Objective To investigate the levels of serum interferon-γ (IFN-γ), CD47 and lymphocyte subsets in patients with sepsis and their relationships with prognosis.

Methods A total of 180 patients with sepsis who were treated in our hospital were selected as observation group, and 180 healthy volunteers in the same period as control group. Based on the survival status of patients within 28 days of hospitalization, the patients were divided into survival group of 120 cases and death group of 60 cases. The levels of serum IFN-γ and CD47 in patients with sepsis were detected by enzyme-linked immunosorbent assay (ELISA); the level of serum lymphocyte subsets was detected by flow cytometry. Logistic regression analysis was performed on the factors affecting the prognosis of patients with sepsis; the clinical value of the levels of serum IFN-γ, CD47 and lymphocyte subsets in predicting the prognosis of patients with sepsis was analyzed by the receiver operating characteristic (ROC) curve.

Results Compared with the control group, the levels of serum IFN-γ, T lymphocytes, B lymphocytes, and natural killer cells in the observation group were decreased, while the level of CD47 was increased (P < 0.05). In the death group, the levels of serum IFN-γ, T lymphocytes, B lymphocytes, and natural killer cells were also decreased, while the acute physiology and chronic health evaluation-Ⅱ (APACHE Ⅱ) score, Sequential Organ Failure Assessment (SOFA) score, C-reactive protein, procalcitonin, endotoxin, and CD47 levels were increased compared with the death group (P < 0.05). The SOFA score was negatively correlated with the levels of serum IFN-γ, T lymphocytes, B lymphocytes, and natural killer cells (r=-0.469, -0.572, -0.521, -0.505, P < 0.05), but positively correlated with the serum CD47 level (r=0.539, P < 0.05). Elevated levels of APACHE Ⅱ score, SOFA score, C-reactive protein, procalcitonin, endotoxin, and CD47 were risk factors for the prognosis of patients with sepsis, while increased levels of IFN-γ, T lymphocytes, B lymphocytes, and natural killer cells were protective factors for the prognosis (P < 0.05). The areas under the curve (AUC) for predicting the prognosis of sepsis patients using IFN-γ, CD47, T lymphocytes, B lymphocytes, and natural killer cells alone and their combination were 0.805, 0.808, 0.888, 0.846, 0.854, and 0.984, respectively, and the AUC of the combined detection was superior to that of the individual detection (P < 0.001).

Conclusion The levels of serum IFN-γ, T lymphocytes, B lymphocytes and natural killer cells in patients with sepsis are decreased, and the level of CD47 is increased, which is related to the prognosis of patients with sepsis and has certain predictive value for the prognosis of patients with sepsis.