Background/Purpose: Tuftsin-PhosphorylCholine (TPC) is a novel bi-specific molecule which has shown immunomodulatory effects in experimental mouse models of lupus, colitis and arthritis but data in human autoimmune diseases are lacking. The present study aimed to investigate the effects of TPC in vitro on samples from patients with a suspicion of giant cell arteritis (GCA), an inflammatory disease of large- and medium-sized arteries.

Methods: Effects of TPC were determined in vitro on peripheral blood mononuclear cells (PBMCs) and temporal artery biopsies (TABs) obtained from six patients who underwent TABs because of a suspicion of GCA. Patients were naïve from therapy. 3 patients had inflamed TABs (GCA). 3 patients had normal TABs and received a different diagnosis (controls). GCA patients satisfied the ACR criteria for GCA. TPC was provided by TPCera (Jerusalem, Israel). Treatment with dexamethasone was included as standard of care. To model in vitro the inflammatory state, PBMCs were activated with CD3/CD28 beads for 48 hours and with phorbol 12-myristate 13-acetate (PMA) plus ionomycin for 4 hours in presence of different doses of TPC or dexamethasone. T helper (Th) cell subsets were analyzed by intracellular flow-cytometry. Cell viability was assessed by the WST-1 assay. To analyze the effects at tissue level, TABs were cut in fragments, placed in culture medium with TPC or dexamethasone in matrigel drops for 5 days. Levels of 18 cytokines in supernatants of TABs and CD3/CD28 activated PBMCs were quantified with the Procarta Plex Th1, Th2, Th9, Th17, Th22, Treg cytokine panel. Data were calculated relative to untreated cells. Column statistics, one-sample t test with an hypothetical value of 100 was used.

Results: Supernatants of PBMCs activated through CD3/CD28 and treated with TPC showed significant lower concentrations of IL-1beta, IL-9, IL-12(p70), IL-13 (>80% decrease), IL-2, IL-5, IL-6, IL-17A, IL-21, IL-23, IFNgamma, TNFalpha, GM-CSF (60-75% decrease) and to a lesser degree of IL-18, IL-22, IL-27. Treatment with TPC had no significant effects on IL-10. It had similar effects on PBMCs from GCA and control patients with the exception of IL-17A which was down-regulated only in PBMCs from GCA patients. IL-1beta, IL-13, IL-17A, IL-18 were detected only in supernatants from inflamed TABs and were significantly down-regulated by TPC treatment. IL-2, IL-5, IL-6, IL-10, TNFalpha were detected in supernatants both from inflamed and normal TABs: IL-6 was down-regulated by TPC treatment while no differences were found in IL-2, IL-5, IL-10 and TNFalpha. TPC and dexamethasone treatments had similar effects on cytokine production by CD3/CD28 activated PBMCs and TABs. Neither TPC nor dexamethasone treatments modified the percentage of Th1, Th17 and Th22 cell subsets induced by PMA plus ionomycin. Both TPC and dexamethasone treatments slightly reduced viability in unstimulated PBMCs while did not have any effects on viability of CD3/CD28 activated PBMCs.

Conclusion: TPC treatment in vitro remarkably down-regulated the production of several cytokines by CD3/CD28 activated PBMCs and TABs, similarly to dexamethasone, supporting further studies to validate the potential use of TPC in autoimmune diseases.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/pre-clinical-evidences-of-immunomodulatory-activities-of-tuftsin-phosphorylcholine-on-samples-from-patients-with-giant-cell-arteritis-in-comparison-to-corticosteroids/