Virus inactivation during production of intravenous immunoglobulin

Mimicking Low pH Virus Inactivation Used in Antibody Manufacturing Processes: Effect of Processing Conditions and Biophysical Properties on Antibody Aggregation and Particle Formation

Low pH virus inactivation (VI) step is routinely used in antibody production manufacturing. In this work, a mimic of the VI step was developed to focus on evaluating adverse effects on product quality. A commercially available lab-scale glass reactor system was utilized to assess impacts of process and solution conditions on process-induced monoclonal antibody particle formation. Flow imaging was found to be more sensitive than light obscuration in detecting microparticles. NaOH as a base titrant increased protein microparticles more than Tris. Both stirring and NaCl accelerated particle formation, indicating that interfacial stress and protein colloidal stability were important factors. Polysorbate 80 was effective at suppressing particle formation induced by stirring. In contrast, trehalose led to higher microparticle levels suggesting a conformational stabilizer may have other adverse effects during titration with stirring. Additionally, conformational and colloidal stability of antibodies were characterized to investigate the potential roles of antibody physicochemical properties in microparticle formation during VI. The stability data were supportive in rationalizing particle formation behaviors, but they were not predictive of particle formation during the mimicked viral inactivation steps. Overall, the results demonstrate the value of testing various solution and processing conditions in a scaled-down system prior to larger-scale VI bioprocesses.

Efficacy, safety, tolerability and pharmacokinetics of a novel human immune globulin subcutaneous, 20%: a Phase 2/3 study in Europe in patients with primary immunodeficiencies

A highly concentrated (20%) immunoglobulin (Ig)G preparation for subcutaneous administration (IGSC 20%), would offer a new option for antibody replacement therapy in patients with primary immunodeficiency diseases (PIDD). The efficacy, safety, tolerability and pharmacokinetics of IGSC 20% were evaluated in a prospective trial in Europe in 49 patients with PIDD aged 2–67 years. Over a median of 358 days, patients received 2349 IGSC 20% infusions at monthly doses equivalent to those administered for previous intravenous or subcutaneous IgG treatment. The rate of validated acute bacterial infections (VASBIs) was significantly lower than 1 per year (0·022/patient‐year, P < 0·0001); the rate of all infections was 4·38/patient‐year. Median trough IgG concentrations were ≥ 8 g/l. There was no serious adverse event (AE) deemed related to IGSC 20% treatment; related non‐serious AEs occurred at a rate of 0·101 event/infusion. The incidence of local related AEs was 0·069 event/infusion (0·036 event/infusion, when excluding a 13‐year‐old patient who reported 79 of 162 total related local AEs). The incidence of related systemic AEs was 0·032 event/infusion. Most related AEs were mild, none were severe. For 64·6% of patients and in 94·8% of IGSC 20% infusions, no local related AE occurred. The median infusion duration was 0·95 (range = 0·3‐4·1) h using mainly one to two administration sites [median = 2 sites (range = 1–5)]. Almost all infusions (99·8%) were administered without interruption/stopping or rate reduction. These results demonstrate that IGSC 20% provides an effective and well‐tolerated therapy for patients previously on intravenous or subcutaneous treatment, without the need for dose adjustment.

Efficacy, Safety, and Pharmacokinetics of a Novel Human Immune Globulin Subcutaneous, 20 % in Patients with Primary Immunodeficiency Diseases in North America

Patients with primary immunodeficiency disease (PIDD) typically require life-long intravenous (IV) or subcutaneous (SC) immunoglobulin (Ig) replacement therapy to prevent recurrent infections. The efficacy, safety, and pharmacokinetics of a highly concentrated (20 %) Ig preparation for SC administration (IGSC 20 %) were evaluated in a prospective trial in patients with PIDD. A total of 74 patients (aged 3-83 years) received 4327 IGSC 20 % infusions over a median of 380.5 days. The rate of validated serious bacterial infections was 0.012 event/patient-year (p < 0.0001 compared with the historical control), and the annualized rate of infection was 2.41 events/patient. Median IgG trough levels were >14.5 g/l. The median maximum infusion rate was 60 ml/h/site (range 4.4-180), resulting in a median infusion duration of 0.95 h. A volume ≥30 ml was infused per site in 74.8 % of IGSC 20 % infusions. Most (84.9 %) infusions were administered using ≤2 infusion sites; for 99.8 % of infusions, there was no need to interrupt/stop administration or reduce the infusion rate. No related serious adverse event (AE) occurred during IGSC 20 % treatment; related non-serious AEs occurred at a rate of 0.036 event/infusion. The incidence of related local AEs was 0.015 event/infusion and of related systemic AEs was 0.021 event/infusion; most were mild in severity, none severe. Increased infusion rates or volumes were not associated with higher AE rates. The investigated IGSC 20 % treatment was shown to be effective and safe, enabling higher infusion rates and volumes per site compared to conventional SC treatments, resulting in fewer infusion sites and shorter infusion durations.

