Western blotting of FXI in purified FXI and 3 Rh immune globulin preparations. Note the presence of FXI 160-kDa dimer and 80-kDa FXI monomer in various concentrations of the WinRho preparation (W) under nonreduced and reduced conditions, respectively. The slanted bands at the higher concentrations of WinRho are caused by overloading the gels by IgG. A faint band is apparent at a high concentration of KamRhoD (K) and is displayed more conspicuously in the reduced gel. No FXI band is demonstrable for Rhophylac (R) but was measurable by ELISA (see “Results and discussion”).