CONGENITAL DEFICIENCY OF HISTIDINE-RICH GLYCOPROTEIN - FAILURE TO IDENTIFY ABNORMALITIES IN ROUTINE LABORATORY ASSAYS OF HEMOSTATIC FUNCTION, IMMUNOLOGICAL FUNCTION AND TRACE-ELEMENTS

Histidine-rich glycoprotein (HRGP) has many biologic activities, but i ts physiologic function is still unclear. To show the physiologic func tion of HRGP, we studied five patients with congenital HRGP deficiency . Hemostatic screening tests, activities of natural anticoagulants and fibrinolytic proteins, markers of thrombin and plasmin generation, pl asma levels of platelet-specific proteins, thrombin times with various concentrations of bovine thrombin, prolongation of thrombin time afte r addition of heparin or dermatan sulfate, and contact activation of b lood coagulation were normal or nearly normal in these patients. Serum concentrations of immunoglobulin, functional activity of the classica l and the alternative pathway of complement, lymphocyte subsets, and s erum concentrations of soluble interleukin-2 receptor were approximate ly normal in all patients, and serum concentrations of copper and zinc were completely normal. These results suggest that the physiologic fu nctions of HRGP are limited when compared with its biologic activities . However, because the patients examined had plasma HRGP levels of 20% to 35% of normal, it is possible that 20% of normal HRGP level is suf ficient for its physiologic functions.