CD11B MESSENGER-RNA EXPRESSION IN NEUTROPHILS ISOLATED FROM PERIPHERAL-BLOOD AND GINGIVAL CREVICULAR FLUID

Adhesion molecule CD11b/CD18 expressed by neutrophils (PMNs) participa tes in cell migration and phagocytosis of C3bi derivatized bacteria, I t is this phagocytic function that eliminates some of the known period ontal pathogens in periodontal pockets. In patients with advanced peri odontitis, homotypic aggregation of crevicular fluid PMNs (CF-PMNs) ma y occur due to overexpression of CD11b/CD18 and this may lead to ineff ective elimination of periodontal pathogens. We have previously shown that CF-PMNs isolated from the periodontal pockets overexpress CD11b c ompared to PB-PMNs. This study tested the hypotheses that (1) overexpr ession of surface CD11b correlates with expression of CD11b mRNA in CF -PMNs isolated from advanced periodontitis subjects. and (2) the intri nsic capacity of CD11b mRNA upregulation by PB-PMNs from periodontitis patients differs from that of control subjects. CF-PMNs and periphera l blood PMNs (PB-PMNs) were isolated from 13 subjects with health!: gi ngiva (control group) and 13 subjects with advanced periodontitis (pat ient group). The surface expression of CD11b was determined by flow cy tometry and CD11b mRNA was determined by extraction of mRNA and revers e transcription to cDNA followed by DNA amplification using primers to detect a segment of the cDNA which encodes CD11b. The results of this study confirm that the surface expression of CD11b on CF-PMNs is sign ificantly higher in periodontitis subjects vs control subjects (p=0.03 ), whereas surface CD11b expression on PB-PMNs does not differ signifi cantly between groups (p=0.06), The level of surface CD11b expression on CF-PMNs did not correlate with the amount of mRNA present in CF-PMN s in either group (p=0.056, 0.07 for control and periodontitis patient s, respectively). Most (9 of 13) individuals in the patient group expr essed CD11b mRNA whereas very few control subjects (2 of 11) had CD11b mRNA in their CF-PMNs. This difference between groups was statistical ly significant (p=0.004). The capacity to upregulate CD11b mRNA upon s timulation with fMLP and/or GPII-CSF was highly variable and there was no statistical difference between the 2 groups.