Immune Complexes In Pathogenesis Research Articles

Drug-induced Glomerulonephritis: The Spectre of Biotherapeutic and Antisense Oligonucleotide Immune Activation in the Kidney.

Prevalence of immune-mediated glomerulonephritis has increased in preclinical toxicity studies, with more frequent use of biotherapeutic agents (especially antigenic humanized molecules) and antisense oligonucleotide (ASO) therapies. Immune complex disease affects a small number of study monkeys, often correlates with antidrug antibody (ADA) titers, and occurs at a dose that favors immune complex formation or impedes clearance. While preclinical glomerulonephritis often fails to correlate with evidence of glomerular or vascular injury in human clinical trials and is not considered predictive, additional animal investigative immunohistochemical work may be performed to substantiate evidence for immune complex pathogenesis. While ADA is most commonly encountered as a predisposing factor with biotherapeutic agents, complement activation may occur without circulating complexes, and other mechanisms of non-ADA immune-mediated glomerulonephritis have been observed including nonendogenous immune aggregates and immunoregulatory pharmacology. Although glomerulonephritis associated with oligonucleotide therapies has been noted occasionally in preclinical studies and more rarely with human patients, pathophysiologic mechanisms involved appear to be different between species and preclinical cases are not considered predictive for humans. ADA is not involved in oligonucleotide-associated cases, and complement fixation plays a more important role in monkeys. Recent screening of ASOs for proinflammatory activity appears to have decreased glomerulonephritis incidence preclinically.

Glyco-engineering for the production of recombinant IgA1 with distinct mucin-type O-glycans in plants

ABSTRACTIgA nephropathy (IgAN) is a common autoimmune disease that is characterized by formation and deposition of IgA1-containing immune complexes frequently leading to end-stage kidney disease. The IgA1 in these immune complexes carries aberrantly glycosylated O-glycans. In circulating IgA1 these galactose-deficient mucin-type O-glycans are bound by autoantibodies and thus, contribute to immune complex formation and pathogenesis. Even though the disease is associated with the overproduction of aberrant O-glycans on IgA1, specific structure-function-studies of mucin-type O-glycans are limited. Compared to other expression hosts, plants offer the opportunity for de novo synthesis of O-glycans on recombinant glycoproteins as they are lacking the mammalian O-glycosylation pathway. Recently, we demonstrated that Nicotiana benthamiana are suitable for the generation of distinct O-glycans on recombinant IgA1. Here, we expand our engineering repertoire by in planta generation of galactose-deficient and α2,6-sialylated O-glycans which are the prevailing glycans detected on IgA1 from patients with IgAN.

Local immune complex formation and pathogenesis of glomerulonephritis.

Local immune complex formation and pathogenesis of glomerulonephritis.

Goodpasture’s syndrome with concomitant immune complex mixed membranous and proliferative glomerulonephritis

Classical Goodpasture's (GP) syndrome is a monophasic illness characterized by pulmonary hemorrhage and rapidly progressive glomerulonephritis with linear IgG deposition along the glomerular and distal tubular basement membrane and estructive necrotizing diffuse extracapillary crescentic glomerulonephritis. The majority of patients have circulating anti-glomerular basement membrane (GBM) antibodies, detectable with standard anti-GBM ELISA. Concurrence of GP syndrome with proliferative glomerulonephritis has only rarely been described. In this report, for the first time we describe in a 21-year-old woman GP syndrome with 50% crescentic sclerosing glomerulonephritis with linear immunofluorescence characteristic of anti-GBM pathogenesis, combined with mixed membranous and membranoproliferative glomerulonephritis with granular immunofluorescence and subepithelial, mesangial and subendothelial deposits characterizing immune complex pathogenesis. The clinical picture was also unusual for GP syndrome, manifesting a recurrent but non-progressive course, nephrotic syndrome, normal renal function and low values of anti-GBM antibodies, identified only by novel more sensitive techniques.

