Eosinophils, Basophils, and Beyond

Recognizing and interpreting these leukogram changes

“Worms, Wheezes, and Weird Diseases”

That’s one of the mnemonic devices I learned to remember what kinds of diseases cause an eosinophilia. Eosinophils are the front-line responder cell for hypersensitivity disorders mediated by IgE antibodies. Some of the cytokines that produce and recruit eosinophils also result in increased basophils and sometimes mast cells.

Eosinophils contain major basic protein (MBP), eosinophil peroxidase, and a number of other enzymes that can damage adjacent tissues. Basophils and mast cells can release histamine and heparin which will cause local vascular changes and impair hemostasis. These lesions are often grossly swollen and inflamed, and microscopically you may see fragments or degenerate collagen or rarely crystals formed from the granule contents.

For anyone interested, this study shows real-time videos of eosinophils in culture swarming worms to destroy them with those granules!

Diseases with Increased Eosinophils +/- Basophils and Mast Cells

The list below includes several of the more common diseases that are classically associated with an eosinophilic response. Keep in mind this is NOT a comprehensive list, and there are lots of, well, weird diseases that are uncommon that may also result in this pattern…