Associations of HLA-DR and HLA-DQ types with anti-GBM nephritis by sequence-specific oligonucleotide probe hybridization

The Association of Class I and II Human Leukocyte Antigen Serotypes With End-Stage Kidney Disease Due to Membranoproliferative Glomerulonephritis and Dense Deposit Disease

RATIONALE & OBJECTIVE

Membranoproliferative glomerulonephritis (MPGN), encompassing several distinct diseases, is a rare but significant cause of kidney failure in the United States. The potential etiologies of MPGN are unclear, but prior studies have suggested dysregulation of the alternative complement pathway and, recently, autoimmunity as potential mechanisms driving MPGN pathogenesis. In this study, we examined HLA associations with end-stage kidney disease (ESKD) due to MPGN and dense deposit disease (DDD) in a large racially and ethnically diverse US-based cohort.

STUDY DESIGN

Case-control study.

SETTING & PARTICIPANTS

Using US Renal Data System (USRDS) and United Network for Organ Sharing (UNOS) data, we identified 3,424 patients with kidney failure due to MPGN and 263 due to DDD. We matched patients to kidney donor controls on designated race and ethnicity in a 1:15 ratio.

EXPOSURE

58 class I and II HLA serotypes.

OUTCOME

Case-control status.

ANALYTICAL APPROACH

For each disease cohort, univariable and multivariable logistic regression analyses were used to investigate associations between the disease and 58 HLA serotypes. In subgroup analyses, we investigated HLA associations in White and Black patients. We also studied antiglomerular basement membrane (anti-GBM) nephritis as a positive-control outcome. We applied a Bonferroni correction to account for multiple comparisons.

RESULTS

Eighteen serotypes were significantly associated with the odds of having MPGN in univariable analyses, with DR17 having the strongest association (odds ratio [OR], 1.55 [95% CI, 1.44-1.68], P=4.33e-28). No significant associations were found between any HLA serotype and DDD. Designated race-specific analyses showed comparable findings. We recapitulated known HLA associations in anti-GBM nephritis.

LIMITATIONS

Reliance on HLA serotypes (rather than genotype), lack of biopsy-confirmed diagnoses.

CONCLUSIONS

HLA-DR17 is associated with ESKD due to MPGN in a racially and ethnically diverse cohort. The strength of association was similar in White and Black patients, suggesting a role in the pathogenesis of MPGN. No HLA associations were observed in patients with DDD.

PLAIN-LANGUAGE SUMMARY

Prior studies have suggested dysregulation of the alternative complement pathway as a potential etiology of membranoproliferative glomerulonephritis (MPGN), but recent evidence from a British White population has implicated an autoimmune mechanism in MPGN pathogenesis. We investigated HLA associations between MPGN and dense deposit disease (DDD) in a large racially and ethnically diverse cohort of patients. We found that HLA-DR17 is associated with end-stage kidney disease (ESKD) due to MPGN in both White and Black patients. By contrast, no significant HLA associations with ESKD due to DDD were identified. These results suggest a role for autoimmunity in some cases of MPGN and highlight differences in the disease etiology of MPGN compared with DDD.

Acquired aplastic anemia complicated with anti-glomerular basement membrane disease successfully treated with immunosuppressive therapy: a case report

BACKGROUND

Aplastic anemia (AA) is a rare but fatal disorder characterized by pancytopenia due to bone marrow hypoplasia. Anti-glomerular basement membrane disease (anti-GBM disease) is an immune complex small-vessel vasculitis that presents as rapidly progressive glomerulonephritis and/or pulmonary hemorrhage. Although both involve autoreactive T cells that are partially triggered by human leukocyte antigen (HLA)-DR15, there have been no reports of their co-existence and the treatment strategy is not well understood.

