Copyright ERS Journals Ltd 1997 European Respiratory Journal

Idiopathic pulmonary fibrosis (IPF) is an increasing-ly recognized problem with a generally poor prognosis [1]. Fifty per cent of patients diagnosed as having IPF may be expected to die within 4 yrs of the diagnosis [2]. Although termed idiopathic or cryptogenic it is increas-ingly acknowledged that an occult inhaled environmen-tal injury precipitates a common histological response, which manifests as the heterogeneous clinical syndrome, IPF [3, 4]. Since many patients date the onset of their symptoms to a viral infection or a "cold", there has been a sugges-tion that IPF may be an expression of injury precipitated or potentiated by a diagnostically occult viral infection. Previously, hepatitis C virus (HCV) [5] and Epstein-Barr virus (EBV) [6] have been implicated in the aetiology o