Association of PHRF1-IRF7 region polymorphism with clinical manifestations of systemic lupus erythematosus in a Japanese population

Interferon regulatory factor 7 ( IRF7) has an essential role in the production of type I interferon. Although recent studies detected association of a single nucleotide polymorphism (SNP) rs4963128 in PHD and ring finger domains 1 ( PHRF1) /KIAA1542, located closely to IRF7, and IRF7 rs1131665 (glutamine (Gln) 412 arginine (Arg)) with systemic lupus erythematosus (SLE), causal variants have not been established. In this study, we resequenced exons and introns of IRF7 to screen for all common polymorphisms, and examined whether they were associated with SLE in 416 Japanese patients with SLE and 505 healthy controls. We also tested whether the association of PHRF1 rs4963128 with SLE was replicated in a Japanese population. None of the IRF7 polymorphisms was associated with SLE. PHRF1 rs4963128T was not significantly associated with occurrence of SLE either; however, this allele was significantly increased in SLE with anti-Sm antibodies (6.8%) as compared with healthy controls (3.1%, P = 0.014, odds ratio [OR] 2.31) and SLE without anti-Sm antibodies (3.3%, P =0.041, OR 2.12). This allele was also increased in SLE with renal disorder (5.1%) as compared with those without renal disorder (2.4%, P = 0.047, OR 2.17). These results confirmed recently reported association of PHRF1 rs4963128T with anti-Sm antibody positive SLE in African-American populations, and supported the role of PHRF1-IRF7 region in the genetics of 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.

Hypocomplementemic urticarial vasculitis with Jaccoud’s arthropathy and valvular heart disease: case report and review of the literature

We describe a female Japanese patient with concomitant hypocomplementemic urticarial vasculitis, Jaccoud’s arthropathy and valvular heart disease. In 1996, she developed arthritis with swelling of both proximal interphalangeal joints and urticarial vasculitis on both arms that was resolved by administration of glucocorticoid (prednisolone 30 mg/day). Tests for antineutrophil cytoplasmic antibodies, antinuclear antibody and rheumatoid factor gave negative results. The findings of a skin biopsy examination were consistent with ‘leukocytoclastic vasculitis’. During 10 years of observation, the patient manifested polyarthritis leading to progressive deformity of the joints of the hands and feet (without loss of cartilage or erosion of bone), persistent urticaria exacerbated by cold and accompanied by hypocomplementemia and progressive cardiac valvular disease with mitral valve regurgitation. There are only three reports described previously documenting five patients with this rare combination of manifestations.

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.

Striking alteration of some populations of T/B cells in systemic lupus erythematosus: relationship to expression of CD62L or some chemokine receptors

Recent studies have revealed new populations of T/B cells, including central/effector memory, follicular T cells and CXCR3+ or CXCR4+ B cells. In the present study, changes in these populations of CD4+ T cells were examined on the basis of the expression of CD62L, CCR7 and CXCR5 in patients with systemic lupus erythematosus (SLE) in relation to CCL21 and CXCL10. Changes in CXCR3+, CXCR4+ and CXCR5+ B cells were also examined. CD62L and various chemokine receptors were examined by flow cytometry analysis using monoclonal antibodies, and CCL21 and CXCL10 were examined by sandwich enzyme-linked immunosorbent assay. In patients with SLE, a decrease of naive T cells and an increase in the ratio of activated effector memory T cells were associated with an increase of CCL21 and CXCL10 in serum, although the correlation was not significant. An increase in the ratio of CXCR3+ B cells was also recognized. These results suggest that naive T cells are transferred to lymphoid tissue by CCL21, and that effector memory T cells are activated by CXCL10. It is also suggested that B cells responsive to follicular helper T cells tend to migrate to inflammatory tissue.

Role of pathogenic auto-antibody production by Toll-like receptor 9 of B cells in active systemic lupus erythematosus

OBJECTIVES

Toll-like receptor 9 (TLR9) is a pattern-associated receptor functioning in innate immunity that may be involved in the recognition of self-antigens and the production of pathogenic auto-antibodies. Therefore, we examined the expression of TLR9 in systemic lupus erythematosus (SLE) to determine whether TLR9 is involved in the production of pathogenic auto-antibodies.

METHODS

B cells were collected from patients with active SLE, and subjected to analysis of the TLR9 molecule using flow cytometry fluorescence activated cell sorting (FACS) and TLR9 mRNA by reverse-transcriptase polymerase chain reaction. SLE B cells were stimulated with CpG-ODN, and subsequent cytokine and anti-dsDNA antibody production was measured by enzyme-linked immunosorbent assay.

