Non-immune Complex-mediated and Non-autoimmune Systemic Vasculitis
The next section is devoted to systemic vasculitis diseases with pathogeneses not involving immune complexes or autoantibodies.
Kawasaki Disease
Kawasaki disease is an acute febrile mucocutaneous and lymph node illness affecting children of mainly Asian ancestry. The most cumbersome coincident complication of Kawasaki disease is medium-sized vessel vasculitis leading to coronary artery lesions, which can be effectively prevented by early treatment with intravenous immunoglobulins.
Growing indications suggest that plasma exchange is effective therapy for Kawasaki disease and especially for the therapeutically challenging subset of cases that fail to respond to intravenous immunoglobulin therapy. In a retrospective analysis of 125 children with Kawasaki disease unresponsive to intravenous immunoglobulin therapy, one to three plasma exchange sessions performed on consecutive days resulted in clinical improvement in all patients and a low rate of late coronary artery lesions, especially when plasma exchange were initiated before day 9 of disease onset. Another retrospective case series of 75 children with Kawasaki disease refractory to two courses of intravenous immunoglobulin therapy showed a significantly lower rate of coronary artery lesions with plasma exchange than with a third course of intravenous immunoglobulin therapy. Plasma exchange has also been reported as effective emergency therapy for children with Kawasaki disease refractory to intravenous immunoglobulin therapy who present life-threatening congestive heart failure. The mechanism of action of plasma exchange in Kawasaki disease is unclear and may be explained by elimination of proinflammatory cytokines or etiological agents.
Idiopathic Polyarteritis Nodosa and Churg-Strauss Syndrome
Idiopathic,non-HBV-related polyarteritis nodosa and Churg–Strauss syndrome are among the medium-sized and small-sized vessel vasculitides, repectively. Inaddition,Churg–Strauss syndrome is characterized by positive ANCA serology in approximately 40% of cases, as well as blood and tissue eosinophilia, asthma and other allergic diatheses. Considering these two diseases together is elicited by the fact that they are combined in clinical studies, although this approach is questionable because they likely have distinct underlying pathogeneses.
Available data do not suggest a benefit of plasma exchange for polyarteritis nodosa and Churg– Strauss syndrome. Two randomized studies assessing the efficacy and tolerance of plasma exchange in addition to standard immunosuppressive therapy did not show an additional effect of plasma exchange in reducing relapse rates. These negative findings need to be viewed in light of the limitation that plasma exchange was tested in unselected patients. Whether plasma exchange may be useful for polyarteritis nodosa or Churg–Strauss syndrome with severe manifestations or refractory to first-line therapy is not known.
Miscellaneous Systemic Vasculitis
Only anecdotal evidence exists for the utility of plasma exchange in other forms of systemic vasculitis. Earlier case reports of plasma exchange for Behçet's disease reported on cure of uveitis or skin disease refractory to first-line therapy. These findings were not followed up with further investigation, and plasma exchange likely has become obsolete for Behçet's disease with the advent of other effective therapies. Virtually, no data are available to support a role of plasma exchange in large vessel vasculitis (i.e. giant cell arteritis, Takayasu arteritis or idiopathic inflammatory aortitis), and we lack a clear underlying mechanistic rationale for this therapeutic approach.