Quantitative studies of argyrophilic APUD cells in airways. III. The effects of sensitization and anaphylactic shock.

A morphometric study of argyrophilic APUD cells in airways and intestine of guinea pigs during sensitization with ovalbumin and anaphylactic shock is reported. The APUD cell densities are expressed as APUD cell number/mm of airway or gut perimeter length and as APUD cell/100 epithelial cells. The latter ratio is useful to distinguish specific changes in APUD cells from generalized epithelial changes. Control guinea pigs have greater densities of APUD cells in the larynx (0.075 +/- 0.021 APUD/100 nuclei) than in more distal airways: trachea (0.025 +/- 0.007), bronchi (0.013 +/- 0.003), and bronchioles (0.003 +/- 0.002). In the ileal mucosa APUD cells are present in greatest density: 10.0 +/- 3.0 APUD/100 nuclei. Immunization with ovalbumin followed by sham challenge with saline results in 2- to 10-fold increases in APUD cell densities in all airway sectors as compared to control subjects. These differences are statistically significant in the trachea and bronchioles when ratios of APUD cells/mm are compared to control subjects but only in bronchioles when the ratios of APUD cells/100 nuclei are calculated. Immunization with ovalbumin followed by challenge with this antigen results in similar changes in large airways. However, bronchiolar APUD cells exhibit a 30-fold decrease in density when compared to immunized-sham challenged animals within the limits of our ability to quantitate them. Our findings suggest that argyrophilic APUD cells participate in the complex physiologic events that take place in the lung during sensitization and anaphylaxis.