Immune complex-mediated rapidly progressive glomerulonephritis in a patient with family history of systemic lupus erythematosus.

We describe here a case of a 53-year-old Saudi female who presented to the emergency room with shortness of breath progressive in nature for the previous one month, associated with a cough and occasional greenish sputum. She turned out to be a case of immunocomplex mediated glomerulonephritis presenting as rapidly progressive glomerulonephritis in a female patient with a history of systemic lupus erythematosus (SLE) in her daughter.

A review of renal disease in children with HIV infection.

Human immunodeficiency virus (HIV) infection continues to be a leading cause of morbidity and mortality. HIV-infected individuals are now surviving for a relatively longer period and this is because of easy accessibility to antiretroviral therapy these days. As a result, chronic disease-related complications are now being recognized more often. Kidney disease in HIV-infected children can vary from glomerular to tubular-interstitial involvement. We searched the database to identify various kidney diseases seen in HIV-infected children. We describe the epidemiology, pathogenesis, pathology, clinical and laboratory manifestations, management and outcome of commonly seen kidney disease in HIV-infected children. We also provide a brief overview of toxicity of antiretroviral drugs seen in HIV-infected children. Kidney involvement in HIV-infected children may arise because of HIV infection per se, opportunistic infections, immune mediated injury and drug toxicity. HIV-associated nephropathy is perhaps the most common and most severe form of kidney disease. Proteinuria may be a cost-effective screening test in the long-term management of HIV-infected children, however, there are no definite recommendations for the same. Other important renal diseases are HIV immune complex kidney disease, thrombotic microangiopathy, interstitial nephritis and vasculitis.

Elucidating the interplay between IgG-Fc valency and FcγR activation for the design of immune complex inhibitors.

Autoantibody immune complex (IC) activation of Fcγ receptors (FcγRs) is a common pathogenic hallmark of multiple autoimmune diseases. Given that the IC structural features that elicit FcγR activation are poorly understood and the FcγR system is highly complex, few therapeutics can directly block these processes without inadvertently activating the FcγR system. To address these issues, the structure activity relationships of an engineered panel of multivalent Fc constructs were evaluated using sensitive FcγR binding and signaling cellular assays. These studies identified an Fc valency with avid binding to FcγRs but without activation of immune cell effector functions. These observations directed the design of a potent trivalent immunoglobulin G-Fc molecule that broadly inhibited IC-driven processes in a variety of immune cells expressing FcγRs. The Fc trimer, Fc3Y, was highly efficacious in three different animal models of autoimmune diseases. This recombinant molecule may represent an effective therapeutic candidate for FcγR-mediated autoimmune diseases.

New milestones ahead in complement-targeted therapy.

The complement system is a powerful effector arm of innate immunity that typically confers protection from microbial intruders and accumulating debris. In many clinical situations, however, the defensive functions of complement can turn against host cells and induce or exacerbate immune, inflammatory, and degenerative conditions. Although the value of inhibiting complement in a therapeutic context has long been recognized, bringing complement-targeted drugs into clinical use has proved challenging. This important milestone was finally reached a decade ago, yet the clinical availability of complement inhibitors has remained limited. Still, the positive long-term experience with complement drugs and their proven effectiveness in various diseases has reinvigorated interest and confidence in this approach. Indeed, a broad variety of clinical candidates that act at almost any level of the complement activation cascade are currently in clinical development, with several of them being evaluated in phase 2 and phase 3 trials. With antibody-related drugs dominating the panel of clinical candidates, the emergence of novel small-molecule, peptide, protein, and oligonucleotide-based inhibitors offers new options for drug targeting and administration. Whereas all the currently approved and many of the proposed indications for complement-targeted inhibitors belong to the rare disease spectrum, these drugs are increasingly being evaluated for more prevalent conditions. Fortunately, the growing experience from preclinical and clinical use of therapeutic complement inhibitors has enabled a more evidence-based assessment of suitable targets and rewarding indications as well as related technical and safety considerations. This review highlights recent concepts and developments in complement-targeted drug discovery, provides an overview of current and emerging treatment options, and discusses the new milestones ahead on the way to the next generation of clinically available complement therapeutics.

Inhibition of the classical and lectin pathway of the complement system by recombinant LAIR-2.

