This study was performed to build region-specific reference ranges of peripheral blood lymphocyte subsets for Chinese healthy adults from the young to the elderly and analyze the trends of changes in lymphocyte subsets for evaluating the impact of age on the values.151 healthy adults aged 19-86 were recruited based on the SENIEUR protocol.Three sets of reference ranges were finally built applicable for the healthy young(19-44 years),middle-aged(45-64 years) and elder adults(≥65).Comparisons in parameters among the three cohorts showed that a statistically significant increase in CD16CD56+ NK cell was observed between the middle-aged and elder cohorts,whereas for the majority of the parameters,a significant decline was observed between the young and the middle-aged cohorts.Further results showed that inverse correlations were observed between the age and CD19+ B,CD3+ T,CD3+CD4+ T,CD4+CD45RA+CD62L+ nave T cell and CD4+CD28+/CD4+,while the positive one was identified between the age and the NK cell.These significant changes of the most of immune parameters provided evidence for immunosenescence.Notably,T cell activation markers of CD8+CD38+ and CD8+HLA-DR+ showed reverse trends of association with age,which provides a clue for further researches on the mechanisms underlying the paradoxical clinical presentation of the elder patients. This study was performed to build region-specific reference ranges of peripheral blood lymphocyte subsets for Chinese healthy adults from the young to the elderly and analyze the trends of changes in lymphocyte subsets for evaluating the impact of age on the values.151 healthy adults aged 19 -86 were recruited based on the SENIEUR protocol.Three sets of reference ranges were finally built applicable for the healthy young (19-44 years), middle-aged (45-64 years) and elder adults (≥65) .Comparisons in parameters among the three cohorts was marked a significant increase in CD16CD56 + NK cell was observed between the middle-aged and elder cohorts, but for the majority of the parameters, a significant decline was observed between the young and the middle-aged cohorts.Further results showed that inverse correlations were observed between the age and CD19 + B, CD3 + T, CD3 + CD4 + T, CD4 + CD45RA + CD62L + nave T cell and CD4 + CD28 + / CD4 + and the NK cell. The significant changes of the most of immune parameters provided evidence for immunosenescence. Notably, T cell activation markers of CD8 + CD38 + and CD8 + HLA-DR + showed reverse trends of association with age, which provides a clue for further researches on the mechanisms underlying the paradoxical clinical presentation of the elder patients.