CASE PRESENTATION

A 67-year-old woman presented with fever, malaise, and acute kidney injury with proteinuria and hematuria requiring hemodialysis. She was diagnosed with anti-GBM antibody disease based on high serum anti-GBM antibody titer and crescentic glomerulonephritis on a renal biopsy. Pulse administration of methylprednisolone (MP), oral prednisolone (PSL), and plasmapheresis were performed. Only 2 weeks after the diagnosis of anti-GBM disease, the patient developed pancytopenia requiring frequent blood transfusions. The blood cell count did not recover even 1 month after discontinuing the drugs that could cause pancytopenia. Bone marrow examination showed hypocellularity without abnormal infiltrates or fibrosis, which led to the diagnosis of severe acquired AA. Further HLA phenotyping revealed that she had HLA-DR15. Increased dose of PSL with the secondary MP pulse and the addition of cyclosporine improved pancytopenia. Although she remained dialysis-dependent, anti-GBM disease and pancytopenia did not recur for more than 2 years.

CONCLUSIONS

We report the first case of acquired AA complicated with anti-GBM disease in an elderly woman with HLA-DR15, which was successfully treated with immunosuppressive therapy (IST). This report is valuable not only because it shows they may co-occur, but also because it provides a therapeutic option for this complex condition. It was also suggested that pancytopenia in patients with anti-GBM disease recalls serious hematologic diseases including AA that require immediate treatment based on bone marrow examination.

Membranous Glomerulonephritis With Crescents

Introduction

Membranous glomerulonephritis (MGN) is rarely associated with necrotizing and crescentic glomerulonephritis (NCGN).

Methods

We report the clinical and pathologic findings in 15 patients with MGN and NCGN associated with anti-neutrophil cytoplasm antibodies (ANCAs), anti-glomerular basement membrane (GBM), or anti-phospholipase A2 receptor (PLA2R) antibodies.

Results

The cohort consisted of 15 patients: 7 males and 8 females with a median age of 63 years (range: 18-79). In 12 of 15 patients, MGN and NCGN were diagnosed at the time of the biopsy, and in 3 cases, MGN predated the NCGN. ANCA was positive in 7 cases (6 MPO myeloperoxidase (MPO)-ANCA and 1 PR3-ANCA), anti-GBM antibodies were detected in 5 cases, and anti-PLA2R antibodies were found in 2 cases. One case was negative for all antibodies. Microscopic hematuria was present in all but one patient who was anuric, and median urinary protein-to-creatinine ratio was 819.5 mg/mmol (range: 88-5600). Pathologic evaluation revealed MGN and NCGN with crescents involving 28% of glomeruli (median; range: 5%-100%). Follow-up was available for all 15 patients; all were treated with steroids; 10 with cyclophosphamide, and 6 also received rituximab. At a median follow-up of 72 months, 9 had stabilization or improvement of renal function, 6 had progressed to end-stage renal disease, and 4 died during the follow-up period.

Conclusion

MGN with crescents associated with ANCAs or anti-GBM antibodies is a rare dual glomerulopathy. Patients present with heavy proteinuria, microscopic hematuria, and acute kidney injury and should be treated for a rapidly progressive glomerulonephritis. Prognosis is variable, and 40% of patients progress to end-stage renal disease.

Basement membranes and autoimmune diseases

Basement membrane components are targets of autoimmune attack in diverse diseases that destroy kidneys, lungs, skin, mucous membranes, joints, and other organs in man. Epitopes on collagen and laminin, in particular, are targeted by autoantibodies and T cells in anti-glomerular basement membrane glomerulonephritis, Goodpasture's disease, rheumatoid arthritis, post-lung transplant bronchiolitis obliterans syndrome, and multiple autoimmune dermatoses. This review examines major diseases linked to basement membrane autoreactivity, with a focus on investigations in patients and animal models that advance our understanding of disease pathogenesis. Autoimmunity to glomerular basement membrane type IV is discussed in depth as a prototypic organ-specific autoimmune disease yielding novel insights into the complexity of anti-basement membrane immunity and the roles of genetic and environmental susceptibility.

