Non-A, non-B hepatitis from intravenous immunoglobulin

The Evolution of the Safety of Plasma Products from Pathogen Transmission-A Continuing Narrative

Chronic recipients of plasma products are at risk of infection from blood-borne pathogens as a result of their inevitable exposure to agents which will contaminate a plasma manufacturing pool made up of thousands of individual donations. The generation of such a pool is an essential part of the large-scale manufacture of these products and is required for good manufacturing practice (GMP). Early observations of the transmission of hepatitis by pooled plasma and serum led to the incorporation of heat treatment of the albumin solution produced by industrial Cohn fractionation of plasma. This led to an absence of pathogen transmission by albumin over decades, during which hepatitis continued to be transmitted by other early plasma fractions, as well as through mainstream blood transfusions. This risk was decreased greatly over the 1960s as an understanding of the epidemiology and viral aetiology of transfusion-transmitted hepatitis led to the exclusion of high-risk groups from the donor population and the development of a blood screening test for hepatitis B. Despite these measures, the first plasma concentrates to treat haemophilia transmitted hepatitis B and other, poorly understood, forms of parenterally transmitted hepatitis. These risks were considered to be acceptable given the life-saving nature of the haemophilia treatment products. The emergence of the human immunodeficiency virus (HIV) as a transfusion-transmitted infection in the early 1980s shifted the focus of attention to this virus, which proved to be vulnerable to a number of inactivation methods introduced during manufacture. Further developments in the field obviated the risk of hepatitis C virus (HCV) which had also infected chronic recipients of plasma products, including haemophilia patients and immunodeficient patients receiving immunoglobulin. The convergence of appropriate donor selection driven by knowledge of viral epidemiology, the development of blood screening now based on molecular diagnostics, and the incorporation of viral inactivation techniques in the manufacturing process are now recognised as constituting a "safety tripod" of measures contributing to safety from pathogen transmission. Of these three components, viral inactivation during manufacture is the major contributor and has proven to be the bulwark securing the safety of plasma derivatives over the past thirty years. Concurrently, the safety of banked blood and components continues to depend on donor selection and screening, in the absence of universally adopted pathogen reduction technology. This has resulted in an inversion in the relative safety of the products of blood banking compared to plasma products. Overall, the experience gained in the past decades has resulted in an absence of pathogen transmission from the current generation of plasma derivatives, but maintaining vigilance, and the surveillance of the emergence of infectious agents, is vital to ensure the continued efficacy of the measures in place and the development of further interventions aimed at obviating safety threats.

Breakthroughs in hepatitis C research: from discovery to cure

In the 1970s, an unknown virus was suspected for documented cases of transfusion-associated hepatitis, a phenomenon called non-A, non-B hepatitis. In 1989, the infectious transmissible agent was identified and named hepatitis C virus (HCV) and, soon enough, the first diagnostic HCV antibody test was developed, which led to a dramatic decrease in new infections. Today, HCV infection remains a global health burden and a major cause of liver cirrhosis, hepatocellular carcinoma and liver transplantation. However, tremendous advances have been made over the decades, and HCV became the first curable, chronic viral infection. The introduction of direct antiviral agents revolutionized antiviral treatment, leading to viral eradication in more than 98% of all patients infected with HCV. This Perspective discusses the history of HCV research, which reads like a role model for successful translational research: starting from a clinical observation, specific therapeutic agents were developed, which finally were implemented in national and global elimination programmes.

Passive Serum Therapy to Immunomodulation by IVIG: A Fascinating Journey of Antibodies

The immunoregulatory and anti-infective properties of normal circulating polyclonal Abs have been exploited for the therapeutic purposes in the form of IVIG as well as several hyperimmune globulins. Current knowledge on the therapeutic use of normal Igs is based on the discoveries made by several pioneers of the field. In this paper, we review the evolution of IVIG over the years. More importantly, the process started as an s.c. replacement in γ globulin-deficient patients, underwent metamorphosis into i.m. Ig, was followed by IVIG, and is now back to s.c. forms. Following successful use of IVIG in immune thrombocytopenic purpura, there has been an explosion in the therapeutic applications of IVIG in diverse autoimmune and inflammatory conditions. In addition to clinically approved pathological conditions, IVIG has been used as an off-label drug in more than 100 different indications. The current worldwide consumption of IVIG is over 100 tons per year.

Historical Aspects of Polyclonal IgG Preparations

Today we can choose between several polyclonal IgG products for both replacement and immunomodulation. However, it was a long way to go to reach this stage. In this chapter, we try to illustrate the major stages of IgG product development which began more than 70 years ago.

