Four cases of anti-myeloperoxidase antibody-related rapidly progressive glomerulonephritis during the course of idiopathic pulmonary fibrosis

We report here 4 cases of rapidly progressive glomerulonephritis (RPGN) whi ch developed during the management of idiopathic pulmonary fibrosis. In eac h patient, pulmonary disease preceded the onset of nephritis by 1 to 6 year s, All patients had a high titer of serum autoantibodies against myeloperox idase (MPO-ANCA) when the diagnosis of RPGN was made. Although the associat ion of pulmonary fibrosis with ANCA-related glomerulonephritis has been occ asionally described in the past literature, the sequence of pulmonary and r enal injury has not been well defined. The present report demonstrates that idiopathic pulmonary fibrosis exists as a preceding condition in some pati ents with MPO-ANCA-related nephritis.