IgG Antinuclear Antibodies Research Articles

IgG, IgM, and IgA antinuclear antibodies in discoid and systemic lupus erythematosus patients.

IgG antinuclear antibodies (ANAs) are elevated in patients with systemic lupus erythematosus (SLE) compared with patients with discoid lupus erythematosus (DLE). To provide an expanded immunologic view of circulating ANAs in lupus patients, we compared the expressions of IgG, IgM, and IgA ANAs in DLE and SLE patients. In this cross-sectional study, sera from age-, gender-, and ethnic-matched SLE (N = 35), DLE (N = 23), and normal patients (N = 22) were tested for IgG, IgM, and IgA ANAs using enzyme-linked immunosorbent assays (ELISAs) and indirect immunofluorescence (IIF) with monkey esophagus as substrate. ELISAs showed elevated levels of IgG ANA, IgM ANA, and IgG/IgM ANA ratios in SLE patients compared with DLE and normal patients. IgA ANA expression was higher in SLE and DLE patients versus normal patients. IIF studies showed higher percentages of patients positive for IgG, IgM, and IgA ANAs in the SLE group. Higher IgG/IgM ANA ratios in SLE than DLE show enhanced class-switching and a more sustained humoral response in SLE. They also suggest a potential connection of IgM ANAs with disease containment.

Murine lupus strains differentially model unique facets of human lupus serology

Systemic lupus erythematosus (SLE) is a polygenic autoimmune disease characterized by the production of anti-nuclear autoantibodies that lead to subsequent end organ damage. Previous array-based studies in patients with SLE have shown that high immunoglobulin (Ig)G anti-nuclear autoantibody reactivity was associated with severe renal lupus, whereas IgM polyreactivity was associated with less severe disease. To ascertain how different murine lupus strains recapitulate these different autoantibody profiles seen in patients, serum from New Zealand black (NZB)/NZ white (W) F(1), Murphy Roths large (MRL)/lpr, NZ mixed (M)2410 and BXSB strains were compared using a comprehensive array-based screen. The array results were verified using enzyme-linked immunosorbent assays (ELISAs). Serum from MRL/lpr mice exhibited high levels of IgG anti-nuclear antibodies as well as anti-glomerular antibodies and variable levels of antibodies to myosin, Matrigel and thyroglobulin. Elevated anti-nuclear IgG antibodies were associated with severe nephritis in this strain. In contrast, NZM2410 mice exhibited lower IgG autoantibody levels with less severe nephritis but a significantly higher polyreactive IgM autoantibody profile. ELISA analysis confirmed these results. The NZB/NZW F(1) and BXSB strains exhibited an intermediate serological profile. Hence, just as in patients with SLE, whereas strong IgG reactivity to nuclear antigens is associated with severe renal disease, a polyreactive IgM seroprofile is also less ominous in murine lupus.

Circulating Antinuclear Antibodies in Patients with Pelvic Masses Are Associated with Malignancy and Decreased Survival

BackgroundCirculating autoantibodies occur more frequently in cancer patients than in patients without cancer.Methods and FindingsWe examined sera from patients referred for pelvic mass symptoms to a tertiary university clinic. A total of 127 were diagnosed with epithelial ovarian cancer while 386 had a benign condition. A screen for IgG anti-nuclear antibodies (ANA) by indirect immunofluorescence on HEp-2 cells confirmed a highly significant overrepresentation of ANA in the cancer group where 40% had detectable (i.e., a titer ≥160) ANA compared with less than 12% in the benign group. The overrepresentation of ANA in the cancer group persisted (p<0.0001) after matching the age-profile of the benign group with the ovarian cancer group. Only 19 out of 127 patients in the age-matched benign subgroup were positive for ANA corresponding to an 85% specificity at 40% sensitivity of ANA as the only marker for malignancy. No correlation of ANA positivity in either group with specific bands in immunoblots could be demonstrated even though immunoblot positivity was clearly increased in the malignant group (41% vs. 3%). The presence, strength, and type of ANA did not correlate with serum CA-125 values or with staging, and ANA outcome did not contribute with independent diagnostic information. However, survival was significantly shorter in ANA-positive compared with ANA-negative cancer patients and patients with CA-125 below the median CA-125 value in the cancer group had a significantly decreased survival when positive for ANA. ANA status made no difference in the group with CA-125 values above the median. Also, there was a significant correlation between speckled ANA-strength and histological tumor grade.ConclusionsCirculating antibodies are a promising source for new biomarkers in cancer. Characterization of epitope specificities and measurements of consecutive samples will be important for further elucidating the role of ANA in evaluating ovarian cancer patients.

