The Study And Clinical Significance Of Soluble CD25 In The Serum Of Patients With Rheumatoid Arthritis

Background and ObjectiveRheumatoid arthritis（RA）is a chronic,systemic autoimmune disease characterized by erosive and symmetrical arthritis as the main clinical manifestation.It causes joint pain,stiffness and swelling,and can lead to permanent structural joint damage and deformity,while it may also be associated with systemic complications from major organ systems including the heart,lungs and blood vessels^[1].The exact pathogenesis of RA is not clear.The basic pathological changes are synovitis and pannus formation,and the destruction of articular cartilage and bone gradually leads to joint deformity and loss of function.Recombinant interleukin-2（rIL2）is a biologic response modifier capable of activating cytotoxic T lymphocytes and natural killer（NK）cells and enhancing their cytotoxic activity against endogenous tumour cells^[2-3].IL-2 exerts these pleiotropic effects through interacting with the heterotrimeric IL-2receptor（IL-2R）complex comprised ofα（CD25）,β（CD122）and commonγ（CD132）chains expressed on the surface of activated T cells^[4].Enzyme linked immunosorbent assay（ELISA）was used to determine the level of sCD25 in serum.The correlation between serum sCD25 level and clinical and laboratory indexes of RA was analyzed.MethodsSera were collected from 108 patients with RA,39 patients of osteoarthritis（OA）and 50 cases of healthy controls.Enzyme linked immunosorbent assay（ELISA）was used to determine the level of sCD25 in serum,and the correlation between serum sCD25 level and the clinical and laboratory indexes of RA was analyzed.The measurement data were compared by independent sample t test,counting data using chi square test and correlation analysis using Spearman correlation analysis.Results1.The concentration of sCD25 in serum of group RA was(（2893.85±1349.22pg/mL）pg/mL,which was significantly higher than that of group OA（2207.87±1021.67 pg/mL,P<0.0001）and healthy control group（1786.07±753.26pg/mL,P<0.0001）.2.The diagnostic concentration of sCD25 was 2284.75 pg/mL,the sensitivity was 67.6%,and the specificity was 81.8%,according to the healthy controls and the patients with osteoarthritis.3.sCD25 was significantly correlated with RA disease activity parameters such as ESR,CRP,tender joint counts,swelling joint counts and DAS28.Furthermore,sCD25 positive RA patients were more likely to show higher disease activity（DAS28>5.1）.4.The predictive value of sCD25 on high disease activity was comparable with those of ESR and CRP.In 50%of the patients with active disease but negative in CRP/ESR,sCD25 was still positive.ConclusionssCD25 is a sensitive serum biomarker to evaluate RA disease activity,and it could be a promising laboratory marker to assist RA disease activity assessment in active RA patients with negative ESR or CRP.