Effect of ciclosporin on active Heymann nephritis

The Modified Vaccination Technique

In addition to active and passive immunizations, there is a third method of immunization, the modified vaccination technique, which is based on injecting a combination of target antigens and antibodies against this antigen. The vaccine is essentially comprised of immune complexes with pre-determined immune-inducing components. When such an immune complex (target antigen × antibody against the target antigen) with a slight antigen excess is administered, it evokes a corrective immune response by the production of the same antibody with the same specificity against the target antigen that is present in the immune complex (pre-determined immune response).

Methods for Testing Immunological Factors

Hypersensitivity reactions can be elicited by various factors: either immunologically induced, i.e., allergic reactions to natural or synthetic compounds mediated by IgE, or non-immunologically induced, i.e., activation of mediator release from cells through direct contact, without the induction of, or the mediation through immune responses. Mediators responsible for hypersensitivity reactions are released from mast cells. An important preformed mediator of allergic reactions found in these cells is histamine. Specific allergens or the calcium ionophore 48/80 induce release of histamine from mast cells. The histamine concentration can be determined with the o-phthalaldehyde reaction.

Effect of rat kidney fraction 3 (rKF3) antigen and specific IgM antibody against rKF3 on the progression of slowly progressive Heymann nephritis

The aim of the present study was to find out if specific IgM (M) antibody (directed against rat kidney fraction 3 (rKF3)) or rKF3 antigen were able to influence disease progression in an experimental autoimmune kidney disease called slowly progressive Heymann nephritis (SPHN). The level of circulating autoantibodies (aabs) and the morphological and functional changes to the kidney were studied in six groups of rats. All of the treatment components (except post-treatment with M) used in the SPHN pre- and post-treated rats and post-treated-only rats had measurable beneficial effects (even during restimulation with the chemically modified renal antigen, 22 weeks after the induction of the disease) as demonstrated by diminished pathogenic IgG aab production, less severe kidney lesions, and proteinuria reductions. The injected rKF3 minimized progression best in this experiment, especially when administered in a pre- and post-treatment regimen. It is thought that the effect of rKF3 in the reduced progression of SPHN was due to increased production of specific IgM aabs, which in turn limited pathogenic aab production and continuous buildup of immune complexes in the glomeruli by facilitating removal or blockage of nephritogenic autoantigens from the circulation.

Reduced incidence of slowly progressive Heymann nephritis in rats immunized with a modified vaccination technique

A slowly progressive Heymann nephritis (SPHN) was induced in three groups of rats by weekly injections of a chemically modified renal tubular antigen in an aqueous medium. A control group of rats received the chemically unmodified version of the antigen in an aqueous solution. One group of SPHN rats were pre- and post-treated with weekly injections of IC made up of rKF3 and rarKF3 IgM antibody at antigen excess (MIC) (immune complexes [ICs] containing sonicated ultracentrifuged [u/c] rat kidney fraction 3 [rKF3] antigen and IgM antibodies specific against the antigen, at slight antigen excess). One group of SPHN rats were post-treated with MIC 3 weeks after the induction of the disease and one group of SPHN animals received no treatment. The control group of rats received pre- and post-treatment with sonicated u/c rKF3.

The incidence of immune-complex glomerulonephritis (ICGN) in the untreated SPHN rats was 87%, in the pre- and post-treated animals 13%, and in the post-treated-only rats 20%. Rats receiving sonicated ultracentrifuged rKF3 antigen did not develop ICGN.

The present experiment demonstrates that the development of SPHN can be not only prevented but also effectively terminated by our newly developed modified vaccination technique.

Downregulation of a pathogenic autoantibody response by IgM autoantibodies directed against the nephritogenic antigen in slowly progressive Heymann nephritis

The purpose of the study was to find out if a new modified vaccination technique would be effective in downregulating immunopathological events during the course of an experimental autoimmune kidney disease (which is morphologically and functionally similar to Heymann nephritis) called 'slowly progressive Heymann nephritis' (SPHN). We have shown that the pathogenic IgG autoantibody (aab)-induced experimental autoimmune kidney disease process can be downregulated early on as well as during the chronic progressive phase, when rats were restimulated. The IgM aab, resulting from stimulation by immune complexes made up of rat kidney fraction 3 (rKF3) antigen and rat anti-rKF3 IgM antibody in antigen excess (MIC), can greatly diminish pathogenic aab production by removing or blocking nephritogenic antigens. Reduced IgG aab production limits the formation of damaging immune complexes (IC) in the glomeruli and development of proteinuria. At the end of the experiment 60% and 80% of the MIC-treated groups had no pathogenic IgG aab in their circulation, while all the untreated SPHN rats had high levels of IgG aab associated with disease progression manifesting in increased proteinuria and severe immune complex glomerulonephritis.

