Feng M, et al. - In this study, researchers analyzed the data to assess the diagnostic function of complement C3, complement C4, C-reactive protein (CRP), procalcitonin (PCT), white blood cell count (WBC), neutrophil CD64 (nCD64) index, lymphocyte subsets and their combination in distinguishing bacterial infection from disease relapse in systemic lupus erythematosus (SLE). They observed elevated CRP, WBC and nCD64 index in the infected group whereas C3, C4 and B cells levels were significantly decreased. A significant improvement in the diagnostic potential of SLE infection was noted with a combination of nCD64 index, CRP, WBC, C3, and C4 (sensitivity 85.29% specificity 62.50%).