Granulocytów

Granulocytów refers to the group of white blood cells known as granulocytes, which are characterized by the presence of cytoplasmic granules and play a central role in the innate immune response. These cells are produced in the bone marrow from myeloid precursor cells and enter the bloodstream as mature neutrophils, eosinophils, or basophils. Each subtype is distinguished by its granule content, staining properties, and specific functions. Neutrophils, the most abundant granulocytes, are frontline defenders against bacterial and fungal infections; they patrol blood and tissues, phagocytose pathogens, and release antimicrobial proteins and reactive oxygen species. Eosinophils are specialized for combating parasites and modulating allergic reactions; they release cytotoxic granules and cytokines that influence immune cell recruitment. Basophils, the least numerous, contribute to allergic inflammation and are key mediators of histamine-driven vascular responses.

Morphologically, granulocytes differ in nuclear segmentation: neutrophils typically possess a multilobed nucleus, eosinophils a bilobed nucleus, and basophils a bilobed or lobed nucleus. The granules within these cells are visible under light microscopy and differ chemically: eosinophil granules contain major basic protein and eosinophil peroxidase, whereas neutrophil granules contain azurocidin, lactoferrin, and neutrophil elastase. Granule content also determines staining characteristics; for example, eosinophil granules stain bright red with eosin, basophil granules stain blue with methylene blue.

The number and proportion of granulocytes can be assessed by a complete blood count and differential. Abnormal granulocyte counts may indicate infection, inflammation, bone marrow disorders, or autoimmune diseases. In acute neutrophilia, elevated neutrophils often accompany infection, whereas neutropenia predisposes individuals to bacterial and fungal infections. Eosinophilia is associated with parasitic infections, allergic disorders, and certain malignancies. Basophilia is less common but may be seen in myeloproliferative diseases. Diagnosis and monitoring of granulocytosis or granulopenia guide therapeutic decisions in a variety of clinical settings.