Objective: The aim was to investigate whether increased Fcgamma-receptor (FcgammaR)-induced chemiluminescence (CL) from peripheral neutrophils in periodontitis could be due to increased sensitivity to non-specific priming by the cell preparation.
Design: Two methods of preparation were used: (1) cells purified by density centrifugation and lysis of erythrocytes; and (2) cells in a leukocyte suspension obtained by lysis of erythrocytes alone.
Methods: Neutrophils from 17 subjects with periodontitis and pair-matched healthy controls were studied by CL and flow cytometry (CD16, CD15 and CD11b).
Results: Higher CL was found in the purified neutrophils, indicating higher non-specific priming by the Percoll density centrifugation. Priming with TNFalpha and lipopolysaccharide abolished this difference. The net effect of specific priming was significantly lower in the purified neutrophils, indicating a depletion of the priming sensitivity by the density centrifugation. Both preparations reduced CD15 in relation to whole blood, while there was no difference between the two methods in any of the membrane markers. Thus, in both preparations, lysis alone changed the membranes to the same extent. Both methods gave nearly the same relative CL increase in the periodontitis patients as in the controls.
Conclusion: There was no difference between the neutrophils from patients and controls in sensitivity to non-specific priming by the preparation method. The higher FcgammaR-induced CL in patients with periodontitis is not related to such a non-specific priming by density centrifugation.