Inactivated pepsin inhibits neutrophil activation by Fcgamma-receptor-dependent and independent stimuli

Pepsin is widely used to produce F(ab')2 fragments of immunoglobulin G (IgG). In many cases, at least part of the pepsin will remain present in the F(ab')2 preparation, albeit in (irreversibly) inactivated form. Here we report on a potent immunomodulatory effect of irreversibly inactivated pepsin on activated human neutrophils. Degranulation, induced by coated IgG or via cytochalasin B/N-formyl-Met-Leu-Phe, was measured by quantifying elastase release, and was found to be inhibited in a dose-dependent manner by inactivated pepsin. Since a number of intravenous immunoglobulin (IVIg) products are also treated by limited digestion with pepsin, we investigated if pepsin would be present in quantities large enough to inhibit neutrophil activation. The amounts of pepsin detected in three different pepsin-treated IVIg products were found to be too low to induce an effect, at least in an in vitro setting.

Safety of snake antivenom immunoglobulins: efficacy of viral inactivation in a complete downstream process

Viral safety remains a challenge when processing a plasma-derived product. A variety of pathogens might be present in the starting material, which requires a downstream process capable of broad viral reduction. In this article, we used a wide panel of viruses to assess viral removal/inactivation of our downstream process for Snake Antivenom Immunoglobulin (SAI). First, we screened and excluded equine plasma that cross-reacted with any model virus, a procedure not published before for antivenoms. In addition, we evaluated for the first time the virucidal capacity of phenol applied to SAI products. Among the steps analyzed in the process, phenol addition was the most effective one, followed by heat, caprylic acid, and pepsin. All viruses were fully inactivated only by phenol treatment; heat, the second most effective step, did not inactivate the rotavirus and the adenovirus used. We therefore present a SAI downstream method that is cost-effective and eliminates viruses to the extent required by WHO for a safe product.

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.

Quality and safety of fresh-frozen plasma inactivated and leucoreduced with the Theraflex methylene blue system including the Blueflex filter: 5 years' experience

BACKGROUND AND OBJECTIVES

The objective of this paper is to present 5 years' experience of pathogen inactivation of fresh-frozen plasma with the methylene blue system in a blood centre in Athens.

MATERIALS AND METHODS

Eight thousand and five hundred units treated by methylene blue and 54 435 untreated were issued for transfusion in four hospitals during the period 2000-2005. Eighty-eight units were evaluated for changes in coagulation factor activity and cytokine concentrations following treatment.

RESULTS

Coagulation factor losses were in the accepted range. Adverse reactions were 1 : 8500 with treated and 1 : 2177 with untreated units. The five serious reactions were all in untreated units. No seroconversions for infectious diseases were reported.

CONCLUSIONS

Methylene-blue-treated fresh-frozen plasma is safer than the untreated product even in patients who require large quantities of plasma transfusion.

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.

Viral safety of Nanogam, a new 15 nm-filtered liquid immunoglobulin product

BACKGROUND AND OBJECTIVES

Producers of plasma derivatives continuously improve the viral safety of their products by, for example, introducing additional virus-reducing steps into the manufacturing process. Here we present virus-elimination studies undertaken for a number of steps employed in a new manufacturing process for liquid intravenous immunoglobulin (Nanogam) that comprises two specific virus-reducing steps: a 15-nm filtration step combined with pepsin treatment at pH 4.4 (pH 4.4/15NF); and solvent-detergent (SD) treatment. The manufacturing process also includes precipitation of Cohn fraction III and viral neutralization, which contribute to the total virus-reducing capacity of the manufacturing process. In addition, the mechanism and robustness of the virus-reducing steps were studied.

MATERIALS AND METHODS

Selected process steps were studied with spiking experiments using a range of lipid enveloped (LE) and non-lipid-enveloped (NLE) viruses. The LE viruses used were bovine viral diarrhoea virus (BVDV), human immunodeficiency virus (HIV) and pseudorabies virus (PRV); the NLE viruses used were parvovirus B19 (B19), canine parvovirus (CPV) and encephalomyocarditis virus (EMC). After spiking, samples were collected and tested for residual infectivity, and the reduction factors were calculated. For B19, however, removal of B19 DNA was measured, not residual infectivity. To reveal the contribution of viral neutralization, bovine parvovirus (BPV) and hepatitis A virus (HAV) were used.

