II. Characteristics
- Forms in Bone Marrow from Myeloblasts as with other Granulocytes (Neutrophils, Eosinophils, Monocytes)
- Basophil granules contain Heparin, vasoactive amines (Histamines, 5-Hydroxytryptamine)
- Released agents increase vascular permeability, allowing inflammatory agents to reach injured tissue
- Function: Immediate Allergic Response
- Similar mechanism of action to Mast Cells
- Related to delayed Hypersensitivity response
- Activated on binding IgE-Antigen complexes via high affinity receptors (FceRI)
- Activation results in release of inflammatory mediators contained in its secretory granules
- Immediate release of preformed mediators (e.g. Histamine, Bradykinin) within first 5 minutes
- Leukotriene C4 released within 5-30 minutes, and results in bronchoconstriction
- Releases Cytokines TNF-alpha and IL4 within hours
- Chemotactic factors attract Neutrophil, Eosinophil
III. Labs: Morphology on Blood Smear
- Granulocyte cytoplasm stains darkly with Wright Stain
- Two lobed nucleus
- Diameter: 5-7 microns
IV. Interpretation: Normal Levels
- Range: 0.4-1.0% (Least common Leukocyte)
V. Causes: Increased Basophils (Basophilia)
- Viral Infections (e.g. Varicella)
- Hodgkin's Lymphoma
- Hemolytic Anemia
- Following splenectomy
- Myeloproliferative disease
- Inflammatory processes
- Inflammatory Bowel Disease
- Chronic dermatitis
- Asthma
- Chronic Sinusitis
- Endocrine causes
- Hypothyroidism
- Increased Estrogen
VI. Causes: Decreased Basophils
- Stress
- Hypersensitivity Reaction
- Corticosteroids
- Pregnancy
- Hyperthyroidism
VII. References
- Mahmoudi (2014) Immunology Made Ridiculously Simple, MedMaster, Miami, FL
- Siracusa (2013) J Allergy Clin Immunol 132(4): 789-801 +PMID: 24075190 [PubMed]