Intravenous immune globulin therapy of lupus nephritis: use of pathogenic anti-DNA-reactive IgG

Update on the use of immunoglobulin in human disease: A review of evidence

Human immunoglobulin preparations for intravenous or subcutaneous administration are the cornerstone of treatment in patients with primary immunodeficiency diseases affecting the humoral immune system. Intravenous preparations have a number of important uses in the treatment of other diseases in humans as well, some for which acceptable treatment alternatives do not exist. We provide an update of the evidence-based guideline on immunoglobulin therapy, last published in 2006. Given the potential risks and inherent scarcity of human immunoglobulin, careful consideration of its indications and administration is warranted.

The expanding role of therapeutic antibodies

Therapeutic antibodies have been used since the end of nineteenth century, but their use is progressively increased and recently, with the availability of monoclonal antibodies, they are successfully employed in a large disease spectrum, which transversally covers different fields of medicine. Hyperimmune polyclonal immune globulin has been used against infectious diseases, in a period in which anti-microbial drugs were not yet available, and it still maintains a relevant place in prophylaxis/therapy. Although immune globulin should be considered life-saving as replacement therapy in humoral immunodeficiencies, its place in the immune-modulating treatment is not usually first-choice, but it should be considered as support to standard approved treatments. Despite therapeutic monoclonal antibodies have been lastly introduced in therapy, their extreme potentiality is reflected by the large number of approved molecules, addressed toward different immunological targets and able to heavily influence the prognosis and quality of life of a wide range of different diseases.

Intravenous immunoglobulin in the management of lupus nephritis

The occurrence of nephritis in patients with systemic lupus erythematosus is associated with increased morbidity and mortality. The pathogenesis of lupus nephritis is complex, involving innate and adaptive cellular and humoral immune responses. Autoantibodies in particular have been shown to be critical in the initiation and progression of renal injury, via interactions with both Fc-receptors and complement. One approach in the management of patients with lupus nephritis has been the use of intravenous immunoglobulin. This therapy has shown benefit in the setting of many forms of autoantibody-mediated injury; however, the mechanisms of efficacy are not fully understood. In this paper, the data supporting the use of immunoglobulin therapy in lupus nephritis will be evaluated. In addition, the potential mechanisms of action will be discussed with respect to the known involvement of complement and Fc-receptors in the kidney parenchyma. Results are provocative and warrant additional clinical trials.

The use of i.v. IG therapy in dermatology

The intravenous administration of exogenous pooled human immunoglobulin (i.v. IG) was originally licensed as antibody replacement therapy in patients with primary immunodeficiencies and there are currently six FDA-approved uses for this agent. Despite a current lack of FDA approval, off-label treatment of a multitude of dermatologic disorders with i.v. IG has shown exciting potential for this unique treatment modality. The diseases successfully treated with i.v. IG include autoimmune bullous diseases, connective tissue diseases, vasculitides, toxic epidermal necrolysis, and infectious disorders (such as streptococcal toxic shock syndrome). Currently the biggest drawback in the consideration of i.v. IG therapy in dermatologic disorders is the lack of randomized controlled trials. Nevertheless, there is a significant body of evidence demonstrating the efficacy of i.v. IG in patients with dermatologic disorders that are resistant to treatment with standard agents. In summary, i.v. IG constitutes a valuable and potentially life-saving agent in managing patients with a variety of dermatologic disorders under the appropriate circumstances.

High-dose intravenous immunoglobulins: an option in the treatment of systemic lupus erythematosus

