Prediction of short-term mortality in elderly patients with sepsis using immunoglobulin G2: An observational study

BACKGROUND: Sepsis is a global healthcare issue and continues to cause high mortality especially in elderly patients. The humoral immune system plays an important role in protecting from microbial contamination. The goal of this study is to investigate the immune status and prognostic evaluation of elderly patients with sepsis. METHODS: A single-center, prospective observational study has been conducted, with the endpoint being the 28-day mortality. Patients 65 years and older who met the diagnostic criteria of Sepsis-3 in the Emergency Department of Beijing Chao-Yang Hospital were divided into survivors and non-survivors groups. Levels of immunoglobulin (Ig) A, IgG, IgM and their subclasses as well as clinical indicators were collected upon enrollment, and the results were statistically analyzed. RESULTS: This study finally enrolled 106 elderly patients, including 68 survivors and 38 non-survivors. Compared with survivors, IgG2 level and IgG4 level were lower in non-survivors ([Formula: see text]). IgG2 could be regarded as an independent predictor of the 28-day mortality in elderly septic patients. IgG2 had a higher predictive value than other immunoglobulins, lactate, procalcitonin, SOFA score and APACHE II score for mortality in elderly septic patients, and the ratio of IgG2 to IgG had a slightly larger area under the ROC curve compared to IgG2 only (AUC: 0.776 v.s. 0.741). CONCLUSION: IgG subclasses play important roles in the prognosis of elderly septic patients, with IgG2 being the main component. IgG2 was found to outperform other immunoglobulins, lactate, procalcitonin, SOFA score and APACHE II score in terms of predicting the mortality. A complete immunological evaluation is helpful to guide the prognosis and treatment of patients with age-related infection.