Detection and characterization of hepatitis C virus RNA in immune globulins

Abstract

Many immune globulin preparations contained HCV RNA, with levels depending upon both the type of starting plasma and the manufacturing process. Exposure to ethanol did not appear to affect the physical characteristics of HCV RNA.

Neutralizing antibodies to hepatitis C virus (HCV) in immune globulins derived from anti-HCV-positive plasma

“…Furthermore, the HCV in this lot had a low buoyant density, 1.08 g͞ml (15) (determined by sucrose gradient ultracentrifugation), suggesting that the virus was not complexed with antibody (3,21). This finding was in contrast to the buoyant density of HCV recovered from anti-HCV-positive immune globulin, 1.16 g͞ml, as found in intramuscular globulin derived from plasma that was not screened for anti-HCV (13) or found in plasma from patients chronically infected with HCV (21).…”

“…Before 1993, globulin-related transmission of hepatitis C by licensed products had not been reported in the U.S. The mechanism of this apparent safety of immune globulins before the Gammagard incident was unknown, although the possible neutralization of HCV by antibodies in products not screened for such antibodies had long been suspected (13,32). Epidemiological and laboratory follow-up studies of the Gammagard incident revealed the following:…”

“…The presence of HCV RNA in plasma or its derived product does not necessarily equate with infectivity, especially when anti-HCV antibodies are present as immune complexes (13,15). It has been suggested that when HCV is present as circulating immune complexes, its infectivity is lower (21).…”

“…immune globulin (IGIV) product prepared from pooled plasma from which anti-HCV-positive plasma donations were excluded transmitted HCV to recipients. Epidemiologic and laboratory studies suggested that such screening might have removed complexing and͞or Nt Abs from plasma and hence compromised the safety of the immune globulins (9,(11)(12)(13)(14)(15)(16).…”

“…The second PCR step was performed by adding 5-l aliquots of the first PCR product to the same ingredients and incubating them under the same conditions as described for the first PCR step but with the inner primer pair (nucleotides 57-76, 5Ј-ACTGTCTTCACGCAGAAAGC, and nucleotides 312-293, 5Ј-ACTCGCAAGCACCCTATCAG). The amount of HCV RNA, expressed as copies per ml, was determined by limiting dilution analysis as described (13). In the RT-PCR assays, two to four copies of HCV RNA were equivalent to 1 international unit when compared to the established international standard for HCV RNA (22).…”