The invention relates to an in vitro method for prognosis, diagnosis or determination of the evolution of a condition involving an altered production of Basic Proline-rich Lacrimal Protein (BPLP) or of any of its maturation products, by detecting, or quantifying in a biological sample of a test subject, a BPLP protein or a maturation product thereof, and comparing the production of BPLP protein or maturation product with the production of the same in a biological sample of a control subject.