High Serum Levels of CXCL11 in Mixed Cryoglobulinemia Are Associated with Increased Circulating Levels of Interferon-γ

Objective: No study has evaluated circulating chemokine C-X-C motif ligand (CXCL)11 in patients with "mixed cryoglobulinemia and chronic hepatitis C infection" (MC+HCV). We measured CXCL11, and correlated this measurement to the clinical phenotype.

Methods: Serum CXCL11, interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α) were assayed in 97 MC+HCV patients and in 97 sex- and age-matched controls.

Results: MC+HCV patients showed significantly higher mean CXCL11 serum levels than controls (254 ± 295, 68 ± 16 pg/ml, respectively; p = 0.0002; ANOVA). CXCL11 was significantly increased in 36 cryoglobulinemic patients with compared to those without active vasculitis (303 ± 208 vs 179 ± 62 pg/ml, respectively; p < 0.001; ANOVA). IFN-γ levels were significantly higher in MC+HCV than in controls [6.1 (range 0.8-114.5), 1.4 (range 0.7-2.4) pg/ml, respectively; p < 0.05; Mann-Whitney U test]. Serum TNF-α mean levels were significantly higher in MC+HCV than in controls [13.4 (range 1.8-369), 1.1 (range 0.7-3.2) pg/ml, respectively; p < 0.0001; Mann-Whitney U test]. A multiple regression analysis considering CXCL11 as a dependent variable, and age, alanine aminotransferase, IFN-γ, and TNF-α as independent variables, showed in MC+HCV patients a significant association only with IFN-γ (p < 0.0001).

Conclusion: Our study demonstrates markedly high serum levels of CXCL11 in patients with MC+HCV compared to healthy controls overall in the presence of active vasculitis. A strong relationship between circulating IFN-γ and CXCL11 was shown, strongly supporting the role of a T helper 1 immune response in the pathogenesis of MC+HCV.