Increased serum concentration of BAFF/APRIL and IgA2 subclass in patients with mixed connective tissue disease complicated by interstitial lung disease

B cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) are known to be crucial for B cell maturation and survival, and increased expression of these factors in various autoimmune diseases has been reported. Human B cells produce two IgA subclasses: IgA1 and IgA2, the latter being abundant in the distal intestine, saliva, colostrum and bronchial fluid. We investigated these parameters in patients with mixed connective tissue disease (MCTD) complicated by interstitial lung disease (ILD+), and compared them with those in MCTD patients without ILD (ILD-). Sixty-three MCTD patients were divided into two groups: 21 ILD+ patients and 42 ILD- patients. In each patient group we analyzed soluble BAFF/APRIL using ELISA, and IgA1 and IgA2 using double immunodiffusion. Furthermore, we analyzed BAFF-APRIL receptors, BCMA, BAFF-R and TACI, using flow cytometry. The ILD+ patients had significantly higher levels of BAFF/APRIL than the ILD- patients. There were significant correlations between BAFF/APRIL, BAFF/KL-6 and APRIL/KL-6. Although there was no significant inter-group difference in the serum IgA1 level, ILD+ patients had a significantly elevated IgA2 level in comparison with ILD- patients. Moreover, although there were no significant inter-group differences in the expression of BCMA, BAFF-R and TACI on B cells, the expression of BAFF-R was significantly decreased in the ILD+ patients. In recent years, relationships between BAFF/APRIL and IgA subclass have been reported. Our results suggest that an elevated level of BAFF/APRIL drives the maturation of B cells, subsequently leading to IgA2 class switching, and possibly to the development of ILD in patients with MCTD.

Elevated serum level of circulating syndecan-1 (CD138) in active systemic lupus erythematosus

OBJECTIVE

Systemic lupus erythematosus (SLE) is characterized by loss of B cell tolerance and by the presence of polyclonal B cell activation. Syndecan-1 (CD138) is expressed on plasma cells derived from B cells, and is suspected to play a role in SLE. We evaluated the level of soluble CD138 (sCD138) and cell surface expression of CD138 in patients with active SLE, and also examined correlations among the serum levels of BAFF, a proliferation-inducing ligand (APRIL), and CD138 in these patients.

METHODS

Peripheral blood samples were obtained from 22 SLE patients in an active disease state and 14 normal controls. The levels of serum sCD138, sBAFF, and sAPRIL were measured using ELISA, and cell surface CD138 was analyzed by flow cytometry. The levels of CD138 mRNA were analyzed by RT-PCR. Blood samples were obtained longitudinally when the patients were in an inactive disease state.

RESULTS

The levels of circulating CD138, CD138 mRNA in PBMC, and the numbers of CD20(- )CD38(+)CD138(+) plasma cells were increased in patients with active SLE in comparison with normal controls. Furthermore, the serum sCD138 level in SLE patients was found to correlate with the proportion of CD20(- )CD38(+)CD138(+) plasma cells. On the other hand, patients with active SLE showed a reduced level of sCD138, and this was inversely correlated with the serum level of sAPRIL.

CONCLUSIONS

These results suggest that sCD138 may be applicable as a surrogate marker of disease activity, and that syndecan-1/APRIL signaling may be a potential therapeutic target for patients with active SLE.

The long-term prognosis of lupus nephritis patients treated with intravenous cyclophosphamide

OBJECTIVE

Patients with lupus nephritis receiving intravenous cyclophosphamide (IVCY) therapy were divided into groups according to their clinical course, and the long-term prognosis was evaluated.

PATIENTS AND METHODS

A total of 67 patients with lupus nephritis were enrolled and divided as follow into the following groups: Group A: patients with fresh nephritis, Group B: patients with relapse nephritis, Group C: patients with nephritis as a transition of the main clinical manifestation. IVCY (500 mg or 750 mg) was administered every month, and continued for two to more than six months.

RESULTS

The rate of remission was 78%; group A revealed a significantly higher rate of remission as compared with the other groups. Although long-term remission was revealed in most patients, some patients in Group B demonstrated a decreased rate of remission. Concerning the total dose administered, there was no relation to prognosis; a high dose was not required, especially for patients in Group A. On the other hand, the combination of steroid pulse therapy with IVCY revealed a moderate relation to the increased rate of remission in Group A. However, this combination therapy was not related to the maintenance of remission. There was no adverse effect at late onset.

