Vital Roles Played By Th17 And Relative Cytokines In Related Pain Of Osteonecrosis Of Femoral Head (ONFH)

ONFH continues to represent a significant challenge for orthopaedic surgeons, and is a devastating disease for affected patients, with complete collapse of the femoral head occurring in 80%of untreated patients. Some of the well accepted and common associations include corticosteroid use, alcohol abuse, systemic lupus erythematous, hemoglobinopathies including sickle cell anemia, Legg-Calve Perthes disease, and exposure to radiation or cytotoxic agents.ONFH is a typical inflammatory disease, but the related research is limited. It is unknown whether there is a relation between the inflammatory environment and clinical manifestation of ONFH.Since their identification, Thl7 cells, which are characterized by the expression of IL-17, have been proposed to play important roles in several human diseases. In healthy individuals, approximately 1%of CD4+T cells in peripheral blood are Thl7 cells. Thl7 cell numbers can dramatically increase in the pathological microenvironment, where they can secrete high amounts of IL-17. Thus, Thl7 cells are actively recruited to and expanded in the pathological site, and their tissue localization could be important for Thl7 cell-associated pathology.Due to great significance in arthritis, the T helper (Th)17 lymphocytes deservedly attract much attention regarding inflammation in ONFH. The purpose of this study was to examine the association between pain, which is the most predominant symptom of ONFH, and Thl7. By detecting the levels of Thl7 and interleukin (IL)-17 in regional tissue or peripheral blood, we identified that preoperative levels of Th17 and IL-17 were significantly higher in an ONFH group than controls. This was to be expected, indicating that Th17 and its related cytokines play a large role in the pathological process of ONFH. In evaluating level of pain and Th17, we found a positive correlation, demonstrating a vital role played by Th17 in the clinical manifestation of ONFH. Our results indicate that immune system activation is responsible, at least in part, for the pain experienced by patients with ONFH, and increased levels of Th17 lymphocytes and IL-17 contribute to the pain. Clinically, Th17 may become a new therapeutic target when dealing with ONFH pain.Although the results of this study are encouraging, there are some limitations to the report that must be considered. Requiring further study is how Th17 lymphocytes migrate to the ONFH, the differentiation and development mechanism of Th17 lymphocytes in ONFH patients, and how IL-17 induces pain.