Anti-idiotypic suppression of autoantibodies to factor VIII (antihaemophilic factor) by high-dose intravenous gammaglobulin

Intravenous immunoglobulin therapy of autoimmune and systemic inflammatory diseases

The proven beneficial effect of intravenous immunoglobulins (IVIg) in certain autoimmune disorders has led to the development of clinical trials in other autoimmune and systemic inflammatory diseases. In parallel, experimental studies are being carried out to better understand the mechanisms of action of IVIg. In this review, we discuss the clinical use of IVIg in autoimmune disorder and the possible mechanisms by which IVIg may be effective in the various diseases. A better understanding of the mechanisms of action of IVIg in autoimmune disease will allow optimization of their use as a therapeutic alternative to conventional immunosuppression.

Pooled human IGG (PHIG) inhibits the binding of anti-myeloperoxidase antibodies to myeloperoxidase

This study demonstrates that pooled human immunoglobulin (PHIG) contains anti-idiotypes to anti-myeloperoxidase (MPO) antibodies and can inhibit the binding of anti-MPO to MPO. The variability seen in the inhibitory effect of different PHIG preparations in the same and also in different patient sera suggests heterogeneity in the idiotypic repertoire of anti-MPO antibodies.

Hypothesis for the control of clotting factor VIII inhibitory antibodies by decreasing potency of helper T-cell-recognized epitopes in factor VIII

The study of the immunobiology of FVIII inhibitors may lead to new therapies for this potentially severe complication of haemophilia A and to new principles for the use of therapeutic proteins. In order to characterize the idiotype-anti-idiotype networks regulating FVIII inhibitors, we developed rabbit anti-idiotypic sera to 7 murine inhibitors and found at least 12 independent FVIII loci to which inhibitors could be raised. Rabbit antisera to the FVIII peptide, Ser1687-Thr1695, characterized one functional site to which about 46% of patients' inhibitor sera reacted. The multiplicity of inhibitor-recognized epitopes in FVIII makes it impractical, at the present time, to develop clinically useful specific anti-idiotypic therapies for FVIII inhibitors. Alternatively, one might induce genomic mutations in recombinant FVIII molecules to decrease immunogenicity of epitopes recognized by T helper cells. Methods to design such altered therapeutic proteins are presented, based on changing the longitudinal hydrophobic strip-of-helix which is in or near many T-cell-presented epitopes.

Suppression of autoantibodies to factor VIII and correction of factor VIII deficiency with a combined steroid-cyclophosphamide-porcine factor VIII treatment in a patient with rheumatoid arthritis

The presence of autoantibodies against factor VIII is an unusual but serious complication in rheumatoid arthritis. We describe the case of a patient who developed this kind of complication, with spontaneous bleeding and marked changes in the haematological parameters, that was unsuccessfully treated with a high dose of intravenous gammaglobulin. Subsequently, combined therapy with porcine factor VIII concentrate, cyclophosphamide and steroids led to the disappearance of the anti-factor VIII autoantibodies.

Acquired von Willebrand disease: correction of hemostatic defect by high-dose intravenous immunoglobulins

High-dose intravenous immunoglobulins (ivIG) were used in a 57-year-old patient with acquired von Willebrand disease in order to correct a hemostatic defect before pneumonectomy for lung carcinoma. IvIG induced a rapid and complete correction of factor VIII (F VIII) and von Willebrand factor (vWF) and allowed surgery without additional factor coverage. F VIII and vWF returned to baseline values within 10 days after ivIG.

Intravenous immune globulins. A review of their uses in selected immunodeficiency and autoimmune diseases

Intravenous immune globulin (IGIV) was introduced a decade ago as a therapy for primary immunodeficiency diseases. It proved to be a valuable therapeutic substance for this purpose and is now considered to be the treatment of choice. The intent was to supply ubiquitous anti-infectious agent antibodies through passive immunisation to replace deficient circulating antibody content. During such therapy, unexpected benefits were noted in thrombocytopenic patients. Since that time, the therapeutic indications for IGIV infusions have greatly increased, with a particular interest in infectious, haematological and autoimmune diseases. This review summarises the status of IGIV therapy in haematological diseases within the categories of primary immunodeficiency diseases, secondary immunodeficiency states and autoimmune syndromes. The majority of firm data have been gathered on the treatment of patients with primary immunodeficiency disease. These data are reviewed from the aspect of anticipated therapeutic response and side effects. Emphasis should be placed on the IgG circulating blood levels as there is a need for individualizing therapy because of marked interindividual patient variation. The use of IGIV therapy in primary and secondary immunodeficiency states should consider the potential benefits to be attained in haematological malignancies and related complications which may be magnified by chemotherapy and radiation therapy. The mode of action of IGIV in autoimmune diseases, although not yet precisely determined, may involve establishing reticuloendothelial blockade or immunomodulation by supplying anti-idiotype antibodies.

