Immunoglobulin and circulating immune complex kinetics during immunoadsorption onto protein A sepharose

The development of immunosorbents for the treatment of systemic lupus erythematosus via hemoperfusion

Systemic lupus erythematosus (SLE) is an autoimmune disease (AID) that involves multiple organ systems and is characterized by elevated levels of autoantibodies (ANA) and immune complexes. The immunoadsorption technique uses an extracorporeal clearance process to remove pathogenic toxins from patients' blood and alleviate disease symptoms. An immunosorbent is a key component of the immunoadsorption system that determines therapeutic efficacy and safety. Immunosorbents are prepared by immobilizing antibodies, antigens, or ligands with specific physicochemical affinities on a supporting matrix. Immunosorbents and pathogenic toxins bind via affinity adsorption, which involves electrostatic interactions, hydrogen bonds, hydrophobic interactions, and van der Waals forces. Immunosorbents are classified on the basis of their interaction mechanism with toxins into three categories: non-selective, semi-selective, and highly selective. This review aimed to summarize the current status of various commercial immunosorbents that are used to treat SLE. Moreover, recent developments in immunosorbents have heightened the need for a brief discussion about specific ligands and a supporting matrix.

Autoantibodies and Cardiomyopathy: Focus on Beta-1 Adrenergic Receptor Autoantibodies

ABSTRACT

Antibody response to self-antigens leads to autoimmune response that plays a determinant role in cardiovascular disease outcomes including dilated cardiomyopathy (DCM). Although the origins of the self-reactive endogenous autoantibodies are not well-characterized, it is believed to be triggered by tissue injury or dysregulated humoral response. Autoantibodies that recognize G protein-coupled receptors are considered consequential because they act as modulators of downstream receptor signaling displaying a wide range of unique pharmacological properties. These wide range of pharmacological properties exhibited by autoantibodies has cellular consequences that is associated with progression of disease including DCM. Increase in autoantibodies recognizing beta-1 adrenergic receptor (β1AR), a G protein-coupled receptor critical for cardiac function, is observed in patients with DCM. Cellular and animal model studies have indicated pathological roles for the β1AR autoantibodies but less is understood about the molecular basis of their modulatory effects. Despite the recognition that β1AR autoantibodies could mediate deleterious outcomes, emerging evidence suggests that not all β1AR autoantibodies are deleterious. Recent clinical studies show that β1AR autoantibodies belonging to the IgG3 subclass is associated with beneficial cardiac outcomes in patients. This suggests that our understanding on the roles the β1AR autoantibodies play in mediating outcomes is not well-understood. Technological advances including structural determinants of antibody binding could provide insights on the modulatory capabilities of β1AR autoantibodies in turn, reflecting their diversity in mediating β1AR signaling response. In this study, we discuss the significance of the diversity in signaling and its implications in pathology.

Protein A immunoadsorption combination with immunosuppressive therapy improves neuropsychiatric systemic lupus erythematosus: A case report

We described protein A immunoadsorption combination with immunosuppressive treatment improved rapidly a patient with Neuropsychiatric systemic lupus erythematosus.

Myocardial Recovery in Patients With Systolic Heart Failure and Autoantibodies Against β1-Adrenergic Receptors

BACKGROUND

Among various cardiac autoantibodies (AAbs), those recognizing the β₁-adrenergic receptor (β₁AR) demonstrate agonist-like effects and induce myocardial damage that can be reversed by β-blockers and immunoglobulin G3 (IgG3) immunoadsorption.

OBJECTIVES

The goal of this study was to investigate the role of β₁AR-AAbs belonging to the IgG3 subclass in patients with recent-onset cardiomyopathy.

METHODS

Peripheral blood samples were drawn at enrollment in patients with recent-onset cardiomyopathy (left ventricular ejection fraction [LVEF] ≤0.40; <6 months). The presence of IgG and IgG3-β₁AR-AAb was determined, and echocardiograms were assessed, at baseline and 6 months. Patients were followed up for ≤48 months.