Immunoglobulin: production, mechanisms of action and formulations

Human immunoglobulin (Ig) began to be applied in the clinical practice with the treatment of primary immunodeficiencies. Quickly, applications of Ig increased, as its anti-inflammatory and immunomodulatory functions were elucidated. Currently, Ig is the most commonly used blood product. Ig is obtained by processing plasma; methods, in particular, techniques to reduce plasma viral loads have been evolving over the years and include: pasteurization, solvent/ detergent treatment, caprylic acid treatment and nanofiltration. These methods contribute to increased safety and quality of blood products. The mechanisms of action of Ig not only involve the blockade of Fc receptors of phagocytes, but also control complement pathways, idiotype-anti-idiotype dimer formation, blockage of superantigen binding to T cells, inhibition of dendritic cells and stimulation of regulatory T cells (Tregs). There are several formulations of Ig available, each one with its own peculiar characteristics. In Brazil, there is stringent legislation regulating the quality of Ig. Only Ig products that completely fulfill the quality control criteria are released for use. These standards involve different tests from visual inspection to determination of anti-complementary activity. This paper will further review the history and current status of Ig, including its production and mechanisms of action. The formulations available in Brazil and also the criteria of quality control currently applied will be presented.

Intravenous immunoglobulin G: trends in production methods, quality control and quality assurance

Intravenous immunoglobulin G (IVIG) is now the leading product obtained by fractionation of human plasma. It is the standard replacement therapy in primary and acquired humoral deficiency, and is also used for immunomodulatory therapy in various autoimmune disorders and transplantation. Over the last 30 years, the production processes of IVIG have evolved dramatically, gradually resulting in the development of intact IgG preparations safe to administer intravenously, with normal half-life and effector functions, prepared at increased yield, and exhibiting higher pathogen safety. This article reviews the developments that have led to modern IVIG preparations, the current methods used for plasma collection and fractionation, the safety measures implemented to minimize the risks of pathogen transmission and the major quality control tests that are available for product development and as part of mandatory batch release procedures.

Intravenous immunoglobulins: evolution of commercial IVIG preparations

Since its first use in 1952, human immunoglobulin has been used to treat people who have inherited antibody deficiencies. This article summarizes IVIG clinical development in primary immunodeficient patients and manufacturing improvements introduced over time. Manufacturing improvements include purification procedures that have reduced the incidence of adverse events and improved clinical efficacy, as well as virus inactivation and removal steps that have increased safety from blood-borne infections. Current manufacturing procedures, IVIG production trends, and recent clinical trial results are also reviewed.

Pathogen inactivation and removal procedures used in the production of intravenous immunoglobulins

Patients with immunodeficiencies or some types of autoimmune diseases rely on a safe therapy with intravenous immunoglobulins (IVIGs) manufactured from human plasma, the only available source for this therapeutic. Since plasma is predisposed to contamination by a variety of blood-borne pathogens, ascertaining and ensuring the pathogen safety of plasma-derived therapeutics is a priority among manufacturers. State-of-the-art manufacturing processes provide a high safety standard by incorporating virus elimination procedures into the manufacturing process. Based on their mechanism these procedures are grouped into three classes: partitioning, inactivation, and virusfiltration.

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.

Virus safety of intravenous immunoglobulin: future challenges

Patients with immunodeficiencies or some types of autoimmune diseases are dependent on safe therapy with intravenous immunoglobulins. State-of-the-art manufacturing processes provide a high safety standard by incorporating virus elimination procedures into the manufacturing process. Based on their mechanism, these procedures are grouped into three classes: partitioning, inactivation, and removal based on size. Because of current socioeconomic and ecological changes, emerging pathogens continue to be expected. Such pathogens may spread very quickly because of increased intercontinental traffic. Severe acute respiratory syndrome-coronavirus and the West Nile virus are recent examples. Currently, it is not possible to predict the impact such a pathogen will have on blood safety because the capacity for a globally coordinated reaction to such a threat is also evolving. The worst-case scenario would be the emergence of a transmissible, small, nonenveloped virus in the blood donor population. Examples of small nonenveloped viruses, which change host and tissue tropism, are discussed, with focus on parvoviridae. Although today's immunoglobulins are safer than ever, in preparation for future challenges it is a high priority for the plasma industry to proactively investigate such viruses on a molecular and cellular level to identify their vulnerabilities.

Women With Primary Antibody Deficiencies Requiring IgG Replacement Therapy: Their Perception of Prenatal Care During Pregnancy

OBJECTIVE

To investigate how a group of women with primary antibody deficiencies (PAD) and receiving replacement therapy with IgG experienced the care they received in their prenatal clinics in relation to PAD and IgG therapy.

DESIGN

An exploratory study using a written questionnaire.

SETTING

The study originates from an immunodeficiency unit but evaluates care experienced at prenatal clinics.

PARTICIPANTS

Nine women (25-43 years) attending an immunodeficiency unit and who fulfilled inclusion criteria for simultaneously having PAD, replacement IgG therapy, and full-term pregnancy (the latter within the past 5 years).

MAIN OUTCOME

Women's perception of the response of midwives and physicians at their prenatal clinics to their PAD and IgG therapy during pregnancy.