Natural antibodies to factor VIII (anti-hemophilic factor) in healthy individuals

Spontaneous inhibitors of factor VIII (FVIII) are pathogenic IgG autoantibodies of restricted isotypic heterogeneity found in the plasma of patients presenting with bleeding episodes and low levels of FVIII. We now report the presence of a natural FVIII-neutralizing activity in 85 of 500 plasma samples (17%) from healthy donors. FVIII-inhibitory activity was present in F(ab')2 fragments of purified IgG and was dose-dependent. The titer of anti-FVIII antibodies in normal plasma ranged between 0.4 (threshold of detection) and 2.0 Bethesda units. Anti-FVIII IgG was also detected in normal plasma by using an ELISA. Anti-FVIII antibodies from healthy individuals did not exhibit restricted isotypic heterogeneity. Mean levels of FVIII activity did not differ significantly between individuals with and without detectable anti-FVIII antibodies in plasma. Natural anti-FVIII IgG inhibited FVIII activity in pools of normal plasma and in plasma of certain donors in the pool but did not inhibit FVIII activity in autologous plasma. These observations demonstrate that polyclonal IgG antibodies against procoagulant FVIII are present in healthy individuals. The antibodies are natural IgG autoantibodies and/or antibodies directed against epitopes associated with a so far unidentified allotypic polymorphism of the human FVIII molecule.

A randomized trial comparing intravenous immune globulin and plasma exchange in Guillain-Barré syndrome. Dutch Guillain-Barré Study Group

BACKGROUND

The subacute demyelinating polyneuropathy known as Guillain-Barré syndrome improves more rapidly with plasma exchange than with supportive care alone. We conducted a multicenter trial to determine whether intravenous immune globulin is as effective as the more complicated treatment with plasma exchange.

METHODS

To enter the study, patients had to have had Guillain-Barré syndrome for less than two weeks and had to be unable to walk independently. They were randomly assigned to receive either five plasma exchanges (each of 200 to 250 ml per kilogram of body weight) or five doses of a preparation of intravenous immune globulin (0.4 g per kilogram per day). The predefined outcome measure was improvement at four weeks by at least one grade on a seven-point scale of motor function.

RESULTS

After 150 patients had been treated, strength had improved by one grade or more in 34 percent of those treated with plasma exchange, as compared with 53 percent of those treated with immune globulin (difference, 19 percent; 95 percent confidence interval, 3 percent to 34 percent; P = 0.024). The median time to improvement by one grade was 41 days with plasma exchange and 27 days with immune globulin therapy (P = 0.05). The immune globulin group had significantly fewer complications and less need for artificial ventilation.

CONCLUSIONS

In the acute Guillain-Barré syndrome, treatment with intravenous immune globulin is at least as effective as plasma exchange and may be superior.

[Intravenous immunoglobulins and anti-idiotypic suppression of auto-immunity]

This review summarizes the clinical use of intravenous immunoglobulins (IVIg) in autoimmune diseases and focuses on the mechanisms by which IVIg suppress autoimmune responses. Evidence is presented of a role of IVIg in modulating the regulatory function of the idiotypic network on the expression of the natural and pathological autoimmune repertoires.

Soluble HLA class I and class II concentrations in commercial immunoglobulin preparations

Soluble HLA class I (sHLA-ABC) and class II (sHLA-RQP) molecules were quantitated in 16 commercially available immunoglobulin (Ig) preparations by enzyme-linked immunosorbent assays. Whereas three Ig preparations contained no detectable sHLA-ABC, all preparations showed concomitant sHLA-RQP molecules. There was a considerable variability with regard to the individual sHLA concentrations. For sHLA-RQP the values exceeded that found in human plasma of healthy individuals, suggesting that the extraction procedure may concentrate not only Ig, but also HLA class II molecules. Based on the total dosage of intravenously administered immunoglobulins (i.v.Ig), contaminating sHLA molecules may become immunogenic. Furthermore, sHLA molecules are discussed in terms of participation in the well-known immunomodulating effects of i.v.Ig therapy.

Modulation of autoimmunity by intravenous immune globulin through interaction with the function of the immune/idiotypic network

Infusion of intravenous immune globulin (IVIG) has resulted in clinical improvement and/or a fall in autoantibody titer in a number of autoimmune diseases in which direct or indirect evidence suggests a pathogenic role for autoantibodies. IVIG may react with disease-associated autoantibodies through idiotypic interactions as shown by the following lines of evidence: (1) inhibition of autoantibody activity in F(ab')2 fragments of patients' IgG by F(ab')2 fragments of IVIG; (2) retention of autoantibodies on affinity columns of Sepharose-bound F(ab')2 fragments of IVIG; and (3) recognition of the same idiotypic determinants on autoantibodies by heterologous anti-idiotypic antibodies and by IVIG. IVIG also interacts with idiotypic determinants on natural autoantibodies as indicated by the binding of monoclonal IgM secreted by Epstein-Barr virus-transformed normal human B cells to F(ab')2 fragments of IVIG and by idiotypic interactions between normal IgG antibodies within the IVIG preparations. Infusion of IVIG into patients with autoimmune diseases alters the kinetic behavior of disease-associated and natural autoantibodies of unrelated specificities. It is our view that IVIG is effective in autoimmune diseases not merely by a passive transfer of suppressive anti-idiotypes, but rather by imposing a normal function on the defective network in autoimmune patients. The intrinsic complexity of IVIG would provide a more logical (physiological) rationale for immunoregulatory therapy of autoimmune disease than idiotype-specific suppression.