RESULTS

For the pH 4.4/15NF step, complete reduction (> 6 log(10)) was demonstrated for all viruses, including B19, but not for CPV (> 3.4 but < or = 4.2 log(10)). Robustness studies of the pH 4.4/15NF step with CPV showed that pH was the dominant process parameter. SD treatment for 10 min resulted in complete inactivation (> 6 log(10)) of all LE viruses tested. Precipitation of Cohn fraction III resulted in the significant removal (3-4 log(10)) of both LE and NLE viruses. Virus-neutralization assays of final product revealed significant reduction (> or = 3 log(10)) of both BPV and HAV.

CONCLUSIONS

The manufacturing process of Nanogam comprises two effective steps for the reduction of LE viruses and one for NLE viruses. In addition, the precipitation of Cohn fraction III and the presence of neutralizing antibodies contribute to the total virus-reducing capacity of Nanogam. The overall virus-reducing capacity was > 15 log(10) for LE viruses. For the NLE viruses B19, CPV and EMC, the overall virus-reducing capacities were > 10, > 7 and > 9 log(10), respectively. Including the contribution of immune neutralization, the overall virus-reducing capacity for B19 and HAV is estimated to be > 10 log(10).

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.

Efficacy, tolerability, safety and pharmacokinetics of a nanofiltered intravenous immunoglobulin: studies in patients with immune thrombocytopenic purpura and primary immunodeficiencies

BACKGROUND AND OBJECTIVES

A nanofiltration step with the capacity to reduce blood-borne pathogens was introduced into the manufacturing process of intravenous immunoglobulin (IVIG). In order to demonstrate the efficacy, safety and pharmacokinetics of the modified product, we conducted Phase II/III studies comparing the nanofiltered IVIG (IVIG-N) with its parent product, Sandoglobulin, in patients with chronic immune thrombocytopenic purpura (ITP) and primary immunodeficiencies (PID).

MATERIALS AND METHODS

Patients with ITP (n = 27) with platelet counts of < 20 x 10(9)/l were treated with Sandoglobulin or IVIG-N infusions at a dose of 0.4 g/kg body weight on five consecutive days. The primary efficacy end-point was the number of patients with an increase in platelet counts to > 50 x 10(9)/l. Secondary end-points were time to and duration of response, and regression of bleeding. Patients with PID (n = 36) were treated for 6 months with Sandoglobulin or IVIG-N at doses of 0.2-0.8 g/kg, infused at 3- or 4-week intervals. The primary end-point was the number of days absent from school/work. Secondary end-points were hospitalization, use of antibiotics and feeling of well-being. In both studies, tolerability was assessed by recording of adverse events and laboratory determinations. Viral safety was ascertained by serology supplemented with nucleic acid detection methods. Pharmacokinetics were analysed in patients with PID using serum concentration-time data for immunoglobulin G (IgG), and IgG antibodies to hepatitis B surface antigen (anti-HBsAg).

RESULTS

In the ITP study, the primary end-point was met by 12/16 patients on IVIG-N and by 10/10 patients on Sandoglobulin (P = 0.123). A shift towards lesser bleeding intensity was seen in both groups. In the PID study, seven of 18 patients on IVIG-N and six of 16 patients on Sandoglobulin missed days at work/school, with monthly mean absences of 0.4 and 0.5 days (P = 0.805). The feeling of well-being was comparable in both groups. In the ITP study, adverse events with a causal relationship to medication were suspected in six patients on IVIG-N and in seven on Sandoglobulin. In the PID study, three patients on IVIG-N and two on Sandoglobulin experienced possible drug-related adverse events. In both studies, serological and polymerase chain reaction (PCR) tests gave evidence for virus safety. Pharmacokinetics showed constant peak and trough serum IgG levels in all patients, indicating almost steady-state conditions for both formulations. The overall half-life (t1/2) for total IgG was 33 +/- 17 days in the IVIG-N arm and 25 +/- 16 days in the Sandoglobulin arm; for anti-HBsAg t1/2, values were 17 +/- 7 and 17 +/- 9 days, respectively.

CONCLUSIONS

IVIG-N is efficacious, well tolerated and safe in patients with ITP and PID. Its pharmacokinetic properties were comparable to those of Sandoglobulin.

