LAUSR

Background: Immune disorder is an important feature of patients with out-of-hospital cardiac arrest (OHCA) after the return of spontaneous circulation (ROSC). We investigated the expression of circulatory T helper type (Th) 1, Th2, and Th17 cells to explore the early immune alteration in OHCA patients after ROSC. Methods: During July–September 2016 and March–September 2017, 65 consecutive OHCA patients with ROSC >12 h and 30 healthy individuals were enrolled in this study. Clinical and 28-day survival data were collected. Peripheral blood samples were analyzed to evaluate the expression of Th1/Th2/Th17 cells by flow cytometry from OHCA patients after ROSC on days 1 and 3 and from healthy individuals. Results: Compared with healthy individuals, T lymphocyte counts and Th1 cell counts decreased on days 1 and 3 after ROSC (1464 [1198, 2152] vs. 779 [481, 1140] vs. 581 [324, 1118]/&mgr;l, &khgr;2 = 30.342, P < 0.001; 154 [90, 246] vs. 39 [19, 78] vs. 24 [12, 53]/&mgr;l, &khgr;2 = 42.880, P < 0.001), and Th2 and Th17 cell counts decreased on day 3 (17.0 [10.8, 24.0] vs. 9.0 [3.0, 15.5]/&mgr;l, Z = –3.228, P = 0.001; 4.7 [2.7, 9.1] vs. 2.7 [1.0, 6.5]/&mgr;l, Z = –2.294, P = 0.022). No change in CD4+/CD3+ lymphocyte ratio was seen on day 1 or day 3 (57.9 [49.4, 63.0] vs. 55.4 [46.5, 66.5] vs. 55.4 [50.2, 67.0]%, &khgr;2 = 0.171, P = 0.918). Th1/CD4+ lymphocyte ratio decreased on days 1 and 3 (19.0 [14.0, 24.9] vs. 9.3 [4.6, 13.9] vs. 9.5 [4.9, 13.6]%, &khgr;2 = 25.754, P < 0.001), and Th2/CD4+ lymphocyte ratio increased on day 1 and decreased on day 3 (1.9 [1.2, 2.5] vs. 2.5 [1.6, 4.0] vs. 1.9 [1.6, 3.8]%, &khgr;2 = 6.913, P = 0.032). Th1/Th2 cell ratio also decreased on both days (9.4 [7.3, 13.5] vs. 3.1 [1.9, 5.6] vs. 4.2 [2.8, 5.9], &khgr;2 = 44.262, P < 0.001). Despite an upward trend in the median of Th17/CD4+ lymphocyte ratio in OHCA patients, there was no significant difference compared with healthy individuals (0.9 [0.4, 1.2] vs. 0.7 [0.4, 1.2] vs. 0.6 [0.3, 1.0]%, &khgr;2 = 2.620, P = 0.270). The dynamic expression of Th1/Th2/Th17 cells on days 1 and 3 were simultaneously analyzed in 28/53 OHCA patients who survived >3 days; patients were divided into survivors (n = 10) and nonsurvivors (n = 18) based on 28-day survival. No significant differences in Th1/Th2/Th17 cell counts, ratios in CD4+ lymphocytes, and Th1/Th2 cell ratio were seen between survivors and nonsurvivors on both days (all P > 0.05). There was no difference over time in both survivors and nonsurvivors (all P > 0.05). Conclusion: Downregulated T lymphocyte counts, including Th1/Th2/Th17 subsets and Th1/Th2 cell ratio imbalance, occur in the early period after ROSC, that may be involved in immune dysfunction in OHCA patients.