RESULTS

Women perceived that the obstetricians and the midwives had insufficient knowledge about PAD and IgG replacement therapy. Two women reported that their IgG therapy during pregnancy had been questioned. All nine women felt marginalized and unheard by staff regarding their PAD and need for IgG therapy. However, the women were satisfied with the checkups regarding the pregnancy as such.

CONCLUSIONS

This study is the first attempt to investigate the prenatal experience of women with PAD (Search of PubMed, 1980 to present, including search terms primary immunodeficiency, pregnancy, and prenatal care). This study demonstrates that increased knowledge about PAD and IgG replacement therapy among midwives and physicians working in prenatal care clinics is needed. This can prevent misleading advice that puts the health of the mother and her fetus at risk. Sensitizing staff about this special group of women can create conditions in which women feel respected, heard, and satisfied with their prenatal care.

Outcome of intravenous immunoglobulin-transmitted hepatitis C virus infection in primary immunodeficiency

Physicians in the United States who treat patients with primary immunodeficiency were contacted to identify subjects who had been infected with hepatitis C due to exposure to contaminated intravenous immunoglobulin (IVIg) in 1993-1994. From this survey we gathered information on 58 PCR-positive hepatitis C-infected patients; 37 had CVID, 9 had XLA, 5 were IgG subclass deficient, 4 were antibody deficient with normal immunoglobulin levels, 2 had SCID after BMT, and 1 had B cell linker deficiency. Of the 58 subjects, 30 had been treated with IFN-alpha in combination with ribavirin in 5 cases, and 26 other subjects were not treated. Of those who were treated, 11 (37%) resolved the infection and became PCR-negative; of the 26 who were not treated, 5 (19%) have resolved the infection, outcomes not significantly different. Patients 20 years of age or younger had a significantly better outcome compared to those older than age 20 (P = 0.02). Five subjects of the 58 have had a liver transplantation, a sixth has had two transplants, and 10 (17%) of the group have died. This survey demonstrates the heterogeneity of the clinical outcome in subjects with primary immunodeficiency who contracted hepatitis C due to viral contamination of IVIg.

Causality assessment of suspected virus transmission by human plasma products

BACKGROUND

Causality assessment of reports on suspected virus transmission is crucial for early detection of infectious plasma products. Commonly used algorithms, such as the WHO criteria, do not meet the specific requirements for causality assessment of suspected virus transmission.

STUDY DESIGN AND METHODS

A special algorithm, based on nucleic acid amplification and gene sequencing technology, effectiveness of validated virus-inactivation methods, empirical data concerning the safety record of the product, and information on batch-related infection clusters, was developed. The algorithm is focused on laboratory test results or otherwise standardized data, with few clinical data being required. To facilitate practical application, the algorithm has been converted into a graphical decision tree.

RESULTS

The feasibility of the algorithm is shown by causality assessment of sample cases. Three cases are presented with the details of each case used in the 12-question checklist. The answers provided by the checklist led to the causality classification.

CONCLUSION

The algorithm is a tool for evaluating reports of suspected virus transmission in a standardized manner. It thus has the potential to improve early signal detection in pharmacovigilance of plasma products by confirmation or exclusion of suspected infectivity in most cases.

Intravenous immunoglobulin: regulatory perspectives on use and supply

Technological advancements in the fractionation of plasma in the early 1970s led to the production of immunoglobulin preparations which could be administered intravenously. The ability to deliver larger doses than was possible with intramuscular products was accompanied by clinical studies demonstrating the efficacy of immunoglobulin treatment in a number of autoimmune and inflammatory conditions. This has led to a continuing increase in the usage of this product such that, currently, it is considered to be the driving force for plasma procurement. In recent years, difficulties have been experienced in the supply of this product in various markets. While intravenous immunoglobulins (IVIG) have undoubted clinical superiority over intramuscular products for the majority of indications, their use should be tempered with caution. Early clinical studies revealed that the risk of viral transmission from these products was higher than that of the traditional intramuscular presentation. This has had a profound impact on blood transfusion science as it has provided a major impetus for nucleic acid testing (NAT) for viral agents in blood donations. Perhaps less widely appreciated are the pressures which may be felt in blood services as the traditional drivers for plasma procurement - factor VIII and albumin - become secondary to IVIG. This review discusses the factors affecting the supply and safety of IVIG and the implications of recent global regulatory decisions on the delivery of this product and other therapeutic products derived from human plasma.

The epidemiology of virus transmission by plasma derivatives: clinical studies verifying the lack of transmission of hepatitis B and C viruses and HIV type 1

During the past 50 years, most US-licensed plasma derivatives have maintained an impressive record of not transmitting HBV, HCV, or HIV Albumin (50-year history) has never transmitted these viruses. PPF (40-year history) transmitted HBV on only one occasion, which was associated with a design flaw in one manufacturing plant. IGIM has never transmitted any of these viruses since the requirement of sensitive serologic screening tests for HBV (24 years). IGIV (17-year history) transmitted HCV in only one outbreak involving the product of one manufacturer. Even AHF and FIX have not transmitted these viruses since effective virus-inactivation processes in manufacturing were developed. In summary, there has been no transmission of HBV, HCV, or HIV by US-licensed plasma derivatives since the introduction of effective virus-inactivation procedures. This means, essentially, that there has been no transmission of these viruses since the end of 1987; the sole exception is IGIV, by which there has been no transmission since 1994.

