Editor,—The report of Hackinget al,1 of a series of infants with very early onset interstitial lung disease (ILD) with good prognosis, is of great clinical interest but sadly represents a lost investigative opportunity.

Firstly, their statement that percutaneous open lung biopsy has fewer side effects than open lung biopsy (OLB) is not supported by any direct comparative trial, and cannot be allowed to stand. Indeed, the largest published series using this technique2 was heavily criticised both for the number of complications and the often non-diagnostic samples obtained.3 ,4 By contrast OLB is safe,5 permits direct inspection of the site of biopsy, and allows the acquisition of specimens large enough to determine the lung architecture in order more precisely to classify the different types of paediatric ILD. OLB thus allows appreciation of the distribution of disease involvement within the acinus, allowing …

Dr D Hacking, Paediatric Specialist Registrar, Department of Paediatrics, Wexham Park Hospital, Slough, UK (hackandmack{at}lwcdial.net).