The use of IVIG in neurological disease

The studies cited herein highlight the potential benefits of IVIG therapy in a group of neurological disorders that are associated with aberrant immune responses. Indeed, all of the disorders discussed, except epilepsy, are associated with autoreactivity. The trials are preliminary and short-term and, except for idiopathic CIDP, uncontrolled. Interpretation of the findings of these uncontrolled studies is complicated by the fact that the natural history of all of these disorders is to show fluctuations. IVIG appears to be a potentially useful and safe agent in the treatment of patients with MG, intractable epilepsy, MS, and CIDP. Its place in the therapeutic approach to these neurological diseases must await the completion of controlled trials. Since other therapeutic modalities have already proven to be useful in several of these disorders, it will be important to determine if IVIG is more efficacious, safer, and more cost-effective. It is also worth considering whether the combination of IVIG and any of these more traditional approaches would provide added therapeutic benefit.

Intravenous immunoglobulin in the treatment of human immunodeficiency virus-related thrombocytopenia

Fourteen patients with sexually transmitted human immunodeficiency virus (HIV)-related immune thrombocytopenia were treated with intravenous gammaglobulin (IVIG). The patients were treated with a uniform program consisting of 1 g/kg of IVIG on day 1 and day 2, followed by 1 g/kg on day 15. Most patients had pretreatment bleeding symptoms, which included petechiae, spontaneous and traumatic ecchymoses, gum bleeding, and epistaxis. Median baseline platelet count was 17,000/mm3 (range 3-61,000/mm3). After the infusion of the IGIV, all patients had a resolution of their bleeding by day 8. The median maximum platelet count achieved with the IGIV was 220,000/mm3 (range 76-426,000/mm3). No patient achieved either a sustained complete or partial remission after the conclusion of the IVIG therapy. Toxicities were minimal with the majority being headache and nausea. In conclusion, patients with sexually transmitted HIV infection and immune thrombocytopenia respond favorably to IVIG. This treatment should be considered as first-line therapy for patients with HIV-related immune thrombocytopenia who require immediate but temporary increase in their platelet count, attributable to symptoms or signs of clinical bleeding or because of the need for an invasive procedure.

The potential role of cytokine-mediated vascular endothelial activation in the pathogenesis of Kawasaki disease

Kawasaki disease (KD) is an acute febrile illness of infancy and early childhood characterized by diffuse vasculitis. Although the disease is generally self-limited, up to 30% of untreated patients with KD may develop coronary artery (CA) abnormalities. The acute phase of KD is characterized by marked activation of the immune system leading to increased cytokine production by immune effector cells, the induction of activation antigens on their vascular endothelium and the generation of lytic antibodies directed against vascular endothelial cells (EC) stimulated with cytokines. Treatment with intravenous gammaglobulin (IVGG) usually rapidly reduces acute clinical symptoms and prevents CA abnormalities. Immunologically, successful IVGG treatment is associated with decreased lymphocyte activation, reduced cytokine secretion and the loss of cytokine induced expression of leukocyte adhesion molecules on vascular endothelium. The association between improvement of clinical symptoms with the reduction of cytokine secretion, and reversal of EC activation supports a role for immune mediated injury to cytokine induced EC antigens in the pathogenesis of this disorder.

Intravenous immunoglobulin in the treatment of spontaneously acquired factor VIII:C inhibitors

Intravenous immunoglobulin (IV Ig) is useful in most patients with spontaneous factor VIII:C (FVIII:C) inhibitors, but some complete failures also are observed. Among patients responding to this therapy, decreases in FVIII:C autoantibody titer occurs within 24-48 hours and may lead to suppression of inhibitor activity. The prolonged response observed in some cases suggest an effect on autoantibody synthesis. The immediate decrease in FVIII:C inhibitory activity after IV Ig infusion indicates a direct interaction between IV Ig and the autoantibody. This effect is reproducible in vitro by mixing the patient's plasma and Ig at an appropriate molar ratio, which differs in each patient. Similarly, incubation of Ig with F(ab)'2 fragments of a patient's IgG and Ig reproduces inhibition, and this result indicates that the interaction is mediated by antigen binding sites (epitopes) on the immunoglobulins. The suggestion is that an idiotype- anti-idiotype mechanism must be at work. The origin of such anti-idiotypes in Ig prepared from pooled plasma of several thousand blood donors is unclear. The F(ab)'2 fragments were prepared from individual blood donors and tested in similar experiments with F(ab)'2 fragments of three distinct spontaneous FVIII:C inhibitors. The plasma level of anti-idiotypic antibodies reacting with FVIII:C inhibitors varied according to age and gender.

