Cystic Fibrosis sweat proteome was characterized by an increase in 25 proteins including proteases (Kallikrein 7 and 13, Phospholipase B domain containing 1, Cathepsin A L2 and B, Lysosomal Pro‐X carboxypeptidase); proinflammatory proteins (Annexin A2, Chitinase‐3‐like protein 1); cytochrome c and transglutaminases. This evidence concerns the gene KLK4 and cystic fibrosis.