Laboratory Diagnosis Of Rheumatoid Arthritis Combined With Infection

ObjectiveTo compare the difference of the concentration of immunoglobulins (Ig) and complements, neutrophil CD64expression between active rheumatoid arthritis (RA) and RA combined with infection and explore the relation between immunoglobulin(Ig), complement, neutrophil CD64and active periods.Methods1. eighty patients with rheumatoid arthritis were divided into inactive RA, active RA and RA combined with infection according to the diagnostic criteria. Thirty age-matched individuals were included as control.2. The expression of neutrophils CD64, immunoglobulin(Ig), complement, erythrocyte sedimentation rate (ESR), Rheumatoid factorand the concentration of C reactive protein (CRP) were detected.3. The expression of neutrophils CD64, erythrocyte sedimentation rate (ESR)and concentration of C reactive protein (CRP) were detected Before and after treatment with antibiotics Results1.The CD64expression of neutrophils was significantly elevated in patients with infection or active RA compared to healthy controls or inactive RA. In the infectious disease group, the expression of CD64was significantly higher than that in active RA group. However, the expression of CD64in inactive RA was no significant difference compared with healthy controls (P>0.05).2. The expression of CD64in RA patients with infection was significantly decreased after effective treatment with antibiotics. However, erythrocyte sedimentation rate (ESR)and concentration of C reactive protein were no significant difference betewwn Before treatment and after treatment with antibiotics3. The sensitivity, specificity, Positive predictive value and Negative predictive value of neutrophils CD64expression in the diagnosis of infection was86.7%,97.5%,97.6%, and93.5%, accordingly.4. There was no significant correlation between neutrophils CD64expression and ESR, CRP in the active RA or RA combined with infection.5. the concentration of serum IgG and IgA levels in active rheumatoid arthritis was significantly higher than that in healthy control and inactive RA. The concentration of Ig M was significantly higher than that in control but not than inactive RA. However, there was no significant difference between the active RA and RA combined with infection either in Ig or complements.6. It was highly correlative between IgG, IgA and RF, CRP or ESR. However, there was no significant difference betweenC3,C4and RF, CRP or ESR.Conclusion1. Neutrophil CD64expression is a high sensitive and specific indicator in the differential diagnosis of active RA and RA combined with infection, which might be facilitated in the early and accurate diagnosis of RA combined with infection.2. Neutrophil CD64can be used as a tool to decide The effectiveness of antibiotic treatment in patients of RA combined with infection.3. Serum IgG、IgA levels can be used as predict markers for activity can not differentiate infection from disease flare in patients with rheumatoid arthritis.