HLA-DR expression on monocytes and systemic inflammation in patients with ruptured abdominal aortic aneurysms

INTRODUCTION: Mortality from ruptured abdominal aortic aneurysms (RAAA) remains high. Severe systemic inflammation, leading to multi-organ failure, often occurs in these patients. In this study we describe the level of HLA-DR expression in a consecutive group of patients following surgery for RAAA and compare results between survivors and non-survivors. A similar comparison is made for IL-6, IL-10 levels and SOFA-scores. METHODS: This is a prospective observational study. Patients with RAAA were prospectively analyzed. Blood samples were collected on day 1, 3, 5, 7, 10 and 14. The fraction of CD-14 positive monocytes expressing HLA-DR was measured by flow-cytometry. Interleukin-6 and interleukin-10 levels were measured by ELISA. RESULTS: Thirty patients with a median age of 70 years were included. There were 27 (90%) men. Six patients died from multiple organ failure, all other patients survived. The Sequential Organ Failure Assessment (SOFA) scores were significantly higher in non-survivors on day 1 through 14. HLA-DR expression on monocytes was significantly lower on day 3, 5, 7, 10 and 14 in non-survivors. Interleukin-6 and IL-10 levels were significantly higher in non-survivors on day 1 and day 1 and 3 respectively. CONCLUSIONS: HLA-DR expression on monocytes was decreased, especially in non-survivors. All patients with RAAA displayed a severe inflammatory and anti-inflammatory response with an increased production of IL-6 and IL-10. Poor outcome is associated with high levels of IL-6 and IL-10 and a high SOFA score in the first three days after surgery, while low levels of HLA-DR expression are observed from day three after RAAA repair.