Polyclonal B-cell activation: Severe periodontal disease in young adults

Abstract The proliferative response stimulated by the polyclonal B-cellactivator staphylococcal protein A (Staph. A) was studied in cultures of peripheral blood lymphocytes obtained from young adults with severe periodontitis. The proliferative response stimulated by Staph. A was enhanced in this patient population in comparison to a control population of the same age. Differences were apparent by Day 3 in cultures stimulated by high doses of Staph. A, and were still apparent at Day 7 in cultures stimulated by low doses. Marked differences were apparent between the two groups at every Staph. A dose at Day 5 (peak response). In preliminary studies of proliferative responses in this select population, similar results were obtained using bacterial extracts from oral and nonoral organisms as the stimulators. To determine if these bacterial extracts contained polyclonal B-cellactivators these same preparations were used in an assay for polyclonal antibodyproduction. The extracts not only contained potent polyclonal B-cellactivators, but in general the polyclonal antibodyassays correlated with the previous proliferative assays. The most potent extracts were from Escherichia coli , followed by Bacteroides melaninogenicus, then Actinomyces viscosus, naeslundii , and israelii . These results support a hypothesis that severe periodontitis, in this select patient population, occurs as a consequence of B-cellhyperreactivity. The data further suggest the possibility that the polyclonal B-cellactivators in dental plaqueorganisms may initiate this disease by nonspecifically stimulating B cellsin the surrounding tissues. These stimulated B cellsand the plasma cells derived from them could then release factorsresponsible for loss of periodontal support. This possible role for B cellsand the potential for T cells and macrophages to regulate these responses are discussed.