Basic Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Nov 7, 2016; 22(41): 9117-9126
Published online Nov 7, 2016. doi: 10.3748/wjg.v22.i41.9117
Altered pattern of tumor necrosis factor-alpha production in peripheral blood monocytes from Crohn's disease
Claudia Loganes, Alessia Pin, Samuele Naviglio, Martina Girardelli, Anna Monica Bianco, Stefano Martelossi, Alberto Tommasini, Elisa Piscianz
Claudia Loganes, Samuele Naviglio, Elisa Piscianz, Department of Medicine, Surgery and Health Sciences, University of Trieste, 34128 Trieste, Italy
Alessia Pin, Martina Girardelli, Anna Monica Bianco, Stefano Martelossi, Alberto Tommasini, Department of Pediatrics, Institute for Maternal and Child Health, IRCCS “Burlo Garofolo”, 34137 Trieste, Italy
Author contributions: Loganes C, Martelossi S and Tommasini A conceived and designed the research; Loganes C, Pin A and Girardelli M performed experiments for data acquisition and performed the statistical analysis; Bianco AM and Piscianz E analyzed the data; Naviglio S and Martelossi S enrolled the patients and provided patient samples; Loganes C, Tommasini A and Piscianz E wrote the paper; Bianco AM and Martelossi S revised the manuscript critically for important intellectual content; all authors read and approved the final version of this manuscript.
Supported by Institute for Maternal and Child Health, IRCCS “Burlo Garofolo”, No. RC 03/2009.
Institutional review board statement: The study was reviewed and approved by the Institutional Review Board of the Institute for Maternal and Child Health, IRCCS ‘Burlo Garofolo’, Trieste, Italy (RC 03/2009).
Conflict-of-interest statement: All the authors declare no conflict of interest.
Data sharing statement: Dataset available from the corresponding author at claudia.loganes@gmail.com.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Claudia Loganes, BSc, Department of Medicine, Surgery and Health Sciences, University of Trieste, Strada di Fiume 447, 34128 Trieste, Italy. claudia.loganes@gmail.com
Telephone: +39-040-3785422
Received: June 28, 2016
Peer-review started: June 29, 2016
First decision: August 8, 2016
Revised: August 25, 2016
Accepted: September 14, 2016
Article in press: September 14, 2016
Published online: November 7, 2016
Processing time: 130 Days and 21.7 Hours
Abstract
AIM

To evaluate the inflammatory state in Crohn’s disease (CD) patients and correlate it with genetic background and microbial spreading.

METHODS

By means of flow cytometry, production of tumor necrosis factor-alpha (TNF-α) was measured in peripheral blood monocytes from patients suffering from CD, ulcerative colitis (UC) and in healthy subjects after stimulation of the NOD2 and TLR pathways. CD patients were genotyped for the three most common NOD2 variants (R702W, G908R and L1007Pfs*2) and basal production of TNF-α was correlated to NOD2 genotype. Also, production of TNF-α was correlated to plasmatic levels of LPS Binding Protein (LBP), soluble (s) CD14 and to the activity state of the disease.

RESULTS

The patients with CD were characterized by a significantly higher monocyte basal expression of TNF-α compared with healthy subjects and UC patients, and after stimulation with Pam3CSK4 (ligand of TLR2/1) and MDP-L18 (ligand of NOD2) this difference was maintained, while other microbial stimuli (LPS, ligand of TLR4 and PolyI:C, ligand of TLR3) induced massive activation in CD monocytes as well as in UC and in healthy control cells. There was no significant difference in the production of TNF-α between patients who carried CD-associated heterozygous or homozygous variants in NOD2 and patients with wild type NOD2 genotype. Although serum LBP levels have been shown to correlate positively with the state of activity of the disease, TNF-α production did not show a clear correlation with either LBP or sCD14 levels in plasma. Moreover, no clear correlation was seen between TNF-α production and activity indices in either CD or UC.

CONCLUSION

Peripheral monocytes from CD express higher basal and stimulated TNF-α than controls, regardless of NOD2 genotype and without a clear correlation with disease activity.

Keywords: Crohn’s disease; Ulcerative colitis; Tumor necrosis factor-α; NOD2 variants; Toll like receptors; Dysbiosis; Activity index; LPS-binding protein

Core tip: Crohn’s disease (CD) is characterized by an aberrant activation of the mucosal immune system in genetically susceptible subjects, who often harbor variants in genes involved in the innate immunity. To study the integrity of innate immune response, the activity of the TLR and NOD2 pathways was investigated, measuring TNF-α expression in peripheral blood monocytes. CD monocytes showed a higher production of TNF-α, which was not clearly related to disease activity, to NOD2 genotype or to the presence of translocated bacteria (indirectly measured by serum LPS-binding protein), indicating that this TNF-α hyper-production may rely on a NOD2-independent pathway and is not due to systemic exposure to LPS.