Use of intravenous immunoglobulin to prevent or treat infections in persons with immune deficiency

Intravenous immunoglobulin (IVIG) concentrates were originally developed as replacement therapy for individuals with primary deficiencies of the immune system. However, in various well-designed, controlled clinical trials, the ability of IVIG to prevent and possibly treat infections in patients with secondary immune deficiencies has also been considered. In this review, we briefly consider these different applications and suggest whether the data are sufficient to employ IVIG in these clinical settings.

Intravenous immunoglobulin and hepatitis C virus: an overview of transmission episodes with emphasis on manufacturing data

A number of episodes of non-A, non-B hepatitis (NANB) have been associated in the recent past with the administration of intravenous immunoglobulin (IGIV). It now appears that hepatitis C virus (HCV) is the cause of NANB, although not all the factors leading to HCV transmission by IGIV are completely understood. Nevertheless, based on a retrospective analysis of two episodes of HCV transmitted by anti-Rh D immunoglobulin (anti-D), cold ethanol fractionation clearly is important in ensuring viral safety; both of these intravenous anti-D preparations were manufactured without benefit of this purification step. Other episodes of HCV transmission have been associated with IGIV produced using chromatography (particularly DEAE-Sephadex chromatography), which has been used after cold ethanol fractionation to further purify immunoglobulin G. DEAE-Sephadex chromatography may have only a marginal partitioning capacity, such that infective HCV virions are not further fractionated into waste fractions. All IGIV preparations associated with HCV transmission were formulated as lyophilized preparations, which may be important in stabilizing HCV before administration to patients. The role of anti-HCV screening in improving the viral safety of IGIV preparations remains unclear, but additional viral inactivation steps, such as solvent-detergent treatment or incubation at pH 4.0, probably are required for IGIV manufactured using chromatographic procedures.

Prevalence of hepatitis C virus in plasma pools and the effectiveness of cold ethanol fractionation

Screening blood donations for antibodies against hepatitis C virus (HCV) greatly reduces the risk of transmitting HCV by transfusions. However, despite such screening programs, plasma pools still contain a high percentage of HCV ribonucleic acid as determined by polymerase chain reaction. This result would not be alarming if the procedures for producing blood products included steps to inactivate or remove HCV. Although this appeared to be the case for all blood products, such as coagulation factors and most immunoglobulins, which are subjected to an inactivation step, the effectiveness of the cold ethanol fractionation process still needed to be determined. In validation experiments using bovine viral diarrhea virus as a model virus for HCV, we demonstrated that the Cohn-Oncley cold ethanol fractionation process neither inactivated nor removed this virus sufficiently. Our observations may help to explain how HCV was transmitted to a number of recipients of intravenous immunoglobulin.

Hepatitis C virus infection in Italian patients with hypogammaglobulinemia

We investigated the presence of hepatitis C virus (HCV) infection in 58 patients with humoral immunodeficiencies. Forty-three of these patients had common variable immunodeficiency (CVI), 2 had sporadic hyperimmunoglobulin M (HIM) syndrome, 2 had immunoglobulin G subclass deficiency, 4 had ataxia-telangiectasia (AT), and 7 had X-linked agammaglobulinemia (XLA). Patients with late-onset hypogammaglobulinemia (those with CVI, HIM, or immunoglobulin G subclass deficiency) had a 38.2% prevalence of HCV infection. In patients with XLA or AT, HCV infection was not detectable. Most of the HCV-infected patients had persistent viremia, with histologic findings of chronic hepatitis. Although patients positive for HCV ribonucleic acid (RNA) had received several lots of immunoglobulin, we were unable to detect any correlation between the time that alanine aminotransferase levels increased and the time that intravenous immunoglobulin therapy was given, except in one patient with CVI. Moreover, we found no differences in the number of blood transfusions, surgical procedures, or administrations of intravenous or intramuscular immunoglobulin between HCV RNA-positive and HCV RNA-negative groups. We concluded that: (1) the incidence of HCV infection in patients with hypogammaglobulinemia is much higher than that reported in the Italian general population; (2) although patients with hypogammaglobulinemia have persistent viremia, they do not show an aggressive course of HCV disease, nor does hepatocarcinoma develop; and (3) intravenous immunoglobulins are only one of several possible causes of HCV transmission in patients with humoral immunodeficiencies.