Inactivation of West-Nile virus during peptic cleavage of horse plasma IgG

Peptic cleavage of horse plasma IgG is a common procedure for the preparation of F(ab)(2) products for human use, such as antivenin and antitoxin. The removal of the Fc fragment from the IgG molecule by enzymatic cleavage at low pH, ensures fewer side-effects of the F(ab)(2) product for passive immunotherapy compared with the whole IgG molecule. Since the starting material may be contaminated by zoonotic horse viruses, it is necessary to demonstrate the removal or inactivation of possible viral contaminants. Guidelines for performing such studies were published by the Commission for Plasma-Derived Medical Products (CPMP), and updated by the Committee for Proprietary Medical Products. It is recommended that viral clearance studies be performed on scaled down production processes that have been identified as possibly contributing to virus clearance and spiking of a model virus to the starting material. The model virus should be non-pathogenic but closely related to the potential infective virus. By quantifying the amount of virus in the product before and after the production process, the amount of virus cleared can be determined. Log(10) reductions of the order of 4 logs or more, and a biphasic inactivation curve (fast initial phase followed by a slower phase), are indicative of a clearance effect with a particular test virus under investigation.

Ion-exchange chromatography separation of the detergent and the solvent from immunoglobulins after solvent-detergent treatment

For inactivation of lipid-enveloped viruses during the immunoglobulin production, the solvent-detergent (S/D) method was applied. Tri-n-butyl phosphate (solvent) and Triton X-100 (detergent) were removed from S/D treated immunoglobulins by ion-exchange chromatography on Q-Sepharose Fast Flow (FF). During the chromatographic procedure immunoglobulins remained bound on a Q-Sepharose FF, whereas solvent and detergent were eluted by washing with starting buffer. Elution of immunoglobulins was achieved by increasing the ionic strength of the starting buffer. The final immunoglobulin preparation contained less than 10 microg/ml of Triton X-100 and less than 2 microg/ml tri-n-butyl phosphate. It was confirmed that the S/D procedure did not cause a significant change in polymers and specific antibodies content. Immunoglobulin classes were also not affected by the same procedure.

Buckminsterfullerene and photodynamic inactivation of viruses

The development of new virus inactivation procedures has become an area of growing interest mainly due to increased demands concerning the safety of biological products. Photochemical processes represent the most promising methods for the future to inactivate viruses. In these methods, dyes are the most widely used photosensitising reagents. The current article covers a new interesting alternative, namely the use of buckminsterfullerene (C60). The unique properties of this molecule make it a valid candidate for future applications in the inactivation of viruses in biological fluids. Copyright 1998 John Wiley & Sons, Ltd.

Intravenous immunoglobulin treatment of neurological autoimmune diseases

Intravenous immunoglobulin (IVIg) has been widely used in neurological diseases during the last decade. The current indications of IVIg in neurological diseases are reviewed and discussed on the basis of the available experimental data and clinical trials. Compared to other immunomodulating treatments used in neurological diseases, IVIg has only few side effects with a small risk of transmission of infectious agents. Good clinical evidence for the effectiveness is available for Guillain-Barré-Syndrome, chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy. In conditions like myasthenia gravis and myositis favourable effects of IVIg were reported, but future studies have to be awaited. For all other neurological conditions where IVIg has been administered, there is currently no support for the use of IVIg other than in controlled trials. In conclusion, IVIg is a promising immunomodulary therapy that has been shown to be effective in some neurological autoimmune diseases. Routine use in neurological practice should be restricted to diseases for which a positive effect has been proven in controlled trials. For all other conditions no definite recommendations can presently be made.

At least three hepatitis C virus strains implicated in Swedish and Danish patients with intravenous immunoglobulin-associated hepatitis C

BACKGROUND

Three reported Swedish cases of hepatitis C in patients receiving an intravenous immunoglobulin (Gammagard, Baxter Healthcare, Deerfield, IL) were among the first to bring to light a worldwide outbreak of hepatitis C associated with non-solvent/detergent (SD)-treated Gammagard. In February 1994, all implicated batches of Gammagard were recalled and exposed patients traced.

STUDY DESIGN AND METHODS

Sera from all identified and hepatitis C-viremic Swedish and Danish patients (n = 14) exposed to the implicated batches underwent hepatitis C virus genotyping and sequencing of the core region and hypervariable region 1 of E2. Genomic amplification was also done on 15 non-SD-treated batches of Gammagard.

