Characterization of anti-endothelial cell antibodies in systemic lupus erythematosus (SLE).

IgG anti-endothelial antibodies (AEA), as measured by ELISA or immunoblotting technique could be detected in serum samples of 56 out of 64 patients with SLE (88%) and mainly occurred in monomeric form. AEA were not cell specific, because the binding reactivity was absorbed partially by both fibroblasts and peripheral blood mononuclear cells. No correlation was found between the presence of AEA and anti-nuclear antibodies. Immunoblotting revealed reactivity of AEA against endothelial antigens ranging in size from 15 to 200 kD. AEA titres were significantly higher in patients with joint or skin abnormalities, compared with patients without these abnormalities. A significant correlation was found between nephritis in SLE and the presence of AEA reactivity against endothelial membrane antigens of 38, 41 and 150 kD. These data show that the pattern of AEA reactivity in serum of SLE patients is heterogeneous, and suggest that AEA against a limited number of antigens may be involved in the pathogenesis of nephritis in SLE.     

Amelioration of experimental systemic lupus erythematosus (SLE) by retrovirus infection

Experimental SLE can be induced in susceptible 129/J mice by immunization with a human anti-DNA antibody bearing a common idiotype designated 16/6 Id. Immunized mice develop autoantibodies, leukopenia, proteinuria, and immune complex deposits in renal glomeruli. Case reports have described clinical improvement in SLE in individuals becoming infected with HIV-1. Because 129/J mice are susceptible to experimental SLE and to infection with the BM5def murine leukemia virus (MuLV) mixture but do not develop the lymphoproliferative/immunodeficiency disorder known as murine AIDS (MAIDS), we superimposed this infection on immunization with the 16/6 Id. Multiple effects were observed. First, we noted an amelioration in the course of experimental SLE. Second, both in experimental SLE and in BM5def MuLV infection, immunoreactivity to HIV-1 gp120 was demonstrated, although gp120 is not present in the BM5def MuLV viruses. Third, production of autoantibodies characteristically found in SLE, e.g., anti-DNA, anti-RNP, and anti-SSA, was seen in BM5def MuLV-infected mice, demonstrating that an immune response as a consequence of infection had occurred despite the absence of MAIDS induction. We conclude that (1) retrovirus inoculation may ameliorate the course of experimental SLE; and (2) retrovirus inoculation, even in the absence of MAIDS induction, induces an immunologic response which promotes the production of potentially pathogenic autoantibodies.     

Loss of suppressor T-lymphocyte function in patients with systemic lupus erythematosus (SLE).

Immunological reactivity in patients with SLE was studied in vitro trinitrobenzene sulphonate (TNP) specific antibody formation by peripheral blood lymphocytes. Lymphocytes from patients with SLE could produce an increased number of TNP-specific plaque-forming cells (PFC), while no such response could be seen in normal controls. Co-culture of lymphocytes from active SLE patients and normal controls was performed with TNP-Horse red blood cells (TNP-HRBC). The number of PFC by B lymphocytes from active SLE patients was suppressed by T lymphocytes from normal controls. On the other hand, the number of PFC by B lymphocytes from normal controls was increased by T lymphocytes from active SLE patients. Co-culture of lymphocytes from identical twins discordant for SLE was also performed, and the same results were obtained. We further examined the effects of Con A on antibody formation. Con A-treated T lymphocytes from a normal control markedly suppressed TNP-specific PFC by peripheral lymphocytes from active SLE patients. However, Con A-treated T lymphocytes from an active SLE patient did not suppress TNP-specific PFC by lymphocytes from another active SLE patient. These results suggest that active SLE patients showed a loss of suppressor T-lymphocyte function.     

C1 inhibitor functional deficiency in systemic lupus erythematosus (SLE).

