Brain reactivity of lymphocytotoxic antibodies in systemic lupus erythematosus with and without cerebral involvement.

A prospective clinical study of cold-reactive lymphocytotoxic antibodies in systemic lupus erythematosus has been completed. A highly significant association between serum lymphocytotoxicity and the development of cerebral manifestations was observed. While lymphocytotoxic antibodies from patients with cerebral lupus were absorbed by homogenates of human brain, those from patients who at no time had evidence of cerebral disease failed to cross-react with brain. It is suggested that subpopulations of lymphocytotoxic antibodies differ in their brain reactivity, and that one population may be causally related to the development of some of the features of cerebral lupus.     

Regulatory T cells in systemic lupus erythematosus

Systemic lupus erythematosus (SLE), an autoimmune disease, develops when immunologic self‐tolerance fails. Treg cells are a subset of CD4⁺ T cells that maintain self‐tolerance by suppressing autoreactive lymphocytes. Defects in Treg cells are therefore considered to be an aspect of SLE pathogenesis. Nevertheless, reports on the numbers and function of Treg cells in SLE are contradictory and the definitive role of Treg cells in SLE remains unclear. In this review, we summarize findings from murine models and ex vivo experiments, which provide insights into the mechanisms that result in the breakdown of tolerance. We also include recent findings about Treg‐cell subsets and their markers in human SLE. The identification of unique markers to identify bona fide Treg cells, as well as therapies to reconstitute the balance between Treg cells and autoreactive T cells in SLE, are the future challenges for SLE research.     

T cells in the pathogenesis of systemic lupus erythematosus

Recent studies in patients with systemic lupus erythematosus (SLE) have demonstrated that autoantigen-reactive T cells can be isolated from peripheral blood and that such cells can support autoantibody production ex vivo, suggesting that they may have a central role in the pathogenesis of disease. In addition, recent work has identified and characterized signaling abnormalities in T cells from SLE that may be fundamental to the disease. This review will examine the role of T cells in the pathogenesis of SLE and it will consider pathogenic mechanisms by which T cells escape normal of immunological tolerance. The focus will be on recent studies characterizing autoantigen-reactive human T cells and signaling abnormalities identified in T cells from patients with SLE.     

Defective generation of alloreactive cytotoxic T lymphocytes (CTL) in human monoclonal gammopathies.

The generation of cytotoxic T lymphocytes (CTL) towards allogeneic cells was investigated in 19 patients with monoclonal gammopathy of undetermined significance (MGUS) and 31 patients with multiple myeloma (MM). This function was significantly decreased in all patients. The cytotoxic deficiency was more pronounced in MM with poor prognosis than MM with good prognosis and MGUS patients. A phenotypic analysis of PBT lymphocytes showed that poor prognosis MM also had the highest proportions of activated cells (HLA-DR+) in CD8+ subpopulations. CTL were generated after depletion of CD11+ lymphocytes (including suppressor cells) or after inhibition of suppressor function with deoxyguanosine. No increase of cytotoxicity was detected under these conditions. Exogenous supplementation of recombinant interleukin 2 (rIL-2) was also ineffective. These data indicate that MG PBT lymphocytes are unable to fully differentiate into CTL following allogeneic stimulation. This deficiency is most evident in MM patients already showing the poorest prognosis and the most altered T cell phenotype.     

Heterogeneous neurocytotoxic antibodies in systemic lupus erythematosus.

Sera from eighteen patients with systemic lupus erythematosus (SLE) were tested for cytotoxic antibody to three neuronal and two glial continuous cell lines of human origin. Eighty per cent (fifteen out of eighteen) of the sera were cytotoxic to at least one of the cell lines, but only seven sera were active against all five lines. Three sera had anti-neuronal but not anti-glial reactivity. No sera were gliocytotoxic without neurocytotoxicity. Three SLE sera with relatively strong cytotoxicity to all five cell lines were abosrbed with each of the cell lines separately and the absorbed sera were then tested for residual cytotoxicity to each of the cell lines. The absorptions uncovered at least six different antibody specificities directed at antigens expressed on some but not all of the neuronal and glial cell lines. Each patient's serum had its own profile of antibody specificities reactive with membrane antigens on nervous tissue-derived cells.     

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.     

