Blood eosinophil degranulation and vacuolation in helminthic infection.
Blood eosinophil degranulation and vacuolation were studied in 21 Nigerian medical patients with helminthic infection and in 10 uninfected controls. For both patients and controls, 200 blood eosinophils were assessed 'blind' by light microscopy for the number of cytoplasmic vacuoles and the loss of specific cytoplasmic granules. In the helminth-infected patients (N = 21) the mean percentage (+/- S.D.) of eosinophils with one or more but less than 10 cytoplasmic vacuoles was 0.7 +/- 0.8%, that with loss of less than half of specific cytoplasmic granules was 1.6 +/- 1.7%, that with 10 or more cytoplasmic vacuoles was 0.1 +/- 0.2%, and that with loss of half or more specific cytoplasmic granules was 0.3 +/- 0.6%. There was no significant difference between patients and controls (P less than 0.05). We conclude that helminthic infection is not associated with blood eosinophil degranulation and vacuolation. The finding of large numbers, e.g. 15% or more, of vacuolated and especially degranulated eosinophils in patients with helminth-related eosinophilia should not be attributed to the helminthic infection alone, but should raise the suspicion of eosinophil-mediated host tissue damage.