C1 inhibitor (C1-inh) was assayed in eight SLE patients presenting with consistently low levels of intact C4. C1-inh antigenic levels were normal in all patients; however, the function of the C1-inh tested against C1s and C1r was variable and outside the normal functional range in seven of the eight patients. The molecular weight of patients' C1-inh protein was 105 kD, corresponding to the size of the intact molecule. The C1-inh gene was analysed in all patients. Restriction fragments generated with TaqI, PstI and HgiAI gave no indication of a major C1-inh gene rearrangement. Direct genomic sequencing of exon VIII revealed three polymorphic point mutations, but there were no changes from the normal gene in or around the reactive-centre residue of C1-inh. Furthermore, we found no evidence for a C1-inh autoantibody in patients which could affect normal C1-inh function in vitro. These results indicate that the etiology of C1-inh dysfunction in SLE is heterogeneous and distinct from that reported in either hereditary or acquired angioedema.     

Complete functional C1q deficiency associated with systemic lupus erythematosus (SLE).

A complete functional deficiency of C1q is described in a patient suffering from SLE. From reduced plasma C1 activity of the parents a hereditary trait was assumed. The defective C1q molecule was haemolytically inactive, did not bind to immune complexes, and was not recognized by the monocyte C1q receptor. C1 activity in the patient's serum could be restored by the addition of purified C1q. Analysis by gel-filtration and ultracentrifugation experiments revealed an immunoreactive molecule of about 150 kD mol. wt, corresponding to one structural subunit of the C1q macromolecule, containing two A chain-B chain dimers and a C-C chain dimer. Applying Southern blot analysis with cDNA clones encoding for the three individual chains of the C1q molecule, no restriction fragment length polymorphism was detected, ruling out possible major alterations of the genetic information.     

Innate immune mechanisms in the pathogenesis of systemic lupus erythematosus (SLE).

Immune imbalance in SLE increases the susceptibility to infectious diseases. The aim of this study was to analyze several mechanisms related to non-specific immunity in this autoimmune disorder. We studied in vivo CD11b expression, phagocytosis, and chemotaxis in polymorphonuclear cells (PMN) from SLE patients. All tests were also performed under hrIL-8 stimulating conditions and analyzed by flow cytometry. Intracellular leucocyte (monocytes and PMN) enzyme activity was evaluated using specific substrates for cathepsin B and D, collagenase, and oxidative burst by flow cytoenzymology. An exaggerated in vivo CD11b expression was observed on PMN from SLE patients without noticeably in vitro effect upon hrIL-8. Similarly both, phagocytosis and chemotaxis were diminished and showed no response to hrIL-8 stimulation. The opposite was found in PMN from controls. Intracellular enzyme activity was comparable between groups as far as cathepsin B and D are concerned. A tendency of decreased oxidative-burst induction was noted in monocytes and PMN from SLE patients, whereas collagenase activity was found clearly increased in both leucocyte subpopulations. Our results may represent a deficient ability of the innate immune mechanisms for the clearance of infectious agents, immune complexes, satisfactory resolution of inflammatory processes and tissue repair in SLE.     

Suppression of haematopoiesis by IgG autoantibodies from patients with systemic lupus erythematosus (SLE).

The inhibiting activity of serum on haematopoiesis has been described in patients with SLE. To explore further the features of serum inhibitor, we first examined the suppression of granulocytic and erythroid colony formation in vitro by serum from patients with SLE using methylcellulose culture. The potent inhibiting activity was demonstrated in six of 20 patients. All of these six patients were associated with leukocytopenia and/or anaemia. Five of 10 sera from patients with active SLE suppressed the colony formation of both burst-forming units of erythrocyte (BFU-E) and colony-forming units of granulocyte/macrophage (CFU-GM), and one serum suppressed BFU-E only. IgG fraction isolated from sera with inhibiting activity suppressed colony formation without complement involvement. The elimination of monocytes and lymphocytes from target mononuclear cells did not affect the suppression by the IgG fractions. The suppressive effect was completely eliminated after incubation of the IgG fractions with progenitor-enriched mononuclear cells. Flow cytometric analysis showed these IgG bound to CD34+ haematopoietic progenitor cells, but not to CD33+ cells. These data suggest that (i) the inhibitor of colony formation in serum was observed in IgG fraction; (ii) its suppressive effect on colony formation was mediated by neither monocytes and lymphocytes nor complements; and (iii) IgG fraction could bind to primitive haematopoietic progenitor cells and suppress the growth of these cells. Thus, IgG autoantibodies to primitive haematopoietic progenitor cells are demonstrated to be present in the sera of a significant proportion of active SLE patients with anaemia and leukocytopenia and to suppress the progenitor cell growth.     

