Studies on blood eosinophils. I. Patients with a transient eosinophilia.

Studies were done on blood eosinophils from six patients with a transient eosinophilia, to see whether blood eosinophils were structurally or functionally different from blood eosinophils in eleven normal individuals. It was found that many of the patients' eosinophils were vacuolated, and some contained less specific granules than normal. These eosinophils also possessed Fc receptors for rabbit IgG. When the eosinophil counts returned to normal these abnormalities were no longer found. The nature of these alterations are discussed in relation to the properties of eosinophils in tissues and other types of phagocytic cells responding to stimulae. Suggestions are made about the mechanisms by which they could have come about. It was concluded that blood eosinophils in patients with an eosinophilia may be functionally mature or altered in response to unknown stimulae while they are in the blood.