Idiotypic and anti-idiotypic elastin autoantibodies: Implications for IVIg and pregnancy loss

The B cell immunobiology that underlies CNS autoantibody-mediated diseases

A rapidly expanding and clinically distinct group of CNS diseases are caused by pathogenic autoantibodies that target neuroglial surface proteins. Despite immunotherapy, patients with these neuroglial surface autoantibody (NSAb)-mediated diseases often experience clinical relapse, high rates of long-term morbidity and adverse effects from the available medications. Fundamentally, the autoantigen-specific B cell lineage leads to production of the pathogenic autoantibodies. These autoantigen-specific B cells have been consistently identified in the circulation of patients with NSAb-mediated diseases, accompanied by high serum levels of autoantigen-specific antibodies. Early evidence suggests that these cells evade well-characterized B cell tolerance checkpoints. Nearer to the site of pathology, cerebrospinal fluid from patients with NSAb-mediated diseases contains high levels of autoantigen-specific B cells that are likely to account for the intrathecal synthesis of these autoantibodies. The characteristics of their immunoglobulin genes offer insights into the underlying immunobiology. In this Review, we summarize the emerging knowledge of B cells across the NSAb-mediated diseases. We review the evidence for the relative contributions of germinal centres and long-lived plasma cells as sources of autoantibodies, discuss data that indicate migration of B cells into the CNS and summarize insights into the underlying B cell pathogenesis that are provided by therapeutic effects.

Intravenous immunoglobulin for the secondary prevention of stillbirth in obstetric antiphospholipid syndrome: A case series and systematic review of literature

OBJECTIVE

To evaluate the efficacy and safety of intravenous immunoglobulin (IVIg) in secondary prevention of pregnancy complications for patients with obstetric antiphospholipid syndrome (APS) and history of stillbirth.

METHODS

We described three cases of obstetric APS patients with history of stillbirth treated with IVIg in four pregnancies. In addition, we conducted a systematic literature review on the use of IVIg in obstetric APS with history of stillbirth.

RESULTS

Three patients with obstetric APS and history of stillbirth were treated with prophylactic IVIg, in addition to standard treatment (hydroxychloroquine, low-dose aspirin, low molecular weight heparin, and prednisone), in four pregnancies (three singleton and one twin). All pregnancies resulted in live healthy newborns. Long-term follow-up re-evaluations (24-53 months) did not shown any sign or symptom of active systemic disease, and the children were healthy. The systematic literature review retrieved only three cases of use of IVIg in obstetric APS patients with history of stillbirth. All three cases resulted in live healthy newborns. Only in one case, mild thrombocytopenia occurred during treatment, although this event was unlikely to be related to IVIg.

CONCLUSION

Our experience suggests that IVIg as secondary prevention of APS-related stillbirth is associated with good pregnancy and long-term outcomes, with no relevant safety concerns. However, the literature evidence on this topic is limited to few isolated cases, and further studies are needed to clarify which obstetric APS patients may benefit the most from IVIg.

IVIG-mediated effector functions in autoimmune and inflammatory diseases

Intravenous immunoglobulin (IVIG) is a pooled preparation of normal IgG obtained from several thousand healthy donors. It is widely used in the immunotherapy of a large number of autoimmune and inflammatory diseases. The mechanisms of action of IVIG are complex and, as discussed in this review, experimental and clinical data provide an indicator that the therapeutic benefit of IVIG therapy is due to several mutually non-exclusive mechanisms affecting soluble mediators as well as cellular components of the immune system. These mechanisms depend on Fc and/or F(ab')2 fragments. A better understanding of the effector functions of IVIG should help in identification of biomarkers of responses to IVIG in autoimmune patients.

The advantage of specific intravenous immunoglobulin (sIVIG) on regular IVIG: experience of the last decade

During the last decade it has been shown that some components of intravenous immunoglobulin (IVIG) are responsible for their broadly therapeutic application. Currently, such specific subfractions are defined as specific IVIG (sIVIG) and are affinity-purified from commercial IVIGs that target specific antigens/antibodies related to a specific autoimmune disease. A remarkable example of the therapeutic potential of sIVIG is the proven enhanced anti-inflammatory potency of sialylated and recombinant sialylated IVIG obtained from total IVIG. In other experimental models, it has also been demonstrated that sIVIG work in many other contrivances, such as revealing anti-idiotypic networks blocking pathogenic antibodies ameliorating disease activity. sIVIG has also been shown to exert its action by modulating specific receptors expressed on immune cells in both inflammatory and autoimmune diseases. Indeed, sIVIG has emerged as a novel approach to treat different immune-mediated conditions in a more accurate antigen-specific manner. Herein we review experimental evidence supporting sIVIG-efficacy in treating autoimmune diseases and inflammation.

Anti-fibrillin-1 autoantibodies in normal pregnancy and recurrent pregnancy loss

PROBLEM

The aim of this study was to investigate anti-fibrillin-1 autoantibody in patients with a history of recurrent pregnancy loss (RPL) and during normal pregnancy.

METHOD OF STUDY

Anti-fibrillin-1 IgG and IgM antibodies were measured by a home made ELISA in serum samples of 48 medically and obstetrically normal pregnant women, classified to three trimester groups, 15 female patients with RPL and 26 healthy non-pregnant women classified to two control subgroups: (a) women who had already had at least one previous successful pregnancy and (b) women who had never been pregnant. Differences in anti-fibrillin-1 autoantibodies between the groups were analyzed for statistical significance (P<0.05) with one-way analysis of variance (ANOVA) and multiple comparison test - Post Hoc test, Least Significant Difference method.

