Assessment of cognitive function in systemic lupus erythematosus,rheumatoid arthritis,and multiple sclerosis by computerized neuropsychological tests

Objective

Computerized neuropsychological testing may facilitate screening for cognitive impairment in systemic lupus erythematosus (SLE). This study was undertaken to compare patients with SLE, patients with rheumatoid arthritis (RA), and patients with multiple sclerosis (MS) with healthy controls using the Automated Neuropsychological Assessment Metrics (ANAM).

Methods

Patients with SLE (n = 68), RA (n = 33), and MS (n = 20) were compared with healthy controls (n = 29). Efficiency of cognitive performance on 8 ANAM subtests was examined using throughput (TP), inverse efficiency (IE), and adjusted IE scores. The latter is more sensitive to higher cognitive functions because it adjusts for the impact of simple reaction time on performance. The results were analyzed using O'Brien's generalized least squares test.

Results

Control subjects were the most efficient in cognitive performance. MS patients were least efficient overall (as assessed by TP and IE scores) and were less efficient than both SLE patients (P = 0.01) and RA patients (P < 0.01), who did not differ. Adjusted IE scores were similar between SLE patients, RA patients, and controls, reflecting the impact of simple reaction time on cognitive performance. Thus, 50% of SLE patients, 61% of RA patients, and 75% of MS patients had impaired performance on ≥1 ANAM subtest. Only 9% of RA patients and 11% of SLE patients had impaired performance on ≥4 subtests, whereas this was true for 20% of MS patients.

Conclusion

ANAM is sensitive to cognitive impairment. While such computerized testing may be a valuable screening tool, our results emphasize the lack of specificity of slowed performance as a reliable indicator of impairment of higher cognitive function in SLE patients.

     

The −169C/T polymorphism in FCRL3 is not associated with susceptibility to rheumatoid arthritis or systemic lupus erythematosus in a case–control study of Koreans

Objective

In Japanese individuals, the −169C/T single‐nucleotide polymorphism (SNP) in FCRL3 has been reported to be associated with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and autoimmune thyroid diseases. The objective of this study was to test the association of this SNP with RA and SLE, in a case–control study of Korean individuals.

Methods

The −169C/T SNP in FCRL3 was genotyped in 1,060 patients with RA, 457 patients with SLE, and 697 unaffected control subjects, using the MassARRAY SNP genotyping system. Associations were tested by multivariate logistic regression, with adjustments for age and sex.

Results

No association was detected between the −169C/T SNP and RA (odds ratio [OR] 1.11, 95% confidence interval [95% CI] 0.83–1.48, P = 0.50) or SLE (OR 1.00, 95% CI 0.73–1.37, P = 0.99). This SNP was not associated with rheumatoid factor status, shared epitope status, radiographic severity in patients with RA, or disease manifestations in patients with SLE.

Conclusion

The association of the −169C/T SNP in FCRL3 with RA and SLE that was observed in Japanese patients was not replicated in a Korean population.

     

Phenotype and function of natural killer cells in systemic lupus erythematosus: Excess interferon‐γ production in patients with active disease

Objective

To determine the phenotype and the functionality of natural killer (NK) cells in patients with systemic lupus erythematosus (SLE).

Methods

A total of 94 patients with SLE (91 women and 3 men) were compared with 26 healthy controls. Active SLE was defined by an SLE Disease Activity Index score ≥4. Immunologic tests were performed using nonactivated and/or interleukin‐2 (IL‐2)–activated peripheral blood mononuclear cells. NK cell phenotype was determined by flow cytometry. NK cell natural cytotoxicity and antibody‐dependent cellular cytotoxicity (ADCC) were determined by ⁵¹Cr release and CD107a degranulation experiments. Intracellular interferon‐γ (IFNγ) production by NK cells was evaluated after overnight stimulation with IL‐12 and IL‐18. IFNα levels were assessed using an antiviral cytopathic bioassay.

Results

The absolute NK cell count was decreased in patients with active SLE, but the relative frequencies of total CD3−CD56^bright NK cells and CD3−CD56^dim NK cells were unaffected. The CD3−CD56^dim NK cells in patients with active SLE displayed unique phenotypic characteristics, including significant increases in CD69 and NKG2A and decreased expression of Fcγ receptor type IIIa/CD16, CD8α, and the killer cell immunoglobulin‐like receptor (KIR) KIR2DL1/KIR2DS1. Concomitant with these findings, NK cells from SLE patients had lower cytotoxicity but a normal level of ADCC compared with NK cells from healthy controls. There was a significant positive correlation between the increased level of IFNα in the serum and the enhanced frequency of IFNγ+ cells in patients with active SLE (r = 0.370, P = 0.04).