Quantitative analysis of IgG antinuclear antibody in chronic periodontitis patients

Periodontitis is a bacterial infection of tooth-support ing tissues; the immunopathologic mechanisms include inflammatory cells and chemical mediators, which persist inflammation and develop a local autoimmune. The presence of autoantibodie s against extracellular matrix components, anti-neutrophil cytoplasmic antibodies (ANCA) and anti-DNA was detected. This study aimed to provide evidence of altered humoral immune response in chronic periodontitis, as well as to determine the presence of auto-antibodies in this disease. Subjects and Methods: Blood samples were collected from 35 patients with chronic periodontitis (20 with sever periodontitis and 15 with moderate periodontitis) and from 30 healthy age and sex matched individuals served as controls. Clinical periodontal parameters used in this study were plaque index, gingival index, probing pocket depth, clinical attachment level and bleeding on probing. The levels of serum IgG-antinuclear antibody were determined using enzyme-linked immunosorbent assays, whereas serum immunoglobulin (IgG, IgM and IgA) were estimated by single radial immune diffusion method. Results: Serum levels of IgG-antinuclear antibody and IgG were significantly higher in sever chronic periodontitis than in moderate chronic periodontitis and healthy controls (p 0.05). Concerning the correlation between serum IgG-antinuclear antibody and clinical periodontal parameters, the level of this autoantibody did not show any correlation with clinical parameters of periodontitis (p>0.05). Conclusion: The production of antibodies against self structures could be involved in the pathogenic mechanism of chronic periodontitis.

Somatic hypermutation as a generator of antinuclear antibodies in a murine model of systemic autoimmunity

Systemic lupus erythematosus (SLE) is characterized by high-avidity IgG antinuclear antibodies (ANAs) that are almost certainly products of T cell–dependent immune responses. Whether critical amino acids in the third complementarity-determining region (CDR3) of the ANA originate from V(D)J recombination or somatic hypermutation (SHM) is not known. We studied a mouse model of SLE in which all somatic mutations within ANA V regions, including those in CDR3, could be unequivocally identified. Mutation reversion analyses revealed that ANA arose predominantly from nonautoreactive B cells that diversified immunoglobulin genes via SHM. The resolution afforded by this model allowed us to demonstrate that one ANA clone was generated by SHM after a VH gene replacement event. Mutations producing arginine substitutions were frequent and arose largely (66%) from base changes in just two codons: AGC and AGT. These codons are abundant in the repertoires of mouse and human V genes. Our findings reveal the predominant role of SHM in the development of ANA and underscore the importance of self-tolerance checkpoints at the postmutational stage of B cell differentiation.

Regulatory T cells control autoimmunity following syngeneic bone marrow transplantation

Sublethally irradiated, immunodeficient, C57BL/6 RAG-2 gene-deleted recipient mice reconstituted with T cell-depleted bone marrow (BM) grafts frequently developed diarrhea, lost weight and showed signs of autoimmunity, dying between 4 and 7 weeks after reconstitution. Mice died despite evidence of efficient donor-derived hemato-lymphoid reconstitution, and disease was associated with the presence of IgG anti-nuclear antibodies. Autoimmunity was initiated by T cells, but could be prevented by transfer of naturally arising regulatory T cells. In contrast, lethally irradiated, BM-reconstituted immunocompetent, C57BL/6 mice survived without signs of autoimmunity. Survival of immunocompetent mice was shown to be due to the presence of residual, extra-thymically located, radio-resistant, functional regulatory T cells. The importance of regulatory T cells was further shown by the reduced survival of immunocompetent BM recipients whose CD25+ T cells had been depleted prior to bone marrow transplantation. The implications of these results in the context of syngeneic graft-versus-host disease following BM transplantation are discussed.

