FRI0208 CORRELATIONS BETWEEN NEUTROPHIL-TO-LYMPHOCYTE RATIO AND TH17/TREG IMMUNE BALANCE IN PATIENTS WITH BEHCET'S DISEASE

Background: Behcet’s disease(BD) is a systemic perivasculitis where mucocutaneous manifestations are well known to show neutrophilic dermatosis denoted by significant neutrophil infiltration [1] . The neutrophil-to-lymphocyte ratio has been proved as an inflammatory biomarkers in BD [2] .At present, the Th17/Treg immune imbalance may be the involved factors in the pathway of BD [3] .However, the correlations between the number of neutrophil, the number of lymphocyte, the neutrophil-to-lymphocyte ratio(NLR) and Th17/Treg immune imbalance remain unclear. Objectives: The aim of this study was to examine correlations between the number of neutrophil, the number of lymphocyte, the neutrophil-to-lymphocyte ratio and Th17/Treg immune balance in patients with BD. Methods: The study included 59 BD patients and 66 healthy controls. The absolute counts of lymphocyte subsets and CD4+T cell subsets were detected by flow cytometry for all participants. The neutrophil and lymphocyte were measured by routine blood test for all BD patients. To calculate the NLR, the ratio of absolute neutrophil count to absolute lymphocyte count was obtained. The Mann–Whitney U test was used to compare continuous measures. Correlations between the number of neutrophil, the number of lymphocyte, the NLR and Th17/Treg immune balance were assessed by Spearman’s rank correlation tests. Results: (1)Compared to healthy controls, the absolute counts of NK cells were decreased ( P =0.047), the absolute counts of B cells were increased( P =0.021), the absolute counts of CD4 + T cells were also increased( P =0.035), the absolute counts of Th1 and Th17 cells were significantly increased( P < 0.005), the absolute counts of Th2 and Treg cells were decreased ( P < 0.05), the ratio of Th1/Th2 and Th17/Treg were increased( P < 0.001) in BD group. (2)The numbers of neutrophil were positively correlated with Th17/Treg( r =0.344, P =0.008); The NLR was positively correlated with Th17/Treg( r =0.291, P =0.026). Conclusion: Our research shows that T cell homeostasis perturbation, especially Th17 expansion, Treg insufficiency and Th17/Treg immune imbalance, is the cornerstone of BD pathogenesis. Except neutrophil, these findings suggest that imbalance Th17/Treg may be dominant in the pathogenesis of BD. The NLR was positively correlated with Th17/Treg.Further studies are required to evaluate these preliminary findings in different patient populations and also examine the possible molecular mechanisms behind our observations. References: [1]Tong B, Liu X, Xiao J et al. Immunopathogenesis of Behcet’s Disease[J]. Front Immunol,2019,10:665.DOI:10.3389/fimmu.2019.00665. [2]Gheita TA, Sakr BR, Rabea RE et al. Value of hematological indices versus VEGF as biomarkers of activity in Behçet’s disease[J]. Clin Rheumatol. 2019,38(8):2201–2210. DOI:10.1007/s10067-019-04513-5. [3]Ahmadi M, Yousefi M, Abbaspour-Aghdam S et al. Disturbed Th17/Treg balance, cytokines, and miRNAs in peripheral blood of patients with Behcet’s disease[J]. J Cell Physiol, 2018,234(4):3985-3994.DOI:10.1002/jcp.27207. Figure 1. The absolute counts of lymphocyte subsets in BD patients and healthy controls. Data are expressed as means ±SD. Figure 2. Correlation coefficient and regression line of the number of Th17 cells, the number of Treg cells, Th17/Treg with the the number of neutrophil, the number of lymphocyte, the NLR were represented as scatter plots. Disclosure of Interests: None declared