Plasma IL-23 and IL-5 as surrogate markers of lesion metabolic activity in patients with hepatic alveolar echinococcosis

Fluorodeoxyglucose (FDG) uptake by alveolar echinococcosis (AE) liver lesions is a signal of their metabolic activity and of disease progression. In order to find a surrogate marker for this status, we investigated whether parameters of the peripheral and/or periparasitic immune responses were associated with metabolic activity in a prospective case-control study of 30 AE patients and 22 healthy controls. Levels of 18 cytokines and chemokines, representative of innate and adaptive immune responses, were assessed in plasma and peripheral cells of two groups of patients with (MAAE) and without (MIAE) metabolically active lesions, and in the liver of MAAE patients. Mixed cytokine profile was observed in the peripheral blood of AE patients, with a predominance of Th2, Th17 and Treg responses. Among the detected markers only plasma IL-5 and IL-23, more elevated in MAAE patients, were found discriminant. Discrimination between MAAE and MIAE patients obtained by using IL-23 was improved when IL-5 was used in combination. The combination of elevated levels of IL-5 and IL-23 is significantly associated with FDG uptake at PET scan. It offers a new tool for the follow-up of AE patients which could substitute to FDG-PET whenever non-available to assess disease progression.