RESULTS

Twelve patients were infected with subtype 1a and surprisingly, two with subtype 2b. Analysis of the core region showed identical sequences in four patients and the only consistently positive batch. Five patients shared another sequence, whereas three other subtype 1a patients each manifested unique sequences. The two subtype 2b isolates were identical. Genomic fingerprinting of the hypervariable region confirmed identity within each group with great stringency. Amplification with isolate-specific primers showed mixed infection in one patient whose exposure was confined to a single batch.

CONCLUSION

The few batches implicated presumably were contaminated with several strains.

Randomized trial comparing intravenous immunoglobulin with methylprednisolone pulse therapy in acute idiopathic thrombocytopenic purpura. Danish I.T.P. Study Group

Forty-three children with newly diagnosed idiopathic thrombocytopenic purpura (ITP), platelet count (PC) below 20 x 10(9)l-1, and either continued bleeding or failure to show a spontaneous rise in the PC after a 3 day observation period were randomized to treatment with either intravenous immunoglobulin (IVIG) infusions 1 g kg-1 (n = 23) or intravenous methylprednisolone pulse therapy (MPPT) 30 mg kg-1 (n = 20) on two consecutive days. After 72 h, IVIG had induced greater platelet responses (mean PC 188 x 10(9) versus 77 x 10(9)l-1, 2p < 0.001) and raised the PC to a haemostatically safe level above 50 x 10(9)l-1 more frequently (91 versus 50%, one-sided exact p = 0.003). Children responding poorly were then given the alternative treatment in addition. After 6 days, a normal PC of over 150 x 10(9)l-1 had been obtained more frequently in the group given first-line IVIG (70 versus 50%, p = 0.16). The relapse rates during 6 months of follow-up were not significantly different (26 versus 40%, p = 0.26). Cross-over treatment in 11 children with relapse confirmed the superior response to IVIG. The treatment given was restricted to the two initial infusions more often in the IVIG group (70 versus 35%, p = 0.05). These results indicate that IVIG may be preferable to MPPT as the initial treatment for ITP.

[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.

Intravenous immunoglobulin in the treatment of paediatric cerebral malaria

Hyperimmune globulin can inhibit and reverse the cytoadherence between Plasmodium falciparum-infected erythrocytes and melanoma cells in vitro. Cytoadherence is believed to mediate disease in cerebral malaria. Therefore we studied the efficacy of i.v. immunoglobulin, purified from the plasma of local semi-immune blood donors, as an adjunct to standard treatment for cerebral malaria in Malawian children. The immunoglobulin preparation (IFAT antimalarial antibody titre 1:5120) recognized erythrocyte-associated antigens of each of 22 Malawian P. falciparum isolates studied, and reversed binding of Malawian isolates to melanoma cells. Immunoglobulin did not reverse binding to human monocytes or to cells of the human histiocytic lymphoma cell line U937. Thirty-one children with P. falciparum parasitaemia and unrousable coma were enrolled. All were treated with i.v. quinine dihydrochloride; in addition patients were randomized to receive either immunoglobulin (400 mg/kg by i.v. infusion over 3 h) or placebo (albumen and sucrose by similar infusion) in a double blind trial with sequential analysis. Of 16 patients receiving immunoglobulin, five (31%) died and five survivors had neurological sequelae. Of 15 patients receiving placebo, one (7%) died and two had sequelae. Parasite clearance, fever clearance and coma resolution times in survivors were similar in the two groups. Although the difference in outcome between the two groups was not significant, the trial was stopped because immunoglobulin was demonstrated not to be superior to placebo.

Safety of intravenous immunoglobulin preparations: a prospective multicenter study to exclude the risk of non-A, non-B hepatitis

The risk of non-A, non-B hepatitis transmission by an intravenous immunoglobulin (IVIG) preparation was assessed in a prospective multicenter trial in 68 patients with primary immunodeficiency disorders (40 children or adolescents and 28 adults). During the 4-week prestudy evaluation period the clinical examinations and liver function tests including alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transpeptidase, alkaline phosphatase, and bilirubin were normal in all patients. The treatment consisted of three infusions of 200 mg IVIG (pH 4; pepsin procedure) per kilogram body weight at 2-week intervals. During the observation period of 24 weeks following the first infusion of the study IVIG, the patients were monitored at regular time intervals. No clinical and laboratory signs of hepatitis or liver dysfunction were noticed. All patients completed the study. In 5 patients, one isolated alanine aminotransferase value and in another patient one gamma-glutamyl transpeptidase value were moderately elevated, but always below 2.5 times the upper limit of the reference range. Similar isolated and transient elevations were observed for aspartate aminotransferase and alkaline phosphatase. It was concluded that the IVIG preparation did not transmit non-A, non-B hepatitis or other viral liver diseases.