Autoimmune-like pulmonary disease in association with parvovirus B19 - A clinical, morphologic, and molecular study of 12 cases

Parvovirus B19, the agent responsible for fifth disease, has been emerging as a significant pathogenetic factor in various acute vasculitic syndromes such as Wegener's granulomatosis, Henoch-Schonlein purpura, and Kawasaki disease. It has also been implicated in more chronic vasculopathic syndromes, specifically in the context of scleroderma and dermatomyositis. The basis of this association is likely multifactorial; implicated mechanisms include the virus's affinity for endothelium, resulting in a state of neoantigenicity through varied mechanisms as well as the induction of tumor necrosis factor alpha, a factor involved in the propagation of ANCA-positive vasculitic syndromes. The authors present a series of 12 patients with interstitial lung disease including idiopathic pulmonary fibrosis, scleroderma-associated pulmonary fibrosis, lymphocytic interstitial pneumonitis, and septal capillaritis. In all cases there was evidence of chronic parvovirus B19 infection based on serologic assessment and the isolation of B19 DNA on lung samples in all patients. Furthermore, in two cases there was in situ localization of B19 RNA and tumor necrosis factor alpha to endothelium and stromal cells. On pathologic examination, there were varying degrees of both septal fibrosis and inflammation along with evidence of septal capillary injury. In those cases categorized as representing either sclerodema or idiopathic pulmonary fibrosis, the immunofluorescent studies showed evidence of anti-endothelial cell antibody formation. The ANCA-associated syndromes were, as expected, negative by fluorescent analysis. Significantly elevated factor VIII levels, a standard serologic index of endothelial cell injury, were seen in four of the six patients tested. The antiphospholipid profile revealed antiphospholipids in 7 of the 1 I patients tested. This report highlights a possible causal role for parvovirus B19 in the pathogenesis of select pulmonary disorders.