Abstract
OBJECTIVE: To study the distribution characteristics of natural killer (NK) cells and their subsets in normal peripheral blood in China, and to explore their normal value and significance. METHODS: In this study, peripheral blood was collected from 200 healthy adults. Their age range was 18-87 years. All the subjects were divided into 6 age groups: 18-30, 31-40, 41-50, 51-60, 61-70, and 71-87 years. With CD16, CD56, CD4, CD19, as surface markers, fluid cytology detection techniques were used to detect NK cells and the relative and absolute counts. SPSS 27.0 was used for systematic analysis of the data, and the measurement data were expressed as mean±standard deviations. A t test, variance analysis or rank sum test were performed to compare the differences between the age groups and the sex groups. The significance level was set at α=0.05, and P < 0.05 was considered statistically significant. RESULTS: The range of NK B cells in the 200 healthy adult subjects was (0.46±0.24)×10(6)/L, that of CD3(-)CD56(+)NK cells was (13.14±7.56)×10(6)/L, that of CD56(dim)CD16(+)NK cells was (5.23±3.12)×10(6)/L, that of CD56(bright)NK cells was (85.61±7.40)×10(6)/L, and that of NK T cells was (4.16±3.34)×10(6)/L. There were no statistically significant differences in CD3(-)CD56(+)NK cells and NK T cells with respect to age (P= 0.417, P=0.217). However, there was a decreasing trend in the number of NK B cells and CD56(dim)CD16(+)NK cells with increasing age (r=0.234, P < 0.001; r=0.099, P < 0.001), particularly after the age of 50. Conversely, CD56(bright)NK cells showed an increasing trend with age (r=0.143, P < 0.001). CONCLUSION: The detection of NK cells and their subsets has significant reference value for the diagnosis, treatment, and prognosis of autoimmune diseases, infectious diseases, and tumors. This study provides a preliminary reference range for clinical detection of NK cell subsets, but further research with a larger sample size and multi-center trials are needed to confirm these findings.