(1379) Evaluation of Complement Activity in Patients With Sepsis

Introduction: Complement is a key component of immunity against the viral or bacterial infections, and its activation leads to acceleration of inflammation and leukocyte activation. On the other hands, excessive complement activation causes vascular endothelial cell injury, resulting in microvascular thrombus formation in systemic organs and thrombus-induced organ injury. The aim of this study is to measure the activity of complement in the patients with sepsis and investigate its association with prognosis.

Methods: Patients with sepsis, admitted to the critical care center were included in our study between August 2019 to September 2021. Patients were divided into two group; blood culture positive and negative cases. We evaluated age, mortality, DIC, complement activity (C5b-9, Ba, C5a, C3a, CD59, factor H, syndecan-1) and association with severity (SOFA score and APACHE II score) between two groups.

Results: Thirty patients with sepsis were included during the study periods, fourteen cases were in positive blood culture group and sixteen cases were in negative blood culture group. Renal/Urinary tract infections and soft tissue infections were the most common disease in the positive group (4 patients each), while pneumonia was the most common disease in the negative group (11 patients), indicating a significant difference in infection site. There was no significant difference in SOFA score (4 vs. 4, p=0.04), APATCH II score (15.5 vs. 12.5, p=0.13), and mortality (7.1 vs. 12.5, p=1) between two groups. Complement activity measurements showed significantly higher in factor H in the negative group (14232.5 ug/dl vs. 227664.5 ug/dl, p< 0.05). There were no significant differences in C5b-9, C3a, C5a, CD59 and syndecan-1 between two groups.

Conclusions: We evaluated the activity of complement in the patients with sepsis. Factor H is an important complementation regulator for enhancing the phagocytosis of C3 factor. It is suggested that complement factor H may have been more expressed in blood culture positive group.