The Antiphospholipid Antibody Syndrome Research in Patients with Retinal Venous Occlusion

The antiphospholipid antibody syndrome (APAS) is a condition associated with abnormal thrombosis and the presence of anticardiolipin antibodies (aCL). Thirty-two patients (20 male and 12 female) aged between 29 and 75 years (mean +/- SD: 56.4 +/- 12.34) with retinal venous occlusive disease were studied. All patients with a history of venous occlusive disease within the previous 8 months were included in the study. Diagnoses were made by fundus examination and fundus fluorescein angiography (FFA). Anticardiolipin IgM and IgG antibodies, antinuclear antibodies (ANA), and IL-1beta were investigated in all patients. Neither aCL-IgM nor aCL-IgG was observed as positive in this group. Only four patients were found to be ANA positive. However, serum levels of IL-1beta were higher than those of controls (p <0.001). Mean IL-1beta was found to be 18.06 +/- 3.39 pg/mL (mean +/- SE), respectively. IL-1beta levels were found to be significantly different from those of controls (2.7 +/- 0.68 pg/mL) (p <0.001). In this study, antiphospholipid antibody positivity was not determined in any patients. As a result, IL-1beta level appears higher in retinal venous occlusive disease. This cytokine measurement might be used as a diagnostic indicator for venous occlusive disease.

Effect of the B cell superantigen protein A from S. aureus on the early lupus disease of (NZB×NZW) F 1 mice

The (NZB×NZW) F 1 mouse develops a spontaneous autoimmune disease process with striking similarities to human systemic lupus erythematosus (SLE). In female (NZB×NZW) F 1 mice, the production of IgG antinuclear antibodies, including antibodies to double-stranded DNA (dsDNA), is associated with the development of a severe immune complex-mediated glomerulonephritis that results in death from renal failure in virtually all animals by 12 months of age. Since B-1 and marginal zone (MZ) cells represent a potential source of pathogenic antibodies and because B cell superantigens have been demonstrated to reduce B-1 and MZ cells in vivo, we tested the effect of repeated injections of the superantigen protein A (SpA) from S. aureus on the disease of this lupus model. We found that weekly intraperitoneal injections of SpA delay the progression of serum anti-DNA IgG and reduce proteinuria early in young female (NZB×NZW) F 1 mice. This superantigen also induced a specific depression in the numbers of peritoneal B-1 cells, as compared to mice treated with a control protein. These results support the role of B-1 cells in the development of the autoimmune disease in this mouse model and suggest that B cell superantigens may be useful in the management of autoimmune conditions.

Use of a novel elution regimen reveals the dominance of polyreactive antinuclear autoantibodies in lupus kidneys.

The autoantibody specificities that dominate the deposits in lupus kidneys remain unclear. Reasoning that previously utilized elution buffers such as acidic glycine and ammonium thiocyanate may not have been maximally effective in eluting all Ig deposits from the kidneys, this study was conducted to experiment with a stronger dissociating agent, urea-glycine. Seven antinuclear antibody-positive, nephritic female (SWR x NZB)F(1) (SNF1) lupus mice were selected for the elution study. Deposited Ig was eluted from their kidneys using 3 different elution buffers: 0.15M glycine-HCl buffer, 1.3M ammonia thiocyanate/0.15M glycine-HCl buffer, and 5M urea/0.15M glycine-HCl buffer. All eluates were tested for specificity against a variety of nuclear and glomerular antigens. Compared with conventional elution buffers, the urea-based regimen eluted severalfold more IgG and IgM antinuclear antibodies from the kidneys of nephritic SNF1 lupus mice. IgG anti-double-stranded DNA (anti-dsDNA) antibodies were not only the most prevalent species in these renal deposits, they were also heavily enriched in the kidneys, relative to the corresponding serum levels. A substantial fraction of the anti-single-stranded DNA and antihistone/DNA (but not antihistone) reactivity in these eluates was due to cross-reactive anti-dsDNA antibodies. No reactivity with SSA, SSB, Sm, RNP, Jo-1, Scl-70, or ribosomal P antigens could be demonstrated in these eluates. Importantly, the urea-glycine eluates differed from the conventional eluates in having significantly greater reactivity to glomerular substrate and laminin. This novel urea-based elution provides further support for the dominance of antibodies in lupus kidneys, with strong polyreactivity to DNA and glomerular substrate.