Anti-interleukin-8 autoantibody:interleukin-8 immune complexes in acute lung injury/acute respiratory distress syndrome

ALI/ARDS (acute lung injury/acute respiratory distress syndrome) is a severe inflammatory lung disease associated with very high mortality. Importantly, no effective therapy has been developed to date for ALI/ARDS. Neutrophils have been implicated in the pathogenesis of ALI/ARDS, and IL-8 (interleukin-8) has been identified as the main chemotactic factor for neutrophils in lung fluids of patients with ALI/ARDS. Significantly, studies from our laboratory have revealed the presence of anti-IL-8 autoantibody:IL-8 immune complexes in lung fluids from patients with ALI/ARDS. Autoantibodies to several cytokines, including IL-8, have been found in human plasma and other tissues. The function of anticytokine autoantibodies is far from clear; however, in some instances, it has been suggested that such autoantibodies may contribute to the pathogenesis of variety of human diseases. In addition, many of these autoantibodies can form immune complexes with target cytokines. Furthermore, immune complexes consisting of anti-IL-8 autoantibodies and IL-8 are very stable due to the high affinity of autoantibodies against IL-8. These complexes are present in various human tissues, including the lung, as they have been detected in lung fluids from patients with ALI/ARDS. In this review, the significance of the latter findings are explored, and the possible involvement of anti-IL-8 autoantibody:IL-8 immune complexes in pathogenesis of ALI/ARDS is discussed.

Is the nephritogenic antigen in post-streptococcal glomerulonephritis pyrogenic exotoxin B (SPE B) or GAPDH?

Acute glomerulonephritis can follow infection by group A streptococci. An immune-complex pathogenesis is accepted, but the causative antigen(s) is still controversial. In recent years, 2 streptococcal antigens, the cationic cysteine proteinase exotoxin B (SPE B) and the plasmin receptor, a glyceraldehyde phosphate dehydrogenase (Plr, GAPDH) have attracted attention because: (1) they were localized in glomeruli in patients with acute post-streptococcal glomerulonephritis (APSGN); and (2) serum antibody to these antigens was associated with nephritogenic streptococcal infections. To date, putative nephritogens were always tested independently. Here, the relevance of SPE B and GAPDH was evaluated in the same renal biopsies and serum samples of well-defined APSGN patients. Renal biopsies (17 patients) and serum samples (53 patients) with APSGN and appropriate controls were examined. Immunofluorescent staining of frozen sections was performed using specific antibodies to SPE B and GAPDH. Serum antibodies were investigated by both enzyme-linked immunosorbent assay (ELISA) and Western blot methodology. Glomerular deposits of SPE B were demonstrated in 12/17 APSGN biopsies, and 2 cases were borderline; circulating antibodies were found in all instances (53/53 patients). Glomerular deposition of GAPDH was detected in 1/17 biopsies, and 2 cases were borderline; circulating antibodies were found in 5/47 patients. In 31 control biopsies, only weak staining for each antigen was found in 2 cases. In this study, glomerular deposits of and antibody response to zymogen/SPE B are more consistently present in APSGN than deposits and antibody response to GAPDH. Zymogen/SPE B is likely to be the major antigen involved in the pathogenesis of most cases of APSGN.

Necrobiosis Lipoidica Is Responsive to PUVA

Necrobiosis lipoidica (NL) is an uncommon palisading granuloma, the origin of which is unknown but is thought to have an immune-complex pathogenesis.

Inflammatory properties of IgG modified by oxygen radicals and peroxynitrite.

In inflammatory arthritis, there is evidence indicating that the affected tissues produce large amounts of oxygen-free radicals and NO. Herein, we examine the biologic effects of exposure of IgG to hypochlorous acid (HOCl) and peroxynitrite (ONOO). The concentrations of IgG modified by chlorination and nitrosation were measured in synovial fluids from inflammatory and noninflammatory arthritis. Human IgG was exposed to increasing concentrations of HOCl and ONOO, and the resulting products were tested for complement component binding; binding to FcgammaRI; activation of polymorphonuclear neutrophils; effect on the Ab-combining site of Abs; and in vivo inflammatory activity in a rabbit model of acute arthritis. Rheumatoid synovial fluids contained significantly greater concentrations of nitrosated and chlorinated IgG compared with ostearthritic specimens. In vitro exposure of human IgG to HOCl and ONOO resulted in a concentration-dependent decrease in C3 and C1q fixation. The decrease in Fc domain-dependent biologic functions was confirmed by competitive binding studies to the FcgammaRI of U937 cells. HOCl-treated IgG monomer was 10 times less effective in competing for binding compared with native IgG, and ONOO-treated IgG was 2.5 times less effective. The modified IgGs were also ineffective in inducing synthesis of H(2)O(2) by human PMN. The Ag-binding domains of IgG also showed a concentration-dependent decrease in binding to Ag. The ability of the modified IgGs to induce acute inflammation in rabbit knees decreased 20-fold as gauged by the intensity of the inflammatory cell exudates. These studies clarify the modulating role of biological oxidants in inflammatory processes in which Ag-autoantibody reactions and immune complex pathogenesis may play an important role.