SLE T细胞功能的改变

探讨Ｔ细胞免疫功能改变与系统性红斑狼疮（ＳＬＥ）的关系。方法 检测３８例ＳＬＥ患者淋巴细胞的Ｅ花环形成率（ＥＲＦ＿Ｒ）,ＰＨＡ刺激的ＰＢＭＣ活化反应（ＰＨＡ淋转反应）,治疗前后血清可溶性ＩＬ－２Ｒ（ＳＩＬ－２Ｒ）、ＩＬ－６及尿ＳＩＬ－２Ｒ、ＩＬ－６水平、抗ｄｓ－ＤＮＡ抗体,用疾病活动性评分（ＳＬＡＭ）判断疾病活动性,进行分析。结果 ＳＬＥ患者腺苷处理前ＥＲＦＲ显著低于正常,处理后ＥＲＦ－Ｒ则显著     

Antiendothelial cell antibodies (AECA) in systemic lupus erythematosus (SLE)

Conclusion There is now overwhelming evidence that AECAs exist and are commonly found in the sera of patients with SLE and other autoimmune connective tissue dieases. In many of these diseases, the antibodies mirror disease activity; in SLE, they are associated with clinical manifestations such as nephritis, vasculitis, and thrombosis. The main challenges for the future include the practical aspects of standardizing a technique for measuring AECAs and assessing the potential role for these antibodies in pathogenicity.     

Regulatory T cells in patients with systemic lupus erythematosus

Regulatory T cells have an important role in the control of self-reactivity, and in the pathogenesis of autoimmune inflammatory conditions. The aim of this work was to perform a quantitative and functional analysis of regulatory T cells in patients with systemic lupus erythematosus (SLE). We studied twenty-three patients with SLE (19 active, 4 inactive), and twenty-seven healthy subjects as well as fifteen patients with rheumatoid arthritis (RA). The following cell subsets were analyzed in peripheral blood mononuclear cells by flow cytometry: CD4+CD25+, CD4+CD25(bright), CD4+Foxp3+ (Treg cells), CD8+CD28- (Ts cells), CD4+IL-10+ (Tr1 cells), and CD4+TGF-beta+ (Th3 cells). In addition, the in vitro suppressive activity of CD4+CD25+ lymphocytes was tested. We found no significant differences in the levels of all regulatory cell subsets studied in SLE patients compared to controls and RA patients. However, a defective regulatory function of CD4+CD25+T cells was observed in a significant fraction (31%) of patients with SLE. Our data indicate that although approximately one third of patients with SLE show an abnormal immunosuppressive function of Treg lymphocytes, their levels of the different regulatory T cell subsets in peripheral blood are not significantly different from those found in controls.     

HLA-DP-positive T cells in patients with systemic lupus erythematosus

HLA-DP+ T cells in peripheral blood from 23 patients with systemic lupus erythematosus (SLE) were examined using two-colour flow cytometry analysis. A marked increase of HLA-DP+ T cells was observed in patients with SLE (20.5-98.7%; 59.8 +/- 20.8%) in comparison to normal subjects (1.3-20.6%; 11.1 +/- 7.2%), and the ratio of these cells greatly exceeded that of the HLA-DR+ T cells (6.5-49.1%; 21.5 +/- 12.7%). This high frequency of HLA-DP+ T cells in patients with active SLE decreased with prednisolone therapy. When the lymphocytes from normal subjects were stimulated with PHA in vitro, HLA-DP+ T cells increased from 1.8 to 59.2%. Therefore, it appears that the HLA-DP antigen expression on T cells is a practical marker for monitoring changes in the proportion of activated T cells in patients with SLE during the course of therapy.     

Complement-dependent cytotoxic antibodies to human T lymphotropic virus type I (HTLV-I)-infected cells in the sera of HTLV-I-infected individuals

