Inhaled platelet-activating factor causes pulmonary neutrophil sequestration in normal humans

Am Rev Respir Dis. 1992 Oct;146(4):1003-8. doi: 10.1164/ajrccm/146.4.1003.


Inhaled platelet-activating factor (PAF) causes bronchoconstriction and transient peripheral neutropenia in humans. We studied eight normal subjects to investigate whether inhaled PAF caused pulmonary neutrophil sequestration. All subjects received autologous 99mTc-red cells as a blood pool marker, seven received 111In-neutrophils, and one received 111In-platelets. Six subjects inhaled 48 micrograms of PAF. There was immediate pulmonary sequestration of 111In-neutrophils, maximal (218% baseline) at 6 min (p less than 0.001), returning to normal by 3 h. There was no change in circulating platelet count or pulmonary 111In-platelet transit. Methacholine inhalation caused equivalent bronchoconstriction to PAF, but it had no effect on neutrophil count or pulmonary 111In-neutrophil activity. We have demonstrated pulmonary neutrophil, but not platelet, sequestration after PAF. This supports a role for PAF as an inflammatory mediator in humans. This may be a useful model for exploring pulmonary neutrophil kinetics and preinflammatory processes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Inhalation
  • Adult
  • Blood Platelets / drug effects
  • Blood Platelets / physiology
  • Bronchial Provocation Tests
  • Erythrocytes
  • Humans
  • Indium Radioisotopes
  • Lung / diagnostic imaging*
  • Male
  • Neutrophils / drug effects
  • Neutrophils / physiology*
  • Organometallic Compounds
  • Platelet Activating Factor / administration & dosage
  • Platelet Activating Factor / pharmacology*
  • Platelet Count
  • Radionuclide Imaging
  • Technetium
  • Time Factors
  • Tropolone / analogs & derivatives


  • Indium Radioisotopes
  • Organometallic Compounds
  • Platelet Activating Factor
  • indium tris(tropolonate)
  • Technetium
  • Tropolone