[Application of molecular biology techniques to pneumology].

Over the past ten years there has been fundamental progress in molecular biology, i.e. concerning the structure and function of genes. The understanding and diagnosis of several diseases, in particular those of the respiratory system, have been profoundly affected and changed. For example alpha-1-antitrypsin deficiency and the emphysema which results have now been dissected down to a molecular level and characterised by anomalies of certain critical portions of the gene coding for this protein. The same thing is found in cystic fibrosis where, thanks to recent technical progress, it is now possible to make a positive diagnosis in most unaffected carriers. The importance of molecular biology in lung cancer is equally established, and in small cell lung cancer one can already isolate a sub group of cancers presenting with an abnormal amplification of the c-myc oncogene. Finally, the role of inflammatory cells, in particular macrophages, in pulmonary fibrosis is best understood by studying the expression by macrophages of the genes coding for mediators which alter the replication of fibroblasts.