Objective:To investigate the characteristics of T cell immunophenotype and its relationship with clinical manifestation in patients with systemic light chain amyloidosis (AL) .Methods:The peripheral blood mononuclear cells from 36 patients with AL were collected and analyzed by multicolor flow cytometry, and the expression of surface antigen CD3, CD56, CD4, CD8, CD25, CD45RA, CD28, CD57 and nuclear antigen FOXP3 were examined. Samples from 28 age-matched healthy donors (HD) were also examined. Patients were divided by Mayo 2012 staging system and the difference between immunophenotype of Ⅰ-Ⅱ and Ⅲ-Ⅳ stage patients were analyzed. The correlations between the proportion of T-cell subpopulation and clinical manifestations in λ light chain type AL patients were analyzed.Results:The differences in the peripheral total T cells and T cell subsets, including CD4 +, CD8 +, regulatory T cells, and natural killer T cells were not significantly between AL and HD. The ratio of CD57 + cells in CD8 + T cells was lower in AL than in HD, and there was no significantly difference in the rate of CD45RA + and CD28 +cells between these two groups. No differences were found in the ratio of total T cells or T cell subsets between stages Ⅰ-Ⅱ and Ⅲ-Ⅳaccording to the standard of Mayo 2012. Within λ light chain type AL patients, peripheral CD8 + T cell ratio was positively correlated with 24-hour urine protein and creatinine level and negatively correlated with estimated glomerular filtration rate (eGFR) . Conclusion:The overall T cell distribution in the periphery is not significantly different between AL patients and age-matched healthy donors. However, the percentages of CD8 + T cells are positively correlated with renal injury, indicating the importance of CD8 + T cell subset in the prognostic evaluation of renal involvement.