Plasma protease inhibitors in alpha 1-antitrypsin-deficient children.

Seven plasma protease inhibitors were analyzed in 8-yr-old children-75 PiZ (severely deficient), one PiZ-(with a null gene), 32 PiSZ (moderately deficient), and 35 normals. In PiZ and PiSZ alpha 1-antitrypsin-deficient children, significantly higher concentrations of alph 2-macroglobulin (p less than 0.001) and antithrombin III (p less than 0.001) were found and significantly lower concentrations of alpha 2-antiplasmin (p less than 0.001), C1-inactivator (p less than 0.01) and plasminogen (PiZ p less than 0.02, PiSZ p less than 0.01). The inter-alpha-trypsin inhibitor concentrations differed in PiSZ children only (p less than 0.01). At this age the high alpha 2-macroglobulin levels may be of importance to protect the lung tissue against free proteolytic activity, while importance of the other differences are unknown or reflect changes of purely theoretical interest.