A Potential Role for Immune Complex Pathogenesis in Drusen Formation

Drusen are abnormal extracellular deposits that accumulate between the retinal pigmented epithelium and Bruch's membrane and are commonly associated with age-related macular degeneration. Our recent work has identified a number of plasma proteins as molecular components of drusen. Of interest is the fact that many of these drusen-associated molecules are acute phase reactant proteins and some have established roles in mediating immune responsiveness. As immune and inflammatory responses appear to play a role in the formation of other pathologic age-related deposits, we examined the distribution of immunoglobulin molecules and terminal complement complexes at sites of drusen deposition. Here, we report that concentrations of immunoglobulin G and terminal C5b-9 complement complexes are present in drusen. In addition, we observe that retinal pigmented epithelial cells overlying or directly adjacent to drusen, as well as some within apparently normal epithelia, exhibit cytoplasmic immunoreactivity for immunoglobulin and the C5 component of complement. Taken together, these results suggest that drusen biogenesis may be a byproduct of immune responsiveness, and they implicate immune complex-mediated pathogenesis involving retinal pigmented epithelial cells as an initiating event in drusen formation.

Adult Still's disease and mesangial glomerulonephritis. Report of two cases

Two patients with adult Still's disease and abnormal urinalysis underwent kidney biopsy 2 to 21 years after onset of the disease. Unexpectedly, mesangial glomerulonephritis was discovered. Even if a fortuitous association could not be excluded, the real prevalence of glomerular involvement in ASD should be determined by further studies in view of a potential immune complex pathogenesis of this condition.

Behcet's Disease with Renal Amyloidosis: Report of a Case from Jordan with Review of the Literature

Behcet's Disease with Renal Amyloidosis: Report of a Case from Jordan with Review of the Literature

Hypersensitivity angiitis.

Hypersensitivity angiitis is a disease in which patients present with palpable purpura dominant on the lower legs. As lesions evolve they become confluent, and sometimes hemorrhagic and ulcerate. Other organ systems may be involved, particularly the joints, gastrointestinal tract, and kidneys. Current evidence supports an immune complex pathogenesis in which a variety of antigens including bacteria, viruses, drugs, or chemicals are involved. Therapy consists of identifying the potential offending agent and administration of antiinflammatory drugs.

Rabbit model of disseminated syphilis: immunoblot and immunohistologic evidence for a role of specific immune complexes in lesion pathogenesis.

Circulating immune complexes (CIC) containing Treponema pallidum proteins have been preliminarily implicated as inducers of a neutrophilic vascular reaction in early human cutaneous lesions of secondary syphilis. To clarify the role of specific CIC in producing cutaneous and renal lesions, 12 rabbits were studied at the following intervals after induction of disseminated syphilis: 20 days (4 rabbits: biopsies of normal and lesional skin for direct immunofluorescence (IMF) for (IgG, IgM, IgA, Clq, C3, C4), fibrin, and T. pallidum proteins; routine histology; and immunoblots of serum for CIC containing T. pallidum proteins); 21 days (4 rabbits: as at 20 days without IMF for T. pallidum protein); 23 days (4 rabbits: as at 20 days without IMF); 30 days (same 12 rabbits restudied with routine histology of normal and lesional skin; kidneys from 4 rabbits removed for routine, IMF, and electron microscopy (EM). Treponemal polypeptide antigen (MW-87 kd) was demonstrated in CIC from rabbits. Routine cutaneous histology showed evolution of lesions from an early neutrophilic vascular reaction to the typical lymphoplasmacytic reaction. IMF showed vessel-based immunoreactants in 3 of the 4 rabbits tested at 20 days and 1 of 4 at 21 days, and T. pallidum proteins in 3 of 4 rabbits at 20 days. Routine histology, IMF, and EM studies of glomeruli showed glomerular abnormalities, but no evidence of immune deposits containing specific T. pallidum protein. Skin and kidney studies of 4 controls were all negative. These data indicate a role for specific immune complexes in the pathogenesis of cutaneous lesions in this rabbit model.