Autoimmunity to the alpha 3 chain of type IV collagen in glomerulonephritis is triggered by 'autoantigen complementarity'

'Autoantigen complementarity' is a theory proposing that the initiator of an autoimmune response is not necessarily the autoantigen or its molecular mimic, but may instead be a peptide that is 'antisense/complementary' to the autoantigen. We investigated whether such complementary proteins play a role in the immunopathogenesis of autoimmune glomerulonephritis. Experimental autoimmune glomerulonephritis, a model of anti-glomerular basement membrane (GBM) disease, can be induced in Wistar Kyoto (WKY) rats by immunization with the α3 chain of type IV collagen. In this study, WKY rats were immunized with a complementary α3 peptide (c-α3-Gly) comprised of amino acids that 'complement' the well characterized epitope on α3(IV)NC1, pCol(24-38). Within 8 weeks post-immunization, these animals developed cresentic glomerulonephritis, similar to pCol(24-38)-immunized rats, while animals immunized with scrambled peptide were normal. Anti-idiotypic antibodies to epitopes from c-α3-Gly-immunized animals were shown to be specific for α3 protein, binding in a region containing sense pCol(24-38) sequence. Interestingly, anti-complementary α3 antibodies were identified in sera from patients with anti-GBM disease, suggesting a role for 'autoantigen complementarity' in immunopathogenesis of the human disease. This work supports the idea that autoimmune glomerulonephritis can be initiated through an immune response against a peptide that is anti-sense or complementary to the autoantigen. The implications of this discovery may be far reaching, and other autoimmune diseases could be due to responses to these once unsuspected 'complementary' antigens.

Crescentic Glomerulonephritis: an update on Pauci-immune and Anti-GBM diseases

Crescentic glomerulonephritis (GN) in a renal biopsy is a widely accepted "critical diagnosis" in Anatomic Pathology practice. Prompt biopsy evaluation and notification of the referring physician is essential to facilitate rapid therapeutic intervention. The differential diagnostic categories of crescentic GN include pauci-immune GN, anti-glomerular basement membrane (GBM) nephritis and immune complex-mediated GN, distinguished from one another by immunofluorescence and electron microscopic study of the renal biopsy. Immune complex-mediated GN is characterized by abundant glomerular deposits and encompasses several diseases including but not limited to lupus nephritis, cryoglobulinemic GN and immunoglobulin A nephropathy. Pauci-immune GN, with paucity of deposits, correlates closely with antineutrophil cytoplasmic antibody disease due to the identifiable circulating pathogenic antineutrophil cytoplasmic antibody in most patients. Recent studies have identified other antibodies in pauci-immune GN and implicated infectious organisms in triggering autoimmunity in a susceptible host by molecular mimicry of host antigens. Anti-GBM nephritis is a rare but potentially life-threatening autoimmune disease with circulating antibodies against GBM epitopes in α3 chain of type IV collagen. It is characterized by a linear immunoglobulin G deposition along GBM on immunofluorescence microscopy. Environmental triggers including infections and solvent exposure seem to change the tertiary structure of the type IV collagen α345 hexamer in GBM, expose neoepitopes, and initiate autoimmunity. Even in light of advances in understanding of pathophysiology and serologic testing, renal biopsy remains the mainstay of diagnosis of crescentic GN.

The association of HLA-DQB1, -DQA1 and -DPB1 alleles with anti- glomerular basement membrane (GBM) disease in Chinese patients

Background

Human leukocyte antigen (HLA) alleles are associated with many autoimmune diseases, including anti-glomerular basement membrane (GBM) disease. In our previous study, it was demonstrated that HLA-DRB1*1501 was strongly associated with anti-GBM disease in Chinese. However, the association of anti-GBM disease and other HLA class II genes, including HLA-DQB1, -DQA1,-DPB1 alleles, has rarely been investigated in Asian, especially Chinese patients. The present study further analyzed the association between anti-GBM disease and HLA-DQB1, -DQA1, and -DPB1 genes. Apart from this, we tried to locate the potential risk amino acid residues of anti-GBM disease.

Methods

This study included 44 Chinese patients with anti-GBM disease and 200 healthy controls. The clinical and pathological data of the patients were collected and analyzed. Typing of HLA-DQB1, -DQA1 and -DPB1 alleles were performed by bi-directional sequencing of exon 2 using the SeCoreTM Sequencing Kits.

