Differential expression of CR3, FcεRll and Fc<em>y</em>Rlll on polymorphonuclear leukocytes in gingival crevicular fluid.

Polymorphonuclear leukocytes (PMNLs) are the most numberous cell population among the cellular infiltrates in gingival crevicular fluid (GCF) and play important roles in the host-defensive system in the gingival crevices. We determined the percentage of neutrophils, eosinophils and basophils in total PMNLs by light microscopic observation using Randolph-methylene blue staining, then assessed flow cytometric differences in the expression of CR3, FcγRIII, Fc∊RII, LFA-1α, and LFA-1β on PMNL in GCF and peripheral blood (PB) from 21patients with adult periodontitis (AP ) and 13 healthy donors. Percentages of basophils and eosinophils were higher in GCF than in PB. In both AP patients and healthy subjects, expression of CR3 and Fc∊RII was higher while FcγRIII was lower in GCF than in PB. The statistical analysis showed that the expressions of FcγRIII and Fc∊RII on GCF PMNLs were lower in AP patients than in healthy subjects. Expressions of LFA-1α and β on GCF were similar to those on PB PMNLs. PB PMNLs stimulated in vitro with Porphyromonas gingivalis culture supernatant and fMLP displayed an expression pattern of CR3, FcγRIII and Fc∊RII on GCF PMNLs. However, C5a and IL-1 failed to induce changes in FcγRIII and Fc∊RII> The results indicate that GCF neutrophils are activated, present enhanced adhesion and a decreased IgG-binding ability which would reflect that they are at the terminal stage of activation, and that GCF contains a larger eosinophil fraction than in PB. Moreover, these GCF eosinophils appear to be activated. [ABSTRACT FROM AUTHOR]