Role of immune complexes in pathogenesis of renal disease

When judged by histological criteria, kidney tissue is practically devoid of immune tissue; as yet a broad spectrum of immunological diseases are targeted at the kidneys, especially at the glomeruli. Glomerular epithelial cells exhibit immune protein receptors and hence could clear immune complexes decorated with complement from the circulation. Alternatively, circulating immune complexes could become trapped in the glomerular filter and start off inflammatory reactions. Anti-glomerular basement membrane antibody reacts with glomeruli and causes glomerulonephritis. The present text is an analysis of the impact of immune complex formation on renal pathology and contains retrospective clinical data of our own hospital obtained on 192 patients undergoing diagnostic renal biopsy.

Renal biopsy findings in Wegener's granulomatosis: Segmental necrotizing glomerulonephritis with glomerular thrombosis

The clinicopathologic features of 14 patients with documented Wegener's granulomatosis (WG), with a detailed analysis of renal biopsy findings, are presented. The characteristic renal lesion found in all initial and in three of eight follow-up biopsies was segmental necrotizing glomerulonephritis (SNGN). The SNGN was generally focal and involved more than 60 per cent of the glomeruli in only two specimens. Light microscopic evidence of glomerular thrombosis, with or without necrosis, was found in 60 per cent of the biopsies. By immunofluorescence fibrin was demonstrated in 54 per cent of the biopsy specimens with "acute" SNGN, while 36 per cent of the specimens lacked both IgG and C3. Electron microscopy showed fibrin(oid) deposition with variable platelet activation associated with mesangionecrosis (two specimens) and peripheral glomerular basement membrane fragmentation/dissolution (three specimens). Rare discrete intramembranous (four specimens) and mesangial/subendothelial (one specimen) dense deposits were identified, but these deposits were associated with necrosis in only two biopsies. These findings fail to demonstrate an immune complex pathogenesis for the SNGN and suggest that glomerular thrombosis and necrosis are the primary findings in WG.

Evidence Supporting a Role for Immune Complex-Mediated Inflammation in the Pathogenesis of Bullous Lesions of Systemic Lupus Erythematosus

Evidence supporting an immune complex pathogenesis of bullous lesions in systemic lupus erythematosus includes immune deposits, acute inflammation, and blister formation at the cutaneous basement membrane zone. Since cutaneous immune deposits are a general feature of lupus, an attempt has been made to determine whether deposits in lupus patients with blisters are functionally different from those in patients without blisters. Skin was obtained from 4 consecutive patients with blisters and 14 controls. The groups were matched for clinical and serologic features, duration and activity of disease, and treatment. Skin was examined by direct immunofluorescence for immune deposits and by the leukocyte attachment assay for quantification of complement-activating immune complexes. Clinically normal, viable skin from 1 patient with blisters and 1 patient without blisters was incubated in organ culture with normal human leukocytes and serum complement. All patients in both groups had immune deposits at the basement membrane zone with an equivalent incidence of the major Ig classes. Deposits in patients with blisters were slightly more intense and a linear pattern of fluorescence seen in 75% of these patients was not seen in controls. The leukocyte attachment assay showed significantly greater (p less than .02) cell attachment in patients with blisters (mean = 167) than in patients without blisters (mean = 64) and greater cell attachment in peribullous than normal skin from the same patient. Organ culture showed complement-dependent migration of leukocytes and histologic features similar to those in spontaneous lesions in skin from the patient with blisters but not in skin from the patient without blisters. These results provide evidence supporting immune complex and complement-dependent inflammation in the pathogenesis of bullous lesions in systemic lupus erythematosus.

