Hx: 48 y M, previous Chron’s disease and pneumonia, admitted with purpuric rash worsening in four limbsLab: c-ANCA+; ANA+; anti-MPO-Skin biopsy: leukocytoclastic vasculitis and multiple fibrin thrombi;Dx: levamisole adulterated cocaine-associated vasculitisTx: supportive therapy. The gene discussed is BTG3; the disease is susceptibility to pneumonia measurement.