Fine morphological changes in blood basophils were examined in 3 healthy controls and 8 atopic asthmatics --- 4 buckwheat allergy patients and 4 mite allergy patients --- by scanning electron microscopy after they had been exposed to specific antigens. The results were as follows.
1) Observation on cell morphology showed 3 different types of basophils; A) Sphericalshaped basophils with short microvilli, B) Pear-shaped basophils with extended flag-like pseudopodia, C) 'Swollen' type basophils over glass-plates. 2) Investigations on surface structures demonstrated 3 different changes: a) Hemispheric projections or spindle-shaped processes on the cell surface, b) Irregular shaped pores among short rod-shaped microvilli, c) Ruptured cell membranes in marked swollen basophils. 3) Basophils in healthy controls did not show any changes of surface structures and were spherical when P.S.S., buckwheat and mite extracts were added. Similar results were obtained with basophils from atopic patients when P.S.S. were added. 4) Basophils from atopic patients, or basophils from healthy controls after passively sensitized with IgE rich serum, were pear-shaped or 'swollen' with surface structural changes.