RESULTS

Among the 353 patients who had blood samples adequate for the analysis, 62 (18%) were positive for IgG3-β₁AR-AAbs (IgG3 group), 58 (16%) were positive for IgG but not IgG3 (non-IgG3 group), and the remaining were negative. There were no significant differences in baseline systolic blood pressure, heart rate, or LVEF among the groups at baseline. Left ventricular end-diastolic and end-systolic diameters were significantly larger in the non-IgG3 group compared with the other groups (left ventricular end-diastolic diameter, p < 0.01; left ventricular end-systolic diameter, p = 0.03). At 6 months, LVEF was significantly higher in the IgG3 group (p = 0.007). Multiple regression analysis showed that IgG3-β₁AR-AAb was an independent predictor of LVEF at 6 months and change in LVEF over 6 months, even after multivariable adjustment (LVEF at 6 months, β = 0.20, p = 0.01; change in LVEF, β = 0.20, p = 0.008). In patients with high New York Heart Association functional class (III or IV) at baseline, the IgG3 group had a lower incidence of the composite endpoint of all-cause death, cardiac transplantation, and hospitalization due to heart failure, whereas the non-IgG3 group had the highest incidence of the composite endpoint.

CONCLUSIONS

IgG3-β₁AR-AAbs were associated with more favorable myocardial recovery in patients with recent-onset cardiomyopathy.

Safety Aspects of Immunoadsorption in IgG Removal Using a Single-Use, Multiple-pass Protein A Immunoadsorber (LIGASORB): Clinical Investigation in Healthy Volunteers

Therapeutic apheresis and immunoadsorption are used to deplete efficiently pathogenic autoantibodies in crises in several acute autoimmune driven diseases. This prospective, non-comparative cohort study was conducted at a single study center under standardized conditions in 10 healthy volunteers. Efficient immunoglobulin G (IgG) removal (-86% versus baseline) was achieved after 3 apheresis treatments on 3 consecutive days. The treatments were well tolerated. Safety laboratory parameters did not show unexpected or pathological changes. The effects were transient, with most parameters exhibiting complete recovery between treatments. Minimal complement activation and moderate transient fibrinogen depletion were observed. Immunoadsorption with LIGASORB® provides a safe and effective treatment alternative to TPE in acute episodes of peripheral neurological diseases mediated by pathogenic IgG autoantibodies.

Autoantibodies Specifically Against β1 Adrenergic Receptors and Adverse Clinical Outcome in Patients With Chronic Systolic Heart Failure in the β-Blocker Era: The Importance of Immunoglobulin G3 Subclass

OBJECTIVE

To elucidate the prevalence and role of β1 adrenergic receptor autoantibodies (β1AR-AAb) belonging to the immunoglobulin (Ig)G3 subclass in patients with heart failure (HF) treated with β-adrenergic blockers.

BACKGROUND

Several cardiac AAbs have been reported to be present in sera from patients with dilated cardiomyopathy and other etiologies. Among AAbs, those recognizing β1AR-AAbs show agonist-like effects, have detrimental effects on cardiomyocytes, and may induce persistent myocardial damage.

METHODS

We quantify total IgG and IgG3 subclass β1AR-AAb in subjects with chronic stable HF with long-term follow-up.

RESULTS

In our study cohort of 121 subjects, non-IgG3-β1AR-AAb and IgG3-β1AR-AAb were found to be positive in 20 (17%) and 26 patients (21%), respectively. The positive rate of IgG3-β1AR-AAb was significantly higher for those with nonischemic compared with ischemic HF etiology (27% vs 8%, P = .01), but the positive rate for non-IgG3-β1AR-AAb was similar between the 2 groups (18% vs 16%, respectively, P = NS). There were no significant differences in clinical and echocardiographic measures among total β1AR-AAb negative, non-IgG3-β1AR-AAb positive, and IgG3-β1AR-AAb positive groups at baseline. During 2.2 ± 1.2 years of follow-up, we observed similar rates of the composite endpoint of all-cause mortality, cardiac transplantation, or hospitalization resulting from HF between total IgG-β1AR-AAb negative and positive patients. However, the composite endpoint events were significantly more common in the patients without than in those with IgG3-β1AR-AAb (P = .048, log-rank test).

CONCLUSIONS

Presence of IgG3-β1AR-AAb, not total IgG, was associated with paradoxically more favorable outcomes in our cohort of patients with chronic systolic HF largely treated by β-blockers.

Autoantibodies and cardiovascular dysfunction: cause or consequence?