CONCLUSION

The long-term prognosis of IVCY differed according to the patient's clinical course, and the result differed from those reported in other countries. Therefore, we should consider the clinical course and race specificity for the Japanese subject.

[Examination of availability of the criteria for protective therapy against Pneumocystis pneumonia]

Twenty patients with collagen diseases complicated with Pneumocystis pneumonia (PCP) were retrospectively examined in reference to the criteria for its protective therapy provided by the Ministry of Health Labor and Welfare. The breakdown of 20 patients was rheumatoid arthritis (RA) in 5 cases, systemic lupus erythematosus (SLE) in 5, dermatomyositis (DM) in 2, systemic scleroderma (SSc) in 1, mixed connective tissue disease (MCTD) in 1, Sjögren syndrome (SjS) in 1, polyarteritis nodosa (PN) in 3, rapidly progressive glomerulonephritis (RPGN) in 1, Schönlein-Henoch purpura in 1. Patients having interstitial pneumonia (IP) or renal dysfunction before acquiring PCP showed poor prognosis. High level of beta-D glucan was observed in all patients, and elevated levels of LDH and KL-6 were also characteristic of PCP. For the treatment of their own collagen diseases, high dose steroids had been given in 11 patients (55%), and immunosuppressive agents in 12 (60%), resulting in severe suppression of immune function in these patients. They were treated with Sulfamethoxazole/trimethoprim (ST) after Pneumocystis infection, however, 10 patients died and 8 of them died of respiratory failure in spite of high dose steroids. Nine patients fulfilled the criteria for PCP protective therapy provided by Ministry of Health Labor and Welfare, and 7 of them died of respiratory failure. The frequency of PCP remarkably decreased in our hospital after we had started the protective therapy with ST using the criteria, suggesting that it is effective for the protection of PCP. However, some patients who do not fulfill the criteria may acquire severe PCP.

Accuracy of cerebrospinal fluid IL-6 testing for diagnosis of lupus psychosis. A multicenter retrospective study

Psychiatric manifestations are relatively common in systemic lupus erythematosus (SLE) patients. Since there are factors causing psychiatric manifestations other than SLE, the diagnosis of lupus psychosis (LP) is often difficult. Previous studies disclosed that cerebrospinal fluid (CSF) IL-6 was elevated in SLE patients with neuropsychiatric manifestation. The current studies were therefore designed to examine the efficacy of CSF IL-6 in diagnosis of LP. Multicenter retrospective study was performed with 45 SLE patients who showed psychiatric manifestations between 1993 and 2000. The diagnosis of LP and psychosis due to causes other than SLE (non-LP) was confirmed by retrospective review of the clinical records. Thirty-two of the 45 patients were reconfirmed as LP in the retrospective study. Receiver operating characteristic curve analysis revealed that the sensitivity and specificity of CSF IL-6 for diagnosis of LP were 87.5% and 92.3%, respectively, at the cut-off value of 4.3 pg/ml. These results indicate that CSF IL-6 might be an effective measure in diagnosing LP, although exclusion of infectious meningoencephalitis and cerebrovascular accident is necessary.

Down-regulation of CD72 and increased surface IgG on B cells in patients with lupus nephritis

The significance of both the acceleratory and inhibitory functions of the CD72 molecule was investigated among patients with systemic lupus erythematosus (SLE) during modification of B cell differentiation. Expression of the CD72 molecule and mRNA on B cells was decreased in SLE with lupus nephritis, while CD100 expression on both CD4+ T cells and CD8+ T cells was not significant in comparison with the controls. When the relationship between CD72 expression and other B cell markers was examined, decreased expression of CD72 was associated with differences in the stage of differentiation. In patients with decreased expression of CD72, switching to IgG was evident, and the disease stage was started to severe. In patients with lupus nephritis, the decreased expression of CD72 was related to class switching on B cells, suggesting that CD72 is a useful marker for determining class switching of B cells in lupus nephritis.

