Chronic hepatitis C after high-dose intravenous immunoglobulin

Immune Thrombocytopenia

Immune thrombocytopenia (ITP) is a rare autoimmune disorder with an incidence of 3 to 5 per 100 000 individuals. In children, the disease is self-limited and is most commonly virus related (acute ITP) whereas in adults, the disease is typically chronic. The age distribution of adult ITP displays 2 peaks; the first in younger adults aged 18 to 40 with a female predominance and the second in people aged older than 60 with men and women affected equally. Our approach to ITP has evolved over the past several years: there has been a change in nomenclature and ITP now denotes “immune thrombocytopenia” (the “I” no longer denoting “idiopathic”) and “purpura” no longer features in the name of the disease; new insights into the pathogenesis of ITP have revealed the importance of impaired megakaryocytopoiesis in the condition; underlying mechanisms of secondary ITP have been elucidated and finally novel thrombopoietic agents have been shown to be effective in the treatment of ITP in randomized clinical trials. In this article, we review important recent advances in the pathogenesis and treatment of ITP.

Intravenous immunoglobulin and anti-RhD therapy in the management of immune thrombocytopenia

Intravenous immunoglobulin and intravenous anti-D are common therapies in the management of patients with immune thrombocytopenia (ITP). Both are pooled plasma products and both result in an increase in the platelet count in approximately 60% to 70% of patients with ITP. Despite immediate increases in the platelet count, the duration of response is limited, with platelet increments lasting between 2 and 4 weeks. Infusion reactions are common but adverse events rare. Although responses are similar, human and murine data suggest that the mechanisms of action of these treatments are complex and likely different.

Intravenous Immunoglobulin for Autoimmune Thrombocytopenic Purpura

Severe autoimmune thrombocytopenic purpura is now commonly treated with high doses of intravenous immunoglobulins (IVIGs). Twenty-four years after this treatment was first demonstrated to be effective, several questions remain to be resolved. We review here current knowledge concerning the frequency and type of side effects and the likely mechanism of action of IVIGs. We suggest that the currently recommended dose of IVIG (2 g/kg) could be halved, that the total dose of IVIG should be administered as a single infusion, that nonresponders could be provided another equal dose on day 3, and that IVIG plus prednisolone should be considered the gold standard for treatment of the most severe forms of the disease. Treatment with anti-D immunoglobulin could be proposed as an alternative if the results recently obtained with high doses (75 microg/kg) are confirmed. Finally, because IVIG has only a transient effect, it cannot be considered a curative treatment for patients with chronic autoimmune thrombocytopenic purpura.

Intravenous immunoglobulin and autoimmune thrombocytopenic purpura: 22 years on

Autoimmune thrombocytopenic purpura is now commonly treated with high doses of intravenous immunoglobulins. Twenty-two years after this treatment was first shown to be effective, several questions remain. We review here current knowledge concerning the frequency and type of side-effects and the probable mechanism of action of intravenous immunoglobulins. We suggest that the currently recommended dose of intravenous immunoglobulins (2 g/kg body weight) could be halved, that the total dose of intravenous immunoglobulins should be administered as a single infusion, that non-responders could be given another equal dose on day 3, and that intravenous immunoglobulins plus prednisolone should be considered as the gold standard for treatment of the most severe forms of the disease. Finally, as intravenous immunoglobulins have only a transient effect, they cannot be considered as a curative treatment for patients with chronic autoimmune thrombocytopenic purpura.

Hepatitis C: an epidemiological review

The aim of the study was to analyse the current literature regarding the mode of transmission of HCV and its global prevalence in different groups of people. A systematic review of the literature on the epidemiology of hepatitis C from 1991 to 2000 using computerized bibliographic databases which include Medline, Current Content and Embase. The prevalence of hepatitis C virus (HCV) varies tremendously in different parts of the world, with the highest incidence in the Eastern parts of the globe compared with the Western parts. Furthermore, certain groups of individuals such as intravenous drug users are at increased risk of acquiring this disease irrespective of the geographical location. Although the main route of transmission is via contaminated blood, curiously enough in up to 50% of the cases no recognizable transmission factor/route could be identified. Therefore, a number of other routes of transmission such as sexual or household exposure to infected contacts have been investigated with conflicting results. Hepatitis C infection is an important public health issue globally. Better understanding of routes of transmission will help to combat the spread of disease. In order to prevent a world wide epidemic of this disease, urgent measures are required to (i) develop a strategy to inform and educate the public regarding this disease and (ii) expedite the efforts to develop a vaccine.