Activation of complement may cause severe tissue damage in antibody-mediated allograft rejection and other antibody-mediated clinical conditions; therefore, novel potent complement inhibitors are needed. Previously, we described binding of the inhibitory receptor LAIR-1 and its soluble family member LAIR-2 to collagen. Here, we investigated binding of LAIR-1 and LAIR-2 to the complement proteins C1q and MBL, which both have collagen-like domains, and evaluated the effect of this binding on complement function. We demonstrate specific binding of recombinant LAIR proteins to both C1q and MBL. Surface plasmon resonance experiments showed that LAIR-2-Fc protein bound C1q and MBL with the highest affinity compared to LAIR-2-HIS. We, therefore, hypothesized that LAIR-2-Fc is a potent complement inhibitor. Indeed, LAIR-2-Fc inhibited C4 fixation to IgG or mannan, reduced activation of C4 by aggregated IgG in plasma and inhibited iC3b deposition on cells. Finally, LAIR-2-Fc inhibited complement-mediated lysis of cells sensitized with anti-HLA antibodies in an ex vivo model for antibody-mediated transplant rejection. Thus, LAIR-2-Fc is an effective novel complement inhibitor for the treatment and prevention of antibody-mediated allograft rejection and antibody-mediated clinical conditions.

Immune complex reaction after successful treatment of meningococcal disease: an excellent response to IVIG.

The convalescence phase of severe meningococcal sepsis is complicated by immune complex reactions with arthritis being the commonest. No standard guidelines exist for management of such complications, but non-steroidal anti-inflammatory drugs and steroids have been used with varying success. We report excellent response to intravenous immunoglobulin in a child with immune complex reaction following meningococcal sepsis.

Therapeutic plasma exchange in systemic vasculitis: an update on indications and results.

PURPOSE OF REVIEW: Therapeutic plasma exchange has been long proposed as a potentially useful modality to treat several systemic vasculitis conditions. This review summarizes the available evidence for the effectiveness of plasma exchange in systemic vasculitis. RECENT FINDINGS: Therapy with plasma exchange, most often combined with immunosuppressive agents, has been found effective for antiglomerular basement membrane disease, antineutrophil cytoplasmic antibody-associated vasculitis (AAV), Henoch-Schönlein purpura, cryoglobulinemic vasculitis, hepatitis B virus-associated polyarteritis nodosa and Kawasaki disease. The most common indications are life-threatening or organ function-threatening manifestations, particularly advanced renal dysfunction and disease refractory to traditional therapy. Thus, most of the available evidence favoring plasma exchange in these circumstances is from small observational studies or expert consensus. Recent advances in findings include results strengthening the notion of a small beneficial effect on preserving renal function with adjunct plasma exchange therapy in AAV with renal failure and observational data suggesting plasma exchange as a promising effective salvage option for children with Kawasaki disease not responding to standard therapy with intravenous immunoglobulins. SUMMARY: Evidence from case reports and case series and a few randomized controlled trials continues to support plasma exchange as a major rescue-treatment modality for several systemic vasculitis diseases. These studies offer some guidance for use of plasma exchange in systemic vasculitis, but additional data from controlled trials are needed for more accurate assessment of the indications, practical modalities, benefits and shortcomings of this treatment approach.

Pathogenesis and therapies of immune-mediated myopathies.

The most common autoimmune muscle disorders include dermatomyositis (DM), polymyositis (PM), necrotizing autoimmune myositis (NAM) and sporadic inclusion body myositis (sIBM). DM is a complement-mediated microangiopathy leading to destruction of capillaries, hypoperfusion and inflammatory cell stress on the perifascicular regions. NAM is an increasingly recognized subacute myopathy triggered by statins, viral infections, cancer or autoimmunity with macrophages as the final effector cells causing fiber injury. PM and IBM are T cell-mediated disorders where cytotoxic CD8(+) T cells clonally expand in situ and invade major histocompatibility complex class I expressing muscle fibers. In sIBM, in addition to autoreactive T cells, there are degenerative features characterized by vacuolization and accumulation of stressor or amyloid-related misfolded proteins; an interrelationship between inflammatory and degeneration-associated molecules is prominent and enhances the cascade of pathogenic factors. These disorders are treatable, hence the need to make the correct diagnosis from the outset. The applied therapeutic strategies are outlined and the promising new agents are reviewed.

Experimental study of δ-ALA-PDT in the treatment in BXSB lupus-prone mice.