Lack of association between tyrosine kinase 2 (TYK2) gene polymorphisms and susceptibility to SLE in a Japanese population

Tyrosine kinase 2 (TYK2) is a type I interferon (IFN) signaling pathway gene and was previously reported to be a risk factor for systemic lupus erythematosus (SLE) in Caucasian populations. In order to test for its genetic association with SLE in a Japanese population, TYK2 single nucleotide polymorphisms (SNPs), rs2304256, rs12720270 and rs280519, were genotyped. A case-control association study was performed in a total of 411 Japanese SLE patients and 467 healthy controls. Linkage disequilibrium (LD) among TYK2 SNPs was examined. According to the data from 94 healthy controls, non-synonymous rs2304256 resulting in Val --> Phe substitution was revealed to be in a LD with rs12720270 and rs280519. Therefore, we further genotyped rs2304256 as a tag SNP in the full sample sets. As a result, no differences in genotype distribution and allelic frequencies of rs2304256 were found between SLE patients and healthy controls. In conclusion, TYK2 is not a genetic risk factor for SLE in a Japanese population. Our result suggests that there is an ethnic difference in the susceptibility genes for SLE.

Increased Foxp3(+) CD4(+) regulatory T cells with intact suppressive activity but altered cellular localization in murine lupus

Foxp3(+) CD4(+) regulatory T (T(reg)) cells play a pivotal role in the maintenance of dominant self tolerance. Understanding how the failures of immune control by T(reg) cells are involved in autoimmune diseases is important for the development of effective immunotherapies. In the present study, we analyzed the characteristics of endogenous T(reg) cells in (NZB x NZW) F1 (BWF1) mice, a murine model of systemic lupus erythematosus. Unexpectedly, T(reg) number and frequency in aged BWF1 mice with developing lupus nephritis were increased, not decreased, and in vitro suppressive activity in lymphoid organs was intact. In addition, T(reg) cells trafficked to target organs because cells were present in the kidney and lung. T(reg) cells of aged BWF1 mice exhibited altered localization within lymph organs, however, and an altered phenotype, with higher expression levels of chemokine receptors and activation markers, suggesting a highly activated cellular state. Notably, the expression levels of co-stimulatory molecules were also markedly enhanced in the T(reg) cells of aged BWF1 mice. Furthermore, T(reg) cells of BWF1 mice did not show any suppressive effects on antibody production in vitro. Taken together, we conclude that T(reg) cells in BWF1 mice are not predisposed to functional incompetence but rather are present in a highly activated state.

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.

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 CD22 on peripheral B cells in patients with rheumatoid arthritis: relation to CD5-positive B cells

B cells in patients with rheumatoid arthritis (RA) are hyperactivated. Although B cell receptor signal transduction may be affected by various response regulators, CD22 plays an important role as a response regulator of B cells. Therefore, we investigated and examined CD22 expression on peripheral blood B cells of patients with RA. Thirty-two RA patients and 16 controls were enrolled in this study, and CD22 expressions on B cells were analyzed by flow cytometry. In patients with RA, CD22(+) B cells significantly decreased in comparison to the controls (ratio: P < 0.05). However, there was no correlation between this decrease and the clinical data. Interestingly, CD5(+) CD22(-) B cells significantly increased in RA patients. The decrease in CD22(+) B cells and increased in CD5(+)CD22(-) B cells play critical roles in the pathogenesis of RA mediated by the activation of B cells.

The relationship between initial clinical manifestation and long-term prognosis of patients with systemic lupus erythematosus

The relationship between clinical manifestations and prognosis was examined and evaluated among systemic lupus erythematosus (SLE) patients. A total of 542 patients with SLE were selected and divided into nine groups according to their main clinical manifestation at the time of initial diagnosis. The relationship between these clinical manifestations and long-term prognosis was evaluated in respect to the survival, remission, relapse rates, the development of a new clinical manifestation, and/or damage index. Patients with neuropsychiatric SLE (NPSLE), accompanied with acute confusional state/seizure disorder, cerebral vascular disease, or pneumonitis had poor survival rates with cause of death related to their major organ involvement. Patients with nephropathy or leukopenia had lower remission rates, and an increase in relapse rates was frequently recognized in patients with pneumonitis. Body damage (damage index) was higher in patients with lupus psychosis, pneumonitis, and/or arthritis. The translation of the main manifestations after diagnosis was confirmed in 64 patients (11.8%), and often observed in patients with autoimmune hemolytic anemia and arthritis. The majority of these manifestations were nephropathy, NPSLE, thrombocytopenia, and pneumonitis, and the prognosis of patients with nephropathy and thrombocytopenia as a new main manifestation had a poor outcome. The results of long-term prognosis in SLE greatly differed with respect to the initial clinical manifestation at the time of diagnosis.

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.

