Dysregulation of anergy-related factors involved in regulatory T cells defects in Systemic Lupus Erythematosus patients: Rapamycin and Vitamin D efficacy in restoring regulatory T cells.

Leontina M Banica, Alina N Besliu, Gina C Pistol, Crina Stavaru, Violeta Vlad, Denisa Predeteanu, Ruxandra Ionescu, Maria Stefanescu, Cristiana Matache

Journal: International journal of rheumatic diseases 2017;19(12):1294-1303

PMID: 25351606

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Abstract

AIM

Systemic Lupus Erythematosus (SLE) patients display dysfunctions in T cell activation and anergy. Therefore the aims of our study were to explore the expression of anergy-related factors in CD4 T cells in relationship with regulatory T cells (Tregs) frequency in SLE patients and to identify strategies to redress these defects.

METHOD

Casitas B-cell lymphoma b (Cbl-b) and 'gene related to anergy in lymphocytes' (GRAIL) proteins were analyzed in peripheral blood mononuclear cells (PBMCs) from SLE patients and healthy donors (HD) by immunoblotting. cbl-b, grail, growth response factors (egr)2 and egr3 messenger RNAs (mRNAs) were evaluated by real-time polymerase chain reaction in SLE and HD PBMCs and CD4 T cells. Phenotypic and functional characterization of CD4 T cells was performed by flow cytometry. Tregs expansion protocol consisted in culturing CD4 T cells for 14 or 21 days of experimental activation with anti-CD3 and anti-CD28 monoclonal antibodies, human recombinant interleukin (hrIL)-2, in the absence or presence of rapamycin (Rapa) or 1,25-(OH)2D3 (vitamin D: VitD).

RESULTS

SLE PBMCs expressed low levels of Cbl-b and GRAIL proteins. Both SLE PBMCs and CD4 T cells expressed low levels of egr2/3 mRNAs. SLE patients had a reduced number of Tregs with impaired suppressive activity. An association between egr2 mRNA level in CD4 T cells and Tregs percentage was identified. Experimental activation of CD4 T cells in the presence of hrIL-2 and Rapa or VitD induced the expansion of SLE Tregs. However, on long-term, only Rapa exposure of SLE CD4 T cells yielded high numbers of Tregs with sustained suppressive activity.

CONCLUSION

Our results suggest a new strategy to correct defects in CD4 T cell tolerance mechanisms that may prove beneficial in SLE.

Address: Cantacuzino National Institute of Research and Development for Microbiology and Immunology, Cellular and Molecular Immunity Laboratory, Bucharest, Romania.; Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, Bucharest, Romania.; Department of Rheumatology and Internal Medicine, Sf. Maria Clinical Hospital, Bucharest, Romania.; Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.

DOI: 10.1111/1756-185X.12509