Treatment of septic thrombocytopenia with immune globulin

Thrombocytopenia frequently complicates systemic infection and results from multiple possible mechanisms. We and others have demonstrated that platelet-associated IgG (PAIgG) levels are elevated in the majority of patients with septic thrombocytopenia. Corticosteroids may be undesirable as a treatment for thrombocytopenia for patients with severe infection because of their potential for suppressing the immune response. We hypothesized that septic thrombocytopenia is, in most cases, an immune disorder analogous to idiopathic thrombocytopenic purpura (ITP) which might respond to intravenous gamma-globulin as a treatment for increasing the platelet count in this disorder. Intravenous immune globulin (IVIG), 400 mg/kg daily for 3 days, was administered in a randomized double-blind placebo-controlled trial. Twenty-nine patients who developed thrombocytopenia during a documented, septic episode were studied. Patients with disseminated intravascular coagulation (DIC), hypersplenism, or drugs known to cause thrombocytopenia were excluded. Elevated PAIgG levels were documented in 52% of evaluable patients. Mean platelet counts in the IVIG group rose from 43K at study entry to 178K (411% rise) by Day 9. In the placebo group platelets rose from 51K to 125K (261% rise; P = 0.02). Seventy-seven percent of the IVIG group had a minimum peak rise of 35K, vs 56% of the placebo group. Three patients in the placebo group had a serious bleeding episode, vs one in the IVIG group. The use of IVIG to treat septic thrombocytopenia not associated with DIC leads to a more rapid, more sustained, and greater increase in platelet count than placebo. Its use is recommended in the septic patient who is bleeding or is likely to need invasive or surgical procedures.

Intravenous immunoglobulins (IVIg) in the treatment of autoimmune diseases

Intravenous immunoglobulin (IVIg) therapy is increasingly used in autoimmune diseases. Although its efficacy has only been established in a few specific antibody-mediated autoimmune conditions, accumulating evidence on the regulatory role of circulating immunoglobulins in the selection of peripheral B cell repertoires makes it an attractive potential therapeutic option to clinical immunologists. This overview briefly discusses the current use of IVIg in human autoimmune diseases with a particular emphasis on the possible mechanisms by which IVIg could suppress pathological autoimmune responses.

In vivo efficacy of intravenous gammaglobulins in patients with lupus anticoagulant is not mediated by an anti-idiotypic mechanism

The authors have investigated the presence in commercially available intravenous gammaglobulins (IVIg) of anti-idiotypic antibodies directed to Lupus Anticoagulant (LA). In vitro incubation of 4 LA plasmas with increasing concentrations of IVIg (from 0 to 39 mg/ml) resulted in a dose-dependent inhibition of LA activity (the highest inhibitions ranged from 14.0 to 53.4%). Similar results were obtained when patients' plasma was substituted with total IgG (the highest inhibitions ranged from 43.0 to 55.0% and were obtained at IgG:IVIg molar ratios ranging from 1:15 to 1:50). Also the incubation of patients' F(ab')2 with F(ab')2 from IVIg produced a similar dose-dependent inhibition of LA activity. These data are suggestive of an in vitro idiotypic-anti-idiotypic interaction between LA and IVIg. However, when injected in patients with LA, IVIg do not seem to operate by this mechanism of action. In fact, reduction or disappearance of LA was only observed in 2 out of 4 patients; also the quick reappearance of LA activity was not consistent with the time course of anti-idiotypic response. Finally, this effect was reached by half the IVIg concentrations necessary to produce an appreciable inhibitory effect on LA activity in vitro. Thus, it is concluded that, even if IVIg contain anti-idiotypic antibodies reacting with LA, the clinical efficacy of IVIg treatment in patients with these autoantibodies should be attributed to other mechanisms.

Monoclonal, natural antibodies prevent development of diabetes in the non-obese diabetic (NOD) mouse

The development of diabetes in the non-obese diabetic (NOD) mouse is mediated by T cells of both the CD4+CD8- and CD4-CD8+ phenotypes, while B cells are not involved in the effector stage of the disease. We have recently found, however, that treatments with heterologous, polyclonal immunoglobulin (Ig) preparations, as well as suppressing the developing B cell repertoire for the first 4 weeks of life dramatically reduce the incidence of disease and the severity of insulitis, in treated mice. We have further investigated the influence of Igs on the development of autoimmunity by testing the effect of polyclonal mouse-Ig or monoclonal, natural antibodies derived from normal, neonatal BALB/c mice. We found that repeated administration of high doses of polyclonal Ig (of xenogenic or isogenic origin), given at birth, inhibits the development of insulitis, as well as diabetes. Furthermore, single injections of moderate doses of isogenic, natural monoclonal antibodies (mAb) administered at the same age, while failing to significantly alter the degree of insulitis, efficiently prevent the development of disease. The effect of mAbs was found to be related to V-region specificity, as only some mAbs of a given isotype and origin had the observed effect.

