De Ceuleneer, Marlies

De Keyser, Filip

Deforce, Dieter

Elewaut, Dirk

Tilleman, Kelly

Van Steendam, Katleen

English

Ghent University Academic Bibliography

Citrullination breaks T-cell tolerance in patients with inflammatory arthritides and in healthy persons. Van Steendam K.1, De Ceuleneer M. 1, De Keyser F.2, Elewaut D. 2, Tilleman K. 1, Deforce D. 1 1 Laboratory of Pharmaceutical Biotechnology, Ghent University  2 Department of Rheumatology, Ghent University Hospital  Objectives: Rheumatoid Arthritis (RA) and Spondyloarthropathy (SpA) are two inflammatory auto-immune diseases. They can be distinguished by their clinical presentations and the presence of antibodies against citrullinated proteins (ACPA), which are specific for RA. Production of these serological markers indicates a predominant role for B-cells in the pathology of RA. However, little is known about the effect of citrullinated proteins on T-cell reactivity. Methods: PBMC were isolated from healthy volunteers, RA-patients (CCP+ and CCP-) and SpA-patients. The IFN-production was evaluated by ELISpot analysis. PBMC (500000) were stimulated with in vitro citrullinated (cit) and non-citrullinated (non-cit) human cell extract, each at a concentration of 20µg/100µL.  In parallel, 10^6 PBMC were cultured for a week in the presence of cit (80µg/ml) or non-cit (80µg/ml). Supernatants were collected and the secretion of cytokines was evaluated by multi-ELISA detecting IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, IL-13, IL-17a, IFN, TNF, G-CSF and TGF. Results: In healthy controls and SpA-patients the number of spots detected by ELISpot differed significantly between stimulation with ‘cit’ and ‘non-cit’. However, this was not seen in RA-patients. These results were confirmed by ELISA. The ELISpot assay showed no significant difference between the number of spots per 500000 PBMCs after stimulation with ‘non-cit’ or with cDMEM. Other cytokines, like IL6, IL10, IL17a and G-CSF, did show a distinct increase when PBMC of healthy persons or patients with arthritis were stimulated with ‘cit’ as opposed to ‘non-cit’. On the contrary, a higher production of TGF was seen in the ‘non-cit’ condition.  Conclusion: These data indicate that, unexpectedly, citrulline-specific IFN producing T-cells are present in the repertoire of healthy people. However, they seem to be underrepresented in the blood of RA-patients compared to healthy controls and SpA-patients. It is possible that the citrulline-specific T-cells in RA may be retained in the joint, the site of inflammation in RA. The Multi-ELISA shows distinct cytokine profile of PBMC after stimulation with citrullinated proteins.  Our results indicate a break in T-cell tolerance against citrullinated proteins. The presence of citrulline specific T-cells could play an important role in the ACPA production in RA.  

Citrullination breaks T-cell tolerance in patients with inflammatory arthritides and in healthy persons

https://biblio.ugent.be/publication/879659/file/879684.pdf

Citrullination breaks T-cell tolerance in patients with inflammatory arthritides and in healthy persons

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Ghent University Academic Bibliography