Efficacy of Intravenous Immunoglobulin Therapy for Patients With Sepsis and Low Immunoglobulin G Levels: A Single-Center Retrospective Study

Purpose The efficacy of intravenous immunoglobulin (IVIG) administration in patients with sepsis or septic shock remains unclear. A single-center retrospective study was conducted to evaluate the association between IVIG supplementation and favorable outcomes in patients with sepsis and low serum immunoglobulin G (IgG) levels. Methods A total of 239 patients with sepsis were identified whose serum IgG levels were determined upon admission to the intensive care unit between January 2014 and March 2021. Patients with low IgG levels (<670 mg/dL) were divided into the IVIG and non-IVIG groups. Patient data were collected from electronic medical records to evaluate the patients’ characteristics, sepsis severity, and prognosis. The primary outcome was 28-day mortality. The propensity score was calculated by using the following variables: age, Sequential Organ Failure Assessment score, immunocompromised status, and serum IgG levels. Logistic regression analysis using propensity score as the adjusted variable was performed to evaluate the outcome. Findings Of 239 patients, 87 had low IgG levels. Of these patients, 47 received IVIG therapy. The 28-day (odds ratio [OR], 0.15; 95% CI, 0.04–0.54; P = 0.004) and 90-day (OR, 0.31; 95% CI, 0.11–0.83; P = 0.020) mortality rates were significantly lower in the IVIG group than in the non-IVIG group. Moreover, the number of days free from renal replacement therapy was significantly higher in the IVIG group than in the non-IVIG group (OR, 1.06; 95% CI, 1.01–1.11; P = 0.025). Serum IgG levels in the IVIG group showed no significant difference compared with those in the non-IVIG group. No significant differences in the patients’ characteristics were observed between the groups. Implications This study found that IVIG administration in patients with sepsis and low serum IgG levels was associated with improved prognosis. Further studies are warranted to evaluate the validity of IVIG therapy for patients with sepsis and low serum IgG levels.