APPLICATIONS OF THE POLYMERASE CHAIN-REACTION (PCR) IN DIAGNOSIS

This paper reports on three applications of the polymerase chain reaction (PCR) in the pathology laboratory, cystic fibrosis carrier status investigation, Staphylococcus aureus identification and HLA-DQalpha tissue typing. Allele specific PCR was used to detect the common cystic fibrosis mutation (DELTAF508) in an Irish family. The genomic status of each member was shown to be either heterozygous (carrier) or homozygous (affected) for the mutation, based on the resolution of allelic amplifications in an agarose gel. Five staphylocci were subjected to PCR designed to amplify a 137 bp DNA fragment from the S. aureus protein A gene (spa). Four isolates gave a coloured ''dot-blot'' positive signal, the fifth was negative. In the final application the HLA-DQalpha region was amplified using DNA obtained from four unrelated individuals. Amplified DNA was tissue typed in a reverse ''dot-blot'' format. All individuals had unique HLA-DQalpha types. These examples have been chosen to demonstrate the versatility of this technique and to illustrate some of its potential applications.