CD19/22 balance relates to improvement of disease activity in systemic lupus erythematosus

B cells in patients with systemic lupus erythematosus (SLE) are hyperactivated and B-cell receptor signal transduction may be affected by various response regulators. CD19 and CD22 play a major role as regulators of B-cell response. Therefore, we examined CD19 and CD22 expressions on B cells of patients with SLE, and how they were related to disease activity. Thirty-one patients with active SLE were selected and enrolled in this study. Evaluation of CD19 and CD22 expressions on B cells was performed prior to and after treatments with flow cytometry analysis. Disease activity was determined according to the SLE disease activity index score. CD19 and CD22 expressions on B cells in SLE patients revealed no significant differences when compared with the controls. However, improvement of SLE was recognized among patients with an increased ratio of CD22-positive cells. Our results suggest that this balance is a useful marker for determining improvement of SLE disease activity, although the CD19/22 balance does not contribute to the pathogenesis of SLE.

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.

Expression of NKB1 on peripheral T cells in patients with rheumatoid arthritis

NKB1 inhibits cytoxic activity of T lymphocytes mediated by superantigens, which is one of the contributing factors in the pathogenesis of rheumatoid arthritis (RA). In this study, we determined the expression of NKB1 on peripheral blood T cells in patients with RA. Our findings revealed that among patients with RA, NKB1(+) CD8(+ )T cells decreased significantly in comparison to controls (ratio: P < 0.05; absolute number: P < 0.005), and this decrease was not related to or influenced by HLA-Bw4 as a ligand of NKB1. This result may suggest that decreased expression of NKB1(+) CD8(+ )T cells contributes to the pathogenesis of RA mediated by the activation of CD8(+) T cells.

Association of the TAP2*Bky2 allele with presence of SS-A/Ro and other autoantibodies in Japanese patients with systemic lupus erythematosus

We previously reported that a new allele of transporter associated with antigen processing (TAP) 2 gene, TAP2*Bky2 (Val577), was significantly increased in Japanese patients with Sjögren's syndrome (SS) and had a strong association with SS-A/Ro antibody production. In the present study, it was investigated whether the association of TAP2*Bky2 with SS-A/Ro antibody production was also found in Japanese patients with systemic lupus erythematosus (SLE). Polymorphisms of the TAP1 and TAP2 genes were determined in 114 Japanese SLE patients by the polymerase chain reaction-single-stranded conformation polymorphism (PCR-SSCP) method. The allele frequencies of the TAP1 and TAP2 genes in SLE patients were not significantly different from those in controls, although the allele frequency of TAP2*Bky2 was slightly higher in SLE patients than in healthy control subjects (9.2% vs 5.5%, P = 0.126). The allele frequency of TAP2*Bky2 was significantly higher in SLE patients with oral ulcers than in those without. It was noteworthy that TAP2*Bky2 was significantly associated with the appearance of not only SS-A/Ro antibody but also SS-B/La, nRNP, and Sm antibodies in the patients. The association of TAP2*Bky2 was found with the antibody production to both 60 and 52kDa SS-A/Ro antigens. As TAP2*Bky2 had a strong linkage disequilibrium with DRB1*08032, TAP2*Bky2 or its haplotype with DRB1*08032 may be involved in SS-A/Ro antibody production not only in SS but also SLE patients, indicating that TAP2*Bky2 may be a susceptible gene not only to the disease of SS but also to the SS-A/Ro autoantibody production.

[The comparison in double immunodiffusion and western blotting methods of anti-SS-A/B antibodies in patients with Sjögren's syndrome]

OBJECTIVE

To investigate the autoimmune responses against SS-A/B antigens by double immunodiffusion (DID) and western blotting (WB) in primary and secondary Sjögren's syndrome (SS).

PATIENTS

Forty-nine patients with primary SS (PSS), 28 patients with secondary SS (SSS) and control group that couldn't be diagnosed as SS were included in this study.

RESULTS

In DID analysis, Anti-SS-A antibody was detected in 69% of PSS and 86% of SSS, and anti-SS-B antibody was found in 22% of PSS and 39% of SSS. No significant difference could be demonstrated between PSS and SSS concerning anti-SS-A/B antibodies. Conversely, WB studies disclosed evidences that 18% of PSS and no SSS reacted only with the 52 kD protein, and there was significantly increased in PSS. Sera reacting with the 60 kD antigen were found in 37% of PSS, 71% of SSS, and 75% of SSS with SLE, 63% of SSS with RA. The ratio of SSS, and SSS with SLE were particularly significantly higher than PSS.