Antibodies against neural, nuclear, cytoskeletal, and streptococcal epitopes in children and adults with Tourette’s syndrome, Sydenham’s chorea, and autoimmune disorders

Background: Some cases of Tourette’s syndrome (TS) are hypothesized to be caused by autoantibodies that develop in response to a preceding group A beta hemolytic streptococcal infection.Methods: To test this hypothesis, we looked for the presence ot total and IgG antibodies against neural, nuclear, cytoskeletal and streptococcal epitopes using indirect immunofluorescent assays and Western blot techniques in three patient groups: TS (n = 81), SC (n = 27), and a group of autoimmune disorders (n = 52) and in normal controls (n = 67). Subjects were ranked after titrations of autoantibodies from 0 to 227 according to their level of immunoreactivity.Results: TS patients had a significantly higher mean rank for total antineural and antinuclear antibodies, as well as antistreptolysin O titers. However, among children and adolescents, only the total antinuclear antibodies were increased in TS patients compared to age matched controls. Compared to SC patients, TS patients had a significantly lower mean rank for total and IgG class antineural antibodies, significantly lower IgG class anticytoskeletal antibodies, and a significantly higher rank for total antinuclear antibodies. Compared to a mixed group of autoimmune disorders, the TS patients had a significantly lower mean rank for total and IgG class antineural antibodies, total and IgG class antinuclear antibodies, IgG class anticytoskeletal antibodies, and a significantly higher rank for antistreptococcal antibodies.Conclusions: TS patients had significantly higher levels of total antineural and antinuclear antibodies than did controls. Their relation to IgG class antineural and antinuclear antibodies, markers for prior streptococcal infection, and other clinical characteristics, especially chronological age, was equivocal.

Self-limiting systemic autoimmune disease during reconstitution of T cell-deficient mice with syngeneic T cells: support for a multifaceted role of T cells in the maintenance of peripheral B cell tolerance.

The T cell compartment can be partially reconstituted in mice with targeted inactivation of the TCR C(beta) and C(delta) genes by injection of mature, syngeneic T cells. Surprisingly, during this reconstitution high titers of IgG anti-nuclear antibodies and symptoms of systemic autoimmune disease develop. However, this autoimmune response is transient and aged, reconstituted mice show no overt signs of disease. The autoantibody response appears to be derived from a pre-existing population of host self-reactive B cells and requires CD40 ligand-mediated co-stimulation from donor cells. Diminution of this response is coincident with a vigorous germinal center reaction and the disappearance of a subpopulation of activated B cells that expresses elevated levels of Fas. Collectively, our data support the idea that T cells play a multifaceted role in the maintenance of peripheral B cell tolerance that includes mediating the activation-induced death of autospecific B cells.

Human Parvovirus B19 Infection in Multiple Sclerosis

The association of human parvovirus B19 (PVB19) infection with the development of several systemic autoimmune diseases has been confirmed in other studies. To determine if there is any association of PVB19 infection with multiple sclerosis (MS), we studied the prevalence of serum anti-PVB19 IgG and IgM by an enzyme-linked immunosorbent assay and PVB19-specific DNA in the cerebrospinal fluid (CSF) by the polymerase chain reaction method in a total of 46 patients during exacerbation or remission of MS. Anti-PVB19 IgG was detected in 65.8% of the patients’ sera. The percentage was significantly higher than that in age-matched healthy control subjects (40%; p = 0.019), but was not higher in patients with other neurological diseases (50%; p = 0.16). There was no correlation between serum anti-PVB19 IgG status and antinuclear antibodies or oligoclonal IgG bands in CSF. Serum anti-PVB19 IgM and PVB19 DNA in CSF were consistently negative in the patients during exacerbation of MS. Although MS patients may be commonly infected with PVB19, our results suggest that there is no active PVB19 infection during exacerbation of MS.