Down-regulation of pathogenic autoantibody response in a slowly progressive Heymann nephritis kidney disease model

In the present article, we describe an antigen-specific down-regulation of a pathogenic autoantibody (aab)-mediated disease process in an experimental autoimmune kidney disease in rats called slowly progressive Heymann nephritis (SPHN). This autoimmune disease is initiated and maintained by pathogenic immunoglobulin G (IgG) autoantibodies (aabs), which cause an immune-complex (IC) glomerulonephritis associated with proteinuria. We achieved down-regulated pathogenic aab response in SPHN rats by injections of an IC containing the native nephritogenic antigen and specific high-titred nonpathogenic IgM aabs, in antigen excess. The injected IC increased the level of circulating nonpathogenic IgM aabs; the increased levels of specific IgM aabs in turn facilitated the removal of the injected altered nephritogenic and liberated autoantigens from the renal tubules and greatly diminished the production of pathogenic aabs and the build up of immune deposits in the glomeruli. While animals treated early had advantages over rats whose kidney disease was well established before treatment; animals treated late into the disease still manifested noticeable improvements in similar areas, i.e. with lessened proteinuria, kidney lesion reduction and a decreased pathogenic aab response. At the end of the experiment at 29 weeks, 80% of all the treated rats had insignificantly low levels of circulating IgG aabs, indicating cessation of pathogenic aab production and corresponding termination of the disease process. In contrast, most untreated rats with the kidney disease still had high levels of circulating pathogenic aabs at the end of the experiment, which maintained disease progression.

Production of a new model of slowly progressive Heymann nephritis

A slowly progressive autoimmune kidney disease was induced in Sprague Dawley rats by subcutaneous injection of a chemically modified kidney antigen (rKF3), incorporated into Alum and Distemper complex vaccine, followed by subcutaneous injections of an aqueous preparation of the same antigen. Pathogenic autoantibodies developed, which reacted with fixed glomerular nephritogenic antigen. Subsequently, immunopathological events lead to chronic progressive immune complex glomerulonephritis and proteinuria. The slowly developing disease was morphologically and functionally similar to Heymann nephritis (HN). The damage observed in the kidneys of experimental animals at 8 weeks and at the end of the experiment was examined by direct fluorescent antibody test, histology and electron microscopy. The changes were similar to the typical lesions found in HN rat kidneys, but less severe. Animals became proteinuric from 17 weeks onward (instead of the usual 4-8 weeks). By the end of the experiment, at 8 months, 100% of the rats were proteinuric. This new experimental model of autoimmune kidney disease, which is not complicated by intraperitoneal deposition and retention of Freund's complete adjuvant and renal tubular antigens, allowed us to investigate the pathogenesis of the disease processes from a different aspect, and promises to be a useful and improved model for the investigation of future treatment options.

Role of T cells in the mediation of Heymann nephritis. ii. Identification of Th1 and cytotoxic cells in glomeruli

The role of immunoglobulin (Ig) and complement as mediators of Heymann nephritis (HN) has been questioned by recent studies showing that HN can be induced in a C6-deficient rat that cannot assemble the membrane attack complex of complement. Also, the severity of HN can be reduced by therapy directed at CD8+ T cells, which has no effect on antibody (Ab) production or immune deposits. To identify whether T cells may contribute to the glomerular injury of active HN in Lewis rats, the mononuclear infiltrate and cytokine mRNA in glomeruli and kidney interstitium were examined. Groups of Lewis rats immunized with Fx1A in CFA developed HN, and were compared to controls that received CFA only. Proteinuria, the marker of glomerular filtration barrier dysfunction, was absent at four weeks but present at eight weeks in HN. Serum anti-Fx1A Ab and glomerular Ig were present in HN at both time points. Immunoperoxidase staining with monoclonal Abs identified, at eight weeks, a glomerular infiltrate of CD4+ and CD8+ T cells, and macrophages, but not NK cells. Semiquantitative RT-PCR of isolated glomeruli at eight weeks demonstrated expression of cytokine mRNA for Th1 CD4+ cells (IFN-gamma and TNF-beta/LT, but not IL-2), cytotoxic CD8+ T cells (granzyme A and perforin), and macrophages (TNF-alpha and IL-10), but not Th2 CD4+ cells (no increase in IL-4, IL-5 and IL-6). At eight weeks, the cellular infiltrate and pattern of cellular activation in glomeruli was different to that in renal cortex. In the cortical infiltrate CD8+ cells were a lesser component, and NK cells were increased, as were CD4+ cells and macrophages. RT-PCR identified increased cytokine mRNA for macrophages, Th1 and Th2 cells, but not cytotoxic effector T cells. At four weeks, T cells including CD4+ and CD8+ cells were identified in the isolated glomeruli of rats with HN, but there was no increase in cytokine mRNA expression. There was no infiltrate or increase in cytokine mRNA detected in renal cortex at four weeks. Anti-Fx1A Ab's and glomerular deposition of Ig develop many weeks before the onset of proteinuria, when there is only a small cellular infiltrate present. The progressive development of infiltrates of activated T cells, principally Th1 and cytotoxic effector cells, and macrophages, within glomeruli is coincident with the development of proteinuria. These findings raise the possibility that these cells contribute to the mediation of the glomerular injury and proteinuria of HN.