Clearance deficiency and systemic lupus erythematosus (SLE)

Systemic lupus erythematosus (SLE) is a fairly heterogeneous autoimmune disease. Impaired clearance functions for dying cells may explain accumulation of nuclear autoantigens in various tissues of SLE patients. Our data show that in a subgroup of patients with SLE, apoptotic cells accumulated in the germinal centres of the lymph nodes. Apoptotic material was attached to the surfaces of follicular dendritic cells. Furthermore, we found an accumulation of apoptotic cells in the skin of patients with cutaneous lupus after UV exposure. Granulocytes and monocytes in whole blood of SLE patients showed a reduced uptake of albumin- and polyglobin-coated beads. Furthermore, we analysed sera from SLE patients in migration assays and observed that the attraction signals for macrophages were reduced by sera of approximately 25% of the SLE patients. Analyses of high-affinity DNA binding IgG autoantibodies of SLE patients revealed that those antibodies had gained their DNA reactivity in a germinal centre reaction. We suggest a stepwise maturation from a non-anti-DNA reactive B cell to an anti-dsDNA autoreactive B cell. We conclude that impaired clearance in early phases of apoptosis leads to a secondary necrotic status of the cells. Danger signals are released; modified autoantigens are accessible, favouring an autoimmune reaction.     

Precursor frequencies for DNA-specific B lymphocytes in patients with systemic lupus erythematosus (SLE).

Precursor frequencies for anti-DNA-secreting B cells were estimated in six healthy donors and 18 SLE patients with active and inactive disease. Precursors for IgG anti-dsDNA-secreting B cells were exclusively detected in SLE patients (73% of active patients and one inactive patient, 0.01-0.99% of IgG-producing B cells). These frequencies were in the same order of magnitude as frequencies of precursors for IgG anti-tetanus toxoid, which were detectable in three healthy volunteers after booster vaccination (0.07-0.8% of IgG-producing B cells), but not before (< 0.01%). Precursors for IgG anti-ss-DNA secreting B cells were observed in 33% of healthy donors and in 78% of SLE patients (0.01-0.32% of IgG-producing B cells). Only patient-derived IgG anti-DNA clones cross-reacted with (33%) or were monoreactive to dsDNA (12%). Precursors for IgM anti-DNA-secreting B cells were observed in healthy donors and SLE patients in comparable frequencies and with similar reactivities with ssDNA and dsDNA. Segregation analyses and sorting experiments showed that > 94% of clones secreting IgG anti-DNA were derived from in vivo sIgG+ B cells. sIgM+ B cells were induced to switch in vitro; however, only twice were cultures containing IgM and IgG anti-DNA antibodies observed under clonal conditions. In conclusion, our results indicate that precursor B cells for IgG anti-dsDNA in SLE patients are similarly selected and expanded as are precursor B cells specific for foreign antigens such as tetanus toxoid.     

Combined total deficiency of C7 and C4B with systemic lupus erythematosus (SLE).