Results

Compared with normal controls, the prevalence of HLA-DPB1*0401 was significantly lower in patients with anti-GBM disease (3/88 vs. 74/400, p = 4.4 × 10^-4, pc = 0.039). Comparing with normal controls, the combination of presence of DRB1*1501 and absence of DPB1*0401 was significantly prominent among anti-GBM patients (p = 2.0 × 10^-12, pc = 1.7 × 10^-10).

Conclusions

HLA-DPB1*0401 might be a protective allele to anti-GBM disease in Chinese patients. The combined presence of DRB1*1501 and absence of DPB1*0401 might have an even higher risk to anti-GBM disease than HLA-DRB1*1501 alone.

Polymerase chain reaction (PCR) and sequence specific oligonucleotide probes (SSOP) genotyping assay for detection of genes associated with rheumatoid arthritis and multiple sclerosis

In this paper an assay for the detection of genes associated with rheumatoid arthritis (RA) and multiple sclerosis, using polymerase chain reaction (PCR) and sequence specific oligonucleotide probes (SSOP) is presented, in order to be further applied in a portable Lab-On-Chip (LOC) device. A substantial part of these reagents were based on the literature (11th International Histocompatibility Workshop, IHW), bearing the advantage of proven successful implementation in genotyping, while others were designed for this study. More precisely, our methodology discriminates HLA-DRB1 as DRB1*01, *04 and *10, which include shared epitope (SE) alleles associated with RA and additionally DRB1*15 allele, including DRB1*1501 associated with MS (broad genotyping method). To further present the basic elements of the assay for high resolution genotyping of SE DRB1 alleles, we provide as an example the case of HLA-DRB1*10 alleles (HLADRB1* 100101, *100102, *100103, *1002 and *1003). Regarding the methodology for developing a detection assay, for SNPs associated with RA or MS the basic steps are presented. DNA sequence data are obtained from IMGT/HLA and SNP database. Online software tools are used to define hybridization specificity of primers and probes towards human DNA, leading to hybridization patterns that uniquely designate a target allele and evaluate parameters influencing PCR efficiency. Respecting current technological limitations of autonomous molecular-based LOC systems the approach of broad genotyping of HLA-DRB1*01/*04/*10/*15 genes, is intended to be initially used, leaving, high resolution genotyping of SE alleles for future implementations. This method is easy to be updated and extended to detect additional associated loci with RA or MS.

The role of HLA-DRB1 alleles on susceptibility of Chinese patients with anti-GBM disease

Anti-glomerular basement membrane (GBM) disease, a rare autoimmune disorder, is associated with HLA-DR15 genotype in Caucasian and Japanese populations. But the distribution of HLA-DRB1 alleles in Chinese patients with anti-GBM disease and their association with clinical characteristics of anti-GBM disease are to be determined. The present study analyzed the HLA-DRB1 alleles by sequence based typing in 44 Chinese patients with anti-GBM disease and 200 healthy controls. The effects of DRB1 alleles on susceptibility to anti-GBM disease were examined by a relative predispositional effects (RPEs) method. The clinical and pathological data of the patients were collected and analyzed. The DRB1*1501 allele was significantly associated with anti-GBM disease (p=1.597 x 10(-7)). The RPEs test also showed a significant increased frequency of DRB1*0404 in anti-GBM disease (p=0.037). Interestingly, the patients with DRB1*1501 or 0404 had more crescent formation in glomeruli than those without the two alleles (p=0.021). But the DRB1*0404 was rare in both patients and control groups, which indicates that the importance of the *0404 allele is limited in anti-GBM disease. We conclude that the HLA-DRB1*1501 allele is a genetic marker for susceptibility to anti-GBM disease.

The HLA-DRB1*1501 allele is prevalent among Japanese patients with anti-glomerular basement membrane antibody-mediated disease

BACKGROUND

We aimed to clarify the relationship between HLA-DRB1(*)1501 and anti-glomerular basement membrane (GBM) antibody-mediated disease in Japanese patients.