RESULTS

The expression and mRNA level of TLR9 on B cells was up-regulated in SLE patients, and SLE disease activity index (SLEDAI) and CH50 were correlated with TLR9 expression on CD20+ B cells. Moreover, TLR9-CpG interaction enhanced the production of anti-dsDNA antibody and IL-10.

CONCLUSIONS

The present study demonstrated that higher expression of TLR9 on peripheral blood B cells from patients with active SLE was significantly correlated with CH50 and SLEDAI to TLR9, and induced the production of anti-dsDNA antibody and IL-10 by TLR9-CpG ligation. These results suggest that an abnormality of innate immunity plays a crucial role in the pathology of SLE, and that blockade of CpG-TLR9 interaction may be a new therapeutic approach for SLE.

Expression of B-cell activating factor of the tumour necrosis factor family (BAFF) in T cells in active systemic lupus erythematosus: the role of BAFF in T cell-dependent B cell pathogenic autoantibody production

OBJECTIVES

To determine whether B cell activating factor of the tumour necrosis factor family (BAFF) is involved in T cell-dependent B cell pathogenic autoantibody production in systemic lupus erythematosus (SLE).

METHODS

Peripheral blood mononuclear cells (PBMCs) from 23 SLE patients were analysed by flow cytometry to examine the intracellular expression of BAFF in CD4+ and CD8+ T cells and the surface expression of BAFF-receptor (R) and TACI on CD20+ B cells. Moreover, peripheral blood was used to determine the level of BAFF messenger RNA (mRNA) in CD4+ and CD8+ T cells and the level of BAFF-R mRNA in CD20+ B cells. Blocking of BAFF function with TACI-Ig measured anti-double-stranded DNA (dsDNA) antibodies by enzyme-linked immunosorbent assay (ELISA).

RESULTS

CD4+ and CD8+ T cells from patients with active SLE expressed intracellular BAFF whereas those from normal subjects did not. BAFF-R and TACI were expressed on B cells from both normal controls and patients with active SLE and there was no significant difference. CD4+ and CD8+ T cells from SLE patients expressed BAFF mRNA whereas those from normal controls did not. Expression of BAFF-R mRNA in CD20+ B cells showed no significant difference between SLE patients and normal controls. TACI-Ig suppressed spontaneous in vitro T cell-dependent B cell anti-dsDNA antibodies production on active SLE with kidney involvement.

CONCLUSIONS

BAFF may play a pathogenic role in SLE by stimulating T cell-dependent B cell autoantibodies production. Blockade of BAFF is a promising therapeutic approach for SLE especially in patients with kidney involvement.

Role of APRIL (TNFSF13) polymorphisms in the susceptibility to systemic lupus erythematosus in Japanese

OBJECTIVES

A polymorphism of APRIL, c.199G > A (Gly67Arg), has been reported to be associated with systemic lupus erythematosus (SLE) in Japanese. To identify the causative polymorphism, we screened for polymorphisms of APRIL as well as TWEAK (TNFSF12), a closely located gene that generates a fusion protein TWE-PRIL by intergenic splicing. Association of APRIL and TWEAK with rheumatoid arthritis (RA) was examined in parallel.

METHODS

Polymorphisms were screened by direct sequencing. Association was analysed by case-control analysis using 266 SLE, 298 RA and 208 healthy individuals. Allele-specific difference in the mRNA level was examined using RNA difference plot analysis. Serum APRIL level was measured by ELISA.

RESULTS

The protective effect of APRIL c.199A/A homozygotes in SLE was replicated (odds ratio 0.50, 95% confidence interval 0.30-0.83, P = 0.0073; pooled P = 0.0001, Pcorr = 0.007). In addition, association of c.287A > G (Asn96Ser, P = 0.0064, allele frequency) and c.*263C > T (3' untranslated region, P = 0.025, allele frequency) was detected. c.199G-c.287A (67Gly-96Asn) haplotype was found to confer risk for SLE, while c.199A-c.287G (67Arg-96Ser) was protective. Association of TWEAK was observed neither for SLE nor RA. APRIL mRNA was increased in SLE-associated c.*263T allele. In addition, serum APRIL was undetectable in all six healthy controls homozygous for the protective c.199A-c.287G haplotype (P = 0.015).

