IgA vasculitis is an acute disorder caused by perivascular deposits of IgA immune complexes and the recruitment of neutrophils that in turn cause fibrinoid destruction and leukocytoclastic vasculitis of small vessels of the skin, kidneys, gastrointestinal tract, and joints and occasionally can affect the lungs and central nervous system. The gene discussed is CD79A; the disease is Henoch-Schoenlein purpura.