FAILURE OF MACROPHAGE ACTIVATION IN DESTRUCTIVE PERIODONTAL-DISEASE

Macrophage populations in 22 biopsies of untreated advanced periodonti tis were compared with those in 26 biopsies of clinically healthy (min imally inflamed) gingival tissue. The immunohistochemical investigatio n used high, specificity monoclonal antibodies, including a pan-macrop hage marker and probes for acute inflammatory, resident histiocytic, a nd reparative phenotypes. Macrophage expression of the functional acti vation markers MHC class II, basic fibroblast growth factor (bFGF), ac id phosphatase (AP), and tartrate-resistant acid phosphatase (TRAP) wa s also examined. The study showed that advanced periodontitis and mini mally inflamed tissues displayed similar distribution patterns and num bers for the macrophage phenotypic markers: there were, however, regio nally-specific differences in the populations. In the advanced periodo ntitis lesion, there was little evidence of macrophage activation for the expression of HLA-DR, bFGF, and TRAP, although strong expression o f HLA-DR and bFGF was observed in association with blood vessels. Macr ophages expressing AP showed a distinct regional distribution; this, h owever, was not associated with foci of degenerate plasma cells. The a pparent failure of recruitment and activation of macrophages may in pa rt be both a cause and a consequence of the pathological features of t his disease. (C) 1998 John Wiley & Sons, Ltd.