CONCLUSIONS

In addition to replicating the protective role of APRIL c.199A/A, two additional SNPs in APRIL were found to be associated with SLE. Presence of a protective haplotype and a risk haplotype was demonstrated. The mechanism of association was suggested to be altered expression at the protein and mRNA levels.

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.

The effect of methotrexate (MTX) on expression of signalling lymphocytic activation molecule (SLAM) in patients with rheumatoid arthritis (RA) and its role in the regulation of cytokine production

OBJECTIVE

To investigate the effect of methotrexate (MTX) on cytokine production by activated CD4+ T-cells in patients with rheumatoid arthritis (RA).

METHODS

The effect of MTX on intracellular expression of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4), and cell surface expression of signalling lymphocytic activation molecule (SLAM) from freshly isolated peripheral blood mononuclear cells (PBMCs), and after in vitro culture with or without MTX, was analysed with flow cytometry in 18 patients with RA and 20 healthy controls.

RESULTS

Intracellular expression of IFN-gamma and IL-4 on freshly isolated CD4+ T-cells was significantly higher in patients with RA than in the controls (p<0.05). Intracellular expression of both IFN-gamma and IL-4 after culture with MTX was significantly lower than those after culture without MTX in patients with RA. Although no significant difference was observed in SLAM expression on freshly isolated CD4+ T-cells between patients with RA and the controls, MTX significantly decreased SLAM expression on both activated IFN-gamma+ and IL-4+CD4+ T-cells in patients with RA.

CONCLUSION

In vitro modulation of the cytokine network by MTX, IFN-gamma, and IL-4 is one of the major targets for MTX, and production of IFN-gamma and IL-4 by PBMCs may be suppressed by SLAM on activated CD4+ T-cell in patients with RA.

Decreased CD161+CD8+ T cells in the peripheral blood of patients suffering from rheumatic diseases

OBJECTIVES

Although it has been reported that the numbers of both CD4(-)CD8(-) and CD4(+) natural killer T (NKT) cells are selectively decreased in the peripheral blood of patients with rheumatic diseases, there have been no reports concerning a novel subpopulation of CD8(+) NKT cells. To examine whether CD161(+)CD8(+) T cells, which are closely related to CD8(+) NKT cells, are also decreased in patients with rheumatic diseases, we have investigated the expression of CD161, together with that of CD28, CD25 and CD62L, on T cells in the peripheral blood of these patients.

METHODS

The rheumatic diseases evaluated in this study were systemic lupus erythematosus (SLE) (n= 54), mixed connective-tissue disease (MCTD) (n= 15), systemic sclerosis (SSc) (n= 14), polymyositis/dermatomyositis (PM/DM) (n= 13) and rheumatoid arthritis (RA) (n= 24). Healthy donors were examined as controls (n= 18). The expression of CD161, CD28, CD25 and CD62L on T cells was analysed by flow cytometry.

RESULTS

Both the frequency of CD161 expression on CD8(+) cells and the absolute number of CD161(+)CD8(+) cells were significantly decreased in patients with SLE, MCTD, SSc and PM/DM. Only the absolute number of CD161(+)CD8(+) T cells was significantly decreased in RA. CD161 expression on CD28(-)CD8(+) T cells was significantly decreased in SLE, MCTD and SSc. The absolute number of CD161(+)CD8(+)CD62L(-) T cells was significantly decreased in SLE, MCTD and SSc.

CONCLUSIONS

Both the frequency and the absolute number of CD161(+)CD8(+) T cells were decreased in the peripheral blood of patients suffering from SLE, MCTD, SSc and PM/DM. This result suggests that there is also an abnormality of NKT cells in the CD8(+) population.

Proviral status of HTLV-1 integrated into the host genomic DNA of adult T-cell leukemia cells