A B cell line from a patient with pure red cell aplasia produces an immunoglobulin that suppresses erythropoiesis

A 4-year-old boy with pure red cell aplasia was investigated. Immunophenotypic analysis of peripheral blood lymphocytes revealed a marked increase of CD20+ cells, which fell from 25.9% in the active stage to 9.7% in remission. The plasma contained a suppressive activity against CFU-e and BFU-e formation by the patient's bone marrow cells, which disappeared when the disease went into remission. Prednisone (2 mg/kg/day) therapy was tried for 5 weeks, but produced no improvement. Subsequently, high-dose gamma-globulin therapy induced complete remission of anemia. A lymphoblastoid B cell line obtained from the patient before therapy produced a factor that suppressed erythropoiesis but not granulopoiesis. The suppressive activity resided in the immunoglobulin fraction and was adsorbed by an anti-immunoglobulin column. These results indicate that expansion of B cells producing an immunoglobulin which suppressed erythropoiesis was involved in the pathogenesis of the disease in this patient.

Immune thrombocytopenic purpura and intravenous immunoglobulin

The observation, in 1980, of a rapid increase in platelet counts as a result of administration of intravenous immunoglobulin (IVIG) in a patient with immune thrombocytopenic purpura (ITP) was followed by clinical studies confirming the efficacy of this new treatment alternative in ITP. Simultaneously, new sensitive assays using monoclonal antibodies against platelet glycoproteins showed that chronic ITP in adults and children is often an autoimmune disorder. There seem to be both immediate and long-term effects of IVIG in ITP which may be explained by mechanisms of action other than immunoglobulin G substitution. The mode of action of IVIG could correspond to interference with Fc receptors on phagocytes or be a result of antiidiotypic antibodies in IVIG that may induce secondary changes in the complex immunologic network. These immunomodulatory effects were the basis for the use of IVIG in the treatment of patients with other immune-related disorders. New aspects regarding definition and treatment of ITP, the possible mechanisms of action of IVIG, and the implications thereof are discussed and updated.

Historic aspects of intravenous immunoglobulin therapy

The earliest preparations of immunoglobulins (Ig) decreased the susceptibility of agammaglobulinemic patients to infections caused by pneumococci, Haemophilus influenzae, meningococci, streptococci, and Pseudomonas aeruginosa. Intramuscular administration of such preparations was painful and traumatic, especially for children. Ethanol-fractionated Ig could not be administered intravenously (IV) because the IgG molecules tended to aggregate and thus were more likely to produce anaphylactoid reactions. New Ig preparations, isolated at low pH (e.g., pH 4) in the presence of traces of pepsin to inhibit reaggregation, were well tolerated when administered IV. Thus a new era of treatment and prophylaxis of disease using IV Ig (IVIG) was launched. The IVIG preparations revolutionized the management of virtually all immunodeficiency syndromes characterized by failure of antibody responses. Amelioration of antibody deficiency secondary to certain chronic diseases or surgical trauma can be achieved with these preparations. Newer uses of IVIG include treatment of some autoimmune diseases; in some conditions, the beneficial influences may be attributable to antiidiotype antibodies present in the IVIG. Another likely explanation is that IVIG inhibits damage to cells and tissues by antibody-mediated cellular cytotoxicity or blocks phagocytosis that is facilitated by Fc receptor mechanisms. The value of IVIG in preventing infection in patients undergoing bone marrow or organ transplantation and in the treatment and prophylaxis of life-threatening infections in neonates and premature infants also is reviewed.

Treatment of HTLV-I-associated myelopathy with high-dose intravenous gammaglobulin

Fourteen patients with HTLV-1-associated myelopathy were treated with high-dose intravenous gammaglobulin (IVGG). Ten received 10 g/day of IVGG and 4 received 400 mg/kg of body-weight/day of IVGG for 5 consecutive days. Improvement of spastic paraparesis was observed in 10 within 7 days of the commencement of IVGG. The therapeutic effects were sustained for more than 3 weeks in some patients. There were no side effects. Analysis of factors of relevance to the clinical improvement with IVGG showed that the beneficial response was preferentially found in patients having a high CSF titre of anti-HTLV-I antibodies, a high CSF IgG level and a marked brain MRI abnormality.

Successful treatment of a patient with postpartum factor VIII inhibitor with recombinant human interferon alpha 2a

A patient who had developed a postpartum inhibitor to factor VIII and who did not respond to repeated therapy with steroid and high-dose intravenous gammaglobulin G was treated with one short course of low-dose recombinant interferon alpha 2a (rhIFN) s.c. Within 7 weeks from the start of rhIFN treatment, the inhibitor disappeared. It remains undetectable 8 months after therapy.

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.

Treatment of systemic vasculitis with pooled intravenous immunoglobulin

The therapeutic effect of a course of high-dose, pooled, intravenous immunoglobulin (IVIg) on disease activity and circulating antineutrophil cytoplasm antibodies (ANCA) was investigated in 7 patients with systemic vasculitis. 5 had active disease despite conventional immunosuppression, and 2 had not received any treatment. All 7 had clinical improvement, which was sustained in 6 and transient in 1. The fall in ANCA concentrations to a mean of 51% of the pre-treatment values was maintained during follow-up. C-reactive protein concentration also dropped considerably. IVIg seemed to confer a useful therapeutic effect without adverse reaction.

