[Effect of immune function on prognosis of patients with sepsis]

To investigate the influence of immune function and its changes on the prognosis of patients with sepsis.

393 patients who met the diagnostic criteria of Sepsis-3 admitted to General Hospital of Southern War Zone of PLA from April 2003 to April 2017 were enrolled. Clinical data were collected and analyzed retrospectively. According to the initial immune status, patients with more than 4 days course of disease were divided into the initial immune suppression group (219 cases) and the initial immune function normal group (174 cases). According to the changes of immune function, patients with more than 7 days course of disease were divided into persistent inhibition group (113 cases), persistent normal group (96 cases), first normal inhibition group (22 cases) and first inhibited normal group (59 cases). In addition, the patients were divided into the elderly group (≥ 65 years old) and the young group (< 65 years old). Acute physiology and chronic health evaluation II (APACHE II), sequential organ failure assessment (SOFA), procalcitonin (PCT), C-reactive protein (CRP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), serum creatinine (SCr) within 24 hours after diagnosis of sepsis, whether respiratory failure and circulatory failure occur, hormone, immunomodulatory drugs and high-volume hemofiltration treatment within 28 days, the absolute value of lymphocyte counts for 4 consecutive days after diagnosis and 4 consecutive days before the end point event (death or survival within 28 days or more than 28 days) were collected and compared between each group.

Among 393 sepsis patients, 174 cases had normal initial immune function, of whom 85 cases were older than 65 years old; 219 cases had depression of initial immune function, of whom 118 cases were older than 65 years old. Compared with the initial immune function normal group, the levels of PCT, CRP, ALT, AST and SCr in the initial immunosuppressive group were significantly increased [PCT (μg/L): 9.32 (2.13, 34.01) vs. 4.28 (1.02, 19.02), CRP (mg/L): 89.00 (26.00, 142.00) vs. 65.25 (19.88, 119.04), ALT (mmol/L): 39.0 (39.0, 99.0) vs. 27.0 (16.2, 73.0), AST (mmol/L): 55.0 (31.0, 148.0) vs. 39.0 (23.0, 100.8), SCr (μmol/L): 132.00 (74.75, 245.00) vs. 100.25 (61.00, 182.54)], the mean absolute value of lymphocyte counts for 4 consecutive days was significantly decreased [0.615 (0.380, 0.810) vs. 1.442 (1.217, 1.742)], SOFA and APACHE II were significantly increased (SOFA: 9.25±4.19 vs. 6.87±4.66, APACHE II: 22.27±8.96 vs. 18.25±9.47), the incidence of circulatory failure (66.2% vs. 50.0%), the incidence of respiratory failure (87.7% vs. 69.0%) and 28-day mortality (65.3% vs. 33.9%) were significantly increased, with statistically significant differences (all P < 0.05). When combined with immunosuppression, there was no significant difference in 28-day mortality between the elderly group and the young group (26.3% vs. 15.8%, P > 0.05); when the immune function was normal, the 28-day mortality of the elderly group was significantly higher than that of the young group (48.2% vs. 20.2%, P < 0.01). The 28-day mortality of the persistent inhibition group and the first normal inhibition group were significantly higher than those of the persistent normal group and the first inhibition normal group [83.2% (94/113), 81.8% (18/22) vs. 26.0% (25/96), 40.7% (24/59), all P < 0.05]. The incidence of immunosuppression in elderly patients [33.3% (14/42) vs. 10.5% (8/76)] and the incidence of persistent immunosuppression [77.0% (67/87) vs. 54.1% (46/85)] were higher than those in young patients (all P < 0.01).

Immune function is closely related to the prognosis of sepsis patients. Elderly patients with sepsis are more likely to have immunosuppression or persistent immunosuppression than young patients, and the prognosis is worse.