Abstract: Anti-neutrophilic cytoplasmic antibody (ANCA) positivity is seen in some systemic necrotizing vasculitides. Wegener’s granulomatosis and microscopic polyangiitis are among the ANCA-associated systemic vasculitides (AASV) and mortality is very high when renal failure occurs together with alveolar hemorrhage. The role of plasmapheresis in the treatment of these diseases has been studi…