Liquid pasteurization of an immunoglobulin preparation without stabilizer: effects on its biological and biochemical properties

Intravenous immunoglobulins (IVIg) purified by cold ethanol fractionation have a very good safety record with regard to the transmission of many viruses. However, a few cases of non-A-non-B hepatitis have been described after intravenous injection of some immunoglobulin preparations. To ensure even higher safety for our IVIg, an additional virus inactivation step, based on pasteurization, was developed. The heating of aqueous IVIg was performed without stabilizer, and at a very low salt concentration (< 1 mM) at acidic pH. No generation of polymer was detected after pasteurization and a significant decrease in the proportion of dimers was observed. Analysis of the secondary structure by circular dichroism showed a very slight change in the secondary structure. The biological properties of the Fc region as well as the Fab region were not affected by the pasteurization. Our method has several advantages: (1) improvement of viral safety; (2) there is no need to add stabilizer which may stabilize viral particles, and (3) the absence of any hypotensive effect and low anticomplementary activity indicates a good clinical tolerance of IgG preparation.

Intravenous immunoglobulin and hepatitis C virus: the Scandinavian experience

In Sweden, 44 patients were reported to have contracted hepatitis C virus (HCV) infections from treatment with intravenous immunoglobulin. Gammagard was the product implicated in HCV transmission in 12 patients; 8 of these 12 patients were HCV ribonucleic acid (RNA)-negative during the 2 years before Gammagard was administered and 10 showed clustering by sequencing of the HCV core gene. Further studies are being conducted to correlate the sequenced HCV RNA with specific batches of Gammagard. Nine patients who received Gammonativ in 1983 and 1984 had a strong time-related possibility of HCV infection. Sequencing analyses are being performed in these patients as is being done for the patients who received Gammagard. Another 21 patients who received Gammonativ from 1982 to 1985 are probably infected with HCV, but confirmation of implicated batches is lacking. The association between Sandoglobulin and HCV is questionable in two patients, although plausible because of a time relationship. In Norway, relationships between Gammonativ and the incidence of HCV infection are similar to those in the 21 sporadic cases in Sweden. Also in Denmark and Finland, HCV infection appears to be related to the lack of additional viral inactivation steps used in the preparation of intravenous immunoglobulin. Clearly, there is a need for increased antiviral inactivation and antiviral screening in the production of intravenous immunoglobulin products.

Gammagard and reported hepatitis C virus episodes

Since first licensed in the United States in 1986, Gammagard, an intravenous immunoglobulin produced by the Hyland Division of Baxter Healthcare Corporation, had been considered an effective and safe form of immunoglobulin. Its safety had been proved in patients with immunoglobulin A (IgA) deficiency, including those with the complication of anti-IgA antibodies. However, in early 1994, there were reported episodes of hepatitis C virus transmission associated with administration of Gammagard manufactured during April 1993 and thereafter. The investigations into the mechanisms to account for these events, including the manufacturing processes, are reviewed. The results of studies and analyses by both Baxter and the US Food and Drug Administration, including first- and second-generation enzyme-linked immunosorbent assays, polymerase chain reaction analyses, and the solvent-detergent viral-inactivation manufacturing step, are discussed. Evaluations of donor histories identified a group of donors who contributed to three target lots of the agent and who were subsequently excluded from donor pools. The classification scheme and criteria for all patient reports of hepatitis associated with administration of Gammagard, as well as the classification of all hepatitis C virus episodes, are presented.

HCV infection in patients with primary defects of immunoglobulin production

We tested for infection with hepatitis C virus (HCV) in 58 patients affected by humoral immunodeficiencies: 43 common variable immunodeficiency (CVI), two hyper IgM syndrome (HIM), two IgG subclass deficiency, four ataxia-telangiectasia (AT), and seven X-linked agammaglobulinaemia (XLA). While the assessment of serum specific HCV antibodies in some of these patients was not informative because of the impairment in specific antibody production, the reverse transcriptase polymerase chain reaction (RT-PCR) assay used to detect serum HCV RNA was a useful method for diagnosing infection. We found that 38% of late onset hypogammaglobulinaemic patients (CVI, HIM or IgG subclass deficiency) had evidence of HCV infection. HCV infection was not detectable in patients with XLA or AT. The majority of our patients had persistent viraemia, and those who underwent liver biopsy showed histological findings of chronic hepatitis. Moreover, we could demonstrate in vitro that eight of 18 HCV-infected patients were actively producing anti-HCV antibodies, despite their impaired antibody production. The high rate of HCV infection in hypogammaglobulinaemic patients could be related to several nosocomial routes of transmission, including intravenous immune globulin administration. Despite the persistent viremia only two patients had cirrhosis and none had hepatocarcinoma.