There has been a long history of the exploration into autoimmunity as a possible pathogenic factor of cardiovascular diseases from unknown cause represented by dilated cardiomyopathy (DCM). Autoantibodies (AAbs) have emerged either as humoral responses provoked by the release of "self-antigens" due to tissue damage or dysregulated humoral immunity itself. The pathogenic roles of some AAbs have been suggested by the findings from basic research using in vitro and in vivo disease models as well as clinical studies including immunoadsorption studies removing AAbs from patients with DCM. In this context, the importance of AAbs belonging to IgG3 subclass has also been implicated. In this review article, we summarize the findings accumulated to date regarding AAbs which have been considered to be involved in the pathology of DCM or pregnancy-related cardiovascular disease. Furthermore, we discuss the significance of AAbs as a possible cause of DCM and their potential roles as a novel therapeutic target.

Anti-A/B antibody depletion by semiselective versus ABO blood group-specific immunoadsorption

BACKGROUND

Recipient desensitization using blood group (BG)-specific immunoadsorption (ABO-IA) has proven to enable successful kidney transplantation across major ABO barriers. In this context, the efficiency of non-antigen-specific (semiselective) IA adsorbers has not yet been established. The objective of our study was to quantify anti-A/B antibody depletion by protein A-, peptide ligand- and anti-human immunoglobulin-based semiselective IA in comparison to ABO-IA.

METHODS

Eight ABO-IA-treated transplant candidates and 39 patients subjected to semiselective IA for a variety of different indications outside the context of ABO-incompatible transplantation were included. Antibody patterns (IgG, IgG1-4 subclasses, IgM, C4d-fixing reactivities) were analysed applying conventional agglutination testing and flow cytometry.

RESULTS

As assessed by sensitive flow cytometric antibody detection, ABO-IA-based desensitization led to a profound even though often incomplete reduction of anti-A/B reactivities. Persistent complement- or non-complement-fixing reactivities, however, were not associated with transplant rejection or capillary C4d deposition. Single sessions of semiselective IA turned out to be more effective than ABO-IA in decreasing levels of anti-A/B IgG [median reduction to 28 versus 59% (ABO-IA) of baseline values, P < 0.001). In contrast, BG-specific IgM (74 versus 30%, P < 0.001) and IgG3 (72 versus 42%, P < 0.05) were reduced to a lesser extent, without differences between tested adsorber types. Analysis of four consecutive IA sessions revealed that inferior efficiency could not be overcome by serial treatment.

CONCLUSION

Our observation of limited adsorption capacities regarding distinct BG-specific Ig (sub)classes suggests caution in applying semiselective IA techniques in ABO-incompatible kidney transplantation.

Role of immunoglobulin G3 subclass in dilated cardiomyopathy: results from protein A immunoadsorption

BACKGROUND

Immunoadsorption (IA) by anti-immunoglobulin G (anti-IgG) columns that effectively eliminates total IgG, including IgG3 subclass, represents an additional therapeutic approach in dilated cardiomyopathy (DCM). A recent study revealed that IA with protein A columns does not effectively remove IgG3 and does not induce hemodynamic improvement in DCM.

METHODS

Eighteen patients with DCM (left ventricular ejection fraction < or =30%) were included in this case-control study. In all patients, IA with protein A was performed in 4 courses, at 1-month intervals until month 3. Nine patients underwent protein A IA with an improved treatment regimen for IgG3 elimination. Data of these patients were compared retrospectively to existing findings for 9 comparable patients treated by protein A IA with ineffective IgG3 reduction.

RESULTS

In both groups, IA induced a comparable reduction of the total IgG level. However, reduction of the IgG3 level was different in the 2 groups (P < .001). Hemodynamics did not significantly change throughout the 3 months in the group with ineffective IgG3 reduction. In contrast, the group with improved IgG3 reduction demonstrated during the first IA course an increase in cardiac index from 2.2 +/- 0.1 to 2.8 +/- 0.2 L min(-1) m(-2) (P < .05). After 3 months before the last IA course, cardiac index was 2.2 +/- 0.1 L min(-1) m(-2) in the group with ineffective IgG3 elimination and 2.8 +/- 0.2 L min(-1) m(-2) in the group with improved IgG3 reduction (P < .01). In the group with ineffective IgG3 reduction, left ventricular ejection fraction increased after 3 months from 21.6 +/- 2% to 24.4 +/- 2% (NS), and from 24.3 +/- 2 to 34.7 +/- 4% in the group with improved IgG3 reduction (P < .05).

CONCLUSIONS

Autoantibodies belonging to IgG3 may play an important role in cardiac dysfunction of patients with DCM. Protein A IA in conjunction with an improved treatment regimen for IgG3 elimination induces hemodynamic benefit in patients suffering from DCM.

