title: Decreased serum level of IL-7 in patients with active Graves' disease.
abstract: BACKGROUND
  Graves' disease (GD) is a common autoimmune disease which is one of the major causes of hyperthyroidism. Interleukin 7 (IL-7) has been recently reported to play an important role in various autoimmune diseases, but its role in the pathogenesis of GD has not been assessed. The aim of this study was to evaluate the levels of IL-7 and the soluble form of its receptor (sIL-7R) in the serum of GD patients, and to identify their association with disease activity.
  
  
  METHODS
  A total of 37 GD patients were enrolled into the experimental group and 16 individuals into the control group. All patients were further classified into three subgroups: a GD-active group (hyperthyroidism and TRAb (thyroid stimulating hormone receptor antibody) >7.5 U/L) (N=15), a GD-inactive group (euthyreosis and TRAb<1 U/L) (N=8), and other GD patients (euthyreosis and TRAb>1 U/L) (N=14). Concentrations of IL-7 and sIL-7R were assayed with ELISA. Additionally, the relationship between IL-7 and sIL-7R serum concentrations with disease activity (free triiodothyronine [FT3], free thyroxine [FT4], thyroid stimulating hormone [TSH] and TRAb) was also analyzed.
  
  
  RESULTS
  The serum concentrations of IL-7 in GD-active patients were significantly lower than those of the control group as well as the GD-inactive and GD-other groups. The serum level of IL-7 in GD patients negatively correlated with FT4 and TRAb concentrations. Moreover, no significant difference was observed in the serum level of sIL-7R in GD patients compared to the control group.
  
  
  CONCLUSIONS
  These observations suggest that IL-7 may play a role in the pathogenesis of GD and may be associated with its clinical activity. To this end, the serum level of IL-7 could be an additional diagnostic biomarker predictive of the disease and could be particularly valuable for TRAb-negative GD patients.
authors.affiliation: Department of Immunoendocrinology, Chair of Endocrinology, Medical University of Lodz, Sterlinga 3, 91-425 Lodz, Poland.
authors.forename: Ewelina
authors.initials: E
authors.lastname: Motylewska
authors.affiliation: Department of Immunoendocrinology, Chair of Endocrinology, Medical University of Lodz, Sterlinga 3, 91-425 Lodz, Poland.
authors.forename: Martyna
authors.initials: M
authors.lastname: Nieć
authors.affiliation: Department of Clinical Endocrinology, Chair of Endocrinology, Medical University of Lodz, Sterlinga 3, 91-425 Lodz, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Siejka
authors.affiliation: Department of Clinical Endocrinology, Chair of Endocrinology, Medical University of Lodz, Sterlinga 3, 91-425 Lodz, Poland.
authors.forename: Jan
authors.initials: J
authors.lastname: Komorowski
authors.affiliation: Department of Immunoendocrinology, Chair of Endocrinology, Medical University of Lodz, Sterlinga 3, 91-425 Lodz, Poland.
authors.forename: Hanna
authors.initials: H
authors.lastname: Ławnicka
authors.affiliation: Department of Neuroendocrinology, Medical University of Lodz, Sterlinga 3, 91-425 Lodz, Poland.
authors.forename: Jacek
authors.initials: J
authors.lastname: Świętosławski
authors.affiliation: Department of Immunoendocrinology, Chair of Endocrinology, Medical University of Lodz, Sterlinga 3, 91-425 Lodz, Poland. Electronic address: henryk.stepien@umed.lodz.pl.
authors.forename: Henryk
authors.initials: H
authors.lastname: Stępień
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006111:Graves Disease / Q000097:blood* / Q000175:diagnosis; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood*; D015851:Interleukin-7 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D020395:Receptors, Interleukin-7 / Q000097:blood*; D011989:Receptors, Thyrotropin / Q000276:immunology; D013961:Thyroid Gland / Q000378:metabolism; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; C508605:IL7 protein, human; D015851:Interleukin-7; D020395:Receptors, Interleukin-7; D011989:Receptors, Thyrotropin; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine
keywords: Autoimmune disease; Graves’ disease; Interleukin 7; Soluble interleukin 7 receptor