Abstract
The pathogenesis of LCV depends initially upon antigenic stimulation of antibodies followed by immune complex formation. Instead of rapid clearing of these
immune complexes from the circulation, other factors come into play that result
in slowing of blood flow and exposure of antigen-antibody complexes to the
endothelial cells, complement activation, and increased vascular permeability. Several mediators of inflammation including TNF-a, IL-2, IL-8, and other proinflammatory chemokines and cytokines result in increased endothelial cell adhesion and
upregulation of endothelial cell adhesion molecules such as intercellular adhesion
molecule-1 or E-selectin (7,8). Coagulation is enhanced by factors such as plasminogen activator inhibitor (PAI-1) (9). Various downregulators of inflammation need to
be employed to stop the pathologic process including tissue plasminogen activator
that induces fibrinolysis and cytokines and chemokines produced by CD4 positive
lymphocytes, macrophages, and endothelial cells. Most likely, fibrogenic or hypercoagulable states enhance the blood-vessel damage in the presence of immune
complex formation. It is also possible, under certain circumstances of vasoconstriction induced by cold temperature, trauma, or other noxious stimuli, to induce
hypercoagulability. Prolonged active vasculitis with repeated recurrences may bring
about granulation response and fibrosis. Erythema elevatum diutinum is the
prototype of chronic fibrosing vasculitis. Thorough evaluation of CV should include
all factors that may lead to immune complex formation and a thorough investigation
of blood flow and coagulation.