• Characterised by Inflammation and damage
to blood vessels.
• Vessel lumen is usually compromised .
• Leads to ishemia of the tissues supplied.
• It may involve a single organ(skin) or it may
involve multiple organs.
Vasculitis may be primary-
I. The primary vasculitis syndromes.
It may be secondary to
1. Infections(Rickettsia, Neisseria,Syphilis,
2. Other Autoimmune diseases(SLE, Rheum.
Immune complex formation and/or
Anti Neutrophil Cytoplasmic Antibodies
T lymphocyte activation with granuloma
Direct Antibody mediated.
Immune complexes get deposited in vessel wall
Activation of Complement components (C5a which is
strongly chemotactic for neutrophils)
Neutrophils phagocytose immune complexes and
release their intracytoplasmic enzymes that damage
the vessel wall.
As the process becomes sub acute or chronic,
mononuclear cells infiltrate the vessel wall.
Many patients with active vasculitis do not
have demonstrable circulating or deposited
The Antigens present in the complexes are
Exeptions are most cases of PAN (hepatitis
B antigen) and Cryoglobulinemic vasculitis
(Hepatitis C antigen)
So the causal role of immune complexes
has not been established in most of the
Antibodies against certain protiens in the
cytoplasmic granules of neutrophils and monocytes
are present in the serum of certain patients with
These are the ANCA associated vasculitis
cANCA is directed against cytoplasmic protienase 3
p ANCA is directed against perinuclear
Either ANCA may be present in any of the
ANCA associated vasculitides.
c ANCA is typically seen in
Wegners granulamatosis with
p ANCA is seen in most cases of
Microscopic polyangitis and
Churg Strauss Syndrome.
Patients may have Wegners granulamatosis
with polyangitis in the absence of ANCA
Titer of antibodies does not correlate with
Patients who are in remission from Wegners
may continue to have high cANCA titers.
Thus the role of these auto antibodies in
pathogenesis of systemic vasculitis remains
Endothelial cells may express HLA II
molecules at their surface similar to antigen
presenting cells. ( following activation
CD4+ T cells get activated following
interaction with these endothelial cells.
Propogation of immunological processes
resulting in cell mediated injury, granuloma
formation, delayed hypersensitivity.
In Kawasaki disease (Mucocutaneous Lymph
Node syndrome), 25% cases are associated
with coronary artery aneurism.
Vasculitis of the coronary arteries are found
in virtually all cases that had been autopsied.
Anti- Endothelial Cell antibodies are believed
to play the central role.