The Inflammation of Preexisting Autoimmunity in Hashimoto’s thyroiditis is a Factor for Malignancy in Papillary Thyroid Carcinoma

Abstract

Background:The association between thyroid carcinoma (TC) and Hashimoto’s thyroiditis (HT) remains unclear. This study was designed to increase our understanding of the potential immunological relationship between HT and papillary thyroid carcinoma (PTC). Methods: A total of 848 patients were enrolled. Clinicopathological factors, pre-operative clinical laboratory data were compared between the various patient groups. The levels of immune-related cytokines and immune cells were measured in serum from patients and the levels of immune-related cell infiltration was investigated.Results: In terms of clinical pathology, patients with PTC and coexisting HT have lower lymph node metastasis rates, and have higher TSH levels (p < 0.05). Multivariate analysis indicated that extracapsular invasion of tumor and tumor size were risk factors for a PTC diagnosis with positive lymph nodes irrespective of HT status. Secondly, PTC patients coexisting HT have higher pre-operative neutrophil levels than do patients with HT alone (p < 0.05). Thirdly, At the immune molecular level, mean IL-2 and INF-γ levels were significantly higher in the PTC without HT group than in the PTC + HT group (p < 0.05). Only IL-6 levels significantly differed between normal controls and HT patients alone. Patients with PTC and HT have lower percentage of CD4+ cells comparing with HT patients alone. Patients with PTC and HT were characterized by highly lymphocyte infiltration in the intact thyroid. Immune inflammation was only observed in patients with PTC and HT. Immune desert was only observed in patients with PTC without HT. Immune exclusion, characterized high peritumor infiltration, was observed in PTC alone and PTC + HT groups. No significant differences were observed in CD4+ expression in PTC patients with lymph node metastasis. In PTC patients coexisting HT, CD20+ expression was higher while CD8+ and CD4+ expression was lower in patients with lymph node metastasis (p < 0.05).Conclusion: Patients with PTC and HT have the same clinicopathological characteristics as do patients with PTC. HT patients with lower levels of thyroid function destruction have a higher risk of differentiated TC . Patients with PTC have higher levels of CD4+ T cellular immunity than do patients with PTC and HT. In patients with HT, chronic inflammation may contribute the development of PTC.