kaolinite and Asthma

Bradykinin release, an end product of contact system activation, is thought to play a significant role in the pathophysiology of asthma. We have found an increased level of native alpha 2-macroglobulin-kallikrein (alpha 2M-KK) in asthma plasmas, and have demonstrated increased levels of contact system activity in these plasmas under certain laboratory conditions. We investigated the possible role of alpha 2M-KK as a modulator of the contact system activity. Alpha 2M-KK potentiated the factor XII activation on kaolin and the kallikrein production in a dextran-sulfate-mediated assay. This potentiation presumably involves a proteolytic effect of alpha 2M-KK on high molecular weight kininogen.

Topics: alpha-Macroglobulins; Asthma; Dextran Sulfate; Dextrans; Dose-Response Relationship, Drug; Drug Synergism; Factor XII; Factor XIIa; Humans; Kallikreins; Kaolin; Kininogens; Methods; Peptide Fragments; Prekallikrein

Factors of significance for the release of kinin were estimated in plasma from patients with specific, exogenous allergies and in that from healthy individuals. There was no evidence that the rapid initial kinin release in plasma from allergic patients caused by submaximum concentrations of hog pancreas kalikrein or by acetone-activated human plasma (2) was due to an increased level of prekallikrein activator (activated factor XII), to prekallikrein itself or to a factor possibly positioned between active factor XII and prekallikrein. In addition, the rapid halt in kinin release observed for the patient plasma could not be ascribed to an increased level of alpha2-macroglobulin, CI-inactivator or alpha1-antitrypsin. It is suggested that the differences in kinin release registered between the patient plasma and the normal plasma might reflect differences in the relative amounts of kininogen fractions present.

Topics: Acetone; Adolescent; Adult; Aprotinin; Asthma; Enzyme Activation; Esterases; Humans; Hypersensitivity; Kallikreins; Kaolin; Kinins; Prekallikrein