The Biological Function And Clinical Significance Of CD14⁺HLA-DR^-/low Myeloid-derived Suppressive Cell In Peripheral Blood Of Peripheral T Cell Lymphoma

Objective:To investigate the frequency of CD14⁺HLA-DR^-/low cells and the subsets of T cells in peripheral blood of patients with PTCL and to determine the biological function of CD14⁺HLA-DR^-/lowcells.To observe prognostic significance of CD14⁺HLA-DR^-/low MDSC and CD4⁺CD25⁺Treg to patients with PTCL.Methods: Flow cytometry was used to investigate the presence and frequency of CD14⁺HLA-DR^-/low cells and T cell subsets in blood of 33 cases of PTCL patients and 23 cases of healthy adults;The CD3⁺ T cells,CD14⁺HLA-DR^-/low cells and HLA-DR+ cells from peripheral blood were sorted by immunomagnetic beads,CD3⁺ T cells were stimulated and proliferated with biotin labeled magnetic beads（CD2/CD3/CD28）.The proliferation of CD3⁺T cellswas detected by flow cytometry of different concentrations of CD14⁺HLA-DR^-/low cells,Detection of the inhibitory effect of IDO inhibitor 1-MT and ARG1 inhibitor nor-NOHA on the proliferation of autologous CD3⁺T cells.The patients were divided into two subgroup by the median of CD14⁺ HLA-DR-/lowMDSC and and CD4⁺CD25⁺Treg,and the clinical features and prognosis were analyzed.Results:1.There were no statistical significance of the proportion of CD14⁺ monocytes /Leukocytes（median 5.7%,0.70%²0.6%）,CD3⁺T cells / lymphocytes ratio（median 61.37%,45.20%⁷6.40%）,CD19⁺ B cells / lymphocytes ratio（median 7.93%,0.10%²2.70%）,CD16⁺CD56⁺NK cells/ lymphocytes ratio（median 30.60%,9.36%⁴9.70%）in lymphoma patients with control（P>0.05）;The rate of CD4⁺CD45RO⁺T cells /CD4⁺ T cells（median 60.00%,33.62%⁸7.23%）,CD4⁺CD45RA⁺T cells /CD4⁺ T cells（median 32.12%,6.67%⁵7.84%）,CD8+CD45RO+T cells /CD8+T cells（median 44.20% ratio.1.52%⁶7.01%）,CD8+CD45RA⁺T cells /CD8⁺T cells（median 61.15%,5.06%⁷9.03%）in lymphoma patients were also similier with control（P >0.05）;2.When we compared the rate of CD14⁺HLA-DR^-/lowcells /CD14⁺cells（median 3.28%,0.40%-17.74%）and CD4⁺CD25⁺ Tregs/CD4⁺ T cells（median 8.81%,0.76%⁷8.11%）,Both of them in lymphoma patients were higher compared with control（P<0.05）;The increased level of CD4⁺ CD25⁺ cells（median 8.81% in patients with lymphoma）was correlated with the level of CD14⁺HLA-DR^-/lowcells（r=0.510）;The difference was statistically significant（P<0.05）;3.Suppressinon of autologous T cell proliferation by CD14⁺HLA-DR^-/low cells was the strongest when T cells and CD14⁺HLA-DR^-/lowcells ratio was 1:1;Blocking the ARG1 by nor-NOHA resulted in a significant recovery of T cells proliferation rate to 75.09±5.18%.Adding IDO inhibitor 1-MT resulted in a increasing of T cell proliferation rate to 84.50 ±2.93%,Combining 1-MT and nor-NOHA group led to T cells proliferation rate to 97.80 ± 2.20%.4.Based on median CD14⁺HLA-DR^-/lowMDSC percentage 3.28%,the patients were divided into the higher MDSC percentage group and the lower MDSC percentage group.Patients with lower CD14⁺HLA-DR^-/low MDSC had significantly higher 3-year OS rate 58.8% and the median survival time was 30 months（6 to 40）,as compared to those with higher MDSC proportion（3-year OS rate 18.8%）and the median survival time was 15 months（6 to 40）;There was significant difference between the two groups（χ=5.134,P <0.05）.According to the IPI score,the patients were divided into low risk group（IPI=0¹）and high risk group（IPI=2⁴）.Results showed that the proportion of CD14⁺HLA-DR^-/lowcell/CD14⁺cellwas4.65%（0.72%¹7.74%）in the high-risk group and 2.80%（0.40%⁵.66%）in the low-risk group,The difference was statistically significant（P<0.05）.Based on median CD4⁺CD25⁺Treg percentage 8.81%,The patients were divided into the higher Tregproportion group and the lower Tregproportion group.Patients with lower CD4⁺CD25⁺Treg had significantly higher 3-year OS rate 60.6% and the median survival time was 32 months,as compared to those with higher CD4⁺CD25⁺Treg percentages（3-year OS rate 13.3%）and the median survival time was 14 months（6 to 39）;There was significant difference between the two groups（χ=8.971,P<0.05）.Univariate analysis showed that CD14⁺HLA-DR^-/lowMDSC,CD4⁺CD25⁺Treg and IPI were independent prognostic factors of PTCL;Multivariate analysis showed that CD4⁺CD25⁺Treg /CD4⁺cell percentage was an independent prognostic factor of PTCL（P <0.05）.Conclusions:1.We defined CD14⁺HLA-DR^-/low cells in peripheral blood of patientswith PTCL.The frequency of CD14⁺HLA-DR^-/low cells was significantly increased in lymphoma patients than control.2.CD14⁺HLA-DR^-/low cells suppressed T cell proliferation in vitro.The CD14⁺HLA-DR^-/low cellsmediated modulation may be related to ARG1 and IDO.A significantly positive correlation was found between the proportion of CD14⁺HLA-DR^-/low cells and the CD4⁺CD25⁺ cells in PTCL.3.CD14⁺HLA-DR^-/lowMDSC in the peripheral blood of PTCLwere related to the IPI and OS,Higher proportion of CD14⁺HLA-DR^-/lowMDSC and CD4⁺CD25⁺Tregwere poor prognostic factors of PTCL.