Despite encouraging reports on the efficacy of intravenous immunoglobulin (IVIG) therapy in systemic lupus erythematosus (SLE), the clinical value of this treatment is not well established, and most of the data are based on case reports and small series of patients. IVIG has been used successfully to treat SLE patients with a broad spectrum of clinical manifestations, such as refractory thrombocytopenia, pancytopenia, central nervous system (CNS) involvement, secondary antiphospholipid syndrome, and lupus nephritis. The beneficial effects of IVIG on overall disease activity are usually prompt, with marked improvement within a few days, but they are often of limited duration. Improvement lasts for several weeks after the last infusion, although clinical response could be maintained by continuous monthly IVIG infusions. IVIG therapy immunomodulates autoimmune diseases by interacting with various Fcgamma receptors in such a way that it downregulates activating FcRIIA and FcRIIC and/or upregulates inhibitory FcRIIB. However, in SLE, additional mechanisms include inhibition of complement-mediated damage, modulation of production of cytokines and cytokine antagonists, modulation of T- and B-lymphocyte function, induction of apoptosis in lymphocytes and monocytes, downregulation of autoantibody production, manipulation of the idiotypic network, and neutralization of pathogenic autoantibodies. At present, IVIG in SLE is indicated either in severe cases that are nonresponsive to other therapeutic modalities, or when SLE can be controlled only with high-dose steroids; in such patients, IVIG thus becomes a useful steroid-sparing agent. However, this needs to be confirmed in double-blind, placebo-controlled studies.

Abetimus sodium (riquent) for the prevention of nephritic flares in patients with systemic lupus erythematosus

Abetimus sodium has been under development for the treatment of systemic lupus erythematosus since the early 1990s. Because its administration results in the selective reduction of circulating double-stranded DNA antibodies, La Jolla Pharmaceutical Company has focused on the agent's ability to prolong time to nephritic flare. Fourteen trials have been initiated since 1994, but the two pivotal registration trials failed to meet primary end points. The US Food and Drug Administration issued a letter in October 2004 that stated abetimus sodium was "approvable" pending the successful completion of a trial demonstrating clinical benefit. The fate of this agent lies in the ability of the company to successfully complete a phase III study.

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.

Intravenous immunoglobulin abrogates dendritic cell differentiation induced by interferon-? present in serum from patients with systemic lupus erythematosus

OBJECTIVE

Alterations in the function of dendritic cells (DCs) may explain the systemic autoimmune responses that characterize systemic lupus erythematosus (SLE). Even though several reports have documented the beneficial effect of intravenous immunoglobulin (IVIG) in SLE, the underlying mechanisms of action remain poorly understood. Considering the effect of serum factors, including interferon-alpha (IFNalpha), on the activity of DCs, we investigated the effects of IVIG on the differentiation of DCs mediated by serum from SLE patients.

METHODS

DCs were differentiated from peripheral blood monocytes obtained from SLE patients and from healthy blood donors, in the presence of SLE serum. IVIG was used at a concentration of 0.15 mM. A functional assay was performed to assess the inhibitory effect of IVIG on the uptake of nucleosomes by DCs.

RESULTS

IVIG interfered with the differentiation of DCs from SLE patients and healthy donors cultured in the presence of SLE serum. Treatment of DCs with IVIG inhibited the ingestion of nucleosomes by immature DCs, by up to 36%.

CONCLUSION

The present findings indicate that IVIG, by down-regulating the IFNalpha-mediated differentiation of DCs and by inhibiting uptake of nucleosomes, may exert an essential immunoregulatory effect in SLE patients at the onset of the immune response, at the DC level. Given the critical role of HLA molecules and the costimulatory signals delivered by CD80 and CD86 in optimal antigen presentation and T cell activation, inhibition of expression of HLA and CD80/CD86 on DCs by IVIG offers a plausible explanation for the efficacy of IVIG in SLE and other immune-mediated inflammatory conditions.

Molecular mimicry: anti-DNA antibodies may arise inadvertently as a response to antibodies generated to microorganisms

The origin of anti-DNA antibodies remains speculative. We argue that some of these antibodies may arise inadvertently in nature during the course of a normal immune response due to their induction by antibodies which bear structures (mimotopes) that mimic DNA. These antibodies are not necessarily DNA specific but, like the T15 idiotype (id)-positive antibodies which bind to phosphorylcholine, are produced normally to some environmental or microbial antigen. Such a mimotope was found in a T15(+) antibody at the highly specific region encoded principally by the D gene, DFL16.1. This mimotope was also found in human antibodies that are encoded by DXP'1, the human counterpart of DFL16.1 and which is used commonly in anti-DNA antibodies. The mimotope is closely related to the epitope responsible for the T15 id and appears to be cryptic or normally hidden in the native protein. The existence of such a common, conserved sequence raises questions about how easily anti-DNA antibodies can be generated in nature and what purpose these proteins may serve. Molecular mimicry with regard to autoimmunity must thus be viewed as existing not necessarily between the infectious agent and self-antigens, but also between the antibodies induced by the organism and the self-antigens.

