Evidence of granule discharge in the bone marrow reserve heterophils after acute anaphylactic shock in the guinea pig.

The heterophils in circulating blood and bone marrow were investigated in sensitized guinea pigs after acute anaphylactic shock (AAS) induced by inhalatory antigen challenge. Using histochemical, ultrastructural and in vitro methods evidence was obtained of a granule discharge from bone marrow reserve heterophils (BMRH). The mean number of primary (Biebrich scarlet positive) granules in BMRH decreased from 91 +/- 23 in the control to 74 +/- 23 after AAS. After AAS about 40% of BMRH and numerous circulating heterophils exhibited in the cytoplasm lucent areas which were surrounded by aggregates of granules. Only about 33% of BMRH were not affected by AAS. The rest of the cells showed different stages of granule aggregation and the lucent areas in the cytoplasm. Bone marrow basophils exhibited an early stage of degranulation. Almost 5% of BMRH ingested basophilic granules after AAS. Neither mortality rates in cytotoxicity tests nor antigen binding capacity were different in the experimental and control groups. It is suggested that the heterophils have a regulatory function during the anaphylactic reaction.