To investigate the correlation of CD4⁺CD25⁺Treg, sICAM-1 and BAFF in cerebrospinal fluid (CSF) with aneurysmal subarachnoid hemorrhage.

120 theaneurysmal subarachnoid hemorrhage (SAH) patients treated in the Department of Neurosurgery, the Affiliated Hospital of Inner Mongolia Medical University from March 2015 to December 2016 were randomly selected as an observation group, and 40 healthy people we selected as a control group at the same period. CD4⁺CD25⁺Treg, sICAM-1 and BAFF in cerebrospinal fluid in both groups were detected.Ttest was used to compare among groups and Pearson parameter method was used to analyze the correlation with disease severity (Hunt-Hess classification method).

The CD4⁺CD25⁺Treg of the observation group (2.52±0.73)﹪was significantly lower than that of the control group (4.52±1.08)﹪, which was statistically different (t=-12.563,P< 0.01); sICAM-1 (853.25±155.36) pg/ml and BAFF (586.23±163.73) pg/ml levels in the observation group were significantly higher than those of the control group sICAM-1:(315.65±132.58) pg/ml, (t= -19.569,P?< 0.01) and BAFF:(272.66±142.58) pg/ml (t = -11.426, P < 0.01), which were statistically different (P< 0.05); with the increase of Hunt-Hess grade, CD4⁺CD25⁺Treg level in SAH patients was gradually decreased:(3.12±0.82)﹪and(2.42±1.05)﹪and(1.28±0.61), sICAM-1(627.21±152.56) pg/ml, (794.78±106.36) pg/ml, (896.56±110.52) pg/ml and BAFF (395.32±162.53) pg/ml, (589.62?±?170.43) pg/ml, (789.61±173.52) pg/ml levels were increased gradually, which were statistically different between 3 groups (F= 7.214, 12.372, 11.581,P< 0.01); CD4⁺CD25⁺Treg and SAH severity was negatively correlated (r=-0.824,P< 0.01), sICAM-1 and BAFF levels and the severity of disease were negatively correlated (r= 0.922, 0.472,P< 0.01) .

CD4⁺CD25⁺Treg is a protective factor for patients with intracranial aneurysms. Decrease of CD4⁺CD25⁺Treg increases the risk of SAH after aneurysm rupture. sICAM-1, BAFF are involved in SAH, the increase of which can increase the level of inflammation aneurysmal SAH.