Recurrent nephrotic syndrome after transplantation: early treatment with plasmaphaeresis and cyclophosphamide

Steroid-resistant nephrotic syndrome (NS) with focal glomerulosclerosis (FGS) and its recurrence after transplantation are mainly seen in children. The recurrence rate approximates 30% and the graft loss is about half this. Several therapeutic regimens have been proposed, giving conflicting results. In an attempt to remove a putative circulating factor and inhibit its production by lymphocytes, three patients with biopsy-proven FGS in the native kidney were included in a prospective uncontrolled trial using early plasmaphaeresis followed by substitutive immunoglobulins in association with methylprednisolone pulses and cyclophosphamide instead of azathioprine over a 2-month period. The patients were girls, aged 6.5, 13.3 and 15.8 years, who received a cadaveric transplant; concomitant immunosuppression included prednisone and cyclosporine A. All three patients exhibited early recurrence of the NS and were treated 5-10 days after the onset of proteinuria. Rapid and sustained remission was achieved in all patients within 12-24 days on therapy. One patient experienced a late acute but steroid-sensitive rejection episode; another suffered from septic ankle arthritis as a complication of reinforced immunosuppression. The latter girl had a second late recurrence of proteinuria that was controlled within 7 weeks. With a 18- to 27-month follow-up, all three patients have normal renal function, normal blood pressure and no proteinuria. We conclude that intensive therapy using plasmaphaeresis, steroid pulses and cyclophosphamide over a 2-month period can induce complete remission in children with early recurrence of NS after transplantation.

Short-term responsiveness of membranous glomerulopathy to cyclosporine

We administered a 12-week course of cyclosporine (CsA) (4 to 6 mg/kg/24 h) to nephrotic patients with membranous glomerulopathy (MG). Nephrotic patients with minimal change nephropathy (MCN) served as a comparison group. We evaluated the effects of CsA on proteinuria, glomerular function, and the release of cytokines by peripheral blood mononuclear cells in culture. Proteinuria was restored to normal levels within 2 to 4 weeks in MCN. Proteinuria declined from nephrotic to subnephrotic levels (< 3,500 mg/24 h) in 10 of 14 patients with MG, also within 2 to 4 weeks of onset of therapy. The four nonresponders exhibited a rapidly progressive and presumably irreversible form of MG culminating in renal failure. On average, fractional clearances of albumin and IgG declined by 59% and 73% in MG (P < 0.005); corresponding declines in MCN were by 99% (P < .0001). Corresponding rates of glomerular filtration in each glomerular injury remained unchanged. A strong trend for proteinuria to relapse after CsA was withdrawn was evident in both disorders. The release of tumor necrosis factor (TNF)-alpha by mononuclear cells in culture was enhanced in each glomerular injury, both before and after the course of CsA. We conclude that the proteinuria in most cases of MG exhibits a responsiveness to CsA that is qualitatively similar to, but less complete than, that in MCN. The rapidity with which barrier function improves suggests a possible role for cell-mediated immune injury in MG.

