Numerous orange-red granules of uniform size evenly fill the cytoplasm of eosinophils. They do not overlap the nucleus. The eosinophil granules contain multiple enzymes, including peroxidase, phospholipase D, catalase, acid phosphatase, and vitamin B12-binding proteins.
The eosinophil's ability to kill bacteria is less than that of neutrophils. Their primary purpose is to counteract parasitic infections and to participate in immune allergic reactions. They may also increase nonimmunologic inflammatory responses from bacteria and fungi, causing chronic infections.
A high percentage of eosinophils may be present in the peripheral blood smears of patients with a variety of non-neoplastic conditions, including:
- Asthma
- Urticaria
- Loeffler syndrome
- Parasitic infections
Malignancies, collagen vascular diseases, and myeloproliferative disorders may also be associated with prominent eosinophils.
