Rheumatology, Allergology and Clinical Immunology, Department of Internal Medicine, University of Rome Tor Vergata, Italy.
Autoimmun Rev. 2011 Aug;10(10):577-81. doi: 10.1016/j.autrev.2011.04.017. Epub 2011 Apr 21.
Natural killer (NK) cells are large, granular lymphocytes devoted to the defense against microbial agents and cancer cells, traditionally recognized as an important arm of the innate immunity, even if more recent data underpin a role also in the responses of acquired immunity. Several studies have led to ascertain that NK cells are involved in the pathogenesis of many immune-mediated diseases, where they may exert both protective and pathogenic roles. In particular, the CD56(bright) NK cell subset, showing immunoregulatory properties, has been found to accumulate in tissue sites of inflammation, such as the skin lesions in psoriatic patients and the synovial membrane in rheumatoid arthritis (RA) patients. In this latter disease, while data on the number of NK cells are still controversial among the different studies, more consensuses exist on the impaired activity of these cells. In another group of inflammatory arthritides, the spondyloarthropathies (SpA), the presence of peculiar allotypes of the killer cell immunoglobulin-like receptors (KIR) superfamily, coding for molecules expressed on NK cells, seems to modulate the susceptibility to this group of diseases, especially ankylosing spondylitis and psoriatic arthritis. Interestingly, in vitro studies showed that NK cells of patients with inflammatory arthropathies might produce pro-inflammatory Th1 cytokines; furthermore, they are involved in bone damage, interact and activate different cell types such as monocytes, dendritic cells and resident fibroblast-like synoviocites cells, thus creating and/or maintaining the inflammatory response. Certainly, these features encourage more research on the role of NK cells in the pathogenesis of inflammatory arthropathies, which could be essential to define potential new therapeutic strategies.
自然杀伤 (NK) 细胞是大型颗粒淋巴细胞，专门用于防御微生物和癌细胞，传统上被认为是固有免疫的重要组成部分，尽管最近的数据支持它们在获得性免疫反应中也发挥作用。多项研究表明，NK 细胞参与了许多免疫介导的疾病的发病机制，在这些疾病中，它们可能发挥保护和致病作用。特别是具有免疫调节特性的 CD56(bright)NK 细胞亚群，已被发现积聚在炎症组织部位，如银屑病患者的皮肤损伤和类风湿关节炎 (RA) 患者的滑膜。在后者疾病中，虽然不同研究中关于 NK 细胞数量的数据仍存在争议，但对于这些细胞活性受损的共识更多。在另一组炎症性关节炎，即脊柱关节病 (SpA) 中，杀伤细胞免疫球蛋白样受体 (KIR) 超家族的特殊同种型似乎调节了对这组疾病的易感性，尤其是强直性脊柱炎和银屑病关节炎。有趣的是，体外研究表明，炎症性关节炎患者的 NK 细胞可能产生促炎 Th1 细胞因子；此外，它们参与骨损伤，与单核细胞、树突状细胞和常驻成纤维样滑膜细胞等不同细胞类型相互作用并激活，从而引发和/或维持炎症反应。当然，这些特征鼓励对 NK 细胞在炎症性关节炎发病机制中的作用进行更多研究，这对于确定潜在的新治疗策略可能至关重要。