To investigate whether HTLV-I induces the development of complement-dependent cytotoxic antibodies in humans, sera of asymptomatic HTLV-I carriers and of patients suffering from tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM) or adult T cell leukaemia (ATL) were used in a cytotoxicity assay against a panel of target cells. This panel included uninfected cell lines (CEM, Jurkat, Molt and H9), cell lines chronically infected with HTLV-I (MT2, MT4, C91PL and HUT102), as well as lines H36 (H9 infected with HTLV-I), H9-IIIB (H9 infected with HIV_IIIB) and H9-MN (H9 infected with HIV_MN). HTLV-I⁺ sera induced lysis of H36 and of lines expressing HTLV-I antigens in the presence of rabbit complement, but did not lyse cells in presence of human complement. The HTLV-I⁺ sera also failed to lyse the HTLV-I⁻ lines and H9 cells, suggesting that lysis was specific for HTLV-I. H36 cell lysis was prevented by IgG depletion of the sera and by dialysis of rabbit complement against EGTA or EDTA. Rabbit complement-dependent cytotoxic antibodies were present in the sera of 14/14 HTLV-I-infected individuals; the highest titres were predominantly found in the sera of the TSP/HAM patients. Such antibodies were also detected in 5/5 individuals coinfected with HIV-1 and HTLV-I, although no cytotoxic antibody could be found against HIV-infected cells. Vice versa, sera of HIV-1-infected individuals did not exert a lytic effect in the presence of complement (of human or rabbit origin) against HIV-1- or HTLV-I-infected cells. Incubation of the sera of four HTLV-I-infected patients with HTLV-I env-specific synthetic peptides demonstrated that some of the complement-dependent cytotoxic antibodies recognized epitopes located on gp46 between amino acids 190 and 209. There is no correlation of rabbit complement-dependent cytotoxic HTLV-I antibodies with the development of disease.     

The significance of antibodies to poly(adenosine diphosphate-ribose) in systemic lupus erythematosus.

Poly(adenosine diphosphate-ribose) and ds-DNA binding activity have been measured in thirty-nine systemic lupus erythematosus (SLE) sera, nineteen rheumatoid arthritis sera, fourteen sera from non-SLE rheumatic and non-rheumatic diseases and in ten normal sera. Antibodies to poly(ADP-ribose) were found only in the SLE and in three SLE-like rheumatic diseases. Anti-DNA antibodies, on the other hand, were found not only in the SLE and SLE-like diseases, but also in rheumatoid arthritis and chronic active hepatitis. Estimation of poly(ADP-ribose) binding was, therefore, more specific for, and more discriminatory of SLE from other diseases, than the estimation of ds-DNA binding. The results indicate that the estimation of poly(ADP-ribose) binding in serum may be more useful in the diagnosis of SLE than the presently employed estimation of DNA binding using the Amersham kit. DNA-anti-DNA immune complexes are detected in some of the SLE sera after deoxyribonuclease I digestion, confirming earlier reports of the existence of circulating DNA-anti-DNA complexes in SLE patients. Snake venom phosphodiesterase treatment of some of the SLE sera also resulted in increased poly(ADP-ribose) binding activity, suggesting the existence of poly(ADP-ribose)-anti-poly(ADP-ribose) immune complexes in the circulation of SLE patients. This observation raises the possiblity that poly(ADP-ribose) immune complexes may play some part in the pathogenesis of some cases of SLE.     

CD8alpha+beta(low) effector T cells in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disorder characterized by the loss of self-tolerance to nuclear antigens. Aberrant T-cell function plays a central role in lupus pathogenesis. We and others previously demonstrated that peripheral TCRαβ⁺CD3⁺ T cells express CD8β either at a high (CD8β^high) or low density (CD8β^low), thereby defining two functionally distinct subsets. CD8β^low T cells express predominantly CD8αα and less CD8αβ as a coreceptor, display a differentiated phenotype and exert effector function. CD8β^high T cells appear to be the precursors expressing predominantly the heterodimeric efficient CD8αβ coreceptor, exhibiting a naïve phenotype and high proliferative capacity. In the present study, the distribution and functional properties of CD8β^high and CD8β^low T cells of SLE patients were compared ( n  = 20) with those of healthy subjects ( n  = 16). It was found that expansion of CD8β^low T-cell subset correlated with disease activity indicating chronic antigenic stimulation leading to a major lack of naïve CD8β^high precursor T cells in SLE. Functional characteristics of CD8β^low T cells including production of cytokines and cytotoxic granules were not significantly different between patients with SLE and healthy individuals. We speculate that unbalanced CD8β^high/CD8β^low T-cell relation reflects a skewed homeostasis within the CD8⁺ T-cell compartment towards fully differentiated effector T cells possibly due to persistent antigen stimulation in SLE.     

