Comparative studies of impurities in intravenous immunoglobulin preparations.

In a comparative study, seven commercially available immunoglobulin preparations and one experimental preparation, processed by various manufacturers in the United States and Europe, were investigated for non-IgG proteins and impurities. The basic fractionation methodology affects the purity of subsequently processed intravenous preparations. Five of the seven products manufactured in Europe contained varying amounts of plasma proteins other than IgG. A residual heterologous protein was detected and quantitated in one product whose processing includes porcine pepsin treatment. Only one of the eight products was low in aggregates (as judged by both anticomplement activity and nephelometric turbidity), while three products contained anticomplement activity at levels high enough to be a potential cause of reactions in patients. In general, the level of prekallikrein activator activity was proportional to that of amidolytic activity; four products had only trace levels of amidolytic activity as well as prekallikrein activator. Only one product contained significant isoagglutinin levels, while six products had detectable IgA levels.