Human T-cell leukemia virus type-1 (HTLV-1) is the etiological agent of adult T-cell leukemia (ATL), and leukemic cells always carry the proviral genome monoclonally integrated into their host genomes at the same sequence site, designated as the monoclonal integration. Using Southern blot hybridization (SBH) and sequenced tagged site polymerase chain reaction assays, we examined the proviral status in 558 clinical specimens from 350 patients who are suspected to have ATL. A total of 321 specimens (57.5%) from 241 patients showed positive results for the monoclonal integration according to SBH, using EcoR1 and Pst1. The 241 patients consisted of 136 patients (56.4%) with the complete provirus (C-type), 62 patients (25.7%) with a defective provirus (D-type), and 43 patients (17.8%) with multibands (M-type). The incidence of the D- and M-types were in the order of smoldering, chronic, and acute subtypes of ATL, suggesting that such an aberrant proviral status is generated on the way to multistep carcinogenesis and is subsequently clinically important for the malignant behavior of the disease. Moreover, our data showed that the partial deletion of the proviral genome is initiated first at the site of the gag region and spreads into the sites of the pol and env regions, whereas the long terminal repeats and pX regions are almost always conserved. These results suggest that analysis of the proviral status provides useful diagnostic and virologic-oncological information about ATL and HTLV-1 pathology, especially the important role of pX gene in tumorigenesis.

Microbial hydrogen production from sweet potato starch residue

Clostridium butyricum could produce hydrogen from a sweet potato starch residue upon supplementation of nitrogen sources. A repeated batch culture using a mixed culture of C. butyricum and Enterobacter aerogenes produced hydrogen with a yield of 2.4 mol H2/mol glucose under a controlled culture pH of 5.25 in a medium consisting of the sweet potato starch residue and 0.1% Polypepton without addition of any reducing agents. Rhodobacter sp. M-19 produced hydrogen from the supernatant of the culture broth obtained in the repeated batch culture containing C. butyricum and E. aerogenes when 50 microg/l Na2MoO4.2H2O and 20 mg/l EDTA were added to the supernatant and it was cultured under a controlled culture pH of 7.5. A high yield of hydrogen of 7.0 mol H2/mol glucose from the starch remaining in the starch residue was attained in two-step repeated batch cultures containing C. butyricum and E. aerogenes, and by Rhodobacter sp. M-19.

Long term prognosis of children born to lupus patients

OBJECTIVE

To determine the long term prognosis of children of patients with systemic lupus erythematosus (SLE).

METHODS

Children of patients with SLE were invited to attend our clinic for physical examination and laboratory tests. A total of 195 children (aged 4 months to 26 years; male = 82, female = 113) were examined in 1991, 1995, 1997, and 1998.

RESULTS

Two cases were diagnosed as SLE at the first visit and were excluded from the second visit. A significantly higher percentage (52/195 (27%)) of patients were positive for antinuclear antibodies (ANA) at a cut off serum dilution of 1/40 compared with controls (4/57 (7%)). ANA were detected more frequently in female subjects than in men (p<0.05). Forty four subjects were examined on more than two occasions. Nine of the 10 patients who were positive for ANA at the second visit were girls aged 4-8 years. The incidence of anti-DNA and antiphospholipid antibodies in children of patients with SLE was similar to that in the controls.

CONCLUSIONS

The finding that children, especially girls, born to maternal lupus patients had a high positive rate for ANA suggests that a genetic factor is involved in SLE pathogenesis. Longitudinal observation of these patients may provide important clinical information and clues to the pathogenesis of SLE.

High diagnostic performance of ELISA detection of antibodies to citrullinated antigens in rheumatoid arthritis

OBJECTIVE

We investigated the rheumatoid arthritis (RA) diagnostic performances of anti-cyclic citrullinated peptide antibody (anti-CCP) and antifilaggrin antibody (AFA) in comparison with RF and matrix metalloproteinase-3 (MMP-3).

METHODS

We used a second generation enzyme-linked immunosorbent assay (ELISA) kit for the detection of anti-CCP. We constructed recombinant human filaggrin, which was citrullinated in vitro by human peptidylarginine deiminase, and subsequently used it as the coating antigen for AFA-ELISA. A total of 549 RA patients and 208 other rheumatic disease patients were included in the study.

RESULTS

The specificities of anti-CCP (88.9%) and AFA (94.7%) were superior to those of RF (81.7%) and MMP-3 (49.5%). The sensitivity of anti-CCP (87.6%) was superior to all others. However, the sensitivity of AFA (68.7%) was inferior to those of RF (69.8%) and MMP-3 (75.7%). Furthermore, receiver operating characteristic curves of anti-CCP and AFA passed closer to the upper left corner than those of RF and MMP-3, and the areas under the curves (AUC) of AFA and anti-CCP were significantly larger. In addition, the AUC of anti-CCP was significantly larger than that of AFA.

CONCLUSION

ELISA detection of antibodies to citrullinated antigens, especially a second generation anti-CCP, showed higher discriminative ability than other assays, including RF, and would be useful to aid the diagnosis of RA in clinical practice.