Intravenous gamma-globulin in myasthenia gravis: interaction with anti-acetylcholine receptor autoantibodies

Clinical improvement has been observed in myasthenia gravis patients treated by intravenous immunoglobulin (IVIg). In order to investigate the mechanism of action of these IVIg, we looked for an in vitro interaction between IVIg and the anti-acetylcholine receptor autoantibodies. Significant inhibition by IVIg of anti-acetylcholine receptor autoantibody activity from 30 MG sera was observed and binding of anti-acetylcholine receptor autoantibodies on IVIg was found for four of five myasthenia gravis sera. These observations suggest that IVIg contains Ig directly binding to and inhibiting pathogenic autoantibodies.

Trophoblast immunity in human pregnancy defined by antiidiotype

Successful reproduction in mammals requires the mother to immunologically accept genetically disparate tissues. Allotypic trophoblast antigens (TLX) are thought to be responsible for influencing maternal acceptance of the feto-placental graft, and faulty regulation of immunity to TLX antigens has been associated with recurrent pregnancy losses. In this report, rabbit antiidiotype (RAb2) was produced to a human TLX antibody (Ab1). This RAb2 detected TLX cross-reactive idiotypes (CRI) on antitrophoblast IgG from women with normal and abnormal pregnancies. These findings support an hypothesis that women respond immunologically to allotypic trophoblast antigens, and that idiotype-antiidiotype regulation of this response is characteristic of normal pregnancy.

Beneficial effect of human therapeutic intravenous immunoglobulins (IVIg) in mercuric-chloride-induced autoimmune disease of Brown-Norway rats

Administration of HgCl2 to the susceptible Brown-Norway (BN) strain of rats induces an autoimmune disease characterized by polyclonal B cell activation, increased serum levels of IgE and the occurrence of anti-glomerular basement membrane antibody-mediated glomerulonephritis. We have observed that the simultaneous administration to BN rats of normal human polyspecific immunoglobulins for therapeutic use (IVIg) with HgCl2 significantly decreased the occurrence and severity of proteinuria, and reduced serum IgE levels in diseased animals. Hypergammaglobulinaemia was potentiated in animals receiving HgCl2 and IVIg, compared with animals receiving HgCl2 alone. In vitro experiments indicated that F(ab')2 fragments from IVIg inhibited the binding to laminin of pathogenic anti-laminin antibodies from diseased rats, as did antibodies from the resistant Lewis strain of rats but not antibodies from susceptible BN rats. These observations suggest that IVIg may interfere with the immune regulatory mechanisms involved in mercury-induced autoimmune disease in an analogous fashion to the ability of IVIg to suppress the expression of certain pathological autoimmune responses in humans.

A human monoclonal IgG reactive with a private idiotope of a monoclonal IgM with autoantibody activity against myelin-associated glycoprotein

One hundred and thirteen sera from patients with monoclonal IgG were tested for reactivity against a panel of 13 human monoclonal IgM having various autoantibody activities: 6 to myelin-associated glycoprotein (MAG), 2 to vimentin intermediate filament protein and 5 to red blood cell antigens [cold agglutinins with specificity directed to I antigen (3 cases), i antigen (1 case) or Pr antigen (1 case)]. One IgG was found to react with a monoclonal IgM with anti-MAG activity. This reactivity was characterized as idiotypic and directed against a private idiotope of the monoclonal IgM. This work provides further evidence for the existence of anti-idiotypic antibody activity of monoclonal Ig occurring in human B cell neoplasias.

Immune thrombocytopenia: surgical therapy and predictors of response

We have reviewed 40 patients with immune thrombocytopenia purpura (ITP) to assess current methods of preparation for surgery and to evaluate perioperative complications and response to splenectomy. Twenty-one patients had chronic ITP (greater than 1 year duration) and 19 patients had severe acute thrombocytopenia (platelet counts less than 10,000). A progression of methods of pretreatment was seen in the 10-year period reviewed. Seventeen patients received no treatment before admission for surgery, and 10 of these received platelet transfusions. Seventeen patients received steroids immediately preceding surgery; 16 of these responded and 1 received a platelet transfusion. Recently, 5 patients received intravenous gamma globulin (IgG) preceding surgery with all patients responding and none receiving platelet transfusions. One patient received a combination of steroids and IgG with good response and did not require platelet transfusion. No major postoperative complications occurred (ie, pancreatitis, small bowel obstruction, or sepsis) except for one patient requiring a secondary exploration for an accessory spleen and recurrent thrombocytopenia. Eight patients (20%), 6 with severe ITP and 2 with chronic ITP (5 males and 3 females) developed recurrence of thrombocytopenia following surgery up to 1 1/2 years after splenectomy. These patients all required further medical therapy. Three additional patients (2 chronic and 1 severe) developed thrombocytopenia following viral illnesses, but required no further therapy. Of the 8 surgical failures, 4 failed to respond to prior treatment with steroids, 1 to IgG, and 2 failed to respond to combination therapy, while one surgical failure responded to both steroid and combination therapy. Of the responders to splenectomy (32 patients), only 3 failed to respond to prior treatment with steroids.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence for a restricted idiotypic and epitopic specificity of anti-thyroglobulin autoantibodies in patients with autoimmune thyroiditis