[Viral safety of intravenous immunoglobulins G for therapeutic use]

Even though IV IgG concentrates are considered to be among the safest products derived from human plasma, some preparations have been associated with the sporadic transmission of NANB hepatitis and, specifically of hepatitis C. The risk of transmission may have decreased markedly for several IgG preparations since the availability of an immunological test to detect the antibodies against HCV in the starting plasma, but it has not been fully eradicated. Thus, in addition to established viral inactivation treatments, such as acid pH incubation, new methods have been (or are being) implemented to further reduce the risk of HCV infection through IV IgG concentrates. Among these methods are the solvent-detergent treatment already shown to be highly effective for the inactivation of HCV and other enveloped viruses in clotting factor concentrates, and nanofiltration for the specific removal of viruses on the basis of their size. Also, chromatographic methods have helped to improve the overall safety of the product not only by removing viruses but also by improving purity and thus favoring a better in vivo tolerance. This paper reviews the reported cases of HCV transmission and the viral validation data for various IV IgG processing steps and current specific viral inactivation methods. An overview of the present safety status of IV IgG concentrates is presented as well as the recent introduction of new promising techniques for the overall improvement of the safety of this plasma derivative.

Hepatitis C infection in patients with primary hypogammaglobulinemia after treatment with contaminated immune globulin

BACKGROUND

In Scandinavia many patients with primary hypogammaglobulinemia contracted non-A, non-B hepatitis after intravenous treatment with an immune globulin product that was later found to contain a non-A, non-B hepatitis virus.

METHODS

We studied the prevalence and clinical course of hepatitis C virus (HCV) infection in a group of 55 Norwegian patients with primary hypogammaglobulinemia and investigated its association with the use of contaminated immune globulin. We used the polymerase chain reaction to detect HCV RNA and performed HCV genotyping. We also analyzed the responses to treatment with interferon.

RESULTS

Of 20 patients who received the contaminated immune globulin, 17 were seropositive for HCV RNA: In addition, 1 of 35 patients not exposed to the contaminated immune globulin was HCV RNA--positive. HCV genotype V was found in all 12 patients for whom genotyping was performed, but 8 patients also had genotype II or III, or both. All HCV RNA--positive patients had abnormal results on biochemical liver tests. All liver-biopsy specimens (from 15 patients) were abnormal, with portal inflammation, bile-duct damage, and focal necrosis. In six patients there was cirrhosis. Two patients died of liver failure. In 4 of the 10 patients treated with interferon there were complete, though transient, biochemical responses, but the follow-up biopsy specimens showed evidence of histologic progression. The poorest responses to interferon were among the patients with multiple HCV genotypes. All but one patient remained positive for HCV RNA:

CONCLUSIONS

In patients with primary hypogammaglobulinemia there was a high rate of HCV infection after treatment with contaminated immune globulin. In these immunocompromised patients HCV infection has a severe and rapidly progressive course, and responses to interferon are poor.

Antibody Fc functional activity of intravenous immunoglobulin preparations treated with solvent-detergent for virus inactivation

We report here results of in vitro comparisons of the Fc functional activity of a second-generation intravenous immunoglobulin (IGIV) preparation (Venoglobulin-I) and a third-generation IGIV product that includes a deliberate virus-inactivation step (Venoglobulin-S). Both formulations showed equivalent Fc-mediated function against viral antigens (rubella, influenza A, and influenza B) by single-radial hemolysis test, and against group B Streptococcus, Staphylococcus aureus and Escherichia coli by opsonophagocytosis assay. In addition, we showed by three different immunochemical reactions and by HPLC analysis that both preparations consisted of mostly monomeric IgG and contained very low levels of complement-fixing IgG aggregates. However, IgG aggregation induced by heating at 63 degrees C markedly enhanced fixation of Clq and C3 and binding to Raji cells, indicating that the IgG molecules retained their complement-fixing capacity. Thus, the incorporation of a virus inactivation step in the manufacture of our third-generation IGIV did not alter the Fc functional activities of the IgG, as measured by these in vitro assay systems.

Inactivation and elimination of viruses during preparation of human intravenous immunoglobulin

We report here the results of our evaluation of virus inactivation during the manufacturing steps of two intravenous immunoglobulin (IGIV) preparations. Virus inactivation and/or removal by processing steps, such as ethanol fractionation and polyethylene glycol precipitation, and deliberate virucidal steps, such as solvent/detergent treatment and pasteurization, were tested on a variety of human pathogenic and experimental model viruses, including human immunodeficiency, Hepatitis C, Mumps, Vaccinia, Chikungunya, Vesicular Stomatitis, Sindbis, and ECHO viruses. All viruses were successfully inactivated and/or eliminated by the processing steps studied. In some cases, however, multiple steps were required. We conclude that the incorporation of steps deliberately designed to inactivate or remove viruses during the production of IGIV provides an extra measure of viral safety.

