Topical distribution of Fc gammaRI, Fc gammaRII and Fc gammaRIII in inflamed human gingiva.

The topical distribution of Fc gamma receptor types I, II and III (Fc gammaRI-III) was analyzed by means of immunohistochemistry in human gingival tissue obtained from 12 patients with chronic periodontitis. CD68+ macrophages expressing all three classes of Fc gammaR were found throughout the whole gingival connective tissue (CT), whereas dense infiltrates of polymorphonuclear granulocytes (identified by staining for neutrophil elastase) with strong staining for Fc gammaRIII and Fc gammaRII were found subjacent to the apical part of the pocket epithelium (PE) and in the PE itself. CD19+ B lymphocytes with variable staining intensity for Fc gammaRII were observed in clusters subjacent to the PE and extending into the central part of the CT. Only a few scattered CD3+ T lymphocytes stained for Fc gammaRIII. Some spindle-shaped cells (CD68-, therefore non-macrophages) and apparently non-cellular fibrous tissue elements stained for Fc gammaRI and Fc gammaRII. In the epithelium, Fc gammaRII+ dendritic cells were frequently observed in the entire oral gingival epithelium and in the coronal part of the PE. Occasionally, some keratinocytes which stained for Fc gammaRII and Fc gammaRIII were found. The observations indicate that Fc gammaR of the various classes are amply expressed on numerous cell types in inflamed gingival tissue. The specific distribution pattern detected suggests that Fc gammaRs may play a role in the mediation of chronic inflammation in the periodontal lesion.