title: The association between osteopontin gene polymorphisms, osteopontin expression and sarcoidosis.
abstract: BACKGROUND
  Sarcoidosis is a systemic inflammatory disease of unknown etiology. Osteopontin (SPP1, OPN) is an extra cellular matrix glycoprotein and cytokine with a known role in granuloma formation and in autoimmune and inflammatory diseases.
  
  
  OBJECTIVE
  To determine whether plasma OPN levels are elevated in patients with sarcoidosis and compare the frequency of four single nucleotide polymorphism (SNPs) variants in the OPN gene in sarcoidosis patients compared to healthy controls.
  
  
  METHODS
  Demographic and clinical information, radiological studies and pulmonary function tests were evaluated in 113 patients with sarcoidosis and in 79 healthy controls. Blood samples were analyzed for SNPs of the OPN gene and for plasma OPN and CRP levels. Association between clinical features of disease and OPN levels as well as SNP frequencies was determined.
  
  
  RESULTS
  Plasma OPN levels were higher in sarcoidosis patients than in healthy subjects, (median: 217 vs 122ng/ml, p<0.001). Area under the curve for receiver operator curves (ROC) was 0.798 (0.686-0.909 95% CI.) No differences were observed between sarcoidosis patients and controls in the frequency of any of the SNPs evaluated. Presence of lung parenchymal involvement was associated with SNP distribution at rs1126772 (p = 0.02). We found no correlation between SNPs distribution and plasma OPN levels.
  
  
  CONCLUSIONS
  Osteopontin protein levels are elevated in sarcoidosis. We found no evidence for an association between SNPs on the osteopontin gene and plasma OPN levels or the presence of sarcoidosis, however, an association between genotype and several phenotypic clinical parameters of disease was observed.
authors.affiliation: Institute of Pulmonary Medicine, Hebrew University Hadassah Medical Center, Jerusalem, Israel.
authors.forename: Hadas
authors.initials: H
authors.lastname: Lavi
authors.affiliation: Institute of Pulmonary Medicine, Hebrew University Hadassah Medical Center, Jerusalem, Israel.
authors.forename: Miri
authors.initials: M
authors.lastname: Assayag
authors.affiliation: Institute of Pulmonary Medicine, Hebrew University Hadassah Medical Center, Jerusalem, Israel.
authors.forename: Assaf
authors.initials: A
authors.lastname: Schwartz
authors.affiliation: Institute of Pulmonary Medicine, Hebrew University Hadassah Medical Center, Jerusalem, Israel.
authors.forename: Nissim
authors.initials: N
authors.lastname: Arish
authors.affiliation: Institute of Pulmonary Medicine, Hebrew University Hadassah Medical Center, Jerusalem, Israel.
authors.forename: Zvi G
authors.initials: ZG
authors.lastname: Fridlender
authors.affiliation: Institute of Pulmonary Medicine, Hebrew University Hadassah Medical Center, Jerusalem, Israel.
authors.forename: Neville
authors.initials: N
authors.lastname: Berkman
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D053495:Osteopontin / Q000097:blood / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D012507:Sarcoidosis / Q000097:blood / Q000235:genetics*; D055815:Young Adult
chemical_list: D020413:3' Untranslated Regions; D053495:Osteopontin