Hepatitis C virus transmission by intravenous immunoglobulin

The polymerase chain reaction was used to detect hepatitis C virus infection in patients who had previously been reported to have developed non-A, non-B hepatitis after intravenous immunoglobulin infusion. Of the 33 patients with intravenous immunoglobulin associated non-A, non-B hepatitis studied, HCV RNA could be detected in 15 out of 17 patients (88%) who were HCV RNA negative prior to the development of non-A, non-B hepatitis after implicated intravenous immunoglobulin batches. Similarly, eight out of nine patients (89%) in whom no sample was available for polymerase chain reaction testing prior to intravenous immunoglobulin therapy, had detectable HCV RNA after intravenous immunoglobulin therapy with intravenous immunoglobulin batches implicated in non-A, non-B hepatitis transmission. Two of the three intravenous immunoglobulin preparations implicated in non-A, non-B hepatitis transmissions that were available for polymerase chain reaction testing also had detectable HCV RNA, confirming that hepatitis C virus is the implicated virus in intravenous immunoglobulin-associated non-A, non-B hepatitis.

Passive transfer of hepatitis antibodies during intravenous administration of immune globulin

We studied the effect of intravenous immune globulin (IVIG) infusion on the levels of hepatitis B and C antibodies in 10 premature babies. All four tested lots of a commercially purchased IVIG preparation were found to contain substantial amounts of hepatitis B core and hepatitis C antibodies. Our results show that passive transfer of hepatitis B and C virus antibodies occurred after IVIG infusion, and that the levels were dependent on the quantity of IVIG given. When assessing neonates for hepatitis, the factor of receipt of blood products, including IVIG, needs to be considered to interpret laboratory results.

Virus inactivation during intravenous immunoglobulin production

Effects of time, temperature, pH and stabilizers (i.e. medium) on inactivation of lipid-enveloped model viruses, Semliki Forest and vesicular stomatitis viruses in the production process of intravenous immunoglobulin were investigated on a laboratory scale. The lowering of pH, the raising of temperature and the increasing of incubation time improved the inactivation effect. However, small changes in pH and stabilizer concentrations did not influence the results. Inactivation was not linear and a clear tailing off could be seen. Therefore, for complete virus inactivation incubation times longer than 20 h are necessary. Inactivation took place much more rapidly in intravenous immunoglobulin solution than in intramuscular immunoglobulin solution. Processing steps such as freeze-dying in the presence of ethanol or storage of intramuscular immunoglobulin in the liquid state at pH7 only partially inactivated these viruses.

Virus safety of human immunoglobulins: efficient inactivation of hepatitis C and other human pathogenic viruses by the manufacturing procedure

Human immunoglobulins are plasma derivatives with a low risk of transmitting viral infections. To the present, no proven case of human immunoglobulins transmitting human immunodeficiency viruses has been reported. However, there have been a few reports on the transmission of hepatitis C virus by these plasma proteins. To improve further the safety of both 5s iv human immunoglobulins and 7s im immunoglobulins, we introduced a 10-hour heat treatment of the aqueous solutions at 60 degrees C (i.e., pasteurization) into the manufacturing procedure. This treatment was not added to the manufacturing procedure of 7s iv immunoglobulin that already contained the S-sulfonation as a virus inactivating method. We now report on experimental data that show that the whole manufacturing procedures of the above immunoglobulins inactivate efficiently hepatitis C virus and that the specific virus inactivation methods alone, namely, pasteurization or S-sulfonation, also inactivate completely viruses of the flavivirus family, to which the hepatitis C virus belongs. The inactivation of the Flaviviridae bovine viral diarrhea virus, tick-borne encephalitis virus, and yellow fever virus by pasteurization or S-sulfonation was at least 10(5). The clearance of HCV achieved by the entire manufacturing process of each of these immunoglobulins was also at least 10(5). The experiments therefore show that pasteurization or S-sulfonation provides a high margin of safety to human immunoglobulins regarding the transmission of hepatitis C virus.

Detection of anti-HIV antibodies in immunoglobulin preparations: the significance of antibodies to the HIV-envelope

Four hundred and sixty-eight immunoglobulin preparations, produced between 1969 and 1989, were examined for anti-HIV antibodies by means of two competitive immunoenzymatic assays and the Western blot test. This study refers the results obtained by the three different methods. Such results show that the detection of anti-HIV antibodies in immunoglobulins may be performed on a routine basis using commercial kits intended for human sera. The meaning of the test and the role of antibodies against the HIV envelope proteins are emphasized.

Use of intravenous immune globulin therapy: an overview

The intravenous immune globulin (IGIV) preparations are reviewed with respect to method of preparation, pharmacokinetics, clinical uses (with emphasis on the labeled indications), and adverse reactions; a brief review of the immune system also is provided. IGIV preparations are approved for the treatment of hypogammaglobulinemia, recurrent bacterial infections due to B-cell chronic lymphocytic leukemia, and idiopathic thrombocytopenic purpura (ITP). The mechanism of action in the first two indications is passive replacement of antibodies, but in ITP the mechanism is not clearly established. The clinical literature on the use of IGIV for these indications is summarized. In patients with ITP, platelet counts return to safe levels and the number of infections is reduced in patients with primary humoral immunodeficiency treated with IGIV. The use of IGIV in pregnant women and premature infants is controversial. Adverse reactions are primarily related to infusion rate, activation of complement, and anaphylactic reactions to a component of the product. There is minimal to no risk of viral transmission with IGIV therapy. IGIV also has been administered safely on an outpatient or homecare basis. This has led to a feeling of greater control by patients over their chronic illness. Other uses of IGIV are under investigation. As our understanding of the immune system and the pharmacology of immune globulin increases, the uses of IGIV will expand.