Anti-thyroglobulin (TG) autoantibodies from patients with autoimmune thyroiditis express a cross-reactive alpha idiotype (Id) termed T44 which is not expressed by IgG from normal individuals. The present study demonstrates that the expression of the T44 Id is strongly associated with the recognition by anti-TG autoantibodies of a specific epitopic cluster on human TG. The epitopic reactivity of anti-TG autoantibodies was determined using a competitive inhibition assay with a panel of 15 monoclonal antibodies that define six antigenic clusters on TG. All T44+ autoantibodies from patients recognized cluster II, whereas no anti-TG IgG from healthy individuals reacted with this region. Affinity columns of Sepharose-bound intravenous therapeutic immunoglobulins which contain anti-T44 activity, retained both T44 Id-expressing antibodies and a subset of region II-specific anti-TG autoantibodies from patients with Hashimoto's disease. Restricted idiotypic and epitopic specificity may demarcate disease-associated from natural anti-TG autoantibodies, suggesting that qualitative rather than quantitative criteria should be used to identify pathological autoantibodies.

Anti-idiotypes against anti-neutrophil cytoplasmic antigen autoantibodies in normal human polyspecific IgG for therapeutic use and in the remission sera of patients with systemic vasculitis

Anti-neutrophil cytoplasmic antigen (ANCA) activity was inhibited in 15 out of 21 sera from patients with acute systemic vasculitis following incubation with normal polyspecific IgG for therapeutic use (IVIg). ANCA antibodies reacted with IVIg through idiotypic-anti-idiotypic interactions, as shown in competitive binding assays using F(ab')2 fragments from IVIg and affinity chromatography of ANCA IgG on Sepharose-bound F(ab')2 fragments from IVIg. Co-incubation of sera from patients with acute systemic vasculitis with paired autologous remission stage sera also resulted in inhibition of ANCA activity in acute sera. Remission sera contain IgM and IgG capable of interacting with beta and or alpha idiotypes of ANCA IgG from acute sera. Anti-idiotypic IgM may account for the lack of expression of ANCA activity in whole serum from patients in remission from systemic vasculitis, which were found to contain high titres of ANCA IgG. These observations suggest that remission of systemic vasculitis is associated with the generation of anti-idiotypes against autoantibodies rather than the suppression of production of ANCA autoantibodies. IVIg may modulate the activity of systemic vasculitis in vivo.

CD4 and CD8 subpopulation changes during high dose intravenous immunoglobulin treatment

High doses of immunoglobulin, when given intravenously (IVIgG), influence lymphocyte subset numbers and function. T-lymphocytes may be subdivided into two functionally different groups, helper/inducer (CD4+) and suppressor/cytotoxic (CD8+). Considerable functional as well as phenotypic heterogeneity exists within the two major subsets. CD4+ cells have been further subdivided into helper/inducer and suppressor/inducer sets by the differential binding of two monoclonal antibodies 4B4 (CDw29) and 2H4 (CD45R). Similarly, the CD8+ subset may be subdivided into suppressor and cytotoxic populations by the differential binding of monoclonal antibodies which identify the C3bi receptor (CD11). During IVIgG treatment of patients with autoimmune thrombocytopenic purpura (ATP) the change in CD4/CD8, due to an absolute increase in CD8+ cells, has been shown to correlate with the response to treatment as determined by platelet increase. However, the total CD4+ and CD8- numbers may not reflect changes in their constituent subpopulations. To examine this possibility the CD4 and CD8 subpopulations were analysed in 15 ATP patients, during IVIgG treatment, using a double fluorescence technique. In 10 of these patients the in vitro response to pokeweed mitogen (PWM) and Staphylococcus aureus Cowan I (STA Cowan I) was determined. There was no correlation between the change in CD8+ subpopulations and response to treatment but there was a correlation between the CD4+ change and platelet increment. In addition there was a correlation between the 4B4/2H4 change and the in vitro response to PWM but no correlation with the response to STA Cowan I. These findings suggest that during IVIgG treatment the CD4+ 4B4+ helper/inducer population is influenced resulting in reduced T-dependent B-cell activation.