The first inherited combined total deficiency of C7 and C4B complement components associated with SLE is described in a young female. Functional C7 assays showed a homozygous C7 deficiency in the propositus and her sister, and an heterozygous one in their parents. C4 molecular analyses showed that both the propositus and her mother had two HLA haplotypes carrying only C4A-specific DNA sequences and a normal C4 gene number. Thus, only C4A proteins could be expressed, with resultant normal C4 serum levels. The coexistence of a combined complete C7 and C4B deficiency may therefore abrogate essential functions of the complement cascade presumably related to immune complex handling and solubilization despite an excess of circulating C4A. These findings challenge the putative pathophysiological roles of C4A and C4B and stress the need to perform both functional assays and C4 allotyping in patients with autoimmune pathology and low haemolytic activity without low serum levels of a classical pathway complement component.     

Antigranulocyte antibodies in patients with systemic lupus erythematosus (SLE)

Antigranulocyte antibodies were studied in patients with systemic lupus erythematosus. The frequency and type of the antibodies were identified with ELISA (Enzyme-Linked Immunosorbent Assay) and MGCT (microgranulocytotoxicity test). To check antibody specificity, a LCT (lymphocytotoxicity test) was used parallel with the above technique. The ELISA proved to be suitable for determining antigranulocyte antibodies. There was a correlation between the serum level of IgG-type antigranulocyte antibodies and granulocytopenia, but the IgM-type antigranulocyte antibodies failed to show a similar correlation. A good parallelism was found between MGCT--a test to be used to determine IgM-type antibodies--and the IgM-type antigranulocyte antibodies determined by ELISA. Of 25 SLE sera, 13 were found positive for antigranulocyte antibodies. LCT was used to examine the presence of HLA antibodies in these sera and 39% of the sera positive for antigranulocyte antibodies appeared to be granulocyte-specific while 61% reacted in the LCT, too.     

Bronchoalveolar lavage cell analysis and lung function impairment in patients with systemic lupus erythematosus (SLE).

We examined the relationship between peripheral blood and bronchoalveolar lavage (BAL) lymphocyte phenotypes and lung function in 19 patients with SLE, and evaluated their association with disease activity. Lung function assessment showed a mildly restrictive pattern with frequent impairment of transfer factor for carbon monoxide (T1,co) and diffusing capacity of the alveolocapillary membrane (Dm), of late-expiratory airflow rates and with a high prevalence of increased airway resistance. T1,co, Kco and Dm correlated inversely with the numbers of CD8+ cells and CD56+/CD16+/CD3- (NK) cells in BAL. Oxygen radical production, both by stimulated and unstimulated BAL cells and blood polymorphonuclear leucocytes (PMN) was significantly increased in SLE. In comparison with healthy controls, patients with SLE had a lower percentage of CD19+ B cells in the BAL versus an increased percentage of these cells in peripheral blood. HLA-DR expression on CD4+ and CD8+ lung lymphocytes was markedly increased in SLE. Current SLE disease activity was not associated with changes in BAL or peripheral blood lymphocyte phenotypes. Our data suggest that an ongoing cell-mediated immune response is present in the lungs in SLE, particularly involving activated CD8+ T cells and CD56+/CD16+/CD3- NK cells. It is associated with up-regulated local production of oxygen radicals and with impaired pulmonary diffusing capacity. This inflammatory process seems to be independent of general SLE disease activity.     

Induction of experimental systemic lupus erythematosus (SLE) in mice with severe combined immunodeficiency (SCID).

A model in which experimental SLE is induced in normal mice by the injection of a human anti-DNA MoAb expressing a common idiotype 16/6 Id has been established in our laboratory. In the present study we have attempted the induction of experimental SLE in mice with SCID by the transfer of lymphocytes obtained from mice with experimental SLE. Disease could not be induced by direct immunization of SCID mice with the 16/6 Id nor by transfusion of normal splenocytes and immunization with the 16/6 Id thereafter. In contrast, disease was induced in SCID mice which were transplanted with splenic lymphocytes obtained from SLE afflicted BALB/c mice. The disease was expressed by the presence of high titres of antibodies and glomerular immune complex deposits were present in the kidney sections of these mice. Mice that received spleen cells from donors with experimental SLE together with the 16/6 Id developed higher titres of autoantibodies and had, in addition to the immune complex deposits, glomerular histological pathology. The model of experimental SLE induction in SCID mice should help in the elucidation of the role of different cell types in the pathogenesis of SLE.     

