Aim: IgG4 is associated with a Th1-to-Th2 switch, which plays a vital role in metastasis, in patients with malignances; thus, we aimed to investigate its clinical significance in predicting hepatocellular carcinoma (HCC) recurrence in the present study. Methods: The correlation between serum IgG4:IgG ratio and recurrence was analyzed in a cohort of 195 patients undergoing curative resection in 2012. Another 100 patients were analyzed in a prospective independent cohort during 2012-2013 to validate the value of serum IgG4. Serum IgG4 and total IgG concentrations were measured with an automatic immune analyzer and the optimal cutoff value for serum IgG4 levels was determined by X-tile software. Results: Our data revealed that serum IgG4:IgG were significantly elevated in patients with tumor recurrence (P<0.05). A cutoff IgG:IgG4 ratio of 0.08 was set to stratify HCC patients into high (>0.08) and low (≤0.08) groups. High serum IgG4:IgG ratio correlated with significantly shorter time-to-recurrence (median 11.85 months vs. 39.20, P=0.005). Univariate and multivariate analyses demonstrated that serum IgG4:IgG ratio is an independent indicator of tumor recurrence and this retained its clinical significance even in conventional low-recurrence-risk subgroups, including patients with low α-fetoprotein and early-stage diseases. Conclusion: Our results demonstrated that elevated serum IgG4:IgG ratio is associated with poor clinical outcomes in HCC patients and therefore, and can serve as a novel prognostic predictor for HCC patients undergoing resection. Analyzing serum IgG4 would be useful to tailor individualized therapies for patients.
Keywords: Hepatocellular carcinoma; IgG4; Th1-to-Th2 switch.; curative resection; prognosis; recurrence; serum biomarkers.