Antibody against chromatin assembly factor-1 is a novel autoantibody specifically recognized in systemic lupus erythematosus.

Autoantibodies to proliferating cell nuclear antigen (PCNA) are specifically, if rarely, present in systemic lupus erythematosus (SLE) patient sera. Even SLE patients lacking PCNA reactivity often show reaction to PCNA-binding protein. Here, immunoreactivity to chromatin assembly factor-1 (CAF-1), an essential molecule for DNA replication and a PCNA-binding protein, was compared for the sera of SLE patients, normal healthy controls (NHCs) and other disease controls, and in autoimmune sera reactive to standard autoantigens, by enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence, and immunoblotting. CAF1 and IRF1 expression in SLE and NHC peripheral mononuclear cells were compared by quantitative real-time polymerase chain reaction. Serum interferon-γ-inducing protein-10 and anti-double-stranded (ds)DNA antibody levels were measured by ELISA. Increased CAF-1 autoimmune reactivity was recognized in SLE or serum anti-dsDNA antibody-positive patients. Significantly greater central nervous system (CNS) involvement (aseptic meningitis) and serum anti-dsDNA antibody titers were present more often in anti-CAF-1 antibody-positive than antibody-negative SLE patients. IFN-γ positively regulated CAF-1 expression in vitro and was associated with anti-CAF-1 antibody production in SLE. Thus, a novel anti-CAF-1 autoantibody is frequently found in patients with SLE and is a useful biomarker for diagnosis, especially in cases with CNS involvement. Aberrant IFN-γ regulation appears to play an important role in anti-CAF-1 antibody production in SLE.

Possible role of the JAK/STAT pathways in the regulation of T cell-interferon related genes in systemic lupus erythematosus.

Changes in gene expression in CD3+ T cells associated with disease progression in systemic lupus erythematosus (SLE) patients were determined. The genes related to SLE disease-related activities were identified and their gene regulatory networks were investigated. Analyses of gene expression were performed by both DNA microarray and real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). The expression of certain genes including interferon (IFN) regulatory factor (IRF)-related genes, such as IFN-regulated, -related, and -signature genes was increased in the active phase of SLE. Pathway network analyses suggested that these IRF-related genes are regulated through the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway. JAK/STAT pathway-mediated regulation of IRF-related genes may have an important role in the disease activity of SLE. Inhibitors of JAK/STAT cascade may be useful as therapeutic agents.

Changes in the gene expression of peripheral blood mononuclear cells during the menstrual cycle of females is associated with a gender bias in the incidence of systemic lupus erythematosus.

OBJECTIVE: The incidence of systemic lupus erythematosus (SLE) is far higher in females than in males and the onset and/or disease activity is influenced by pregnancy and the menstrual cycle. Sex hormones seem to influence the pathogenesis of SLE, therefore, changes in gene expression in peripheral blood mononuclear cells (PBMC) were examined during the menstrual cycle in females, under the comparison of gene expression of patients with SLE. METHODS: The detection and a quantitative analysis of the gene expression was performed by DNA microarray or real-time quantitative polymerase chain reaction (RQ-PCR) method. RESULTS: There were thirteen known genes which showed significant quantitative changes during the menstrual cycles of females, but not in males. Among these genes, statistical quantitative differences between normal controls and SLE patients were observed in six genes. CONCLUSION: Based on these findings, certain genes (such as the tumor necrosis factor receptor superfamily, member 14; TNFRSF14, and signal regulatory protein, gamma; SIRPG) appear to contribute to gender difference of SLE.

Protein biomarker analysis by mass spectrometry in patients with rheumatoid arthritis receiving anti-tumor necrosis factor-alpha antibody therapy.

OBJECTIVE: To investigate the mechanism of action of anti-tumor necrosis factor-alpha (TNF-alpha) antibody in patients with rheumatoid arthritis (RA), we analyzed serum or plasma proteins by mass spectrometry system. METHODS: Ten RA patients who received treatment with anti-TNF-alpha antibody were studied. Samples obtained before and after therapy were analyzed by a two-dimensional liquid chromatography tandem mass spectrometry (2D LC-MS/MS) system after pretreatment by a recently developed method to remove high molecular weight proteins. RESULTS: Using this system, certain proteins were identified after treatment with anti-TNF-alpha antibody, including proteins related to the TNF-alpha-mediated pathway for nuclear factor kappa B (NF-kappaB) activation and/or to the metabolism (including regeneration) of articular cartilage. CONCLUSION: Our mass spectrometry system appears to be useful for proteomic analysis. The efficacy of anti-TNF-alpha antibody therapy for RA may be related to various consequence of the inhibition of TNF-alpha activity.

DNA methylation: its contribution to systemic lupus erythematosus.

