Oriented fibrin crystallization: a phenomenon of hypersensitivity to bacteria in psoriasis, vasculitis and other dermatoses

Heparinized blood from patients with a variety of dermatological problems was incubated with killed bacteria, bacterial extracts or Gram-negative bacterial endotoxin. Within 18-24 h asteroid bodies consisting of an amorphous centre with fine radiating needle crystals were seen. These bodies, not found in the blood of healthy volunteers, were most consistently observed in blood from patients with psoriasis, vasculitis and bacterial infections. Immunofluorescent studies disclosed the asteroid formations to be crystals of fibrin radiating presumably from a central platelet aggregate. The failure to demonstrate IgG, A, M or D suggests that the phenomenon results from the bacterial activation of complement by a non-immune yet specific pathway which in turn involves white cells, platelet aggregation and release of procoagulants.