CONCLUSION

Our results revealed data that there are the difference of reactivity against SS-A/B antigens in WB between PSS and SSS.

Activated peripheral blood mononuclear cells detected in lupus patients using cDNA coding for proliferating cell nuclear antigen

Abstract The expression of proliferating cell nuclear antigen (PCNA) mRNA in peripheral blood mononuclear cells (PBMCs) from patients with systemic lupus erythematosus (SLE) was measured by dot blot hybridization using a PCNA cDNA, and correlated with the percentage of PCNA-positive cells detected immunohistochemically using a monoclonal anti-PCNA antibody. PCNA-positive PBMCs were detected in 72.2% of SLE patients (n = 36), which is significantly more than among healthy controls. In addition, among those in whom PCNA expression was detected, the percentage of PBMCs expressing PCNA was significantly higher in SLE patients (mean 2.5% vs. 0.15%). The level of PCNA mRNA was increased in PBMCs from 83.3% of SLE patients, and was significantly correlated with the percentage of PCNA-positive cells (r = 0.54, P < 0.01) and with the disease activity score (r = 0.56, P < 0.01). A longitudinal study of two SLE patients confirmed that PCNA mRNA expression and the percentages of PCNA-positive cells varied in parallel with disease activity. Thus, an analysis of activated PBMCs from SLE patients using PCNA cDNA may be a useful method by which to estimate SLE disease activity.

Decreased IL-4 producing CD4+ T cells in patients with active systemic lupus erythematosus-relation to IL-12R expression

The balance of interferon-gamma (IFN-gamma) and/or interleukin-4 (IL-4) producing T cells and interleukin-12 receptor (IL-12R) expression on T cells were evaluated in patients with active systemic lupus erythematosus (SLE). Assessment of intracellular IFN-gamma and/or IL-4 were conducted with cytoplasmic staining. IL-12R presenting T cells were also assessed by flowcytometry without in vitro stimulation. In SLE, the number of IFN-gamma producing CD4+ T cells was increased, and the absolute number of IL-4 producing CD4+ T cells was significantly decreased. Although the ratio of IL-12R presenting CD4+ T cells was significantly greater, the absolute number did not increase. The ratio of IFN-gamma/IL-4-producing CD4+ T cells correlated with the SLE disease activity index (SLEDAI) and was significantly higher among patients with lupus nephritis. Therefore, the imbalance of IFN-gamma/IL-4 producing CD4+ T cells was due to the decrease in IL-4 producing CD4+ T cells and may play an important pathogenic role in active SLE.

The increased interleukin-13 in patients with systemic lupus erythematosus: relations to other Th1-, Th2-related cytokines and clinical findings

The levels of interleukin-13 (IL-13) in patients with systemic lupus erythematosus (SLE) were examined and related to other Th1-/Th2- related cytokines, clinical manifestations and other markers. Serum levels of IL-13 and other cytokines, soluble markers were measured by enzyme-linked immunosorbent assay (ELISA). Patients with active SLE had a significantly increased level of IL-13. Most patients with high levels of IL-13 had higher levels of IL-6, and some patients had high levels of gammaIFN. These patients were divided into two groups according to the patterns of these increased cytokines; one with a high level of only Th2 related cytokines (IL-13 or IL-6) and another with high levels of both Th2 related and Th1 related cytokines (gammaIFN or IL-2). The latter patients had high levels of soluble CD8 and CD23, and some of them had hemolytic anemia or pulmonary involvement, while most of the former patients had nephropathy. Thus, in SLE, the levels of IL-13 were increased, and the heterogeneity of increased Th2- and Th1-related cytokines was related to that of activation markers and clinical manifestations.

Serum levels of interleukin 15 in patients with rheumatic diseases

OBJECTIVE

The role of the cytokine interleukin 15 (IL-15) in rheumatic disease is unclear. We examined serum levels of IL-15 in patients with various rheumatic diseases.

METHODS

Serum levels of IL-15 were determined by sandwich ELISA.

RESULTS

Serum levels of IL-15 were significantly increased in patients with polymyositis/dermatomyositis, polyarteritis nodosa, and systemic sclerosis; and significantly increased as well in disease complicated by interstitial pneumonitis (IP), hemophagocytic syndrome (HPS), and/or vasculitis. Patients with serum IL-15 levels < or = 5 pg/ml showed significantly high rates of survival.