Recent studies on epigenetics, including the methylation of DNA and the enzymes regulating methylation, seem likely to contribute to understanding the pathogenesis of autoimmune diseases such as systemic lupus erythematosus (SLE). In fact, the relationship between DNA methylation and SLE has long been the subject of investigation. To obtain a deeper understanding of the role of DNA methylation in the onset of SLE, we reviewed the findings reported in the literature and our own data about DNA methylation and SLE. Various studies have indicated the possible importance of DNA methylation, especially hypomethylation, in the aetiology of SLE. Epigenetic studies may provide clues for elucidating the pathogenesis of SLE and for developing new strategies to treat this disease.

Detection of antibodies to a recombinant gag protein derived from human endogenous retrovirus clone 4-1 in autoimmune diseases.

To investigate whether human endogenous retroviruses (HERV) contribute to autoimmune diseases, we prepared a recombinant p30gag protein derived from clone 4-1 of the HERV family, using a baculovirus-vector system. This p30gag protein (CA41B) was approximately 30 kDa, as expected, and reacted with antibodies for p30gag purified from both murine and feline leukemia virus. This result suggested that the antigenic determinant for p30gag was well conserved in CA41B. Analysis of serum antibodies to p30gag in patients with autoimmune diseases was done by Western blotting. CA41B detected anti-p30gag antibodies in 48.3% of systemic lupus erythematosus (SLE) patients, 35.0% of Sjögren's syndrome (SS) patients, and 33.3% of mixed connective tissue disease (MCTD) patients, whereas no anti-p30gag antibodies were found in healthy subjects. This suggested that HERV p30gag or other retroviral p30gag proteins possessing the same antigenic determinant as CA41B may play a role in these diseases. Although detection of antibodies to HERV p30gag in autoimmune diseases is indirect evidence that HERV proteins are involved, this study showed that patients with autoimmune diseases have antibodies to HERV p30gag using a recombinant HERV protein rather than synthetic peptides based on HERV or retroviral proteins of other species.

Sequence analysis of human endogenous retrovirus clone 4-1 in systemic lupus erythematosus.

Human endogenous retroviruses (HERV) have emerged as a possible cause of systemic lupus erythematosus (SLE). We previously detected serum antibodies to the gag region of HERV clone 4-1 in patients with SLE, but not in normal volunteers. In the present study, we detected clone 4-1 messenger RNA (mRNA) in peripheral blood mononuclear cells (PBMC) from SLE patients and performed sequence analysis of the cDNA or genomic DNA from clone 4-1 in these patients. Clone 4-1 mRNA was detected in all of the SLE patients tested, although it was not found in normal controls. Sequence analysis of clone 4-1 in these SLE patients revealed inactivation of the stop codons in part of the gag region. In addition, a computer search of current sequence libraries revealed that the clone 4-1 gag genomic DNA from SLE patients was more highly homologous with the clone 4-1 sequence in chromosome 11 from normal individuals when compared with the sequence of clone 4-1 integrated in the other chromosomes. It is possible that transcription of clone 4-1 from chromosome 11 occurs in SLE, and that the stop codon inactivation contributes to the translation of clone 4-1 gag proteins in patients with this disease.

A possible pathogenic role of CD8+ T cells and their derived cytokine, IL-16, in SLE.

Current investigations into the role of CD8+ T cells and their derived cytokine, interleukin (IL)-16, in the induction of CD4+ T cell abnormalities in systemic lupus erythematosus (SLE) were reviewed and discussed on the basis of results mainly obtained in our laboratory.

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.

Allergic diseases in systemic lupus erythematosus: prevalence and immunological considerations.

We attempted to obtain a deeper understanding of the relationship between systemic lupus erythematosus (SLE) and allergic diseases through comparative studies. Accordingly, we reviewed the association of both disorders and compared their immunological features based on the literature and our own findings. Recent studies (including ours) have indicated that the risk of IgE-mediated and/or associated allergic diseases is not markedly increased in SLE patients despite their more allergic family history when compared with controls, in contrast with earlier studies. This may be related to a change of the environmental factors contributing to allergy. In addition, assessment of the immunological similarities and differences between SLE and various allergic diseases seems to be useful for understanding the relationship between them.

Possible role of DNA hypomethylation in the induction of SLE: relationship to the transcription of human endogenous retroviruses.

OBJECTIVE: We investigated the contribution of DNA methyltransferase activity to the transcription of human endogenous retroviruses (HERV), which have been reported to be a plausible causative agent for systemic lupus erythematosus (SLE). METHODS: The reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time quantitative-PCR (RQ-PCR) were used. RESULTS: Our results indicated that treatment with 5-aza-deoxycytidine (5-aza C), a demethylating agent, increased the transcription of messenger RNA (mRNA) for HERV clone 4-1 and decreased mRNA for DNA methyltransferase-1 (DNMT-1; methylation-regulating enzyme) in peripheral blood mononuclear cells (PBMC) from normal individuals. Also, transcription of DNMT-1 mRNA in PBMC from patients with SLE was lower than in cells from normal controls. CONCLUSION: DNA hypomethylation seems to play a significant role in the transcription of HERV clone 4-1 and may be related to the pathogenesis of SLE.

