Kalmar "mastocyte" (wanda kuma aka rubuta "mast cell") yana nufin wani nau'i na tantanin halitta a cikin tsarin rigakafi wanda ke taka muhimmiyar rawa wajen rashin lafiyan halayen da kumburi. Ana samun mastocytes a cikin nama mai haɗawa a ko'ina cikin jiki, musamman a wuraren da ke kusa da tasoshin jini da jijiyoyi. Sun ƙunshi granules waɗanda ke adana histamine da sauran sinadarai waɗanda ake fitarwa lokacin da tantanin halitta ya kunna, yana haifar da rashin lafiyan ko kumburi. Mastocytes kuma suna taka rawa wajen warkar da raunuka da kuma kariya daga ƙwayoyin cuta.