Extracorporeal photochemotherapy can correct immune disease and treat many autoimmune diseases. The aim of this study was to investigate the effects of delta-aminolevulinic acid photodynamic therapy (δ-ALA-PDT) on BXSB mouse. The 24-h urine protein, titers of serum antinuclear antibodies, peripheral blood lymphocyte apoptosis and deposition of immune complex in renal glomeruli were determined in BXSB mice after δ-ALA-PDT treatment. Results showed that δ-ALA-PDT treatment could reduce 24-h urine protein, titers of serum antinuclear antibodies, and deposition of immune complex in renal glomeruli. The δ-ALA-PDT treatment could also lead to significant increase in the rate of peripheral blood lymphocytes.

[Therapy-refractory thrombocytopenia in a 28-year-old patient]. / Therapierefraktäre Thrombozytopenie bei einem 28-jährigen Patienten.

We report a case of a patient with thrombocytopenia. A sporadic MYH9-associated disease, May Hegglin anomaly, was identified by giant platelets, leucocyte inclusion bodies and the typical distribution of NMMHC-IIA in granulocytes in the absence of impaired renal function, cataract and hearing loss. MYH9-associated diseases are an underestimated differential diagnosis of idiopathic thrombocytopenia. The correct diagnosis is important to prevent unnecessary treatment of a patient with thrombocytopenia and to provide sufficient patient information and genetic counseling. Therefore, careful examination of the blood smear has to be the first diagnostic step in a case of unexplained thrombocytopenia.

Immunoadsorption in dermatology.

Immunoadsorption (IA), also termed immunoapheresis, has been established as effective and specific tool advantageous to plasmapheresis to remove immunoglobulin and immune complexes and in cytapheresis, immune cells from the circulation. IA was successfully used in various autoantibody-mediated diseases, e.g. acquired hemophilia, myasthenia gravis, dilated cardiomyopathy, and Guillain-Barré syndrome. In dermatology, IA has been applied as an effective adjuvant treatment for autoimmune bullous diseases. Autoimmune blistering disorders are a heterogeneous group of diseases that are associated with autoantibodies to desmosomal (pemphigus group) and basal membrane zone proteins (pemphigoid group, epidermolysis bullosa acquisita). Because the pathogenic relevance of autoantibodies was clearly demonstrated in the majority of these disorders, removal of autoantibodies, therefore, appears to be a rational therapeutic approach for these patients. IA has been shown to effectively lower the autoantibody levels and leads to rapid clinical responses in patients with immunobullous disorders. Here, clinical effects and adverse events of IA in more than 50 reported patients with autoimmune blistering disorders are reviewed. In addition, an overview of the available IA systems and treatment protocols is provided and guidelines of a recent consensus of German, Austrian, and Swiss experts for the use of IA in autoimmune bullous diseases are summarized.

Role of IgA and IgA fc receptors in inflammation.

INTRODUCTION: Signals delivered by serum monomeric IgA (mIgA) are essential in controlling the immune system by preventing the development of autoimmunity and inflammation. However, IgA can also, when aggregated, be deleterious to the host, inducing inflammatory diseases. This Janus-like nature of IgA is mainly due to their heterogeneity in molecular forms and their interaction with IgA receptors. DISCUSSION: While serum mIgA are mainly involved in FcalphaRI-mediated inhibition of immune responses, macromolecular serum IgA or circulating IgA immune complexes are often deleterious to the host by inducing sustained activation through IgA receptors including FcalphaRI and transferrin receptor. CONCLUSION: FcalphaRI-mediated inhibitory function is able to suppress several inflammatory diseases in mice including asthma and glomerulonephritis. Intravenous mIgA (mIgAIV) and anti-FcalphaR monovalent antibodies represent thus promising tools for immunotherapy.

The complement system in systemic autoimmune disease.

Complement is part of the innate immune system. Its major function is recognition and elimination of pathogens via direct killing and/or stimulation of phagocytosis. Activation of the complement system is, however, also involved in the pathogenesis of the systemic autoimmune diseases. Activation via the classical pathway has long been recognized in immune complex-mediated diseases such as cryoglobulinemic vasculitis and systemic lupus erythematosus (SLE). In SLE, the role of complement is somewhat paradoxical. It is involved in autoantibody-initiated tissue damage on the one hand, but, on the other hand, it appears to have protective features as hereditary deficiencies of classical pathway components are associated with an increased risk for SLE. There is increasing evidence that the alternative pathway of complement, even more than the classical pathway, is involved in many systemic autoimmune diseases. This is true for IgA-dominant Henoch Schönlein Purpura, in which additional activation of the lectin pathway contributes to more severe disease. In anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis the complement system was considered not to be involved since immunoglobulin deposition is generally absent in the lesions. However, recent studies, both in human and animal models, demonstrated complement activation via the alternative pathway as a major pathogenic mechanism. Insight into the role of the various pathways of complement in the systemic autoimmune diseases including the vasculitides opens up new ways of treatment by blocking effector pathways of complement. This has been demonstrated for monoclonal antibodies to C5 or C5a in experimental anti-phospholipid antibody syndrome and ANCA-associated vasculitis.