The Course of Anticardiolipin Antibody Levels Under Immunoadsorption Therapy

BACKGROUND

The emergence of anticardiolipin antibodies in patients with systemic lupus erythematosus is a serious occurrence in regard to a high risk for thrombosis and thromboembolic complications, fetal loss, and renal insufficiency. In an observational analysis, we studied anticardiolipin antibodies during immunoadsorption therapy.

METHODS

We analyzed the magnitude and time course of serum concentrations of the immunoglobulin G (IgG) and IgM subtypes of anticardiolipin antibodies (CIgG and CIgM) along with IgG and IgM, antinuclear antibodies, and antibodies to double-stranded DNA before and after single immunoadsorption sessions and their long-term course in 11 patients with systemic lupus erythematosus.

RESULTS

Single immunoadsorption sessions (n = 842) led to a rapid decline in CIgG and CIgM levels by 62.94% +/- 21.60% and 42.02% +/- 22.14%, respectively (P < 0.0001), along with a corresponding decline in serum levels of antinuclear antibodies (65.04% +/- 18.83%), antibodies to double-stranded DNA (64.67% +/- 21.20%), IgG (58.11% +/- 16.84%), and IgM (32.15% +/- 15.58%). Reduction rates of CIgG and CIgM levels were greater when high initial concentrations (P < 0.0001) and low IgG levels (P < 0.0001) were present. Mean reductions in pretreatment values of CIgG and CIgM during 6 months of immunoadsorption therapy were 42.85% +/- 39.94% and 29.39% +/- 70.41% (mean number of sessions/patient = 21.55) and for the 1-year period were 63.20% +/- 22.49% and 58.05% +/- 40.16% (mean number of sessions/patient = 30.46).

CONCLUSION

We observed that immunoadsorption therapy is an effective method to reduce anticardiolipin antibody levels rapidly and keep them at a low level in the long term.

Removal of Pathogenic Autoantibodies by Immunoadsorption

Autoimmune diseases result from disrupted tolerance to self-antigens and subsequent damage to tissues and organs. In several diseases, specific autoantibodies have been either proved or suspected to play a role in this process. Consequently, several strategies have been devised in an attempt to discard the destructive immunoglobulins. Currently, both nonselective and epitope-specific methods are applied in several diseases. In this review, we provide a summary of the available data on elimination of pathogenic autoantibodies and discuss the advantages and pitfalls of the different approaches.

Autoimmune-associated Congenital Heart Block: Treatment of the Mother With Immunoadsorption

Autoimmune-associated congenital heart block (CHB) is a rare complication of pregnancy in mothers with Anti-Ro/SSA antibodies (SSA-abs), resulting in fetal myocarditis, atrioventricular block, hydrops fetalis and/or intrauterine fetal death. As these antibodies are supposed to be directly involved in the pathogenesis of CHB, their removal should be associated with an improved clinical course. Extracorporeal immunoadsorption (IA) is the most efficient method to remove IgG-immunoglobulins like SSA-abs selectively. Two women with high titers of those auto-antibodies [mothers serum 615 and 612, respectively (normal range <3.0 IU/mL)] were treated with IA two to three times per gestation week in the outpatient department of the University of Rostock. In both patients, the mean removal of IgG (65 +/- 6%) to a target near 2.0 g/L after IA was successful. The SSA-abs were reduced from mean 328 +/- 138 and 247 +/- 105 pre IA to 88 +/- 124 and 98 +/- 42 post IA, respectively. One child received a pacemaker due to the persisting atrioventricular block grade III after birth. The second was unaffected. The removal of highly elevated SSA-antibodies by immunoadsorption is a possible treatment option in pregnant woman with high titers of those antibodies and/or a positive history of clinical complications. Further clinical studies are necessary.

Protein A immunoadsorption: a novel and effective adjuvant treatment of severe pemphigus

BACKGROUND

Pemphigus foliaceus (PF) and pemphigus vulgaris (PV) are autoimmune blistering skin diseases usually treated with high-dose systemic corticosteroids and other immunosuppressants that may cause severe side-effects. Plasmapheresis also has been demonstrated to be of benefit in the treatment of pemphigus. In contrast to plasmapheresis, staphylococcal protein A immunoadsorption (PA-IA) specifically removes immunoglobulin from the circulation, allows treatment of larger plasma volumes, and does not require the substitution of plasma components.

