Renal disease and vasculitis

Childhood vasculitis

Vasculitis can and does occur in childhood. Apart from the relatively common vasculitides (Henoch-Schönlein purpura, Kawasaki disease and in world wide terms Takayasu disease) there are a number of important but comparatively rare disorders affecting children. These include macroscopic and microscopic polyarteritis, cutaneous polyarteritis, Wegener's granulomatosis, Churg-Strauss syndrome, primary angiitis of the central nervous system, hypersensitivity angiitis, hypocomplimentaemic urticarial vasculitis, vasculitis associated with various connective tissue disorders and vasculitis associated with conditions such as Behçets syndrome, familial Mediterranean fever and Cogan's syndrome. Distinguishing these conditions from other disorders is often difficult and requires clinical acumen and appropriate investigative procedures. With modern therapeutic agents, it is possible to implement appropriate therapy but in spite of this, there remains a not inconsequential morbidity and mortality.

Rare vasculitic syndromes

Vasculitis can and does occur in childhood. Apart from the common vasculitides (Henoch-Schönlein purpura, hypersensitivity angiitis and Kawasaki disease) there are a number of important but comparatively rare disorders affecting children. These include macroscopic and microscopic polyarteritis, cutaneous polyarteritis, Wegener's granulomatosis, Churg-Strauss syndrome, primary angiitis of the central nervous system, hypocomplimentaemic urticarial vasculitis, vasculitis associated with various connective tissue disorders, Takayasu's disease and vasculitis associated with conditions such as Behcet's syndrome, familial Mediterranean fever and Cogan's syndrome. Distinguishing these conditions from other disorders is often difficult and requires clinical acumen and appropriate investigative procedures. With modern therapeutic agents it is possible to implement appropriate therapy but in spite of this, there remains a not inconsequential morbidity and mortality.

The absence of anti-neutrophil cytoplasmic antibodies in patients with Henoch-Schönlein purpura

Sera from 14 patients with acute Henoch-Schönlein purpura (HSP) and 5 patients with a past history of HSP were assessed using a immunofluorescence technique for the presence of IgG, IgA, and IgM anti-neutrophil cytoplasmic antibodies (ANCA). There was no evidence of IgG, IgA, or IgM ANCA in the sera of these patients. These results suggest that ANCA are not involved in the pathogenesis of HSP.

Antibodies to endothelial cells in primary vasculitides mediate in vitro endothelial cytotoxicity in the presence of normal peripheral blood mononuclear cells

Twenty-eight out of 62 patients with Wegener's granulomatosis and micropolyarteritis display circulating antiendothelial cell antibodies (AECA) detectable by a cell surface radioimmunoassay. These antibodies do not induce an in vitro endothelial damage either alone or in the presence of fresh complement; however, 50% of IgG-AECA positive sera can be cytotoxic in the presence of human normal peripheral blood mononuclear cells (PBM) at high effector/target ratios. The specificity of the PBM-mediated cytotoxicity is supported by the absence of the phenomenon in AECA negative sera, by the disappearance of the lytic effect after absorption of AECA, and by the finding that cellular-mediated cytotoxicity can be reproduced by purified IgG-AECA positive fractions. On the contrary, polymorphonuclear leukocytes or adherent mononuclear cells are not involved in such a cytotoxic activity. AECA seem to be directed against determinants consitutively expressed on the endothelial surface since the activation of endothelial cells by interleukin-1 beta or interferon-gamma affects neither the antibody binding nor their ability to mediate 51Cr release in the presence of PBM. These findings favor the hypothesis for a possible direct pathogenetic role of circulating AECA in the in vivo vascular damage.