Immunoglobulin preparation: safe from virus transmission?

The incidence of non-A, non-B hepatitis associated with the administration of immunoglobulin preparations, especially intravenous preparations, which had been considered to be free from virus transmission, is reported. Research efforts to improve the safety of intravenous immunoglobulin preparations which could be administered in a large volume must be continued. Adding sorbitol under weakly acidic conditions, heat treatment of IgG at 60 degrees C for 10 h is possible. Intravenous immunoglobulin preparation manufactured by polyethylene glycol fractionation followed by the heat treatment is not only intact, but also much closer to the ideal intravenous immunoglobulin preparation in the safety and stability.

Transmission of non-A, non-B hepatitis by pH4-treated intravenous immunoglobulin

Four patients (2 with X-linked, one with common variable hypogammaglobulinaemia, and 1 with ulcerative colitis) developed non-A, non-B hepatitis (NANBH) following administration of a specific batch of intravenous immunoglobulin (IV IgG) manufactured by the Scottish National Blood Transfusion Service using the pH4/mild pepsin method. Each patient had normal serum ALT levels over a preceding period of 12-67 months, with raised values developing within 4-18 weeks of first administration of the implicated batch. Two patients had very mild symptoms of hepatitis, the other 2 being asymptomatic. Over a follow-up period of 8-12 months, ALT levels returned to normal in 3 patients, but biopsy-proven chronic NANBH developed in the fourth. The level of NANBH virus in the starting plasma used to manufacture this batch may have exceeded the capacity of the process to inactivate the virus. The transmission of NANBH by one of approximately 110 batches administered demonstrates the importance of continued close surveillance of recipients of IV IgG, even if asymptomatic, by regular monitoring of liver function tests and recording of all batches received.

Inactivation and elimination of viruses during the fractionation of an intravenous immunoglobulin preparation: liquid heat treatment and polyethylene glycol fractionation

A method for the heat treatment of human IgG solution at 60 degrees C for 10 h was established. Human immunodeficiency, mumps, vaccinia and 4 other viruses were added to the IgG solution in 33% sorbitol and heated at 60 degrees C. Those viruses were inactivated within 1 h. Heat-treated intravenous IgG (IVIG-H) was prepared by heat treatment and polyethylene glycol (PEG) fractionation. Conventional nonheated intravenous IgG (IVIG-C) was prepared from the same source paste by the fractionation method. No physicochemical or biological difference was observed between the heated and control IVIG preparations.

High dose intravenous gammaglobulins in autoimmune disorders: mode of action and therapeutic uses

Gammaglobulins administered intramuscularly have been used for more than 40 years to treat antibody deficiency states. In the last decade intravenous preparations were developed. They do not aggregate and contain IgG molecules with intact recognition and effector functions. These compounds are safe and only minor side effects were reported even when high doses were given. While studying their effect when given in high doses to hypogammaglobulinemic patients, an accidental finding was observed regarding their beneficial effect in idiopathic thrombocytopenic purpura (ITP). This observation led to many studies looking at the effect of high dose gammaglobulin in several other autoimmune diseases. While the effect in acute ITP is well established, there are encouraging reports in respect to the effect of intravenous gammaglobulin in many other disorders, but no final conclusion can be drawn due to the small numbers of cases studied. The mechanism by which intravenous gammaglobulin exerts its function is still unclear. It may work through the Fc receptor in the reticuloendothelial system, as an immunoregulator agent or interact in the idiotype-antiidiotype network. Intravenous gammaglobulin seems to be an important therapeutic tool in a large number of autoimmune disorders of various etiologies.

Inactivation of the Hutchinson strain of hepatitis non-A, non-B virus in intravenous immunoglobulin by beta-propiolactone

beta-propiolactone (beta-PL) treatment has been evaluated for its ability to inactivate 10(3.5) chimpanzee infectious doses (CID50) of the Hutchinson strain of hepatitis non-A, non-B virus (HNANBV). Two chimpanzees were inoculated with a beta-PL-treated immunoglobulin solution to which this dose of the titrated virus had been added prior to beta-PL treatment. beta-PL treatment was performed in accordance with the production procedure used for a licensed intravenous immunoglobulin preparation. Neither animal developed hepatitis. When subsequently challenged with the same spiked immunoglobulin solution that had not been beta-PL treated, both animals developed clear-cut hepatitis non-A, non-B. The results of this experiment demonstrate that beta-PL treatment is effective for the inactivation of hepatitis non-A, non-B virus in intravenous immunoglobulin.