CONCLUSION

IL-15 is related to the pathogenesis of IP, HPS, and/or vasculitis. Serum IL-15 level could possibly be used as a marker of prognosis.

Molecular and cellular analyses of HLA class II-associated susceptibility to autoimmune diseases in the Japanese population

Abstract It is well known that individuals who are positive for particular HLA class II alleles show a high risk of developing autoimmune diseases. HLA class II molecules expressed on antigen-presenting cells present antigenic peptides to CD4(+) T cells. Their extensive polymorphism affects the structures of peptides bound to HLA class II molecules to create individual differences in immune responses to antigenic peptides. In order to gain a better understanding of mechanisms of the association between HLA class II alleles and susceptibility to autoimmune diseases, it is important to identify self-peptides presented by disease-susceptible HLA class II molecules and triggering disease-causative T cells. Many of the autoimmune diseases are observed in all ethnic groups, whereas the incidence of diseases, clinical manifestations and disease-susceptible HLA class II alleles are different among various ethnic groups for some autoimmune diseases. These phenomena suggest that differences in autoimmune self-peptide(s) in the context of disease-susceptible HLA class II molecules may cause these differences. Therefore, comparisons among disease-susceptible HLA class II alleles, autoantigenic peptides, and clinical manifestations of autoimmune diseases in different ethnic groups would be helpful in elucidating the pathogenesis of the diseases. In this review, we describe our recent findings on (1) the uniqueness of both clinical manifestations and the HLA-linked genetic background of Asian-type (opticospinal form) multiple sclerosis, (2) the characteristics of glutamic acid decarboxylase 65 (GAD65) or β2-glycoprotein I (β2-GPI) autoreactive T cells in Japanese patients with insulin-dependent diabetes mellitus (IDDM) or anti-β2-GPI antibody-associated autoimmunity, respectively, and (3) the generation of an efficient delivery system of peptides to the HLA class II-restricted antigen presentation path-way by utilizing a class II-associated invariant chain peptide (CLIP)-substituted invariant chain, which may be applicable to an evaluation of the "molecular mimicry hypothesis" for the activation of autoreactive T cells.

Multicenter cooperative study of HLA class II alleles in Japanese patients with systemic lupus erythematosus

Abstract The relation between HLA class II alleles and clinical findings were examined in Japanese patients with systemic lupus erythematosus (SLE). In 284 patients with multicenter SLE, HLA class II alleles were examined using the DNA typing method, and the results were compared with the clinical findings. The frequency of DRB1*0101 and DQB1*0501 significantly increased in male patients, and that of DRB1*0803 significantly increased in patients over 50 years of age. In relation to cutaneous manifestations, there were positive photosensitivity associations with DQA1*0101 and/or DQA1*0301, malar rash with DQA1*0101 and/or DRB1*0901, alopecia with DQA1*0101, skin ulcers with DRB1*0401, and oral ulcers with DQA1*0301. In addition, there were also positive associations of myalgia with DRB1*1406 and negative associations of aseptic bone necrosis with DQA1*0601, and hepatomegaly with DRB1*0405 and/or DQA1*0401. In relation to laboratory findings, there were positive associations of hemolytic anemia with DRB1*1402 and negative associations of leukopenia with DQA1*0601, lymphopenia with DQA1*0301, and proteinuria with DRB1*0901. Interestingly, DQA1*0101 and/or DQB1*0501 were significantly associated with WHO classification type II rather than type IV. In patients with SLE, some HLA types related to clinical or laboratory findings.

CD134L engagement enhances human B cell Ig production: CD154/CD40, CD70/CD27, and CD134/CD134L interactions coordinately regulate T cell-dependent B cell responses

CD134 is a member of the TNFR family expressed on activated T cells, whose ligand, CD134L, is found preferentially on activated B cells. We have previously reported that the CD70/CD27 interaction may be more important in the induction of plasma cell differentiation after the expansion phase induced by the CD154/CD40 interaction has occurred. When CD134-transfected cells were added to PBMCs stimulated with pokeweed mitogen, IgG production was enhanced in a dose-dependent fashion. Addition of CD134-transfected cells to B cells stimulated with Staphylococcus aureus Cowan I strain/IL-2 resulted in little if any enhancement of B cell IgG production and proliferation. We found that while CD134-transfected cells induced no IgG production by themselves, it greatly enhanced IgG production in the presence of CD40 stimulation or T cell cytokines such as IL-4 and IL-10. The addition of CD134-transfected cells showed only a slight increase in the number of plasma cells compared with that in the culture without them, indicating that an increased Ig production rate per cell is responsible for the observed enhancing effect of CD134L engagement rather than increase in plasma cell generation. These results strongly suggest different and sequential roles of the TNF/TNFR family molecules in human T cell-dependent B cell responses through cell-cell contacts and the cytokine network.