High-dose intravenous immunoglobulins for lupus nephritis--a salvage immunomodulation

Systemic lupus erythematosus (SLE) is a multisystemic autoimmune disease with a great diversity of clinical manifestations which is difficult to manage. IVIGs represent promising immunoregulatory agents with the ability to control SLE without subsequent predisposition to infectious complications. Despite the implied risk of developing renal failure due to IVIG, considerable beneficial effects on lupus nephritis are reported. In this review, the clinical and adverse effects, and mechanism of action, with special emphasis on modulation, of idiotypic network is discussed.

Intravenous immunoglobulin application following immunoadsorption: benefit or risk in patients with autoimmune diseases?

OBJECTIVE

To evaluate infection rates, side-effects and autoantibody resynthesis after immunoadsorption with and without intravenous immunoglobulin substitution.

METHODS

Thirty-five patients with autoimmune diseases who were on long-term immunoadsorption therapy participated in a prospective, randomized study. Results and conclusions. Infections were rare but similar in frequency in patients receiving combined immunoadsorption and intravenous immunoglobulins (intervention group, n=17, 1.3 infections per patient-year) and in a control group (n=18, 0.9 infections per patient-year) treated by immunoadsorption alone. The reduction in IgG achieved with two immunoadsorptions within 3 days was 95.0+/-2.5%. The extent of removal of pathogenic autoantibodies was similar to the removal of IGG: Substitution of immunoglobulins was not associated with an increased circulating IgG level before the following immunoadsorption. Infusion of immunoglobulins at a dose of 0.14 g/kg (interquartile range 0.12-0.16) body weight in patients in whom circulating immunoglobulins had been depleted was associated with a high incidence of serious side-effects; these necessitated the termination of treatment in 24% of the patients. No evidence was found that immunoglobulin administration had any beneficial effect with respect to autoantibody resynthesis after immunoadsorption.

Cationic myeloma M-components frequently show cross-reacting anti-DNA, Anti-F(ab')2 and anti-nucleosome specificities

134 cationic human IgG myeloma proteins were studied for expression of anti-DNA Idiotypic markers. 64 were studied for 16/6, F4, 3I, and 8.12, and 70 for expression of F4 and 3I. 31.3% showed at least one anti-DNA Id marker and many cationic myelomas were also positive for anti-DNA ELISA reactivity as well as anti-F(ab')2. Five M-components showed anti-nucleosome reactivity and one without detectable anti-DNA Id markers showed very strong anti-nucleosome antibody which was also inhibited by DNA and Sm antigens. Anti-idiotypic antisera produced either against Id(+) anti-DNA reactive M components or F(ab')2 fragments of affinity purified SLE IgG anti-DNA showed preferential cross-reactive idiotype reactivity between Id(+) anti-DNA reactive M components. Our findings indicate that human IgG monoclonal proteins positive for several common anti-DNA Ids and possessing anti-DNA ELISA reactivity, can serve as models for SLE Id marker antigens and as a source to prepare anti-Ids from IVIG.

A human and a mouse anti-idiotypic antibody specific for human T14(+) anti-DNA antibodies reconstructed by phage display

Little is known about human anti-idiotypic antibodies. Phage display methodology was used to reconstruct these antibodies from lupus patients, which recognize a subset (T14(+)) of anti-DNA antibodies. Antigen-specific B cells were isolated from the blood using a peptide based on a complementarity determining region (V(H)CDR3) of the prototypic T14(+) antibody. cDNA fragments of the V(H) and V(L) genes prepared from the cells were expressed as phage displayed single chain Fv (scFv) fragments using the pCANTAB-5E phagemid vector. From a reactive clone obtained, the Ig genes used were identified to be V(H)3, D5-D3, J(H)4b, V(kappa)I and J(kappa)2. The heavy chain was highly mutated, especially in CDR3, which bears mutations mostly of the replacement type; this region is also unusual in being extremely long due to a D-D fusion. In contrast, a mouse hybridoma antibody, made to the same T14(+) peptide and transformed as a scFv fragment, uses a short V(H)CDR3 comprising five amino acids, three of which are tyrosines. Tyrosines may be important for antigen binding because two of these also exist in the human V(H)CDR3. The light chains of both antibodies may also contribute to the specificity of the protein, because their V(L) segments, including the CDRs, are highly homologous to each other.

