Möller B, Kukoc-Zivojnov N, Kessler U, Rehart S, Kaltwasser J P, Hoelzer D, Kalina U, Ottmann O G
Centre for Rheumatic Diseases, Department of Internal Medicine, University Hospital Frankfurt, Germany.
Rheumatology (Oxford). 2001 Mar;40(3):302-9. doi: 10.1093/rheumatology/40.3.302.
To investigate the expression of and monokine induction by interleukin 18 (IL-18; also called interferon-gamma inducing factor, IGIF), in peripheral blood mononuclear cells (PBMC) and cultured synoviocytes from rheumatoid arthritis (RA) patients.
We carried out IL-18 Western blotting and semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) of cytokines in PBMC [IL-18, IL-1beta and tumour necrosis factor alpha (TNF-alpha)] and long-term cultured fibroblast-like synoviocytes (FLS) [IL-18, IL-1beta, TNF-alpha, IL-6, interferon gamma (INF-gamma) and [granulocyte-macrophage colony stimulating factor (GM-CSF)] from RA patients and controls. FLS were isolated from RA synovial membranes (FLS(SM)) and RA synovial fluids (FLS(SF)), osteoarthritis (OA) FLS(SM) and FLS(SF) from spondyloarthropathy patients. FLS were characterized by fluorescence-activated cell sorting of the FLS. PBMC and FLS from RA patients and control subjects were stimulated with recombinant human IL-18 and IL-1beta (rHuIL-18/rHuIL-1beta), and TNF-alpha, IL-1beta and MMP-1 were measured by ELISA in supernatants.
Constitutive expression of IL-18 mRNA was significantly reduced whereas that of TNF-alpha was enhanced in RA PBMC. Persistent low expression of IL-18, TNF-alpha, GM-CSF and IL-1beta was observed in RA and OA FLS(SM) as well as spondyloarthropathy FLS(SF). In contrast, high constitutive expression of IL-18 in FLS (CD90/Thy-1- and CD54-positive, CD14- and CD86-negative), accompanied by persistent high levels of TNF-alpha, GM-CSF and IL-1beta expression, was restricted to synovial fluid-derived FLS obtained from RA patients. IFN-gamma was not detectable in any culture, but IL-6 mRNA was equally expressed in all FLS cultures. rHuIL-18 was effective in stimulating TNF-alpha and IL-1beta secretion in PBMC from healthy controls, but failed to stimulate TNF-alpha and IL-1beta secretion from PBMC in 11 of 12 RA patients, and all FLS cultures. rHu-IL-1beta, but not rHu-IL-18, induced interstitial collagenase (MMP-1) in FLS.
Persistent high production of proinflammatory cytokines in RA-FLS(SF) may be relevant for chronic progression in RA synovitis. Levels of TNF-alpha and IL-1beta expression are increased in RA-FLS(SF), but are independent of IL-18. The pathological function of enhanced IL-18 expression in RA-FLS(SF) remains to be further elucidated.
研究白细胞介素18（IL-18；也称为干扰素-γ诱导因子，IGIF）在类风湿关节炎（RA）患者外周血单个核细胞（PBMC）和培养的滑膜细胞中的表达及单核细胞诱导情况。
我们对PBMC[IL-18、IL-1β和肿瘤坏死因子α（TNF-α）]以及来自RA患者和对照的长期培养的成纤维细胞样滑膜细胞（FLS）[IL-18、IL-1β、TNF-α、IL-6、干扰素γ（INF-γ）和粒细胞-巨噬细胞集落刺激因子（GM-CSF）]进行了IL-18蛋白质印迹分析和细胞因子的半定量逆转录-聚合酶链反应（RT-PCR）。FLS从RA滑膜（FLS(SM)）和RA滑液（FLS(SF)）、骨关节炎（OA）FLS(SM)以及脊柱关节病患者的FLS(SF)中分离得到。通过FLS的荧光激活细胞分选对其进行鉴定。用重组人IL-18和IL-1β（rHuIL-18/rHuIL-1β）刺激RA患者和对照受试者的PBMC和FLS，通过酶联免疫吸附测定法（ELISA）检测上清液中的TNF-α、IL-1β和基质金属蛋白酶-1（MMP-1）。
RA患者PBMC中IL-18 mRNA的组成性表达显著降低，而TNF-α的表达增强。在RA和OA的FLS(SM)以及脊柱关节病的FLS(SF)中观察到IL-18、TNF-α、GM-CSF和IL-1β持续低表达。相反，FLS（CD90/Thy-1阳性、CD54阳性、CD14和CD86阴性）中IL-18的高组成性表达，伴随着TNF-α、GM-CSF和IL-1β的持续高水平表达，仅限于从RA患者获得的滑液来源的FLS。在任何培养物中均未检测到IFN-γ，但IL-6 mRNA在所有FLS培养物中表达水平相同。rHuIL-18可有效刺激健康对照PBMC中TNF-α和IL-1β的分泌，但在12例RA患者中的11例以及所有FLS培养物中，均未能刺激PBMC分泌TNF-α和IL-1β。rHu-IL-1β而非rHu-IL-18可诱导FLS中的间质胶原酶（MMP-1）。
RA-FLS(SF)中促炎细胞因子的持续高产生可能与RA滑膜炎的慢性进展有关。RA-FLS(SF)中TNF-α和IL-1β的表达水平升高，但与IL-18无关。RA-FLS(SF)中IL-18表达增强的病理功能仍有待进一步阐明。
