Morphological Alterations Affecting the Microvasculature in Nasal Allergy

Abstract

The fine structure of human nasal blood vessels was studied in 15 nasal allergic patients. Biopsies were taken at different stages after provocation. In the early stage (two minutes after provocation), characteristic alterations of capillaries and venules were congestion, gap formation between two endothelial cells, and swollen vascular endothelial cells. Evidence of locally increased vascular permeability and congestion causing mucosal edema was found. In the late stage (20 minutes after provocation), evidence of congestion disappeared. Vascular dilatation and marked interendothelial cell gaps were observed. In both perivascular space and sometimes in intravascular space, de-granulated eosinophils were observed, suggesting that not only histamine but also lysosomal enzymes in eosinphil granules may be involved in causing increased vascular permeability.