['To investigate the role of group-specific component globulin (Gc-globulin) in the early process of severe acute pancreatitis (SAP).', 'A total of 37 patients with SAP and 31 patients with mild acute pancreatitis (MAP) were enrolled in the study. Twenty healthy individuals served as controls. Blood samples were taken from SAP and MAP patients on the day of admission (day 1), day 7, and day 14. Serum total Gc-globulin levels were measured using an enzyme-linked immunosorbent assay.', 'On admission, the total Gc-globulin levels of patients in the SAP group were 368 (270-455) mg/l (expressed as medians with interquartile range), which were significantly lower (P=0.007) compared with the control group [420 (299-585) mg/l]. In the SAP group, a significant decrease in serum total Gc-globulin was observed in patients who developed organ dysfunction [267 (242-306) mg/l] compared with patients who did not [414 (329-513) mg/l, P<0.001]. Patients with lower Gc-globulin levels were at a higher risk of developing organ dysfunction (P=0.005). Furthermore, serial measurements displayed increasing total Gc-globulin levels in survivors.'] Are serum Gc-globulin levels reduced in patients with severe acute pancreatitis?