The inflammatory response to anaphylaxis and intravenous antibody or antigen

Immune complex-induced disseminated intravascular coagulation (DIC). An experimental study

Disseminated intravascular coagulation (DIC) was induced in rabbits by administration of antibody and antigen. The rabbits were sensitized passively by i.v. injection of antiferritin antiserum and challenged simultaneously by an i.p. inoculation of ferritin. After the challenge, circulating white blood cells, platelets and plasma fibrinogen levels showed an early fall, reaching minimum values at 3, 10 and 6 h, respectively. Fibrin thrombi appeared first at 2 h, reached a maximum at 5-7 h, and had mostly disappeared by 24 h. Formation of fibrin thrombi was frequent in the lung, liver, kidney and spleen. Early morphological changes included neutrophilic infiltration and accumulation of platelets in capillaries. Ferritin-antiferritin complexes were noted among fibrin thrombi or phagocytized by reticuloendothelial cells and neutrophils. The capacity of Kupffer cells to remove circulating immune complexes was saturated transiently; at this time fibrin thrombosis in various organs was most widespread and severe. It seems likely that formation of antigen-antibody complexes in the microcirculation initiates activation of platelets and neutrophils with subsequent release of mediators responsible for triggering DIC. Activation of complement was another possible factor inducing the reaction. In addition, blockade of the reticuloendothelial system promotes the progression of DIC. It is considered that the methods described constitute a useful model for further elucidation of immune complex-induced DIC.

A comparative study of the morphology of the systemic anaphylactic reaction (SAR) and the shock reaction induced by antigen-antibody complexes in rabbits

Differences in the morphological picture of the systemic anaphylactic reaction (SAR), and of the shock reaction induced by antigen-antibody (ag-ab) complexes in rabbits, are described. In rabbits SAR is characterized by acute distension of the lungs, with oedematous swelling in the vicinity of bronchi and veins, intravascular stasis of basophils without degranulation or visible fixation of the inducing antigen, small clusters of blood platelets, leukostasis, minimal decomposition of neutrophil granulocytes and absence of circulating or fixed ag-ab complexes. The shock reaction induced by ag-ab complexes is characterized by acute distension of the lungs without bronchospasm, swelling of the vicinity of bronchi and veins, hyaline thrombi particularly in the pulmonary microcirculation, leukostasis, formation of antigen-antibody complexes and thrombocyte clusters in the microcirculation, and by phagocytosis of these complexes and thrombocytes by various cells.

Fc and C3b receptors on pulmonary endothelial cells: induction by injury

Receptors for the activated third component of complement and for the Fc portion of immunoglobulin G are not expressed by apparently normal bovine pulmonary endothelial cells, but are expressed when the cells are exposed to white cell lysates or are infected with influenza or cytomegalovirus. The unmasking of these latent receptors may contribute to the pulmonary inflammatory response characteristic of, for example, anaphylaxis and to those lung diseases characterized by the deposition of immune complexes.