MATERIALS

Samples were collected from 16 anti-GBM antibody-positive patients who were admitted to our department or related hospitals from December 1990 to October 2005. We analysed clinical and laboratory data, kidney biopsy findings, and the HLA-DR phenotypes and HLA-DRB1 alleles of the patients.

RESULTS

Among the 16 patients, 15 had HLA-DR15 [the phenotype frequency (PF) was 93.8%], 7 were positive for DR4 (the PF was 43.8%) and 5 were positive for DR9 (the PF was 31.3%). The allele frequency of HLA-DRB1(*)1501 was 46.4% (13/28), which was significantly different from Japanese controls (11.6%) (P < 0.001). In contrast, the frequency of HLA-DRB1(*)1502 was not different from controls (0/28). The odds ratio of HLA-DRB1(*)1501 in these patients was 6.4 (95% CI: 2.4-16.5).

CONCLUSION

The present study demonstrated that Japanese patients with anti-GBM antibody-mediated disease are very likely to carry the HLA-DRB1(*)1501 but not the HLA-DRB1(*)1502 allele.

Characterization of the T-cell epitope that causes anti-GBM glomerulonephritis

BACKGROUND

We have demonstrated that a single T-cell epitope pCol(28-40) (SQTTANPSCPEGT) alone, which is derived from NC1 domain of alpha3 chain of type IV collagen (Col4alpha3 NC1), can induce severe glomerulonephritis in Wistar Kyoto rats. This study further characterized this T-cell epitope.

METHODS

A series of synthetic peptides derived from pCol (28-40) were tested in vivo and in vitro for their T-cell epitope activity and nephritogenicity. Major histocompatability complex (MHC) class II molecules in Wistar Kyoto rats were cloned, and MHC restriction of pCol(28-40) was determined.

RESULTS

The T-cell epitope pCol(28-40) was restricted by rat MHC class II RT.1Bl. Ten amino acid residues (29 to 38) were mapped to be the minimum core of the T-cell epitope, which was capable of inducing the T-cell response and severe glomerulonephritis. Only three residues were identified as absolutely critical for the T-cell epitope: position 31 (T) was an anchor residue to the class II molecule, and positions 33 (N) and 34 (P) contributed to the specificity of the T-cell epitope. Thus, only substitution at those positions completely abrogated nephritogenicity of the T-cell epitope. Interestingly, pCol (28-40) also bound to human MHC class II human MHC class II molecule HLA-DRB*1501, which has been linked to human anti-glomerular basement membrane (GBM) disease, suggesting that human homologue of pCol(28-40) could be a potential human T-cell epitope.

CONCLUSION

Our study demonstrated that only few residues in the nephritogenic T-cell epitope pCol(28-40) were critical. Our finding also revealed that pCol(28-40) is a potential nephritogenic T-cell epitope in Goodpasture's syndrome.

Pathogenesis of Goodpasture syndrome: a molecular perspective

Goodpasture (GP) syndrome is a form of anti-glomerular basement membrane (GBM) disease, in which autoantibodies bind to alpha3(IV) collagen in GBM causing rapidly progressive glomerulonephritis and pulmonary hemorrhage. The conformational GP epitopes have been mapped to 2 regions within the noncollagenous (NC1) domain of the alpha3(IV) chain. Recently, we described the molecular organization of the autoantigen in the native alpha3alpha4alpha5(IV) collagen network of the GBM. The crystal structure of the NC1 domain has revealed how the GP epitopes are sequestered in the native GBM. Further insight into the pathogenesis of disease has been obtained from better animal models. These advances provide a foundation for the development of new specific therapies.