Myasthenia gravis and hepatitis C virus infection

Chronic hepatitis C virus (HCV) infections are often associated with extrahepatic immunological manifestations, including various autoimmune disorders. The aims of this study were to determine the prevalence of HCV markers in patients with myasthenia gravis (MG) and to determine any relationship with HCV infection. Eighty-three patients with MG. 40 men aged 20-93 years and 43 women aged 13-87 years (mean age 54 years) were studied. The MG patients were positive for antibody to acetylcholine receptor in addition, their sera was analysed for antibody to HCV (HCVAb) and HCV RNA, HCVAb was detected in two of the 83 patients (2.4%). Four patients were repeatedly HCV RNA positive. They were infected by HCV genotype 1 (one patient), HCV genotype 2a (two patients) and an undetermined HCV genotype in one patient. They received plasmapheresis or intravenous immunoglobulin treatment. Among the four patients, one was infected after the onset of MG without receiving a blood transfusion or using intravenous drugs. The other three had chronic hepatitis C which was discovered at the same time as MG and only one patient had been exposed to blood products. The prevalence of HCV markers in patients with MG (4.8%) was higher than that reported for the general French population, about 1%. This prevalence is similar to that occurring in patients exposed to plasmapheresis or intravenous immunoglobulin. In conclusion, HCV appears to play little, if any, role in causing MG. The higher prevalence of infection among MG patients may be related to transmission in the course of therapy.

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.

Hepatitis C virus infection and autoimmune thrombocytopenic purpura

BACKGROUND/AIMS

Chronic hepatitis C virus infections are often associated with extra-hepatic immunological manifestations, including various autoimmune disorders. The aims of this study were: (i) to determine the prevalence of hepatitis C virus markers in patients with autoimmune thrombocytopenic purpura, and (ii) to determine whether a relationship could exist between autoimmune thrombocytopenic purpura and hepatitis C virus infections.

METHODS

One hundred and thirty-nine patients with autoimmune thrombocytopenic purpura (45 men, 94 women, mean age 42 years, range 16-90) were studied.

RESULTS

Anti-HCV antibodies were sought in their first and last available cryopreserved sera. In case of seropositivity, all their available cryopreserved sera were tested for anti-HCV antibodies and for HCV-RNA. Anti-HCV antibodies were detected in 14 of the 139 patients (10%). Four patients had transient anti-HCV seropositivity due to passive transfer of anti-HCV antibodies secondary to the infusion of intravenous immunoglobulin concentrates. Three patients seroconverted during follow up, due to intravenous drug use in one case, transfusion of non-HCV-screened blood units in one case, and infusion of intravenous immunoglobulins in one case. Seven patients had chronic hepatitis C discovered at the same time as autoimmune thrombocytopenic purpura. In two of them, hepatitis C virus transmission was the consequence of autoimmune thrombocytopenic purpura treatment but, in five cases, hepatitis C virus infection predated autoimmune thrombocytopenic purpura, so that the role of hepatitis C virus in autoimmune thrombocytopenic purpura could be suggested.

CONCLUSIONS

Whereas hepatitis C virus does not appear to be the main etiological agent of autoimmune thrombocytopenic purpura can be envisaged. On the other hand, treatment of autoimmune thrombocytopenic purpura or autoimmune thrombocytopenic purpura-related symptoms by blood product infusion can be complicated by hepatitis C virus transmission.

Tolerability and kinetics of a solvent-detergent-treated intravenous immunoglobulin preparation in hypogammaglobulinaemia patients

The tolerability and kinetics of a solvent-detergent-treated 6% intravenous immunoglobulin (IVIG) preparation were studied in 15 hypogammaglobulinaemia patients during 3-4 regular substitution infusions of 9-48 g, the mean dose being 359 mg/kg. The infusions were well tolerated, and the trough serum IgG levels achieved were comparable to two commercial IVIG preparations. The stepwise increase of the infusion rate up to 5 mg/kg/min and the use of this IVIG as a 12% solution were possible without serious adverse events in all the 6 studied hypogammaglobulinaemia patients. This greatly reduced the time needed for the infusions.

[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.