The presence of hypodense eosinophilic granulocytes in allergic children.

To evaluate hypodense eosinophils known very little in children, peripheral blood from asthmatic, allergic-non-asthmatic and non-allergic children was evaluated by density Percoll gradient techniques. A significantly higher number of eosinophils were hypodense in asthmatic children (n = 24) compared with allergic non-asthmatic (n = 10) and non-allergic children (n = 13), namely 484 +/- 348 cells/40 microliters versus 113 +/- 109 and 39 +/- 61 (p less than 0.001) respectively. We also observed by light and electron microscopy that the hypodense eosinophils of asthmatic children were swollen and their granules were dispersed, but the normodense eosinophils of the same patient were small and compact. In three cases of severe asthmatic attack, hypodense eosinophils found on admission decreased in number after intravenous aminophylline therapy and relief of symptoms. Moreover, a decreased number of hypodense eosinophils were found in seven cases of allergic children (p less than 0.05) after 2 weeks of anti-allergic drug treatment associated with relieved symptoms. From these data we concluded that the presence of hypodense eosinophils in the peripheral blood might be related to the development of allergic symptoms and might participate in the pathophysiology of allergic diseases in children.