RESUMO
Objective To investigate the clinical diagnostic value of plasma soluble leukocyte differentiation antigen 14 (presepsin) in patients with rheumatoid arthritis (RA) complicated with pulmonary bacterial infection.Methods A total of 133 patients with RA and 60 healthy controls were enrolled in this study.Fifty-eight RA patients were infected with lung bacterial infection and 75 patients were non-infected with RA.Among them,RA activity was performed in 43 patients and RA was stable in 32 patients.Chemilluminescence immunoassay was used to detect presepsin (P-SEP) in all subjects,and its correlation with inflammatory markers such as white blood cells,blood sedimentation rate and C-reactive protein was analyzed.Results The P-SEP of RA (561 ±142) pg/ml combined with pulmonary bacterial infection group was significantly higher than that of active RA group (378±100) pg/ml (t=8.12,P＜0.01),higher than that of stable RA group (197±68) pg/ml (t=8.51,P＜0.01) and healthy control group (113±9) pg/ml (t=13.75,P＜0.01).There was a positive correlation between P-SEP and leukocyte count in patients with RA complicated with pulmonary bacterial infection (r=0.627,P＜0.01).The degree of the disease activity was correlated with CRP (r=0.63,P＜O.O1),regardless of the P-SEP level (r=0.47,P=0.521).The optimal threshold value of P-SEP in diagnosing RA patients with bacterial infection was 458.9 pg/ml,with a sensitivity of 79.3％ and a specificity of 81.4％.Conclusion P-SEP has an important diagnostic value for the identification of bacterial infection in RA patients,which is not related to RA disease activity.