Effect of intravenous cyclophosphamide in systemic lupus erythematosus: relation to lymphocyte subsets and activation markers

Since the mechanism mediating the beneficial effect of intravenous cyclophosphamide (IVCY) in systemic lupus erythematosus (SLE) is unknown, we investigated lymphocyte subsets and markers of activated lymphocytes in patients received IVCY, and compared the results with the effect of steroid pulse. In 55 patients with SLE, 34 patients receiving IVCY [21 cases (61.8%) were responsive] and 25 patients received steroid pulse [21 cases (84.0%) were responsive] (four patients who were resistant to steroid pulse therapy were transferred to IVCY). When the lymphocyte subsets and markers of activated lymphocytes were compared in the responsive and unresponsive group of IVCY, soluble CD4 levels and the ratio of HLA-DP-positive T cells were significantly higher in the unresponsive group. Further, the changes of these markers and costimulatory molecules [LFA-1 (CD11a), ICAM-1 (CD54), CD40 and CD40-ligand (CD154)] were also examined in the responsive patients. The ratio of HLA-DP-positive T cells did not change in the IVCY-responsive group, while it decreased in the steroid pulse therapy-responsive group. The ratio of CD11a on T cells increased and CD54 on B cells decreased in the IVCY-responsive group. The ratio of CD154 on T cells increased in the steroid pulse-responsive group, while it decreased in the IVCY-responsive group. These results suggest that the effect of IVCY is different to that of steroid pulse therapy and mainly related to B cell activation, and that these markers may contribute to predict the responsiveness of IVCY.

Analysis of T cell responses to the beta 2-glycoprotein I-derived peptide library in patients with anti-beta 2-glycoprotein I antibody-associated autoimmunity

Antiphospholipid syndrome (APS) is an autoimmune disease that accompanies anti-phospholipid antibodies measured as either anti-cardiolipin antibodies (aCL) or lupus anticoagulant. beta(2)-glycoprotein I (beta(2)GPI) is the most common and apparently the best-characterized antigenic target for aCL. To investigate T-cell responses to beta(2)GPI, we stimulated PBMC of 18 APS or systemic lupus erythematosus (SLE) patients carrying anti-beta(2)GPI and 10 healthy controls, using a peptide library covering the beta(2)GPI sequence. We established seven CD4(+) T cell lines reactive with beta(2)GPI peptide. Three of four epitopes for patient-derived T cell lines were p244-264, whereas one T cell line from a control subject also recognized p244-264. Furthermore, there was no tendency for particular HLA class II molecules to present beta(2)GPI peptides. However, cytokine producing patterns were significantly different between T cell lines from patients and those from healthy individuals (p =.028); patients' T cells tend to exhibit higher IL-4 and lower IFN-gamma responses. These T cell lines did not react to beta(2)GPI purified from human plasma. These results indicate that beta(2)GPI-reactive CD4(+) T cells of APS/SLE patients mainly recognize cryptic p244-264 in the context of various HLA class II molecules, and exhibit Th0-Th2-type responses. Our findings may provide a clue to the pathogenesis of APS.

Levels of IL-12 in the sera of patients with systemic lupus erythematosus (SLE)--relation to Th1- and Th2-derived cytokines

IL-12 is a cytokine that induces Th1-derived cytokines (interferon-gamma (IFN-gamma) and IL-2). The significance of IL-12 in human autoimmunity is no clear, and the serum levels of IL-12 in SLE are not clearly established. Therefore, we examined the levels of IL-12 in 39 patients with active SLE, with sandwich ELISA. The levels of IL-12 in patients were significantly higher than in normal subjects. Patients with high levels of IL-12 also had high levels of IFN-gamma, while their levels of IL-13 were significantly lower than in patients with normal levels of IL-12. Patients with pulmonary involvement had high levels of IL-12, and steroid therapy decreased the IL-12 level in three patients. In a retrospective study of seven patients, various changes of IL-12 and IL-13 were recognized before disease flare. Thus, in SLE patients, the level of IL-12 was increased and this increase was related to the change of Th1- or Th2-derived cytokines with some organ involvement.

