCR Vbeta repertoire and the expression levels of CD3gamma, CD3delta, CD3epsilon, and CD3zeta genes in T cells from patients with multiple myeloma (MM) were investigated. Specific Vbeta subfamily primers, reverse transcription polymerase chain reaction, and the GeneScan® technique were used to analyse the expression of the TCR Vbeta subfamily and the clonality of Vbeta T cells in 11 patients with MM. Real-time reverse transcription polymerase chain reaction was used to detect the expression levels of CD3gamma, CD3delta, CD3epsilon, and CD3zeta genes in peripheral blood mononuclear cells from 19 patients with MM. The beta2-microglobulin gene was used as an endogenous reference. A total of 5-22 Vbeta subfamily T cells were detected in different patients (mean value of expressed Vbeta subfamilies was 12.55±6.11), whereas all 24 Vbeta genes were identified in all control samples. The most frequently expressed Vbeta subfamilies were Vbeta1 (100%), Vbeta2, Vbeta3, Vbeta9, Vbeta13, and Vbeta16 (81.8%), while the expression of Vbeta20 was undetectable in all MM samples. Oligoclonal expansion of one or more Vbeta subfamily of T cells was detected in all patients. Such expansions involved different MM stages, and the numbers of expanded clonal Vbeta subfamilies seemed higher in stage I/II groups than in stage III; however, there was no significant difference. Among MM samples, of the Vbeta subfamily members, Vbeta13, Vbeta1, and Vbeta21, were expanded most frequently. A significant decrease in the expression level of the CD3gamma gene was observed in MM samples; in contrast, a higher expression of CD3epsilon was found in the MM group than in the healthy group. The expression pattern of the four CD3 chains was epsilon>zeta>delta>gamma in peripheral blood mononuclear cells from MM, while a gamma>epsilon>zeta>delta expression pattern was found in healthy controls. In conclusions, the present study presents precise data on changes in the variability of Vbeta patterns and expression of TCR signal transduction molecules in MM patients compared to controls, which may be associated with immune dysfunction. This study contributes to a better understanding of the cellular immune features in MM patients.