Pro-inflammatory cytokine levels in human apical periodontitis: Correlation with clinical and histological findings

This study aimed to compare the levels of tumour necrosis factor-alpha (TNF-), interleukin-1 beta (IL-1) and interleukin-6 (IL-6) between apical periodontitis lesions with different clinical and histological features. Based on clinical data and history of disease, 100 human apical periodontitis lesions were categorised as either asymptomatic or symptomatic lesions. According to histological examination, lesions were divided into periapical granulomas and radicular cysts. Pulp tissues of 25 impacted wisdom teeth were used as controls. Homogenised tissue samples were centrifuged and supernatants were used for the determination of cytokine levels by enzyme-linked immunosorbent assay. Significantly higher levels of IL-1 and IL-6 were found in symptomatic lesions compared with asymptomatic lesions and control tissues (P<0.001, P<0.001, respectively). The concentration of IL-1 was significantly higher in radicular cysts compared with periapical granulomas (P=0.003). Symptomatic lesions, as judged by high local production of IL-1 and IL-6, represent an immunologically active stage of the disease.