Budd-Chiari syndrome and renal failure in behcet disease: Report of a case and review of the literature

A case of Behcet syndrome associated with three rare complications is presented. The patient initially presented with asymmetric polyarticular arthritis, subcutaneous nodules, conjunctivitis, and episcleritis. Necrotizing vasculltis and renal failure subsequently evolved. Despite immunosuppressive therapy, Budd-Chiari syndrome with high grade hepatic obstruction developed. A Denver shunt procedure failed to alter the terminal course. At postmortem examination, skin lesions, carditis, hepatic vein thrombosis, gastric ulcerations, and focal proliferative glomerulonephritis were found. The immunoglobulins and complement present in skin and renal tissue suggest an immune complex pathogenesis.

Evidence Against an Immune Complex Pathogenesis of Primary Biliary Cirrhosis

In an attempt to confirm the presence of immune complexes in the sera of patients with primary biliary cirrhosis, sera of patients with primary biliary cirrhosis were studied with four sensitive radioimmunoassays. Thirty-one sera from 27 patients with well-characterized primary biliary cirrhosis, stages 1–4, were negative for immune complexes using three assays, the monoclonal rheumatoid factor inhibition assay, the C1q binding inhibition assay, and the C1q solid-phase assay. Nine of 31 sera were weakly positive with the C1q binding assay. Attempts at confirming the presence of immune complexes in sera positive in the C1q binding assay were unsuccessful because none of the sera were sufficiently positive for the reactant to be studied after fractionation. The positivity in the C1q binding assay was not due to greater sensitivity of that assay. Two assays used, the monoclonal rheumatoid factor binding inhibition assay and the C1q solid-phase assay, were 2–3 times more sensitive than the C1q binding assay. Neither could the negative results be explained by processing or storage artifacts because immediate assays of freshly drawn sera were also negative. There were no inhibitors of immune complex assays in our primary biliary cirrhosis sera. The addition of primary biliary cirrhosis sera that were negative for immune complexes to lupus serum did not inhibit the detection of immune complexes in lupus serum. To eliminate the likelihood that our negative results were due to some unrecognized methodologic problem in our own laboratory, we sent 25 primary biliary cirrhosis sera to an independent laboratory that used the Raji cell assay. Twenty-two of 25 sera were negative. In addition, at least one-third of the serum reactivity in the three positive sera was due to substances other than immune complexes. The data strongly suggest that circulating immune complexes are not involved in the pathogenesis of primary biliary cirrhosis.

Isolation and characterization of feline C3 and evidence for the immune complex pathogenesis of feline infectious peritonitis.

Infections of cats with feline peritonitis (FIP) virus are usually inapparent but may lead to fatal polyserositis. We have recently advanced the hypothesis that immune complexes play an essential role in the pathogenesis of the condition. To support this hypothesis, the role of the third component of complement in FIP was investigated. In the present paper, the isolation of C3 from normal cat serum and some of its physical and immunologic properties are described. The final protein had an apparent m.w. of 185,000 and was composed of 2 polypeptide chains with m.w. of 128,000 and 71,000, respectively. When tested against whole cat serum, an antiserum raised in rabbits against purified C3 recognized only 1 protein whose identity with C3 was established. With the aid of this antiserum, depositions of C3 in renal glomeruli of FIP-affected cats were demonstrated by immunofluorescence. Their localizaton coincided with that of deposited IgG, thereby supporting the concept of an immune complex pathogenesis of FIP.

The immune complex pathogenesis of glomerulonephritis and pulmonary vasculitis in Behçet's disease

A kidney and lung biopsy were performed on a patient with active Behçet's disease with renal and pulmonary involvement. Histologic, immunohistochemical and electron microscopic studies of the kidney biopsy specimen revealed a focal segmental necrotizing glomerulonephritis characterized by the presence of numerous subendothelial and occasional intramembranous deposits containing immunoglobulin G (IgG), the third component of complement (C3), the fourth component of complement (C4) and fibrin(ogen). Histologic and immunohistochemical studies of the lung biopsy specimen showed an acute venulitis and septal capillaritis associated with the presence of identical deposits within the walls of affected vessels. Circulating immune complexes were detected in the patient's serum by Raji cell assay. The findings indicate that the glomerulonephritis and pulmonary vasculitis occasionally occurring in Behçet's disease are due to the deposition of circulating antigen-antibody complexes. In addition, they strongly suggest that the majority of the major and minor manifestations of the disease, such as uveitis, cutaneous vasculitis, synovitis and meningoencephalitis, are a result of vascular immune complex deposition.