macrophages in the inflammatory response; they become the major cell type in the inflammatory site after the neutrophils are spent. At the same time that the macrophages become active at the site of inflammation, fibroblasts near the site and undifferentiated mesenchymal cells in the adventitia of small vessels at the site begin to divide and differentiate into fibroblasts and myofibroblasts that then secrete the fibers and ground substance of the healing wound. Like neutrophils, monocytes are attracted to the inflammatory site by chemotaxis. Lymphocytes, eosinophils, and basophils also play a role in inﬂammation, but they are more involved in the immunologic aspects of the process (see Chapter 14, Lymphatic System). Eosinophils and lymphocytes are more commonly found at sites of chronic inﬂammation.
Eosinophils are about the same size as neutrophils, and their nuclei are typically bilobed (Fig. 10.9; Plate 17, page 302). As in neutrophils, the compact heterochromatin of eosinophils is chiefly adjacent to the nuclear envelope, whereas the euchromatin is located in the center of the nucleus.
Eosinophils are named for the large, eosinophilic, refractile granules in their cytoplasm.
The cytoplasm of eosinophils contains two types of granules: numerous, large, elongated specific granules and azurophilic granules (otherwise, the eosinophil contains only a sparse representation of membranous organelles).
 FOLDER 10.4 Clinical Correlation: Inherited Disorders of Neutrophils; Chronic Granulomatous Disease (CGD)