Three cases of acquired factor VIII: C inhibitors in non-hemophilic patients

During the last ten years we observed three non-hemophilic patients with factor(F) VIII: C inhibitors (2 women aged 68 and 80 and a man aged 51). In all three cases, a sudden bleeding tendency was observed shortly after an injury or surgery. Coagulation tests showed a prolonged aPTT and a decreased F VIII: C level. Other deficiencies of blood-clotting factors and acquired or hereditary von Willebrand's disease could be excluded. Therapy with F VIII: C concentrate, cryoprecipitate, or fresh-frozen plasma did not produce the expected increase in F VIII: C. Measurement of F VIII: C inhibitor levels (Bethesda Units, BU) revealed values in the range between 9 and 64 BU. The two patients subjected to long-term therapy with a combination of prednisone (initially 2-3 mg/kg BW) and azathioprine (2-3 mg/kg BW) responded positively; the F VIII: C concentration increased. The third patient, treated only with a low dose of prednisone (30 mg/day), did not show any reaction at all. Since hereditary hemophilia A could be excluded, the inhibitors apparently were acquired. Malignant tumors did not appear. In conclusion, long-term therapy of an acquired F VIII: C inhibitor with a combination of prednisone and azathioprine may lead to complete disappearance of the inhibitor, normalization of the coagulation tests, and complete remission of the bleeding tendency.

Cytokine induction in human mononuclear cells stimulated by IgG-coated culture surfaces and by IgG for infusion

The effect of IgG on cytokine production by human mononuclear cells (MNC) was studied. Tumor necrosis factor-alpha (TNF) was determined both by bioassay and by immunoassay. Interleukin-1 (IL1) was measured by a thymocyte costimulator assay, which was shown to be completely inhibitable by polyclonal anti-IL1. Precautions were taken to avoid inadvertent exposure of the studied cells to endotoxin. In a first model, TNF and IL1 production by adherent MNC in IgG-coated cluster plates were determined. IgG induced a strong TNF response, usually leveling off after 6 hr, and was comparable in kinetics and magnitude with an LPS-induced response. The thymocyte co-stimulatory activity response was relatively weak and peaked at 6 hr. In contrast, LPS-induced co-stimulatory activity production steadily increased over 24 hr. In a second model, MNC in suspension cultures containing autologous serum were exposed to IgG for intravenous use (IgG-IV). Cells exposed to IgG-IV produced higher amounts of cytokines than control counterparts and were primed for enhanced production of cytokines upon a second, unrelated stimulus. This implies that the effect of IgG-IV on suspended MNC resembles that of surface-adsorbed IgG and raises the possibility that cytokine release is an integral part of the mechanism of action of infused IgG. Evidence is presented suggesting that both surface IgG and IgG-IV act directly on monocytes, in a Fc-dependent manner.

Recurrent cerebral infarction and the antiphospholipid syndrome: effect of intravenous gammaglobulin in a patient with systemic lupus erythematosus

A 23 year old woman with systemic lupus erythematosus and antiphospholipid syndrome developed severe thrombocytopenia (5-10 X 10(9)/l) and cerebral infarction. Treatment with high doses of corticosteroids and cytostatic drugs was not effective. The condition was successfully treated only when three courses of intravenous gammaglobulin at 400 mg/kg daily was added. A clear relation was found between the immunoglobulin infusions and rising platelet counts, whereas an effect on the levels of anticardiolipin antibodies could not be recorded. The findings suggested that the mechanisms responsible may be modification and solubilisation of immune complexes or interference with anticardiolipin binding to platelet membranes, or both.

A vascular effect of IgG therapy may prevent transplacental red cell leakage and spontaneous thrombocytopenic haemorrhages

It is postulated that intravenous immunoglobin therapy may improve the red cell barrier of placenta and of capillary endothelia; the former protecting against anti-Rh antibody booster reaction and the latter preventing spontaneous thrombocytopenic bleedings. The effect on permeability may also reduce the passage of anti-Rh antibodies to the foetus.

A monoclonal anti-idiotypic antibody against the antigen-combining site of anti-factor VIII autoantibodies defines and idiotope that is recognized by normal human polyspecific immunoglobulins for therapeutic use (IVIg)

The present study demonstrates that normal human immunoglobulins for therapeutic use (IVIg) contain anti-idiotypes that recognize an antigen-binding site-related idiotope of anti-Factor VIII autoantibodies defined by a mouse monoclonal antibody (MoAb). MoAb 20F2 was obtained by immunizing a mouse with affinity-purified anti-Factor VIII F(ab')2 fragments prepared from the IgG fraction of a patient with anti-Factor VIII autoantibodies. The monoclonal antibody was directed against an overlapping epitope on the antigen-binding site of the patient's anti-Factor VIII autoantibodies and the CH1 domain of human IgG1. The anti-Factor VIII activity of the patients's autoantibodies was neutralized by MoAb 20F2 in a dose-dependent manner. A fraction of the patient's anti-Factor VIII auto-antibodies was specifically retained on affinity columns of Sepharose-bound MoAb 20F2; anti-Factor VIII activity of antibodies in this fraction was totally inhibited by MoAb 20F2, indicating an idiotopic homogeneity of retained anti-Factor VIII autoantibodies. IVIg inhibited the anti-Factor VIII activity of 20F2 idiotope-positive F(ab')2 antibodies, thus indicating that the IVIg recognize the 20F2 idiotope on patient's autoantibodies. These observations further support the concept of the presence in IVIg of anti-idiotypes against autoantibodies associated with human autoimmune diseases.