title: Peripheral blood regulatory T cell measurements correlate with serum vitamin D level in patients with psoriasis.
abstract: Vitamin D is the precursor of a hormone (1,25-dihydroxyvitamin D3), which has many biological effects in the skin. The immune modulator properties of vitamin D are mediated in part through effects on regulatory T cells (T-reg). Currently, in psoriasis, the relationship between vitamin D and T-reg has not well elucidated. We assess whether vitamin D status is correlated with circulating T-reg in patients affected by psoriasis and if there is a correlation with the severity of the disease evaluated with Psoriasis Area Severity Index (PASI) score.
  
  
  
  For each patient we have analyzed, PASI-score, serum levels vitamin D and regulatory T cell percentages. Spearmen's coefficient was used between serum vitamin D levels and the predictors. Subsequently, the independent predictive factors were assessed by Multiple Regression.
  
  
  
  A total of 26 patients were included in our analysis. Using no parametric Spearman's Coefficient test between serum levels of vitamin D and the single variables, we found an association with T-reg population (p < 0.001) and with PASI-score (p = 0.04).
  
  
  
  While vitamin D treatment induces a cytokine profile known to favor the differentiation of T cells with suppressive activity, at the same time, several studies showed how vitamin D can prime for tolerogenic dendritic cells able to favor the differentiation of Treg from T naïve cells. Low levels of vitamin-D may decrease the number of circulatory T-reg, disrupting the immunological homeostasis in psoriatic patients and encouraging the inflammatory activity.
authors.affiliation: Department of Dermatology and Venereology, "Sapienza" University of Rome, Rome, Italy. paolgio@libero.it.
authors.forename: C
authors.initials: C
authors.lastname: Mattozzi
authors.forename: G
authors.initials: G
authors.lastname: Paolino
authors.forename: M
authors.initials: M
authors.lastname: Salvi
authors.forename: L
authors.initials: L
authors.lastname: Macaluso
authors.forename: C
authors.initials: C
authors.lastname: Luci
authors.forename: S
authors.initials: S
authors.lastname: Morrone
authors.forename: S
authors.initials: S
authors.lastname: Calvieri
authors.forename: A G
authors.initials: AG
authors.lastname: Richetta
mesh_terms: D002117:Calcitriol; D006801:Humans; D011565:Psoriasis / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood
chemical_list: C118756:dihydroxy-vitamin D3; D014807:Vitamin D; D002117:Calcitriol