A modified caprylic acid method for manufacturing immunoglobulin G from human plasma with high yield and efficient virus clearance.

BACKGROUND AND OBJECTIVES: The increasing demand for intravenous immunoglobulin (IVIG) necessitates the development of improved plasma fractionation methods, providing higher immunoglobulin G (IgG) recovery. Here, we describe a new IVIG production process resulting in a high yield of IgG and effective reduction of physico-chemically resistant viruses.

MATERIALS AND METHODS: IgG was purified from Cohn fraction II+III by caprylic acid treatment, polyethylene glycol precipitation, anion-exchange chromatography, nanofiltration and ultrafiltration. Stability of the purified IgG was studied in different formulations. Virus reduction was studied with two viruses: bovine viral diarrhoea virus, assessed by an infectivity assay; and human parvovirus B19, assessed by polymerase chain reaction.

RESULTS: The combination of caprylic acid treatment with polyethylene glycol precipitation and a single anion-exchange chromatography yielded polymer-free, pure IgG. The purified IgG could be filtered through a small pore-size virus filter (Millipore V-NFP) with high throughput and excellent yield. The formulated product was stable as a 100 g/l IgG solution. Bovine viral diarrhoea virus was effectively inactivated by the caprylic acid treatment, and parvovirus B19 was effectively removed in the polyethylene glycol precipitation and nanofiltration stages, the total reduction of parvovirus being approximately 14 log10.

CONCLUSIONS: The new process gives pure and stable IgG solution with an average yield of 4.8 g of IgG per kg of recovered plasma and has a very high capacity to remove even physico-chemically resistant viruses.