PROOF-OF-PRINCIPLE EVALUATION OF IMMUNOMODULATORY DRUGS IN PROMOTING PHAGOCYTOSIS CAPACITY IN PATIENTS WITH LIVER FAILURE.

Background and Aims: Secondary infections are the main cause of death in patients with acute- (ALF) and acute-on-chronic liver failure (ACLF) and have been attributed to monocyte dysfunction. The use of steroids in these patients is common but controversial. Beneficial effects on haemodynamics do not confer survival benefit. Their immunomodulatory effect in liver failure syndromes is poorly understood. Steroid clearance was found decreased in critically ill patients. We determined monocyte phagocytosis in patients with liver failure and developed an ex-vivo proof-of-principle evaluation of drugs aimed at boosting innate immune responses. Methods: Phagocytosis of E. coli and oxidative burst by monocytes was studied ex-vivo on monocytes from patients with ALF (n = 24), ACLF (n = 26), cirrhosis (n = 5) and compared to healthy controls (HC, n = 16) using pHrodo assay (Invitrogen) and Phagoburst (Glycotope). Immunophenotype (CD14, CD16, HLA-DR, CD163, MERTK, Fcyreceptors CD32, CD64) was assessed by flow cytometry. PBMCs from ALF/ACLF patients were treated ex-vivo with Interferon-g (IFN-g, 50 ng/ml), N-acetylcysteine (NAC, 250 mg/l) and hydrocortisone (500–10,000 nmol/l) for 48 h. Baseline plasma cortisol levels were assessed by liquid chromatography-mass spectrometry. Results: Phagocytosis of E. coli was impaired in patients with ALF compared to HC (p < 0.0001) and ACLF compared to cirrhosis and HC (p = 0.004/p = 0.0028); and correlated negatively with activation marker CD163 (r = −0.365, p = 0.043). Oxidative burst was impaired in ALF (p = 0.0369) but not ACLF (p = 0.1275/p = 0.9897). Expression of Fcy-receptors was preserved. Ex-vivo treatment with IFN-g (p = 0.0133) and NAC (p = 0.0156) decreased, and hydrocortisone at doses up to 2000 nmol/l increased phagocytosis (500 nmol/l, p = 0.0039; 1000 nmol/l, p = 0.0137; 2000 nmol/l, p = 0.371). Plasma cortisol levels >2000 nmol/l in patients on hydrocortisone treatment were associated with impaired phagocytosis (p = 0.0401) and high 28-day mortality (83.3%). Conclusions: Defective phagocytosis occurs in patients with ALF and ACLF and may impair host defence. IFN-g and NAC inhibited, while hydrocortisone enhanced monocyte phagocytosis capacity ex-vivo. High plasma cortisol levels in patients on hydrocortisone treatment conferred phagocytic defect and poor outcome. Decisions to use approved agents with immunomodulatory effects in patients with liver failure syndromes need careful consideration, hydrocortisone dosing and drug-monitoring require evaluation in clinical studies.