Properties of HLA class II molecules divergently associated with Goodpasture's disease

Goodpasture's disease provides an opportunity to analyse molecular mechanisms that may underlie MHC class II associations with autoimmune disease because it is caused by autoimmunity to a defined antigen [the 230 amino acid NC1 domain of the alpha3 chain of type IV collagen (alpha3(IV)NC1)] and has strong HLA class II associations. We compared the alpha3(IV)NC1 peptide binding of class II molecules with strong positive (DR15) and dominant negative (DR7/1) associations using an inhibition binding assay and short synthetic peptides spanning the sequence of alpha3(IV)NC1. DR15 in general bound the peptides with low affinity (three of 23 < 100 nM) compared to DR1 and DR7 (12 and 10 < 100 nM respectively), and no peptide bound DR15 with much higher affinity (>10-fold) than both DR1 and DR7. Thus DR15 molecules are unlikely to increase susceptibility to Goodpasture's disease by presenting a particular alpha3(IV)NC1-derived peptide uniquely well and DR1/7 are unlikely to protect by their inability to present particular peptides. However DR1/7 could protect by capturing alpha3(IV)NC1 peptides and preventing their display bound to DR15; the binding data suggest that all the major (biochemically detectable) alpha3(IV)NC1 peptides presented bound to DR15 by DR15 homozygous antigen-presenting cells (APC) would bind preferentially to DR1/7 in DR15, 1/7 heterozygote APC.

Reactive oxygen species expose cryptic epitopes associated with autoimmune goodpasture syndrome

Goodpasture syndrome is an autoimmune disease of the kidneys and lungs mediated by antibodies and T-cells directed to cryptic epitopes hidden within basement membrane hexamers rich in alpha3 non-collagenous globular (NC1) domains of type IV collagen. These epitopes are normally invisible to the immune system, but this privilege can be obviated by chemical modification. Endogenous drivers of immune activation consequent to the loss of privilege have long been suspected. We have examined the ability of reactive oxygen species (ROS) to expose Goodpasture epitopes buried within NC1 hexamers obtained from renal glomeruli abundant in alpha3(IV) NC1 domains. For some hexameric epitopes, like the Goodpasture epitopes, exposure to ROS specifically enhanced recognition by Goodpasture antibodies in a sequential and time-dependent fashion; control binding of epitopes to alpha3(IV) alloantibodies from renal transplant recipients with Alport syndrome was decreased, whereas epitope binding to heterologous antibodies recognizing all alpha3 NC1 epitopes remained the same. Inhibitors of hydrogen peroxide and hydroxyl radical scavengers were capable of attenuating the effects of ROS in cells and kidney by 30-50%, respectively, thereby keeping the Goodpasture epitopes largely concealed when compared with a 70% maximum inhibition by iron chelators. Hydrogen peroxide administration to rodents was sufficient to expose Goodpasture epitope in vivo and initiate autoantibody production. Our findings collectively suggest that ROS can alter the hexameric structure of type IV collagen to expose or destroy selectively immunologic epitopes embedded in basement membrane. The reasons for autoimmunity in Goodpasture syndrome may lie in an age-dependent deterioration in inhibitor function modulating oxidative damage to structural molecules. ROS therefore may play an important role in shaping post-translational epitope diversity or neoantigen formation in organ tissues.

The HLA complex in Goodpasture's disease: a model for analyzing susceptibility to autoimmunity

Human lymphocyte antigen (HLA) associations are recognized for many autoimmune diseases, but the mechanisms are not clear. Goodpasture's disease provides a unique opportunity to investigate possible mechanisms because strong HLA associations are known, the autoantigen is well defined, and major antigen-derived peptides presented bound to HLA molecules have been identified. Therefore, it may be possible to directly analyze interactions between the antigen and HLA molecules associated with the disease, and to examine influences on antigen presentation to T cells. Towards this goal, we present a detailed analysis of HLA associations with the disease and examine molecular mechanisms that could account for them.

Pulmonary manifestations of Goodpasture's syndrome. Antiglomerular basement membrane disease and related disorders

Goodpasture's syndrome, or antiglomerular basement membrane disease, is a disorder in which lungs and kidneys are affected by the binding of anti-GBM antibodies, leading to pulmonary hemorrhage and glomerulonephritis with rapidly progressive renal insufficiency. Recent advances in the understanding of disease pathogenesis and diagnosis and treatment have significantly improved our ability to recognize the syndrome, distinguish it from other similar disorders, and offer successful treatment. This article focuses on the pathogenetic features, clinical manifestations, diagnostic strategies, and therapeutic principles of anti-GBM disease.

