Topical distribution of FcgRI, FcgRII and FcgRIII in inflamed human gingiva

Abstract. The topical distribution of Fc gamma receptor types I, II and III (FcγRI–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 FcγR 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 FcγRIII and FcγRII 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 FcγRII 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 FcγRIII. Some spindle-shaped cells (CD68−, therefore non-macrophages) and apparently non-cellular fibrous tissue elements stained for FcγRI and FcγRII. In the epithelium, FcgRII+ 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 FcγII and FcγRIII were found. The observations indicate that FcγR of the various classes are amply expressed on numerous cell types in inflamed gingival tissue. The specific distribution pattern detected suggests that FcγRs may play a role in the mediation of chronic inflammation in the periodontal lesion.