Kaminer M S, Murphy G F, Zweiman B, Lavker R M
Department of Dermatology, University of Pennsylvania, Philadelphia, USA.
Clin Diagn Lab Immunol. 1995 May;2(3):297-301. doi: 10.1128/cdli.2.3.297-301.1995.
Previous studies have identified two ultrastructurally distinct forms of mast cell (MC) degranulation following activation. Immunoglobulin E (IgE)-mediated reactions are characterized by a very rapid swelling and fusion of MC granules and abrupt mediator release. In certain chronic disease states (e.g., bullous pemphigoid), there is "piecemeal" degranulation with a more-gradual mediator release effected by microvesicular transport of "pieces" of granules to the cell surface. It is unclear whether these two degranulation patterns are determined by the different natures of the stimuli, heterogeneity among responding MC granules, or temporal factors. To investigate these issues, we have carried out electron microscopic studies with skin biopsies obtained from ragweed-sensitive subjects 15 and 30 s and 1, 3, 5, and 10 min after intradermal ragweed injection. "Anaphylactic"-type granule changes began by 15 s after ragweed injection and were complete by 5 min; unaffected granules were juxtaposed with granules that were swollen and fused. The remaining granules subsequently underwent changes in appearance similar to those seen in piecemeal degranulation. However, microvesicular transport of granule components to the surface was not observed. These findings indicate that skin MC changes in sites of IgE-mediated reactions include not only the typical very rapid anaphylactic degranulation but also a slower onset of gradual alteration of other granules, frequently within the same MC. These different patterns could reflect MC granule heterogeneity with attendant different responses to IgE-mediated stimuli.
先前的研究已经确定，肥大细胞（MC）激活后会出现两种超微结构不同的脱颗粒形式。免疫球蛋白E（IgE）介导的反应的特征是MC颗粒非常迅速地肿胀和融合，并突然释放介质。在某些慢性疾病状态（如大疱性类天疱疮）中，存在“逐片”脱颗粒现象，通过将颗粒“碎片”以微泡运输的方式逐渐释放介质。目前尚不清楚这两种脱颗粒模式是由刺激的不同性质、反应性MC颗粒之间的异质性还是时间因素决定的。为了研究这些问题，我们对豚草敏感受试者皮内注射豚草后15秒、30秒、1分钟、3分钟、5分钟和10分钟获取的皮肤活检组织进行了电子显微镜研究。“过敏反应性”颗粒变化在豚草注射后15秒开始，5分钟时完成；未受影响的颗粒与肿胀和融合的颗粒并列。其余颗粒随后外观发生变化，类似于逐片脱颗粒中所见。然而，未观察到颗粒成分向表面的微泡运输。这些发现表明，IgE介导反应部位的皮肤MC变化不仅包括典型的非常迅速的过敏反应性脱颗粒，还包括其他颗粒逐渐改变的较慢起始，通常发生在同一个MC内。这些不同模式可能反映了MC颗粒的异质性以及随之而来的对IgE介导刺激的不同反应。