Susceptibility to anti-glomerular basement membrane disease and Goodpasture syndrome is linked to MHC class II genes and the emergence of T cell-mediated immunity in mice

We developed a new mouse model of human anti-glomerular basement membrane (GBM) disease to better characterize the genetic determinants of cell-mediated injury. While all major histocompatibility complex (MHC) haplotypes (H-2a, k, s, b, and d) immunized with alpha3 NC1 domains of type IV collagen produce anti-alpha3(IV) NC1 antibodies that cross-react with human Goodpasture [anti-GBM/anti-alpha3(IV) NC1] autoantibodies, only a few strains developed nephritis and lung hemorrhage associated with Goodpasture syndrome. Crescentic glomerulonephritis and lung hemorrhage were MHC-restricted in haplotypes H-2s, b, and d (A beta/A alpha region in H-2s) and associated with the emergence of an IL-12/Th1-like T cell phenotype. Lymphocytes or anti-alpha3(IV) NC1 antibodies from nephritogenic strains transfer disease to syngeneic recipients. However, passive transfer of isogenic alpha3(IV) NC1 antibodies into -/- T cell receptor-deficient mice failed to produce nephritis. Finally, nephritis and its associated IL-12/Th1-like T cell response attenuate in disease-susceptible mice tolerized orally to alpha3(IV) collagen before immunization. Our findings suggest collectively, as a hypothesis, that anti-GBM antibodies in mice only facilitate disease in MHC haplotypes capable of generating nephritogenic lymphocytes with special T cell repertoires.

Susceptibility to anti-glomerular basement membrane disease is strongly associated with HLA-DRB1 genes

Anti-glomerular basement membrane (anti-GBM) disease is caused by autoimmunity to a component of glomerular basement membrane. The major autoantigen has been identified as the NC1 domain of the alpha 3 chain of type IV collagen, and patients are characterized by the presence of specific autoantibodies to this molecule. In common with other autoimmune disorders, there is a strong association with HLA genes, with up to 80% of patients inheriting an HLA-DR2 haplotype. To examine the genetic basis of susceptibility to anti-GBM disease in more detail, the HLA-DRB and DQB alleles inherited by 82 patients were analyzed using sequence specific oligonucleotides. This identified a hierachy of association of DRB1 genes with anti-GBM disease, including susceptibility (DRB1*15, DRB1*04), neutral (DRB1*03) and protective (DRB1*07) alleles. Analysis of inherited haplotypes, particularly DRB1*04 and DRB1*07 carrying haplotypes, provided further evidence that the primary association was with genes at the DRB1 locus. Comparison of the sequences of the positively and negatively associated alleles showed that polymorphic residues in the second peptide binding region of the HLA Class II antigen binding groove segregated with disease. This work supports the hypothesis that the HLA associations in anti-GBM disease reflect the ability of certain Class II molecules to bind and present peptides derived from the autoantigen to T helper cells.

Direct identification of naturally processed autoantigen-derived peptides bound to HLA-DR15

Biochemical analysis of HLA class II-associated peptides from antigen-pulsed cells is a potentially useful approach to the analysis of antigen processing and presentation because it examines directly which antigen-derived peptides are presented. This is especially advantageous in the analysis of self-antigen presentation where conventional approaches utilizing antigen-specific T cells may be biased by the presence of self-tolerance. However, successful biochemical analysis has been reported for only one exogenous antigen and no autoantigens. We have used a novel analytical approach coupling biochemical data with the reported properties of class II-associated peptides to characterize the peptides derived from a clinically relevant autoantigen presented on the disease-associated class II type. Incubating the target of autoimmune attack in patients with Goodpasture's disease, the 230-amino acid NC1 domain of the alpha3 chain of type IV collagen (Goodpasture antigen, alpha3(IV)NC1), with human B cells homozygous for HLA-DR15, the allele carried by 80% of patients, we find that alpha3(IV)NC1 is presented as at least two sets of three to five peptides centered on common core sequences (nested sets). Synthetic peptides containing these core sequences bind to HLA-DR15 with intermediate affinity (IC50, 1.1-6 microM).