Opsonization by anti-dsDNA antibodies of apoptotic cells in systemic lupus erythematosus

In order to asses the role of the soluble mediators of serum from patients with SLE in the apoptotic cell clearance, we measured the in vitro phagocytosis of apoptotic Jurkat cells by normal healthy donor macrophages in the presence of SLE patients' sera. A significant increase of the phagocytic index (NHD = 1.0 +/- 0.3; SLE = 1.9 +/- 0.6; p < 0.01) was to be observed in the presence of serum from patients with SLE. The increased phagocytic index correlated to the anti-dsDNA antibodies titers. We conclude that anti-dsDNA antibodies present in sera of patients with SLE favor the apoptotic cell phagocytosis by opsonization of the target cells. This may represent a deviation of the clearance process towards inflammation and a new pathologic feature of these autoantibodies in SLE.     

Modulation of T3 antigen in systemic lupus erythematosus (SLE)

One of the first steps in the T cell activation is modulation of T3-Ti complex from the cell membrane. This process was studied in patients with SLE by immunofluorescence staining and measured in a cell sorter. The modulation of T3 antigen was impaired in a number of patients. The mitogen-induced proliferation was also decreased in these cases, but decreased blast transformation occurred also with efficient modulation. Pretreatment of normal T lymphocyte with sera from patients with decreased modulation caused only moderate inhibition of T3 antigen modulation. Modulation in vitro was not influenced by steroids.     

Specificity of anti-nucleoside antibodies in systemic lupus erythematosus

The titer of IgG antinucleoside antibodies in the sera of 162 individuals was determined by an enzyme-linked immunosorbent assay. The nucleosides used in the assay were adenosine, cytidine, guanosine, and thymine-riboside conjugated to human serum albumin. The specificity of IgG antinucleoside antibodies was indicated by appropriate reduction in antibody binding after solid-phase adsorptions of antibody with specific immobilized nucleoside conjugates. Disease-associated increases in serum IgG antibodies to cytidine and guanosine but not to adenosine or thymine-riboside occurred in patients with systemic lupus erythematosus (SLE). The epitope density of nucleosides in the conjugates and differences in the sensitivity of each nucleoside assay were not responsible for disease-associated IgG antinucleoside antibody responses. These findings support a possible pathogenic role for cytidine and guanosine as antigens or crossreactive antigenic determinants in some patients with SLE.     

Character of anti-DNA antibodies in systemic lupus erythematosus

Anti-DNA antibodies in twenty-one systemic lupus erythematosus (SLE) sera were analysed by precipitation in gel, complement fixation, and the Farr globulin precipitation technique. Fifteen sera precipitated in agarose with both native and denatured DNA (Group 1) and six precipitated solely with denatured DNA (Group 2). Prior incubation of the sera with RNA or DNA digest abolished the precipitin reactions of all Group 2 sera, but had no appreciable effect on the precipitin patterns of the Group 1 sera. Molecular class of anti-DNA antibodies did not correlate with precipitation pattern. The ability of sucrose density gradient fractions of serum to fix complement with denatured DNA at 4°C did not correspond with the presence of precipitating antibodies against denatured DNA.The Farr globulin binding assay probably allowed detection of all anti-DNA antibodies, and each of the sera bound most of the [¹⁴C]DNA. No binding was observed when ¹⁴C-labelled nucleotides were substituted for the [¹⁴C]DNA. Both native and denatured unlabelled DNA were able to significantly inhibit binding by all sera tested (Groups 1 and 2), while RNA and DNA digest gave minimal inhibition. Three types of antigenic sites on the DNA molecule are postulated. It is suggested that all anti-DNA sera, regardless of their behaviour in precipitin or complement fixation tests, contain antibodies reactive with all three determinants on the DNA molecule.     

Mitochondrial dysfunction in T cells of patients with systemic lupus erythematosus

Activation, proliferation, or programmed cell death of T lymphocytes are dependent on controlled reactive oxygen intermediates (ROI) production and ATP synthesis in mitochondria. The mitochondrial transmembrane potential (Delta Psi(m)) also plays a decisive role in cell survival by controlling activity of redox-sensitive caspases. T lymphocytes of patients with systemic lupus erythematosus (SLE) exhibit mitochondrial hyperpolarization, increased ROI production, diminished intracellular glutathione levels, cytoplasmic alkalinization, and ATP depletion that mediate enhanced spontaneous and diminished activation-induced apoptosis and sensitize lupus T cells to necrosis. These redox and metabolic checkpoints represent novel targets for pharmacological intervention in SLE.