"Ultimate activation" of eosinophils in vivo: lysis and release of clusters of free eosinophil granules (Cfegs)
Authors: C. G. Persson, J. S. Erjefalt
Journal: Thorax (1997)

During the last decade in vitro data have ac-eration of clusters of free eosinophil granules have repeatedly been depicted by transmission cumulated showing cytokine mediated inhibition of the programmed eosinophil death electron microscopy. 2 6-10 The micrographs even suggest the possibility that lysis of eos-called apoptosis. 1 If valid to eosinophilic diseases, this action would increase the dwell time inophils, and an intriguing distribution of free eosinophil granules, may be a major feature of of eosinophils in the target tissue where they could repeatedly release fractions of their po-many eosinophilic diseases including bullous pemphigoid, 11 atopic dermatitis, 12 eosinophilic tent granular mediators. 2Underscoring a potential importance of these mechanisms, the pneumonia, 13 allergic rhinitis, 14 nasal polyposis, 14 and asthma. 6-10 14 Yet, this phenomenon pharmacology of steroids includes both antirelease effects and pro-apoptotic actions, as is disregarded in discussions on the mechanisms of eosinophils in inflammation and determined in eosinophil test systems ex vivo. 3 Although its role in vivo has yet to be es-allergy. 1 2 15-18 This manifest disinterest may reflect a com-tablished, eosinophil apoptosis is now at the cutting edge of experimental and conceptual bination of circumstances.Authors may rightly be cautious in their interpretation of trans-research activities. 1 4 5 In contrast, the nonapoptotic death or lysis of eosinophils is poorly mission electron microscopy data due to the possibility that artefacts may have been inflicted recognised, not to say completely ignored.This imbalance in scientific interest is remarkable, both at the taking of biopsy specimens and at the sectioning of tissue samples.The fact that particularly in consideration of evidence indicating eosinophil lysis and its immediate only small, potentially non-representative, tissue areas have been examined may also con-result -clusters of free extracellular eosinophil granules (Cfegs) in the target tissues of several tribute to a lack of interest or disbelief in this phenomenon.In addition, free eosinophil common diseases.This review highlights old and recent ob-granules in the airways have not previously been made evident by experimental de-servations on Cfegs and focuses on their occurrence in the respiratory tract.Regrettably, monstrations of when and how they are induced.Fourthly, the non-apoptotic death of we cannot provide the usual review mix of molecular and in vitro cell aspects with arrows eosinophils and the occurrence of free extracellular granules in vivo are, and have been, linking biology data with clinical features of the airway diseases, nor do we present any scheme outside the acknowledged in vitro research paradigms in this field.The last mentioned of reductive mechanisms involved in the present "cell activation" process.Also, this may point gains particular weight by modern requirements on medical research which tend not be a proper time to discuss in any detail the balance of roles in inflammation, disease, to favour studies of molecular mechanisms in isolated cell systems at the expense of the ex-defence, and repair of the "ultimately activated" eosinophils.This brief overview is ploratory research that observes and assesses basic in vivo phenomena. 19meant rather as a reminder that Cfegs do exist Department of and that they should probably no longer be Clinical Pharmacology, ignored.Despite all these shortcomings, and University Hospital of notwithstanding the fact that eosinophil lysis Acute generation of Cfegs in vivo in the Lund, Department of and generation of Cfegs have no place in cur-Physiology and airway mucosa Neuroscience, rent scientific literature and discussions, we The tracheal mucosa of guinea pigs is rich in University of Lund endeavour to suggest that these events may, eosinophils 20 that reside in great numbers at and Department of indeed, be a major modus operandi of eos-Pharmacology, the epithelial basement membrane. 21 22This Astra Draco AB, inophils in vivo.particular homing of airway eosinophils co-Lund, Sweden incides with epithelial expression of eotaxin 23 C G A Persson J S Erjefa ¨ltwhich is a selective chemoattractant originally discovered in guinea pig lungs. 24 The mucosal Eosinophil lysis and Cfegs: seeing is not