Objective: To explore the significance of expression of peripheral blood neutrophil CD(64) to distinguish infection from disease activation in systemic lupus erythematosus (SLE).
Methods: 19 patients with infection and 46 patients with non-infection in 65 SLE patients were studied. The levels of peripheral blood neutrophil CD(64) were measured by flow cytometry.
Results: The levels of peripheral blood neutrophil CD(64) in SLE infection patients were [(7.8 +/- 2.1)%], which were significantly higher than that of non-infection group [(3.2 +/- 1.4)%] and healthy control [(3.0 +/- 1.1)%, P > 0.05]. However, there were no significance between the levels of non-infection group and healthy control (P > 0.05). There were no significance between the levels of CD(64) of disease activation and silence group and non-infection group (P > 0.05). In SLE infection group, the levels of CD(64) expression in patients with Gram-negative [(9.2 +/- 1.6)%] were compared with [(7.2 +/- 2.2)%] those with Gram-positive. The differences were not significant (P > 0.05). The levels of CD(64) of SLE patients with infection were decreased by treatment with antibiotics. The correlation of the levels of CD(64) with anti-dsDNA, C(3), ESR, CRP, SLE-disease activity index and IFANA were not found (respectively r = 0.104, P = 0.409; r = -0.125, P = 0.322; r = -0.138, P = 0.274; r = 0.228, P = 0.068; r = 0.204, P = 0.310; r = -0.213, P = 0.089).
Conclusion: The levels of peripheral blood neutrophil CD(64) may help us distinguish infection from disease activation in SLE.