To investigate the relation between the change of serum IL-21 level and other laboratory indexes by detecting serum IL-21 level from patients with primary Sjogren's syndrome (pSS) and explore the role of IL-21 in pSS.
The level of serum IL-21 from 40 pSS patients diagnosed according to 2002 revised international classification criteria for pSS and 30 healthy persons were detected by enzyme-linked immunosorbent assay(ELISA) respectively. Meanwhile, FT3, FT4, TSH, TgAb, TPOAb were detected by Immunochemiluminescent technique. Double diffusion method, Westergren and automatic gel method detected ant-SSA and ant-SSB antibody, ESR and serum protein electrophoresis respectively. The relationship between serum IL-21 level and other clinical symptom of the patients was analyzed.
The level of serum IL-21 in patients with pSS (1051+/-335) ng/L was obviously higher than that in healthy control (466+/-90 ng/L), (P<0.05). The levels of serum IL-21 in the self-antibody positive group, parotid gland swelling pain group, rash group and incorporating hypothyroidism group were higher than those in their negative control groups, and there were significant differences(P<0.05). In addition, The level of serum IL-21 level in pSS patients showed positive correlation with gamma-globulin (r=0.719, P<0.05) and ESR level(r=0.745, P<0.05).
The evident increase of serum IL-21 level in pSS patients has positive correlation with the levels of gamma-globulin and ESR, which suggests that IL-21 may play a critical role in the pathogenesis of pSS.