RESULTS

Anti-fibrillin-1 IgM autoantibodies were significantly decreased in the second and third trimester pregnant women compared to the nulligravida controls. RPL patients had significantly increased anti-fibrillin-1 IgM antibody compared to control group (a).

CONCLUSION

Fibrillin-1 degradation seems to be decreased during the second and third trimester of normal pregnancy. Increased anti-fibrillin-1 IgM antibodies in RPL patients may be a secondary phenomenon of increased fibrillin-1 degradation and contribute to the pathogenesis of pregnancy losses.

High-dose intravenous immunoglobulin (IVIG) therapy in autoimmune skin blistering diseases

Treatment of autoimmune bullous skin diseases can often be challenging and primarily consists of systemic corticosteroids and a variety of immunosuppressants. Current treatment strategies are effective in most cases but hampered by the side effects of long-term immunosuppressive treatment. Intravenous immunoglobulin (IVIG) is one potential promising therapy for patients with autoimmune bullous skin diseases, and evidence of its effectiveness and safety is increasing. A number of autoimmune bullous skin diseases have been identified in which IVIG treatment may be beneficial. However, experience with IVIG in patients with autoimmune skin blistering disease is limited, where it is recommended for patients not responding to conventional therapy. The mode of action of IVIG in autoimmune diseases, including bullous diseases is far from being completely understood. We here summarize the clinical evidence supporting the notion, that IVIG is a promising therapeutic agent for the treatment of patients with autoimmune bullous skin disease. In addition, we review the proposed modes of action. In the future, randomized controlled trials are necessary to better determine the efficacy and adverse effects of IVIG in the treatment of autoimmune bullous skin diseases. In addition, insights into IVIG's mode of action might enable us to develop novel therapeutics to overcome the current shortage of IVIG.

Pregnancy and catastrophic antiphospholipid syndrome

Antiphospholipid syndrome (APS) is clearly related to maternal morbidity. The most characteristic feature is pregnancy loss; however, several other serious complications had been reported including fetal growth restriction, uteroplacental insufficiency, fetal distress, pre-eclampsia, and HELLP syndrome. Herein, we review the different aspects of obstetric APS features, with special emphasis on its life-threatening variant known as catastrophic APS (Asherson's syndrome) and its relationship with a thrombotic microangiopathy such as HELLP syndrome.

Autoantibodies in patients with chronic obstructive pulmonary disease

RATIONALE

Adaptive immune responses are present in patients with chronic obstructive pulmonary disease (COPD), and it has been postulated that these processes could be autoreactive.

OBJECTIVES

To ascertain if humoral autoimmunity could play a role in COPD pathogenesis.

METHODS

Circulating IgG autoantibodies were detected by immunofluorescence and immunoprecipitation. Immunohistochemistry and immunofluorescence were used to evaluate intrapulmonary IgG and complement (C3) deposition in human lung explants. Autoantibody pathogenicity was also investigated with an antibody-dependent cell-mediated cytotoxicity assay.

MEASUREMENTS AND MAIN RESULTS

The prevalence of anti-HEp-2 epithelial cell autoantibodies in 47 smokers/former smokers with COPD (GOLD stages 1-4) was greater than among 8 subjects with a smoking history but normal spirometry and 21 healthy control subjects who had never smoked (68 vs. 13 vs. 10%, respectively; P < 0.0001). Antibodies against primary pulmonary epithelial cells were found in 12 of 12 patients with COPD versus 3 of 12 never-smoked control subjects (P < 0.001). Self-antigens immunoprecipitated from 34 of 35 (97%) of COPD plasmas (vs. 0/12 never-smoked controls). Antibodies against a particular 130-kD autoantigen (n = 7) were associated with decreased body mass index (23.2 +/- 2.1 vs. 29.5 +/- 1.0 kg/m(2), P = 0.007). Intrapulmonary immune complexes were present in six of six and C3 was seen in five of six COPD lung explants, unlike zero of six and one of six normals, respectively. Cytotoxicity of pulmonary epithelial cells by allogeneic mononuclear cells also increased 46% after incubation with COPD plasmas (n = 10), compared with identical treatments with eight normal specimens (P = 0.03).

CONCLUSIONS

IgG autoantibodies with avidity for pulmonary epithelium, and the potential to mediate cytotoxicity, are prevalent in patients with COPD. Autoreactive adaptive immune responses may be important in the etiology of this disease.

Pathogenesis of PR3-ANCA associated vasculitis

Wegener's Granulomatosis (WG) is closely associated with antineutrophil cytoplasmic autoantibodies (ANCA), particularly those directed to proteinase 3 (PR3). ANCA directed to myeloperoxidase (MPO) are associated with microscopic polyangiitis (MPA) and the Churg Strauss syndrome. PR3-ANCA associated vasculitis differs from MPO-ANCA associated vasculitis particularly in the occurrence of granulomatous inflammation and more widespread disease in the former condition. Studies in experimental animals strongly suggest a pathogenic role for MPO-ANCA, but this is less clear for PR3-ANCA. Here, we review pathogenic pathways in PR3-ANCA associated vasculitis focussing on unique patterns of PR3 expression on the neutrophil membrane in WG, as surface expression of PR3 is a prerequisite for stimulation by PR3-ANCA; (PR3-specific) cellular immunity in WG; and the role of Staphylococcus aureus carriage in this disease. These factors, together, may explain, at least in part, differences in clinical expression between MPO-ANCA and PR3-ANCA associated vasculitis.