title: Serum soluble interleukin-2 receptor measurement in patients with sarcoidosis: a clinical evaluation.
abstract: OBJECTIVE
  To date, insufficient evidence is available to recommend serum soluble interleukin-2 receptor (sIL-2R) measurement as a routine test in the assessment of sarcoidosis. Therefore, we evaluated the clinical value of this test.
  
  
  METHODS
  Forty-seven patients with sarcoidosis, all presenting with active disease, were included in the study. Initial serum sIL-2R levels were determined by enzyme-linked immunosorbent assay, and clinical data at presentation and follow-up were collected retrospectively.
  
  
  RESULTS
  The median follow-up period of all patients was 44 months (range, 6 to 100 months), and 38 patients had follow-up data present over at least 24 months. The median sIL-2R level was 1,068 U/mL (range, 248 to 4,410 U/mL; upper limit of normal, 710 U/mL). A positive correlation was found between serum sIL-2R levels and the number of CD4+ T lymphocytes in BAL (rs = 0.53, p < 0.001). In accordance with this result, both sIL-2R level and the number of CD4+ T lymphocytes were elevated in stage I compared to stage III disease (p < 0.05). Patients with extrapulmonary disease (ED) [excluding Löfgren's syndrome] showed higher sIL-2R levels than those presenting with only pulmonary sarcoidosis (p = 0.001). No relation was found between sIL-2R level and response to treatment, and there was no association between sIL-2R levels and radiographic evolution and lung function outcome.
  
  
  CONCLUSIONS
  Our data suggest a role for serum sIL-2R as marker of pulmonary disease activity and ED in patients with sarcoidosis.
authors.affiliation: Heart Lung Center Utrecht, Department of Pulmonology, Sint Antonius Hospital, Nieuwegein, the Netherlands.
authors.forename: Jan C
authors.initials: JC
authors.lastname: Grutters
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Fellrath
authors.forename: Leontine
authors.initials: L
authors.lastname: Mulder
authors.forename: Rob
authors.initials: R
authors.lastname: Janssen
authors.forename: Jules M M
authors.initials: JM
authors.lastname: van den Bosch
authors.forename: Heleen
authors.initials: H
authors.lastname: van Velzen-Blad
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology; D002452:Cell Count; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D015375:Receptors, Interleukin-2 / Q000097:blood*; D012189:Retrospective Studies; D017565:Sarcoidosis, Pulmonary / Q000097:blood* / Q000175:diagnosis; D013997:Time Factors
chemical_list: D015415:Biomarkers; D015375:Receptors, Interleukin-2