Immunoglobulin isotype distribution of antinuclear antibodies in dogs with leishmaniasis

A modified indirect immunofluorescence method, using rat liver as substrate, was developed to determine the immunoglobulin isotypes forming antinuclear antibodies in sera from 12 antinuclear antibody-positive dogs out of 121 dogs with natural Leishmania infection. Immunoglobulin M was found to be the most frequent component of antinuclear antibodies (91·7 per cent), followed by IgG (41·7 per cent) and IgA (33·2 per cent). When these immunoglobulin isotypes were titrated, IgG antinuclear antibodies showed higher titres (1:200) than IgM and IgA antinuclear antibodies (1:50 and 1:20 respectively). Most of the antinuclear antibody-positive dogs simultaneously had two immunoglobulin isotypes, whereas none had all three immunoglobulin isotypes at the same time. Spearman rank correlation analysis showed no significant correlation between antinuclear antibody titres and circulating immune complexes or immunoglobulin levels. The low incidence of antinuclear antibodies and the absence of a clear relationship between isotype titres and clinical signs suggest a minor pathogenic role of antinuclear antibodies in canine leishmaniasis.

Assessment of enzyme linked immunosorbent assay based diagnostic kits (Toxokit-G and Toxokit-M) for the detection of IgG and IgM antibodies to Toxoplasma gondii in human serum

An enzyme linked immunosorbent assay (ELISA) using penicillinase was developed in the form of diagnostic kits (Toxokit-G and Toxokit-M) for the detection of IgG and IgM antibodies to Toxoplasma gondii. The performance of both the kits was compared with commercially available diagnostic kits, i.e. Enzygnost-Toxoplasmosis/IgG (Behring Co., Germany), TOXOTEK-G (Flow Lab., U.K.) and Toxoplasma IgM Microassay (Diamedix Corp., U.S.A.) by testing toxoplasma-suspected human serum samples. The results indicate a good reliability between these diagnostic kits. Toxokit-G has 86.66 and 96.05% sensitivity and specificity respectively. The main advantage of Toxokit-G is that the end result can be assessed visually without using sophisticated instruments. Toxokit-M has 100% sensitivity and specificity and test results were not affected by the presence of antitoxoplasma IgG antibodies, rheumatoid factor or antinuclear antibodies.

Anti-salivary antibodies in primary Sjögren's syndrome.

Earlier studies have described an antibody that recognized salivary ductal epithelium in sera from 15-50% of patients with primary Sjögren's syndrome; however, the specific salivary antigen in those studies was not identified. The present study further investigated this unknown salivary antigen. Twenty-nine of 31 patients (94%) with primary Sjögren's syndrome demonstrated IgG antinuclear antibodies that bound to an epithelial cell line with ductal characteristics derived from a human salivary gland. Seventy-seven percent of these patients had serum antibodies that bound to ductal cells of normal human parotid tissue after formalin fixation. Western blots of cell extracts, immunofluorescence, and adsorption studies indicated that SS-A/Ro and SS-B/La were the antigens recognized in the salivary cell line. The pattern of fluorescence seen when anti-SS-B/La bound to normal parotid tissue was identical to the fluorescence pattern of the anti-salivary ductal antibodies described in earlier literature.

