Eosinophilic coronary periarteritis presenting with vasospastic angina and sudden death: a new cause and manifestation of Kounis syndrome?

Abstract

Dear Editor, In a very interesting report published in Virchows Archives [1], seven patients were described suffering from angina pectoris who died suddenly in the morning hours. Histological diagnosis revealed a new pathological entity, which was named eosinophilic coronary periarteritis. All of these patients had inflammatory infiltrates, mainly eosinophilic, in coronary adventitia and periadventitial soft tissue. One of them also had eosinophilic infiltration of the intima and another had infiltration of the medial smooth muscle layers by a small number of eosinophils. This report raises important issues concerning the causality and clinical presentation of hypersensitivity-associated acute coronary syndrome, also known as Kounis syndrome [2]. This is a hypersensitivity angina syndrome, which can progress to acute myocardial infarction and sudden death. It is a ubiquitous disease affecting patients of any age, with a continuously increasing list of causes, broadening clinical manifestations, and covering a wide spectrum of activation disorders of mast cells and other interrelated and interacting inflammatory cells. Platelets with FcγRI, FcγRII, FceRI, and FceRII receptors are also involved in the development of this syndrome. Kounis syndrome can complicate the Churg–Strauss syndrome, which is sometimes associated with coronary artery spasm with repeated angina pectorislike attacks and/or acute myocardial infarction [3]. Eosinophilic coronary arteritis can also complicate Churg–Strauss syndrome and can clinically present as type I and type II variants of Kounis syndrome [2]. Eosinophilic coronary periarteritis might be a further evolution of entities previously described as “isolated eosinophilic coronary arteritis,” “eosinophilic arteritis,” “eosinophilic coronary arteritis,” and “limited form of Churg–Strauss syndrome.” Indeed, the first description already more than six decades ago was named “diffuse eosinophilic arteritis” [4]. Although the authors of the above report [1] did not describe any presence of mast cells during histological examination, other reports emphasized eosinophilic infiltration of adventitia, media, and intimal subendothelium together with diffusely distributed mast cells [5]. This could be an important finding because eosinophilic receptors facilitate eosinophil chemotaxis toward mast cells that are the major producers of an array of inflammatory soluble mediators, including histamine, which can induce Kounis syndrome. Soluble mediators secreted by mast cells and eosinophils modulate reciprocal interactions between these two cells in the socalled “allergic effector unit.” Eosinophils are bone marrow-derived granulocytic leukocytes, which normally reside in tissues and express H4 histamine receptors. Eosinophils respond to histamine in changing cell shape and upregulation of adhesion molecules and chemotaxis, and these responses are mediated by the H4 receptor N. G. Kounis (*) Department of Medical Sciences, Patras Highest Institute of Education and Technology, Queen Olgas Square, 7 Aratou Street, Patras 26221, Greece e-mail: ngkounis@otenet.gr