Low Protein Rh Immane Globulin (Rh IgG)

Abstract

After 16-32 months in solution at 4°C, ultracentrifuge and immunoelectrophoresis assays of five lots of low protein Rh IgG protein concentrations 3.9, 5.8, 4.1, 3.4 and 3.1%, revealed each lot to consist of a single unaggregated and unfragmented protein with an s20^w constant of 6.5-7.3. The lots were 94.0-98.5% pure IgG. Autoanalyzer studies demonstrated no loss of anti-D for 16-37 months except in one lot stable at 20 months which showed a drop from 363 to 298 μg/ml at 26 months. 125I antiglobulin measurements revealed a 23- to 40-percent early loss of anti-D with stability thereafter. Low protein Rh IgG cleared Rh-positive cells from 11 Rh-negative volunteers and protected 2,093 Rhnegative women at risk of Rh immunization at least as effectively as standard Rh IgG. Low protein Rh IgG is a pure, stable, active, protective and economical agent for use in Rh prophylaxis.