THU0037 The Effects on T-Cell Immune Phenotype in Patients with Systemic Lupus Erythematosus Treated with Two Different Regimens of Vitamin D Supplementation
Authors: S. Piantoni, L. Andreoli, F. Dall’Ara, M. Scarsi, A. Tincani
Journal: Annals of the Rheumatic Diseases (2013)

<h3>Background</h3> Recent studies highlight that Vitamin D (VD) may have an immunomodulatory action on T cells, inhibiting Th-1 and Th-17 response and enhancing Th-2 and Treg function. After repeated antigenic presentation, T cells undergo different functional and phenotypical modifications, leading to the differentiation into highly experienced memory T cells (CD45RA+CCR7-). Similarly, the down-modulation of CD28 may lead to the peripheral expansion of the CD28- T cells, a subpopulation with peculiar effector activities (high g-IFN production and cytotoxic function), that in Rheumatoid Arthritis has been related to a worse prognosis. At the best of our knowledge, little is known about the effect of VD on CD28- T-cell population and in the differentiation of memory T cells. Systemic Lupus Erythematosus (SLE) is an autoimmune disease in which activation of autoreactive T and B lymphocytes and alteration of Treg functionality may have a pathogenic role[1]. A great prevalence of VD insufficiency has been described in SLE patients (pts), probably due to the low direct sunlight exposition. <h3>Objectives</h3> To verify the effect of VD supplementation on the circulating levels of effector memory T cells (CD45RA+/-CCR7-), Treg cells (CD25highCD127low) and CD28- T cells. <h3>Methods</h3> 41 female SLE pts (median age=33 (range 10-90<sup>th</sup> percentile: 24-41) years; median duration of disease=7 (2-16) years) with a clinically quiescent disease (SLEDAI=4 (0-4)) were enrolled. 20 pts were supplemented with an intensive regimen (IR) of colecalciferol (300.000UI for the first month and 50.000UI/monthly as maintenance), whereas 21 pts were supplemented with a standard regimen (SR) (25.000UI monthly). Phenotypic analysis of peripheral T lymphocyte was evaluated by flow-cytometry at baseline and after every 6 months of treatment. <h3>Results</h3> At baseline, no difference emerged in VD levels and among main T-cell subtypes in SLE pts. During the study no flare of disease was recorded. After 6 months of treatment, a significant decrease in the percentage number of Treg cells was observed, independently from the regimen of supplementation (IR: from 8.5 (4.8-14.7) to 6.3 (3.9-14)% of CD4+ T cells; p=0.02; SR: from 7.5 (5.6-11.7) to 6.6 (4.7-9.1)% of CD4+ T cells; p=0.04). Within Treg subtype, an increase in peripheral induced (CCR7-) Treg cells was seen (IR: from 29.7 (15.7-43.1) to 42.9 (13.1-54.6)% of total Treg cells; p=0.04; SR: from 26.3 (16.1-43.1) to 34.8 (24-54.1))% of total Treg cells; p&lt;0.01). After 12 months of treatment, we also observed an increase in the total amount of circulating CD4+CD45RA+CCR7- T cells (IR: from 8 (4-23) to 9 (3-33) cells/μl; p&lt;0.01; SR: from 8 (3-24) to 17 (10-51) cells/μl; p&lt;0.01), whereas a reduction of the CD8+CD28- T cells in SLE pts on SR was seen (from 30.2 (14.6-73.2) to 19.0 (7.4-34.6)% of CD8+ T cells; p=0.01). On the contrary, no significant variation of CD28- T cell-subtypes was observed in IR group. No correlation was observed among the levels of main T-cell subtypes, clinical disease activity and VD levels. <h3>Conclusions</h3> VD may have immunomodulatory properties on T cells, acting on Treg, on highly experienced memory and on CD28- T cells differentiation. <h3>References</h3> Bonelli M, Ann Rheum Dis 2010;69 Suppl 1:i65-66. <h3>Disclosure of Interest</h3> None Declared