HIV infection and SLE: their pathogenic relationship.

Retroviruses have repeatedly been suggested as a possible trigger mechanism for systemic lupus erythematosus (SLE). We review the role of human immunodeficiency virus (HIV)-1 envelope glycoprotein (gp120) in the induction of immune dysregulation including autoimmunity in HIV-1 infection, and discuss the possible relationship between HIV and SLE in the retroviral etiology.

Systemic lupus erythematosus-like autoimmune abnormalities induced by bacterial infection.

Recent evidence has revealed that bacterial DNA can promote several of the autoimmune abnormalities observed in systemic lupus erythematosus (SLE), and a possible pathogenic role in the induction of SLE has been highlighted. We have recently encountered patients in whom bacterial infection (septicemia) triggered the production of several autoantibodies. This seems to be interesting with respect to the consideration of the relationship between SLE and bacterial infection.

Hemophagocytosis in autoimmune disease.

Reactive hemophagocytic syndrome (HPS) is known to be associated with various autoimmune diseases, as well as infection and/or malignancy. Here we review the features of autoimmune-associated HPS and describe the possible role of autoantibodies, especially antiphospholipid antibodies (aPL), in HPS based on data obtained from our own patients.

Cytomegalovirus infection in patients with systemic lupus erythematosus.

Cytomegalovirus (CMV) infection is known to induce several autoimmune abnormalities in mice that resemble those found in systemic lupus erythematosus (SLE). In addition, a potential role for CMV in the development and/or progression of SLE has been suggested. In order to further clarify this issue, we reviewed the relationship between SLE and CMV infection on the basis of the clinical and immunological features of cases reported in the literature and our own patients.

Lessons from similarities between SLE and HIV infection.

OBJECTIVE: We attempted to obtain deeper understanding of systemic lupus erythematosus (SLE) and human immunodeficiency virus (HIV) infection through comparative studies between both diseases. METHOD: For this purpose, we reviewed and discussed lessons from similarities in both diseases based on our own and reported findings in literatures. RESULT: Such comparative studies may contribute to the progress in understanding the clinical or pathogenetic features of these diseases. CONCLUSION: Further studies into the relationship between SLE and HIV infection may bring to light important clues to assist in the development of better treatments for each disease.

Changes of CD4/CD8 ratio and interleukin-16 in systemic lupus erythematosus.

The authors investigated changes in the ratio of CD4+ to CD8+ T cells (CD4/CD8 ratio) and T-cell activation, indicated by human leukocyte antigen (HLA)-DR expression, in patients with systemic lupus erythematosus (SLE) following treatment. An increase was observed in the CD4/CD8 ratio as well as a decrease in the expression of HLA-DR on T cells with the improvement of clinical manifestations on treatment with steroids or cyclosporine (CSA). In addition, steroid treatment suppressed whereas CSA treatment exerted no perceptible influence on the serum interleukin (IL)-16 level, concurrent with changes in T-cell phenotypes. This indicated that the mechanism of the change in the CD4/CD8 ratio differed depending on the drug, and CD8+ T cells could play an important role in reducing this ratio. The CD4/CD8 ratio and HLA-DR expression may be good indicators of therapeutic efficacy in some SLE patients.

Very low-dose cyclosporin treatment of steroid-resistant interstitial pneumonitis associated with Sjögren's syndrome.

Cyclosporin is known to be effective for both transplantation and a spectrum of immune-mediated diseases. Because this agent also causes severe adverse effects, especially nephrotoxicity, careful monitoring is required for the development of such reactions. Here we report the successful treatment with extremely low-dose cyclosporin (1 mg/kg/day) of a patient who had steroid-resistant interstitial pneumonitis and Sjögren's syndrome.

Low-dose cyclosporin for multiple colonic ulcers associated with mixed connective tissue disease.

This report describes a patient with multiple colonic ulcers and mixed connective tissue disease. The histological findings of the colonic lesions showed vasculitis with T-cell infiltration, and the peripheral T cells were frequently in the activated phase of the cell cycle. In this patient, low-dose cyclosporin treatment (2.5 mg/kg/day) inhibited the T-cell activation in the peripheral lymphocytes and was very effective in the gastrointestinal disorder, which might be related to T-cell activation. This case suggests the possibility that even low-dose cyclosporin can exert a great influence on peripheral T cells and directly inhibit T-cell activation, thereby improving symptoms related to T-cell activation.