They exert powerful antibacterialand antifungal activities, belonging to the host defense antimicrobialpeptides (AMPs), and thus are key components of the innate immunesystem.41,42 All the cystatins detectable in saliva,except cystatin B, showed a low abundance in the patients: S-typecystatins and cystatin A were less concentrated especially in SM patients,cystatin D-R26 were less concentrated in all the patients especially in CM patients,and cystatin C was almost absent. Here, CST4 is linked to systemic mastocytosis.