瑞典研究人员日前发现了人体免疫系统的一种控制机制，这一发现对治疗多发性硬化症、风湿性关节炎及全身性红斑狼疮等免疫系统疾病有重要帮助。
瑞典卡罗林斯卡医学院3日在一份新闻公报中说，患有全身性红斑狼疮或其他免疫系统疾病的病人体内缺少一种名为NKT的细胞，他们的研究结果证明NKT细胞的减少是这些免疫系统疾病的主要致病原因。
人体免疫系统中有一类特殊的细胞被称为B细胞，当人们患有免疫系统疾病时，B细胞不但无法发挥作用，反而会不断分裂并伤害人体。研究人员发现，NKT细胞直接控制着B细胞，指导它对人体组织产生影响。当人体内缺少甚至没有NKT细胞时，B细胞会被错误地激活，伤害人体。但当NKT细胞广泛存在时，它能及时制止B细胞的错误“行为”，从而终止发病过程。(生物谷Bioon.com)
生物谷推荐原文出处：
JEM doi: 10.1084/jem.20091314
Invariant NKT cells limit activation of autoreactive CD1d-positive B cells
Fredrik Wermeling1, Sara M. Lind1, Emilie Domange Jord?1, Susanna L. Cardell2, and Mikael C.I. Karlsson1
Faulty activation of autoreactive B cells is a hallmark of autoimmune diseases like systemic lupus erythematosus (SLE). An important feature restricting activation of autoreactive B cells is efficient removal of apoptotic material. Mounting evidence also connects a primary defect in invariant natural killer T (iNKT) cells to autoimmune disease development. However, exactly how this unconventional T cell subset is involved remains to be defined. Here, we identify a suppressive role for iNKT cells in a model where autoantibody production is triggered by an increased load of circulating apoptotic cells, resembling the situation in SLE patients. Absence or reduction of iNKT cells as well as absence of CD1d-expression on B cells, needed for direct iNKT–B cell interaction, leads to increased autoreactive B cell activation and symptoms of disease. The suppression mediated by the iNKT cells is observed before B cell entry into germinal centers and can be rescued by transferring iNKT cells to deficient mice. This links iNKT cells to handling of dying cells and identifies a novel peripheral tolerance checkpoint relevant for autoimmune disease. Thus, these observations connect two clinical observations in SLE patients previously considered to be unrelated and define a new target for immunotherapy.
