THE PANCREATITIS-ASSOCIATED PROTEIN (PAP) - A NEW CANDIDATE FOR NEONATAL SCREENING OF CYSTIC-FIBROSIS

Neonatal screening of cystic fibrosis (CF) is presently based on immun oreactive trypsin (IRT) assay in blood spots, whose low specificity is a matter of concern. Because the pancreatitis-associated protein (PAP ) proved to be a better serum marker of pancreatic alteration than exo crine enzymes, it might be an interesting alternative for CF screening . We report here a preliminary evaluation of the PAP test, conducted i n retrospect on blood spots from groups of neonates already screened f or CF with the IRT. Neonates with elevated IRT were submitted to subse quent analysis of the Cystic Fibrosis Transmembrane Conductance Regula tor (CFTR) gene. Neonates with normal IRT (n=990) or high IRT but norm al genotype (n=28) had normal PAP. Elevated PAP was observed in all CF neonates (n=11). False-positives for the PAP test were found only amo ng neonates with high IRT and heterozygotes for a mutation in the CFTR gene (6 out of 17 cases). That group represents less than 0.2% of new borns. These results therefore suggest that PAP discriminates CF neona tes with a significantly better specificity than IRT.