Multiparameter flow cytometric analysis of polymorphonuclear leucocytes in whole blood from patients with adult rapidly progressive periodontitis reveals low expression of the adhesion molecule L-selectin (Cd62L).

Numerous studies of polymorphonuclear leucocyte (PMN) function in patients with adult periodontitis, including rapidly progressive periodontitis, have yielded conflicting findings, perhaps because most of the assays were performed on PMNs that had been separated from whole blood by a variety of procedures. To avoid the problems associated with in vitro analysis of isolated cells, PMN function and antigen expression in live whole unmanipulated blood of eight patients with rapidly progressive periodontitis were compared with those of age-, race-, and sex-matched controls. Using multiparameter flow cytometry, a) L-selectin (CD62L) expression, b) cell size, and c) respiratory burst activity were measured in PMNs in whole blood immediately ex vivo and during incubation with Porphyromonas gingivalis and Staphylococcus aureus. By comparison with PMNs from the control group, PMNs from the patient group expressed significantly lower levels of CD62L and had an increased size before stimulation. PMNs from both groups produced respiratory bursts similar to those of the two bacteria, but in both groups the responses to S. aureus were significantly greater than those to P. gingivalis. The significantly reduced expression of the adhesion molecule CD62L on PMNs in the patient group may lead to reduced tethering of neutrophils at sites of inflammation and may partly explain the susceptibility of these individuals to recurrent and severe periodontal infections.