OBJECTIVES

To determine the effectiveness and side-effects of PA-IA in patients with severe pemphigus.

METHODS

Five patients with severe pemphigus (PV, n = 4; PF, n = 1) were treated by PA-IA. Three of these patients had been refractory to various treatment regimens. In addition to PA-IA, methylprednisolone, 0.5 mg x kg-1 body weight day-1 was given initially and subsequently tapered.

RESULTS

In all patients, a dramatic clinical improvement was seen within 2 weeks after initiation of therapy. Patients were free of lesions after 3, 4, 4, 10 and 21 weeks of treatment, respectively. Concurrently, autoantibody levels decreased rapidly.

CONCLUSIONS

PA-IA is a rational, effective, and safe adjuvant therapy for severe pemphigus and warrants wider use for this indication. A controlled study should compare side-effects and effectiveness of PA-IA with other treatment options for pemphigus.

Background and indications for protein A-based extracorporeal immunoadsorption

Protein A (SPA), a major cell wall component of Staphylococcus aureus, has occupied numerous investigators from its discovery in the late fifties. Its availability and avid binding to human immunoglobulins have led to extensive usage for diagnostic and research purposes. Today, SPA-based extracorporeal immunoadsorption relies on two rather different systems, namely, SPA-silica (Prosorba), and SPA-Sepharose (Immunosorba). Both systems are approved by the Food and Drug Administration for the core indications of rheumatoid arthritis and idiopathic thrombocytopenic purpura (SPA-silica) or hemophilia with inhibitors (SPA-Sepharose). Off label indications include immune disorders with a conceivable connection between autoantibody titers and disease activity, like forms of glomerulonephritis, systemic lupus erythematodes, myasthenia, and the Guillain-Barré syndrome as well as alloantibody formation in the context of e.g., transplantation. This review summarizes historical developments and important properties of SPA. Indications for extracorporeal therapy are discussed on the basis of available information and personal experience.

Immunoadsorption onto protein A induces remission in severe systemic lupus erythematosus

BACKGROUND

Reduction of pathological autoantibodies and circulating immune complexes can be useful in the treatment of autoimmune disease. Plasmapheresis has been shown to reduce autoantibody levels in systemic lupus erythematosus (SLE), but its effect on patients' outcome was not better compared with conventional immunosuppression in the past.

AIM OF THE STUDY

Immunoadsorption as a selective extracorporeal immunoglobulin elimination technique was evaluated as rescue therapy in patients suffering from SLE.

METHODS

Eight patients with severe, therapy-resistant SLE underwent immunoadsorption onto protein A sepharose without concomitant immunosuppressants.

RESULTS

Remission of the disease was achieved in seven patients. Therapy had to be stopped in one patient because of side-effects. The best results were obtained when immunoadsorption was carried out daily, without supplementary intravenous immunoglobulin therapy. Oral cyclophosphamide for 3-6 months during follow-up was used to suppress relapse. Autoantibodies and circulating immune complexes were effectively eliminated regardless of their IgG subclass.

CONCLUSION

Immunoadsorption onto protein A might be used as an extracorporeal treatment option in SLE when other therapies are ineffective.

Immunoadsorption as a tool for the immunomodulation of the humoral and cellular immune system in autoimmune disease

Immunoadsorption onto staphylococcal protein A is a newly developed semiselective extracorporeal adsorption technique for immunoglobulins applied in patients suffering from severe autoimmune disease. Its effect on the humoral and cellular immune system was investigated using standard immunological assays. The elimination capacity for total IgG and IgG subclasses 1, 2, and 4 was more than 90% but for subclass IgG3 varied between 30 and 90%. Autoantibodies, e.g., anti-dsDNA, anti-glomerular basement membrane (anti-GBM), anti-cardiolipin, and anti-human leukocyte antigen (anti-HLA) antibodies, were eliminated in comparable amounts. The affinity of protein A for circulating immune complexes (CIC) was 300 times greater than for soluble IgG. HLA-II expression on monocytes and T lymphocytes was reduced over time during repeated IAs (IA). The number of activated T lymphocytes declined while the percentage of naive T cells increased. A diminished CD4/CD8 ratio normalized during IA treatment. These results indicate that IA actively modulates the humoral as well as the cellular immune system in addition to its immunoglobulin reducing effect.