de Paulis A, Marinò I, Ciccarelli A, de Crescenzo G, Concardi M, Verga L, Arbustini E, Marone G
University of Naples Federico II, Italy.
Arthritis Rheum. 1996 Jul;39(7):1222-33. doi: 10.1002/art.1780390723.
To examine the ultrastructure of human synovial mast cells in situ, to identify immunologic and nonimmunologic stimuli that activate these cells in vitro, and to quantify a number of preformed and de novo-synthesized mediators.
We conducted an ultrastructural study of synovial mast cells in situ and performed immunoelectron microscopy localization of tryptase and chymase. Isolated synovial mast cells were analyzed biochemically, immunologically, and functionally in vitro and compared with cells from human lung, heart, and skin.
Ultrastructural study of synovial tissue revealed mast cells with homogeneously dense, scrolled, crystal, and mixed granules, and lipid bodies in the cytoplasm. A small percentage of mast cells showed evidence of degranulation. Immunoelectron microscopy demonstrated the subcellular localization of tryptase and chymase over granules of > 90% of the mast cells, which were of the MCTC subtype. Isolated synovial mast cells released histamine in response to immunologic (anti-IgE and anti-Fc epsilon receptor I [anti-Fc epsilon RI]) and nonimmunologic (substance P, recombinant human stem cell factor, and 48/80) stimuli, but did not respond to recombinant human C5a in vitro. Synovial mast cells differed from those isolated from other human tissues, in a variety of immunologic and biochemical features. There was a linear correlation between the percentage of histamine secretion and tryptase release (r = 0.79, P < 0.001) induced by cross-linking of Fc epsilon RI. Cross-linking of IgE with anti-IgE on synovial mast cells induced de novo synthesis of prostaglandin D2 (mean +/- SEM 87.5 +/- 4.9 ng/10(6) cells) and of leukotriene C4 (57.6 +/- 17.8 ng/10(6) cells).
Mast cells ultrastructurally characterized in situ in synovial tissue were seen to differ from mast cells previously isolated from other human tissues. This raises the possibility that the local microenviroment influences their phenotype. Isolation of mast cells from human synovia can be useful for studying their role and their mediators in patients with arthritis.
研究人滑膜肥大细胞的原位超微结构，确定在体外激活这些细胞的免疫和非免疫刺激因素，并对一些预先形成和重新合成的介质进行定量分析。
我们对滑膜肥大细胞进行了原位超微结构研究，并对类胰蛋白酶和糜蛋白酶进行了免疫电子显微镜定位。对分离出的滑膜肥大细胞进行了体外生化、免疫和功能分析，并与来自人肺、心脏和皮肤的细胞进行了比较。
滑膜组织的超微结构研究显示，肥大细胞的细胞质中有均匀致密、卷曲、结晶和混合的颗粒以及脂质体。一小部分肥大细胞有脱颗粒的迹象。免疫电子显微镜显示，超过90%的MCTC亚型肥大细胞的颗粒上存在类胰蛋白酶和糜蛋白酶的亚细胞定位。分离出的滑膜肥大细胞在受到免疫刺激（抗IgE和抗Fcε受体I [抗FcεRI]）和非免疫刺激（P物质、重组人干细胞因子和48/80）时释放组胺，但在体外对重组人C5a无反应。滑膜肥大细胞在多种免疫和生化特征方面与从其他人体组织分离出的肥大细胞不同。FcεRI交联诱导的组胺分泌百分比与类胰蛋白酶释放之间存在线性相关性（r = 0.79，P < 0.001）。在滑膜肥大细胞上用抗IgE交联IgE可诱导前列腺素D2（平均±SEM 87.5±4.9 ng/10⁶细胞）和白三烯C4（57.6±17.8 ng/10⁶细胞）的重新合成。
滑膜组织中原位超微结构特征的肥大细胞与先前从其他人体组织分离出的肥大细胞不同。这增加了局部微环境影响其表型的可能性。从人滑膜中分离肥大细胞有助于研究它们在关节炎患者中的作用及其介质。