Intravenous immunoglobulin treatment of lupus nephritis

OBJECTIVE

To evaluate the clinical response of treatment-resistant membranous and membranoproliferative lupus nephritis to intravenous immunoglobulin (IVIg).

METHODS

Seven lupus nephritis patients who failed to respond to at least prednisone and cyclophosphamide were studied. A kidney biopsy showing either membranous or membranoproliferative glomerulonephritis was available in six patients. They were treated with six courses (patients 1 and 2) or 1 or 2 courses (patients 3 through 7) of high-dose IVIg. For patients 3 through 7, the plasma levels of albumin, total cholesterol, urea, creatinine, dsDNA antibody titers, and daily proteinuria were measured just before the IVIg therapy, immediately on completion, and 6 months later.

RESULTS

All seven patients had a beneficial response to IVIg. In patient 1, decrease in proteinuria was evident 2 weeks after IVIg was started, nephrotic syndrome gradually disappeared, and she had no proteinuria in 3 years' follow-up. Decline in proteinuria was evident in patient 2 after the 4th IVIg course, but proteinuria reached the pretreatment level 4 months after the therapy ended. In patients 3 through 7, the mean daily proteinuria before IVIg (5.3 +/- 2.1 g) decreased after 1 or 2 IVIg courses (3.3 +/- 1.4 g), and further decreased when measured 6 months later (2.1 +/- 1.3 g). Similarly, the plasma cholesterol level decreased while the plasma albumin level increased after IVIg.

CONCLUSIONS

IVIg might be effective in treatment-resistant membranous or membranoproliferative lupus nephritis. Future studies should concentrate on determining the preferred treatment protocol of IVIg for the various classes of lupus nephritis.

Dehydroepiandrosterone and biologics in the treatment of systemic lupus erythematosus

Our understanding of the immune system in health and disease has greatly increased over this past decade. An outgrowth of this burgeoning knowledge has been the discovery of novel strategies to treat a variety of autoimmune diseases. As a result, significant advances have been made in the treatment of arthritis with a half-dozen new treatments approved between September, 1998 and November, 1999. Although no new therapies have been approved for the treatment of systemic lupus erythematosus (SLE), this decade has witnessed an unprecedented amount of activity in drug development for this disease. This article specifically addresses the current status of drug development in the area of hormonal and biologic therapies for SLE.

A study of 20 SLE patients with intravenous immunoglobulin--clinical and serologic response

OBJECTIVE

To test the clinical response of systemic lupus erythematosus (SLE) patients to intravenous immunoglobulins (IVIg), and whether the clinical response of IVIg treatment in SLE is accompanied by modification of SLE-associated autoantibodies/antibodies (Abs) and complement levels.

METHODS

Twenty SLE patients were treated with high-dose (2 g/kg) IVIg monthly, in a 5-d schedule. Each patient received between 1-8 treatment courses. They were evaluated for the clinical response, Systemic Lupus Activity Measure (SLAM) score before and after IVIg, levels of antinuclear antibody (ANA), dsDNA (double-stranded DNA), SS-A or SS-B, ENA (extractable nuclear antigens), C3 and C4 levels before and after the treatment, and before and after each treatment course.

RESULTS

A beneficial clinical response following IVIg treatment was noted in 17 out of 20 patients (85%). Few clinical manifestations responded more to treatment: arthritis, fever, thrombocytopenia, and neuropsychiatric lupus. In 9 patients evaluated before and after IVIg, mean SLAM score decreased from 19. 3+/-4.7 to 4+/-2.9 (P<0.0001). There was a tendency towards abnormal levels of complement and Abs before IVIg courses among the treatment responders compared with the non-responders, and similarly the former tended to have normalization of their abnormal levels more than the latter. These differences were found statistically significant only with respect to C4 and SS-A or SS-B levels before IVIg courses.