A study of immune responses to myelin and cardiolipin in patients with systemic lupus erythematosus (SLE).

Sera from 39 patients with SLE, 20 patients with cerebrovascular disease with no evidence of SLE, and 20 normal controls were tested for antibodies to cardiolipin (CL), brain total upper (UPG) and lower phase (LPG) glycolipids, myelin basic protein (MBP), myelin, and single strand DNA (ssDNA) by ELISA. Binding to the glycolipids and MBP was negative or negligible in all the groups, but significant binding was observed against CL, myelin and ssDNA in some of the SLE patients. Many sera from SLE patients with cerebral disorders and high CL binding also demonstrated high binding to myelin. These sera also labelled cell surface antigens on neonatal mouse neurons and astrocytes by immunofluorescence in tissue culture. A correlation was found to exist between anti-CL and antimyelin antibodies in SLE patients with cerebral lesions, but not between anti-ssDNA and anti-CL antibodies. As much as 80-90% of the specific activity of these antibodies could be absorbed out by the relevant antigens but only partially by the other antigens. In the control groups binding was low and no specific absorption could be demonstrated.     

Graves' disease complicated with systemic lupus erythematosus (SLE): a case report

A 25 year old man had been subjected to subtotal thyroidectomy under the diagnosis of Graves' disease. About a year later the patient developed systemic lupus erythematosus (SLE). Reports on cases of Graves' disease complicated with SLE have barely been observed so far. Consequently, the authors reckoned, with reference to the other literatures on the subject, our case worth reporting.     

Vascular lesions in systemic lupus erythematosus (SLE) with pulmonary hypertension

An autopsy case with SLE suffering from Raynaud's phenomenon and pulmonary hypertension was reported. Histological examinations revealed systemically marked fibrous intimal thickening of arteries and arterioles with or without thrombus throughout the whole body, especially of the pulmonary arteries and arterioles. Pulmonary arterial changes in the present case were compared with those in 52 autopsied cases with SLE without pulmonary hypertension, but there were no cases with such marked arterial changes as the present case. In addition, the incidence of pulmonary thrombosis was significantly higher in the cases with Raynaud's phenomenon than the cases without this phenomenon. However, the relation between pulmonary hypertension and Raynaud's phenomenon, pulmonary thrombosis, fibrous pericarditis, or type of lupus nephritis in SLE could not be clarified with a significant difference.     

C-myc gene binding factors in peripheral blood mononuclear cells from patients with systemic lupus erythematosus (SLE).

We characterized the nuclear proteins with specific binding ability against c-myc gene by gel-shift assay in cell extracts of peripheral blood mononuclear cells (PBMC) from SLE patients and SLE-prone mice with use of distinct c-myc fragments. With the fragment named Fmyc in our experiments, two kinds of complexes which we call C1 and C2 respectively were found in PBMC from SLE patients and SLE-prone mice. The C1 was shown to be inducible in PBMC from healthy persons without nascent protein synthesis after lectin binding to the cell and found to be elevated in the SLE patients and in all of the established cell lines we examined. The C2 seemed to be peculiar to SLE subjects. The binding site of the C1 factor (C1F) and C2 factor (C2F) which forms C1 and C2 respectively with Fmyc appeared to be common and were found to reside at 51 kbp sequence (from XhoI to Sau3A) of exon I of c-myc gene. Interestingly, XhoI site of the binding site was highly demethylated in PBMC of SLE patients as compared with healthy persons. The roles of these binding factors for the pathogenesis of SLE are discussed.