The effect of cyclosporin A on cationized bovine serum albumin-induced nephropathy in NZW rabbits

The effect of cyclosporin A (CyA) was studied on the morphology and protein excretion of a rabbit chronic serum sickness nephritis using cationized bovine serum albumin (cBSA). One group of rabbits was given intravenous (i.v.) immunizing doses of cBSA and Escherichia coli endotoxin. One week later, these animals began a 6-week i.v. injection schedule of cBSA only. A second group followed the same injection protocol, but was given intramuscular (i.m.) CyA for 3 days prior to the immunizing dose of cBSA/endotoxin and throughout the subsequent cBSA schedule. A third group was given i.m. CyA only. Regular blood samples for CyA levels were taken from animals given the drug. Two 24-h urine samples were obtained from all animals in the study. Analysis of the blood samples showed that immunosuppressive levels of CyA were achieved after two i.m. doses of CyA. These levels were maintained during the course of the schedule. Morphologically, all rabbits completing the cBSA only injection schedule showed evidence of an immune-mediated glomerulopathy with variably severe membranous and endocapillary proliferative change. Less than half the rabbits in the cBSA/CyA group showed any evidence of membranous change. The glomeruli of animals given CyA only were normal. No morphological evidence of CyA toxicity was seen in any animal given the drug. The proteinuria profiles, however, suggested that as well as reducing protein excretion in rabbits given cBSA, CyA may interact with the immunizing dose of cBSA to produce an early, reversible, nephrotoxic effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Cyclosporin reduces proteinuria in rats with aminonucleoside nephrosis

The effect of cyclosporin (CS) was assessed in Sprague-Dawley rats with puromycin aminonucleoside (PA) nephrosis induced by a single intraperitoneal injection of PA. Three groups of rats were injected intraperitoneally with CS (10 mg/kg body weight) daily, beginning 1 day before PA administration, or 5 or 10 days after PA administration, for 10 days. CS significantly reduced proteinuria in rats with PA nephrosis in comparison with untreated nephrotic controls. After discontinuation of the CS treatment, proteinuria gradually increased, reaching values similar to those in control nephrotic rats. CS pretreatment did not prevent the induction of PA-induced nephrotic syndrome. Light microscopy and assessment of anionic sites in the glomerular basement membrane revealed no differences between normal rats, nephrotic controls, and CS-treated rats. These results show that CS can reduce proteinuria in PA nephrosis, but cannot ameliorate the glomerular changes.

FK506, a novel immunosuppressive agent, induces antigen-specific immunotolerance in active Heymann's nephritis and in the autologous phase of Masugi nephritis

FK506 is a new drug which has potent immunosuppressive activity. We studied its immunosuppressive effects on active Heymann's nephritis and the autologous phase of Masugi nephritis. The induction of active Heymann's nephritis was completely suppressed by FK506 injected simultaneously with the antigen (day 1) and then daily for 14 days at a dose of 0.64 mg/kg per day or more. With a lower dosage of this agent, antibody production and immune deposits in the glomerular basement membrane occurred despite the suppression of proteinuria. Similar results were obtained in rats on other treatment schedules (1-7 days or day 8-14 days duration). Rats that were prevented from developing Heymann's nephritis or the autologous phase of nephrotoxic antiserum nephritis by FK506 treatment exhibited a suppressed immune response to a second immunization of the same antigen even 4 weeks after cessation of drug administration: however, they developed antibodies when inoculated with other antigens. Rat peripheral leucocyte counts and serum creatinin were not remarkably influenced by the administration of FK506. These results indicate that FK506 has potent immunosuppressive activity, and it is suggested that it is able to induce an antigen-specific immunotolerance.

Spontaneous immune complex orchitis in brown Norway rats

Immune complexes occur spontaneously in the testis of Brown-Norway (BN) inbred rats between the basal lamina of the seminiferous tubules and the outer lamina of the myoid testicular cells. The deposits can be detected immunohistologically (IgG; C3) and by electron microscopy. The immune complexes appear between the 8th and 12th weeks of life, increase in amount up to the 30th week and decrease thereafter. After about the 20th week, of life, 15% of the animals show destruction of the germinal epithelium accompanied by an infiltration of lymphocytes and plasma cells. The final stage of this disease, which initially shows no signs of inflammation, is characterized by diffuse tubular atrophy. However, up to the 70th week of life, 85% of the animals with immune complexes show no pathological alterations. Antibodies eluated from the testes react with spermatocytes I and structures close to the lumen of the seminiferous tubules, but not with mature sperms. Serum antibodies to sperms occur in about 25% of the BN rats, but the presence of these antibodies shows no correlation with the immunohistological findings. This newly described spontaneous immune complex orchitis is regarded as a further example of an in-situ-induced immune complex disease. The observations made here can be compared with those in (peri-) membraneous glomerulonephritis, another example of a disorder resulting from in-situ-formation of immune deposits.