CONCLUSION

IVIg has a high response rate among SLE patients. A combination of clinical manifestations, Abs and complement levels may aid in the future in predicting who among SLE patients will benefit more from IVIg treatment.

Immunotherapy for autoimmune and inflammatory renal diseases

New treatments for autoimmune renal disease are required, and a developing knowledge of its underlying immunopathogenesis has identified sites where immunotherapy is likely to be effective. Experience with intravenous immunoglobulin and lymphocyte depletion by monoclonal antibodies in systemic vasculitis and systemic lupus erythematosus is awaiting confirmation by randomized trials. Treatments at or near clinical testing include monoclonal antibody blockade of leucocyte-endothelial interactions and CD40 mediated B-cell activation, and immunoablation with autologous stem-cell transplantation for more severe multisystem autoimmune disease.

Affinity columns containing anti-DNA Id+ human myeloma proteins adsorb human epibodies from intravenous gamma globulin

OBJECTIVE

To study eluates of intravenous gamma globulin (IVGG) prepared from affinity columns of human cationic IgG myeloma proteins bearing anti-DNA idiotype (Id) markers 16/6, F4, 3I, and 8.12 for possible anti-Id (combining site) blocking activity.

METHODS

Anti-DNA idiotypic antibody activity was studied in 3 preparations of IVGG containing high, medium, and low levels of IgG anti-F(ab')2, and in 4 other commercial IVGG preparations. Affinity-purified IgG anti-DNA (APAD) from systemic lupus erythematosus (SLE) patients was biotinylated, and binding to DNA coated on enzyme-linked immunosorbent assay plates was used to measure anti-DNA antibody activity. IVGG was adsorbed to Sepharose 4B affinity columns linked to a panel of cationic human IgG myeloma proteins positive for anti-DNA Id markers 16/6, F4, 3I, and 8.12. Material adsorbing to such columns was eluted at low pH (2.5) and after neutralization, tested for its ability to inhibit biotinylated APAD reacting with DNA.

RESULTS

Only 0.05-0.9% of IVGGs bound firmly to Id affinity columns. These IVGGs were then eluted, using pH 2.5 glycine-saline and eluates neutralized to pH 7.4. Column flowthrough and eluate fractions were compared for their ability to block SLE APAD reacting with DNA. Significant inhibition of SLE APAD combining sites was observed with eluates from anti-DNA Id affinity columns; however, no correlation between IVGG anti-F(ab')2 activity and true anti-Id blocking of APAD was apparent. No residual anti-Id activity remained in column flowthrough fractions. No anti-Id blocking activity was recorded for IVGG eluates from human cationic myeloma columns devoid of the 4 anti-DNA Id markers. DNase treatment of IVGG or Id column eluates did not affect anti-Id blocking activity. Thus, all detectable anti-DNA idiotypic antibody capable of blocking SLE anti-DNA combining sites bound to Id+ affinity columns. Column eluates also showed some relative concentration of IgG anti-DNA activity, which was of lower affinity for DNA than antibodies also present in eluates which blocked anti-DNA combining sites.

CONCLUSION

The presence of both anti-DNA and antiidiotypic (anti-combining site) activity in human anti-DNA Id column eluates indicates that epibodies from IVGG are relatively concentrated when this strategy is used. This approach may lead to a new strategy for treatment of SLE nephritis.

[Autoimmunity: a concept to be revisited?]

Autoimmunity is thought to be a defect in immunologic tolerance, resulting in the activation and expansion of self antigen-specific T and B lymphocyte clones and the production of circulating antibodies, and a myriad of cytokines and other inflammatory mediators. This hypothesis, which speculates on an aberrant response of the immune system to normal self antigens has exerced a powerful influence on clinical investigations and therapeutic researches. Although much information has accumulated, the mechanism of autoimmune disease remains poorly understood and little attention has been paid to the hypothesis that autoimmune diseases might be caused by a conventional immunological response against self antigens for which tolerance has never been established. Clinical practice would undoubtedly get a lot out of it, as well as new therapeutic measures.