Provided herein are methods of treating a subject, methods of predicting the response of a subject and selecting a subject suffering from a disease associated with KLK5, such as asthma or Netherton Syndrome. In particular, provided herein are uses of KLK5 antagonists for the treatment or diagnosis of asthma or Netherton Syndrome, such as an antibody or an Fc fusion polypeptide as well as pharmaceutical formulations comprising the same.