Abstract： Objective To investigate T-cell receptor(TCR)ζchain gene expression level in peripheral blood T cells from patients with multiple myeloma(MM),thereby to estimate the feature of T cells activation status.Methods Real-time PCR with SYBR Green I technique Was used for detecting TCR ζchain expression level in peripheral blood mononuelear cells(PBMC)of 24 cages with MM and 24 normal individuals.β2-microglobulin(β2M)gene expression was used as an endogenous reference.Relative changes in TCRζchain expression level were analyzed by the 2-△α×100%method between patients with MM and normal individuals.Results Compared with normal individuals,TCRζchain gene expression was obviously down regulated in PBMC from patients with MM(P=0.019).The expression level of TCR ζchain gene is not significantly age-associated in MM patients[(1.83±1.72)%,(3.46±2.75)%](P=0.525).Conclusion This is the first description in the expression feature of TCRζchain gene in MM patients.TCRζchain expression Was decreased in most of MM patients,which might be related to celhar immunodeficiency.