Periodontal study of β-defensin 4 immunolocalization in the epithelium of human radicular cysts

Introduction Periapical lesions are a host response that involves immune reaction to prevent dissemination of bacteria from an infected root canal. The present work was undertaken to identify the expression of human β-defensin 4 in 10 radicular cysts, thus providing new insights into the development of periapical lesions. Materials and methods Ten patients who were diagnosed with radicular cysts based on clinical criteria (pain, swelling of gingivae around the apex of a tooth, X-ray, percussion, etc.), were subjects in the present study. A radiolucency (12 to 30 mm in size) was seen around the apex of the subject teeth in all patients. No systemic disease was observed in any patients, and antibiotics had not been taken during the previous 6 months. Results Cytoplasmic staining for human β- defensin 4 was detected in theepithelium of radicular cysts; there- fore, detection of human β-defensin 4 suggests the involvement of innate immune response in radicular cyst formation. Conclusion These cysts play a protective role in preventing infection without ex- panding into adjacent tissues, such as alveolar bone. This study dem- onstrates that human β-defensin 4 may also contribute to the protective mechanism of radicular cysts.