Composition of immune deposits present in glomeruli of NZB/W F 1 mice

This paper describes the results of experiments designed to investigate the composition of immune complexes present, in the form of immune deposits, in glomeruli of NZB/NZW F1 mice. Granular deposits of mouse IgG were present along the glomerular capillary walls of 6- to 12-month-old mice. Disappearance of mouse IgG from glomerular deposits, indicating a dissociation of immune complexes, was observed following incubation of kidney sections with an excess of mouse IgG, mouse Fc fragments, rat IgG, and rat Fc fragments, but not with human and rabbit Cohn fraction-II (FII), DNA, nucleohistone, and PBS. Antinuclear antibody activity in mouse sera or in glomerular eluates was removed by absorption with mouse IgG or mouse Fc fragments, rat IgG or rat Fc fragments, DNA, and nucleo-histone, but not by absorption with human or rabbit FII. These results suggest that the IgG antinuclear antibodies present in the sera and in glomerular deposits possess rheumatoid factor (RF) activity. In other experiments, kidney sections were incubated with various concentrations of pepsin, which digests the Fc portion of the IgG. After digestion, the sections were washed and stained for mouse IgG, IgG F(ab')2, and IgG Fc. At concentration of 10 micrograms/ml, pepsin completely removed IgG and IgG Fc, whereas faint IgG F(ab')2 deposits persisted in glomerular deposits. At the concentration of 1 microgram/ml, deposits of mouse IgG, F(ab')2, and Fc persisted, while F(ab')2 was observed bound to nuclei of glomerular cells. At the pepsin concentration of 0.1 microgram/ml or 0.01 microgram/ml, IgG F(ab')2 was bound to the nuclei of glomerular and tubular cells, indicating that the digestion of the Fc portion of IgG had released F(ab')2 with nuclear reactivity from glomerular deposits. The solubilization of mouse IgG from glomerular immune deposits with mouse IgG and the demonstration that pepsin digestion releases mouse F(ab')2 with nuclear reactivity are consistent with the interpretation that the immune deposits present in glomeruli of NZB/NZW F1 mice contain complexes formed by antinuclear IgG and IgG RF. These two antibodies probably cross-react and form multilayer aggregates which contribute to the formation of immune deposits.

Relation between serological data at the time of biopsy and renal histology in lupus nephritis

As autoantibodies are thought to participate in the pathogenesis of renal inflammation in systemic lupus erythematosis (SLE) we investigated associations between serological markers of disease activity in SLE and the activity of renal histopathological lesions in thirty-five patients with lupus nephritis (LN). We found the following prevalence of serum auto-antibodies in LN: IgG antinuclear antibodies (ANA) 100%, IgM ANA 69%, IgA ANA 60%, IgG anti-dsDNA 60%, IgM anti-dsDNA 71%, IgA anti-dsDNA 60%, anti-RNP 20%, anti-Sm 14%, anti-SSA 31%, anti-SSB 14%, anti-histone 37%, anti-cardiolipin 80% and antibody to ribosomal protein (anti-P) 6%. No correlation was found between serological parameters and the WHO-classification of biopsies. The activity-index of histological lesion, assessed according to the NIH-renal histology scoring system, correlated with IgM ANA and IgM anti-dsDNA titers. Of all the specific features of histological renal inflammation, glomerular proliferation showed the best overall correlation with serological parameters of disease activity. Anticardiolipin antibodies were correlated with overall disease activity, but not with renal histological activity. Thus, serological markers of disease activity did not adequately reflect the amount of renal inflammation in LN and cannot replace renal biopsy as a diagnostic tool.

Self-reactive T cells in murine lupus: Analysis of genetic contributions and development of self-tolerance