Circulating levels of beta-chemokines in systemic lupus erythematosus

OBJECTIVE

Recent evidence suggests the role of beta-chemokines and their receptors in human immunodeficiency virus infection. We examined the serum levels of beta-chemokines in patients with systemic lupus erythematosus (SLE).

METHODS

The serum levels of beta-chemokines, macrophage inflammatory protein-1alpha (MIP-1alpha), MIP-1beta, RANTES, and monocyte chemoattractant protein-1 (MCP-1) in patients with SLE were determined by ELISA.

RESULTS

There were significant differences between the patients with SLE and healthy controls in the serum concentrations of RANTES (p < 0.001) and MCP-1 (p < 0.01), but not MIP-1alpha (p = 0.07) and MIP-1beta (p = 0.68). A decrease of RANTES and an increase of MCP-1 was observed with the progression of disease activity in the patients with SLE.

CONCLUSION

Changes in the serum levels of RANTES and MCP-1 may indicate an interaction between SLE disease activity and the production of beta-chemokines.

Circulating interleukin-16 in systemic lupus erythematosus

OBJECTIVE

To investigate the relationship between interleukin (IL)-16 and systemic lupus erythematosus (SLE).

METHODS

Serum levels of IL-16 were examined in SLE patients using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

The serum level of IL-16 in the patients was much higher than that in healthy volunteers (P < 0.001). An increase in IL-16 was observed in proportion to the activity of SLE assessed by the SLE Disease Activity Index (SLEDAI) score (P < 0.0001).

CONCLUSIONS

Our observations suggest an interaction between disease activity and the production of IL-16 in SLE, and reveal that IL-16 is a useful indicator of disease activity. This is the first report describing the relationship between IL-16 and SLE.

Significance of stem cell factor and soluble KIT in patients with systemic lupus erythematosus

To determine the significance of stem cell factor (SCF) and soluble KIT (sKIT) in the serum of patients with systemic lupus erythematosus (SLE), levels of SCF and sKIT in patients with SLE were estimated, and their correlations with clinical parameters were examined. The sKIT levels in SLE patients (n = 106) were significantly lower than those in healthy controls (n = 40). A significant negative correlation was found between the SCF and sKIT levels of SLE patients. Although the SCF levels correlated with the titre of anti-RNP antibody, no significant relationship was found between SCF levels and blood cell counts, such as white blood cell, red blood cell and platelet counts. sKIT levels were significantly correlated with the platelet count, and were negatively correlated with the white blood cell count, titre of anti-DNA antibody, and SLE activity index (SLEDAI). sKIT levels were also negatively affected by high doses of corticosteroid. These results indicate that serum sKIT levels may be more closely related than SCF to the haematological abnormalities in SLE patients, and may reflect the clinical status of SLE patients and the effectiveness of high-dose corticosteroid treatment.

HLA-DRB1 alleles and beta 2 glycoprotein I-dependent anticardiolipin antibodies in Japanese patients with systemic lupus erythematosus

OBJECTIVE

To investigate the association of HLA DRB1 alleles with beta 2 glycoprotein I (beta 2 GPI)-dependent anticardiolipin antibodies (aCL) in Japanese patients with systemic lupus erythematosus (SLE).

METHODS

One hundred and forty-five Japanese patients with SLE were studied. beta 2 GPI-dependent aCL was measured by enzyme-linked immunosorbent assays. DNA typing of the DRB1 alleles was performed by the polymerase chain reaction sequence specific oligonucleotide probe method.

RESULTS

beta 2 GPI-dependent aCL was positive in 29 (20.0%) out of 145 SLE patients. SLE patients with beta 2 GPI-dependent aCL had a significantly higher frequency or one or more of the clinical manifestations assumed to be associated with aCL, compared to those without beta 2 GPI-dependent aCL (p < 0.05). The frequency of DRB1*0901 was lower in SLE patients than in healthy subjects. SLE patients with beta 2 GPI-dependent aCL were significantly associated with DRB1*0901 as compared to those without beta 2 GPI-dependent aCL (41.4% vs 15.5%, p < 0.005, R.R. = 3.8), although the corrected P value was not significant.

CONCLUSION

A possible association of DRB1*0901 with Japanese SLE patients with beta 2 GPI-dependent aCL was found. This association indicates an association between the disease and the HLA-DR53 (DRB4)-bearing haplotypes in different ethnic groups.