Autoreactive T-cells in Goodpasture's syndrome recognize the N-terminal NC1 domain on alpha 3 type IV collagen

Goodpasture's syndrome is mediated by immunopathogenic autoantibodies to the alpha 3 NC1 domain of type IV collagen. It is not known whether collaborating T-cells participate in this autoreactive response. Here we describe the first T-cell clone isolated from a Goodpasture patient autoreactive to alpha 3 type IV collagen of glomerular basement membrane. To investigate cellular autoreactivity, T-cells from Goodpasture patients or controls were isolated and stimulated by purified native or recombinant type IV collagen proteins and synthetic oligopeptides. Cell surface markers, the T-cell receptor repertoire, and MHC-restriction were analyzed. T-cell clones specific for the alpha 3 (IV) NC1 domain were established in two Goodpasture patients, but not in controls. One of the three CD8+ T-cell clones was characterized further. It was MHC class I restricted (HLA-A11) and expressed the T-cell receptor V beta 5.1. chain. This clone specifically recognized a motif at the N-terminal area of the alpha 3 (IV) NC1 domain (AA 51 to 59: GSPATWTTR). We conclude that autoreactive T-cells exists in Goodpasture patients and may play a crucial role in the inflammatory process. T-cell clones are autoreactive to the alpha 3 (IV) NC1 domain. At least for one of the clones, the T-cell epitope is different from the putative antibody-binding site.

Goodpasture's disease and Alport's syndromes

Goodpasture's, or anti-glomerular basement membrane, disease is an uncommon, usually severe disease caused by autoimmunity to a component of certain basement membranes. Alport's syndrome is an inherited, degenerative disorder that affects specific basement membranes. The two are linked by the involvement of type-IV collagen (basement membrane collagen) in their pathogenesis.

[Goodpasture syndrome: role of an epidemiological factor? Apropos of two cases]

Goodpasture's syndrome is a rare pneumorenal syndrome. Although the antigenic target of this auto-immune disorder is now known, its etiology remains debated. We report two cases of Goodpasture's syndrome occurring in similar epidemiologic conditions concerning the moment the disease began, the age and sex of the patients, their place of residence and work and manipulation of chemicals. Thus, a common environmental factor could have been the trigger event of the Goodpasture's syndrome. The epidemiologic features of this disease are reviewed.

Analysis of T cell responses to the autoantigen in Goodpasture's disease

Goodpasture's disease is a rare form of glomerulonephritis characterized by the production of autoantibodies to the glomerular basement membrane (GBM). In order to understand the development of autoimmunity to the GBM, it is important to examine mechanisms underlying T cell responses to the autoantigen. A MoAb P1, with the same specificity as patients' autoantibodies, was used to affinity-purify the antigen from collagenase-digested human GBM. This material was enriched in the NC1 domain of the alpha 3 chain of type IV collagen (alpha 3(IV)NC1), known to be the principal target of anti-GBM antibodies, but also contained lower quantities of alpha 4(IV)NC1. In proliferation assays, T cells from 11/14 patients with Goodpasture's disease showed significant responses (SI > or = 2.0) to affinity-purified human GBM. Peak responses were demonstrated at 7 or 10 days at antigen concentrations of 10-30 micrograms/ml. As in other autoimmune disorders, the presence of autoantigen-reactive T cells was also demonstrated in 5/10 healthy volunteers. Tissue typing revealed that all patients possessed HLA-DR2 and/or -DR4 alleles, while normal individuals whose T cells responded possessed DR2 and/or DR7 alleles. The specificity of the T cell response in Goodpasture's disease was further investigated using monomeric components of human GBM purified by gel filtration and reverse phase high performance liquid chromatography (HPLC). Two antigenic monomer pools were obtained, which were shown by amino-terminal sequence analysis to contain alpha 3(IV)NC1 and alpha 4(IV)NC1, respectively. In all patients tested, significant T cell proliferation was observed in response to one or both of these alpha (IV)NC1 domains. These results demonstrate that patients with Goodpasture's disease possess T cells reactive with autoantigens known to be recognized by anti-GBM antibodies.