title: Vitamin D levels in adults with Crohn's disease are responsive to disease activity and treatment.
abstract: BACKGROUND
  Vitamin D deficiency is common in patients with Crohn's disease (CD), although whether this impairs immune responsiveness, and is related to disease activity per se, remains unclear. We sought to investigate vitamin D pathways in patients with CD according to measures of inflammation and immune response.
  
  
  METHODS
  Prospectively collected samples of a well-characterized cohort of patients with CD were used to measure serum 25(OH)-vitamin D levels by enzyme-linked immunoassay. Related gene expression was determined by polymerase chain reaction in T cells. The effect of vitamin D on the proliferation of isolated CD4 cells was determined.
  
  
  RESULTS
  Patients with active CD had lower serum vitamin D levels than those in clinical remission; this measurement was independent of season or reported use of vitamin D supplements. Harvey-Bradshaw Index scores, but not C-reactive protein, correlated with serum vitamin D levels. Gene expression of the vitamin D receptor was higher in peripheral blood T cells from patients with active disease than in those in remission. The proportion of CD25hi CD4 cells from patients with CD increased in the presence of vitamin D. After treatment with infliximab, significant increases in serum vitamin D levels were noted in patients.
  
  
  CONCLUSIONS
  Low vitamin D levels are associated with disease activity in CD and increase after infliximab treatment.
authors.affiliation: Division of Gastroenterology, Center for Inflammatory Bowel Disease, Beth Israel Deaconess Medical Center, Boston, Massachusetts.
authors.forename: Maggie
authors.initials: M
authors.lastname: Ham
authors.forename: Maria S
authors.initials: MS
authors.lastname: Longhi
authors.forename: Conor
authors.initials: C
authors.lastname: Lahiff
authors.forename: Adam
authors.initials: A
authors.lastname: Cheifetz
authors.forename: Simon
authors.initials: S
authors.lastname: Robson
authors.forename: Alan C
authors.initials: AC
authors.lastname: Moss
mesh_terms: D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use*; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D002097:C-Reactive Protein / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects; D003424:Crohn Disease / Q000097:blood* / Q000188:drug therapy / Q000473:pathology; D019587:Dietary Supplements; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D005500:Follow-Up Studies; D006801:Humans; D000069285:Infliximab; D008297:Male; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood* / Q000188:drug therapy / Q000473:pathology
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D000911:Antibodies, Monoclonal; D014807:Vitamin D; D002097:C-Reactive Protein; D000069285:Infliximab