Elevated circulating levels of IL-21 and IL-22 define a cytokine signature profile in type 2 autoimmune hepatitis patients

Abstract

Background and aims. Autoimmune hepatitis (AIH) is a chronic inflammatory condition of the liver in which the immunological mechanisms involved in tissue destruction and/or repair are still unclear. Different pro-inflammatory cytokines have been shown to play a determinant role in AIH pathogenesis. Here, we aim to compare the circulating levels of pro-and anti-inflammatory cytokines such as IL-6, TNF-α, IL-17A/F, IL-21, IL-22, IL-23, and IL-10 in patients with type 2 AIH compared to patients with type 1 AIH and healthy controls (HC). Fourty-six Mexican patients with AIH were recruited in our study. Patients were classified as type 1 or 2 AIH based on immune serological markers. Fourty-four serum samples from healthy individuals were included as controls. Serum cytokine levels were determined by ELISA technique.Results. Compared to healthy controls, serum levels of IL-17F, IL-21, IL-23, IL-10, IL-6, and TNF-α, but not IL-17A and IL-22, were significantly increased in AIH patients. When patients were grouped by aminotransferase activity, a biomarker of active disease, a positive correlation between serum IL-17F and alanine transaminase (rs: 0.4739; P = 0.0009) and aspartate transaminase (rs: 0.4984; P = 0.0004) levels was found. A cytokine signature profile associated with type 2 AIH was characterized by high serum IL-21 (type 1 AIH: 0.66 pg/mL; type 2 AIH: 331.1 pg/mL; P = 0.0042) and IL-22 (type 1 AIH: 0.1 pg/mL; type 2 AIH: 55.26 pg/mL; P = 0.0028) levels.Conclusions. We show for the first time, differential regulation of certain pro-inflammatory cytokines associated with disease progression and AIH type in Mexican patients.