[Postinfectious acute glomerulonephritis]. / Glomérulonéphrite aiguë postinfectieuse.

Postinfectious acute glomerulonephritis mostly happens in children aged two to 10 years old. Typically, it follows group A beta-hemolytic streptococcus skin or upper respiratory tract infection. There is a latent period of one to three weeks before nephritic syndrome appears. Microscopic or macroscopic hematuria is always present. Proteinuria and decreased glomerular filtration rate are usually mild. By contrast, salt and water retention can be severe and complicated with hypertension, congestive heart failure or pulmonary edema. Fluid overload must be urgently treated by loop diuretics or renal replacement therapy in the most severe cases.

Fibrillary glomerulonephritis with hepatitis C viral infection and hypocomplementemia.

Fibrillary glomerulonephritis (FGN) is a relatively rare cause of renal disease, found in only 0.6-1.5% of native renal biopsies. The pathogenesis of FGN is not well described, and very few associations with disease processes other than hepatitis C virus (HCV) have been made. We describe a case that provides evidence in support of the FGN-HCV association, as well as introduces the association of FGN-HCV and hypocomplementemia. The case is a 53-year-old African-American female demonstrating a classical presentation of FGN complicated by a concomitant HCV infection. Treating an HCV infection with alpha-interferon has been shown to result in subsequent improvement in the nephrotic syndrome and renal function. However, this patient is unique in that she is complicated with hypocomplementemia, creating a complex treatment situation.

The spectrum of complement alternative pathway-mediated diseases.

SUMMARY: The complement system has once again come into prominence in the therapeutic development arena. The recent approval of an inhibitory monoclonal antibody, eculizumab, which is directed against complement component C5 for the disease paroxysmal nocturnal hemoglobinuria has provided the initial validation of this system as a therapeutic target. Preclinical studies using animal models and human-derived samples demonstrate that inhibition of complement ameliorates many inflammatory and autoimmune disease manifestations. Major efforts continue to define the most optimal means to block complement activation in a cost-effective manner. Because the system is initiated through three pathways and generates at least six immunoregulatory and pro-inflammatory mediators, there is substantial complexity to this problem. One pathway, designated the alternative pathway, has recently been shown to play a particularly important role in preclinical disease models. Further evidence of the importance of the alternative pathway has been provided by studies of human diseases, where mutations or dysfunctional polymorphisms that promote activation of this pathway are highly associated with the diseases atypical hemolytic uremic syndrome, dense deposit disease, and age-related macular degeneration. This article reviews evidence in support of the essential role of the alternative pathway in the generation of tissue injury and the rationale for development of therapies that modulate its activity.

Activating and inhibitory IgG Fc receptors on human DCs mediate opposing functions.

Human monocyte-derived DCs (moDCs) and circulating conventional DCs coexpress activating (CD32a) and inhibitory (CD32b) isoforms of IgG Fcgamma receptor (FcgammaR) II (CD32). The balance between these divergent receptors establishes a threshold of DC activation and enables immune complexes to mediate opposing effects on DC maturation and function. IFN-gamma most potently favors CD32a expression on immature DCs, whereas soluble antiinflammatory concentrations of monomeric IgG have the opposite effect. Ligation of CD32a leads to DC maturation, increased stimulation of allogeneic T cells, and enhanced secretion of inflammatory cytokines, with the exception of IL-12p70. Coligation of CD32b limits activation through CD32a and hence reduces the immunogenicity of moDCs even for a strong stimulus like alloantigen. Targeting CD32b alone does not mature or activate DCs but rather maintains an immature state. Coexpression of activating and inhibitory FcgammaRs by DCs reveals a homeostatic checkpoint for inducing tolerance or immunity by immune complexes. These findings have important implications for understanding the pathophysiology of immune complex diseases and for optimizing the efficacy of therapeutic mAbs. The data also suggest novel strategies for targeting antigens to the activating or inhibitory FcgammaRs on human DCs to generate either antigen-specific immunity or tolerance.