Our understanding of the immune mechanisms that lead to systemic lupus erythematosus has been greatly advanced by the availability of murine models which display both serological and clinical features of the human disease. Studies have demonstrated that CD4 + T cells are required for the full expression of disease in these mice. (NZB × NZF)F 1 mice exhibit a lupus-like disease (elevated levels of IgG antinuclear antibodies and a fatal glomerulonephritis) that is not characteristic of either parent. At least three gene loci have been identified in NZW mice that could potentially contribute to a T cell-dependent autoimmune disease, including the T cell receptor α- and β-chain gene complexes and the major histocompatibility complex (MHC). The NZW T cell receptor β-chain complex appeared to be particularly unusual in that the Cβ1, Dβ2, and Jβ2 gene segments have been deleted. However, an analysis of (NZB × NZW)F 1 × NZB backcross mice revealed no association of disease expression with the presence of this allele. There was also no correlation of disease incidence with the presence of the NZW T cell receptor α-chain allele. In contrast, nearly 90% of the backcross mice with the NZW MHC expressed severe autoimmune disease compared with 12% of the mice that did not carry this haplotype. Additional studies strongly suggested that the gene(s) within the NZW MHC is the only dominant NZW genetic contribution to F 1 disease. We also determined if self-reactive T cells are able to escape thymic tolerance in autoimmune New Zealand and MRL lpr lpr mice. In nonautoimmune mice expressing I-E, T cells utilizing Vβ17a and Vβ11 encoded domains have been shown to be clonally eliminated in the thymus. Similarly, Vβ8.1 + and Vβ6 + T cells are tolerized in nonautoimmune mice expressing Mls-1 a. These T cell subsets were quantitated in the lymph nodes and spleens of (NZB × NZW)F 1, (NZB × SWR)F 1, and MRL- lpr lpr mice before and after the development of lupus-like disease. The results indicate that peripheral T cells in these mice, including the massive CD4 −, CD8 − T cell population in lpr mice, have been modified by normal mechanisms of tolerance such that potential self-reactive Vβ specificities have been eliminated in the thymus.

Genetic analysis of the imperfect association of H-2 haplotype with lupus-like autoimmune disease.

Unlike parental New Zealand Black (NZB) or New Zealand White (NZW) mice, (NZB x NZW)F1 mice exhibit a lupus-like disease characterized by high serum levels of IgG anti-nuclear antibodies and a fatal immune complex glomerulonephritis. Previous results from studying [(NZB x NZW)F1 x NZB] backcross mice indicated that the NZW major histocompatibility complex (MHC) or gene(s) closely linked to this locus provides the major dominant NZW genetic contribution to the F1 disease. A surprising feature of the results was the 12% frequency of discordance between the autoimmune phenotype and the presence of the NZW H-2z haplotype. In the current study, we attempted to precisely define the position of the NZW gene(s) required for lupus-like renal disease by mapping genes in individual backcross mice that are both centromeric and telomeric to the MHC and then correlating genotypes for each locus with disease. The data indicate that an adjacent NZW locus does not provide a more accurate correlation with the autoimmune phenotype compared with MHC genes themselves. Thus, the imperfect association of MHC haplotype with disease in this murine model is not explained by genetic recombination with linked genes. These data may provide insight into the mechanisms by which MHC antigens increase the probability of developing autoimmune disease and may help explain the difficulty of defining MHC relationships in human systemic lupus erythematosus.

T cell tolerance to self antigens in New Zealand hybrid mice with lupus-like disease.

We determined if self-reactive T cells are able to escape thymic tolerance in autoimmune New Zealand mice. T cells utilizing V beta 17a and V beta 11 encoded receptors have been shown to be clonally eliminated in nonautoimmune mice expressing I-E because of their potential self-reactivity. Similarly, V beta 8.1+ and V beta 6+ T cells are tolerized in the thymus of nonautoimmune mice that express Mls-1a. These T cell subsets were quantitated in the lymph nodes and spleens of (NZB x NZW)F1 and (NZB x SWR)F1 mice. In young mice from both autoimmune strains, deletion was similar to that observed in control animals matched for I-Ed and Mls-1a expression. Furthermore, older female autoimmune mice with elevated levels of IgG antinuclear antibodies and severe lupus-like renal disease did not demonstrate evidence of a global tolerance defect. We also found that the levels of residual V beta 17a+ cells in MHC-matched control F1 strains were further reduced by up to 80% in autoimmune (NZB x SWR)F1 mice. The greater in vivo elimination corresponded to an enhanced ability of NZB spleen cells, compared with other H-2d spleen cells, to stimulate V beta 17a+ hybridomas in vitro. The increased stimulation in culture could not be attributed to quantitative differences in I-E Ag expression. The results suggest that autoreactive T cells have been eliminated in these autoimmune mice by normal mechanisms of self-tolerance. Furthermore, the data demonstrate the existence of an NZB minor locus not present in other H-2d strains that influences T cell repertoire and enhances stimulation of T cells potentially reactive to self class II MHC Ag.