Characterization of the inflammatory cell infiltrate and expression of costimulatory molecules in chronic echinococcus granulosus infection of the human liver.

A Vatankhah,J Tímár,V Piurkó,J Halász,T Barbai,E Rásó

doi:10.1186/s12879-015-1252-x

Abstract

BackgroundThe local immune responses to chronic echinococcal infections in various organs are largely unknown. Since the liver is the most frequently involved organ in such infections in human we aimed to characterize the inflammatory as well as immune cell infiltrate around hydatid cysts in the liver and compared to common inflammatory processes of the liver.MethodSurgical samples from the liver of 21 cystic echinococcosis (CE) patients were studied and the distribution of different types of inflammatory and immune cells were determined by immunohistochemistry. Furthermore, expression levels of costimulatory CTLA4, CD28, CD80 and CD86 molecules were measured at RNA level by PCR. Liver biopsy samples from patients with steatohepatitis (SH, n = 11) and chronic hepatitis (CH, n = 11) were used as non-inflammatory and chronic inflammatory controls, respectively. The composition and density of the inflammatory and immune cell infiltrates have been compared by using morphometry.ResultsCD3+ T cells predominated the inflammatory infiltrate in all pathological processes, while in CE samples CD20+ B cells, in CH samples CD68+ macrophages were also frequent. Both myeloperoxidase (MPO) + leukocytes and CD68+ macrophages were found to be significantly decreased in CE as compared to either SH or CH samples. Concerning T cell subtypes, only CD8+ T cells were found to be significantly decreased in SH samples. CD1a + dendritic cells were almost completely missing from CE biopsies unlike in any other sample types. There were no differences detected in the mRNA expression of costimulatory molecules except decreased expression of CD28 in CE samples.ConclusionIn the hydatid lesions of the liver of chronic echinococcal infections T cell-mediated immunity seems to be impaired as compared to other types of chronic inflammatory processes, suggesting an immunosuppressive role for Echinococcus granulosus, which deserve further attentions.

Highlights

The local immune responses to chronic echinococcal infections in various organs are largely unknown
CD3+ T cells predominated the inflammatory infiltrate in all pathological processes, while in cystic echinococcosis (CE) samples CD20+ B cells, in chronic hepatitis (CH) samples CD68+ macrophages were frequent
There were no differences detected in the mRNA expression of costimulatory molecules except decreased expression of CD28 in CE samples

Summary

Introduction

The local immune responses to chronic echinococcal infections in various organs are largely unknown. It is mostly due to the persistent activation of immune system which imposes unfavorable changes on normal homeostasis of the organ, the parasite can usually evade the host defense and the infection becomes chronic [2]. A widely accepted scenario defines the role of T helper (Th) 1 cytokines which induce classical activation of macrophages (MΦs) and infiltration of non-resident polymorphonuclear (PMN) cells in acute responses [4]. The modal shift in cytokine profiles from Th1 to Th2 is known as a hallmark of immune responses to tissue-dwelling helminths [2, 9] It may facilitate the parasite survival in the host but results in chronic granulomatous reactions and fibrosis [2]. Little is known about the arrangement of resident and non-resident cells in chronic responses to hydatid cyst in the human liver

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