Conclusion

NK cells in patients with active SLE display phenotypic and functional features associated with activation. Furthermore, NK cells from patients with active SLE have the capacity to produce large amounts of IFNγ. This could contribute to the dysregulation of the link between innate and adaptive immunity seen in SLE.

     

Functional assay of type I interferon in systemic lupus erythematosus plasma and association with anti–RNA binding protein autoantibodies

Objective

Peripheral blood mononuclear cells (PBMCs) from patients with systemic lupus erythematosus (SLE) have increased expression of genes typically induced by type I interferon (IFN). However, it has been difficult to identify and quantify the factors responsible for activation of the IFN pathway in SLE. To characterize these mediators, we developed an assay that measures the functional effects of plasma or serum components on the gene expression of cultured target cells.

Methods

WISH epithelial cell line cells were cultured with medium, with recombinant IFNα, IFNβ, or IFNγ, or with 50% plasma from SLE patients (n = 73), rheumatoid arthritis (RA) patients (n = 19), or healthy donors (n = 30). Real‐time quantitative polymerase chain reaction was used to determine WISH cell expression of IFN target genes, including PRKR, IFIT1, IFI44, MX1, and C1orf29 (preferentially induced by IFNα) and CXCL9 (Mig) (preferentially induced by IFNγ).

Results

IFNα‐regulated genes were induced by SLE plasma samples, but not by most of the RA or healthy control plasma samples. The activity in SLE plasma was inhibited >90% by anti‐IFNα antibody, but not by anti‐IFNβ or anti‐IFNγ antibodies. The expression of each IFNα target gene induced by SLE plasma correlated with the expression of that gene studied ex vivo in PBMCs from the same patients and with the titer of anti–RNA binding protein (anti‐RBP)–specific autoantibodies. Plasma activity paralleled PBMC expression of IFNα‐inducible genes over time.

Conclusion

IFNα in SLE plasma is a major stimulus of IFN target gene expression and is related to expression of those genes in PBMCs from SLE patients and to the titer of anti‐RBP autoantibodies. These data provide additional support for the view that IFNα mediates immune system activation and dysregulation in SLE.

     

Natural killer T cell deficiency in active adult‐onset Still's disease: Correlation of deficiency of natural killer T cells with dysfunction of natural killer cells

Objective

To examine the levels and functions of natural killer (NK) and natural killer T (NKT) cells, investigate relationships between NK and NKT cells, and determine the clinical relevance of NKT cell levels in patients with adult‐onset Still's disease (AOSD).

Methods

Patients with active untreated AOSD (n = 20) and age‐ and sex‐matched healthy controls (n = 20) were studied. NK and NKT cell levels were measured by flow cytometry. Peripheral blood mononuclear cells were cultured in vitro with α‐galactosylceramide (αGalCer). NK cytotoxicity against K562 cells and proliferation indices of NKT cells were estimated by flow cytometry.

Results

Percentages and absolute numbers of NKT cells were significantly lower in the peripheral blood of AOSD patients than in that of healthy controls. Proliferative responses of NKT cells to αGalCer were also lower in patients, and this was found to be due to proinflammatory cytokines and NKT cell apoptosis. In addition, NK cytotoxicity was found to be significantly lower in patients than in healthy controls, but NK cell levels were comparable in the 2 groups. Notably, this NKT cell deficiency was found to be correlated with NK cell dysfunction and to reflect active disease status. Furthermore, αGalCer‐mediated NK cytotoxicity, showing the interaction between NK and NKT cells, was significantly lower in AOSD patients than in healthy controls.

Conclusion

These findings demonstrate that NK and NKT cell functions are defective in AOSD patients and suggest that these abnormalities contribute to innate immune dysfunction in AOSD.

     

Expansion and enhanced survival of natural killer cells expressing the killer immunoglobulin‐like receptor KIR3DL2 in spondylarthritis

Objective

The spondylarthritides (SpA) are strongly associated with possession of HLA–B27. We hypothesized that the expression of abnormal forms of HLA–B27 in SpA may have a pathogenic role through interaction with cells bearing natural killer (NK) receptors, in particular, killer immunoglobulin‐like receptor (KIR) KIR3DL2, a receptor for HLA–B27 homodimer (B27₂). We therefore undertook the present study to determine the number and function of NK and T cells bearing KIR3DL2 in SpA.

Methods

Expression of KIR3DL2 on NK and T cells was quantified in peripheral blood (PB) from 35 patients with SpA and 5 patients with juvenile enthesitis‐related arthritis (juvenile ERA); samples were compared with samples from healthy and rheumatoid arthritis (RA) controls. Paired synovial fluid (SF) was studied where available. Expression of other KIRs as well as activation, memory, and homing markers on KIR3DL2+ NK and T cells was quantified. NK cell survival was assessed using the apoptotic markers annexin V and 7‐aminoactinomycin D, and cytotoxicity by ⁵¹Cr release assay.

Results

In SpA, an increased number of PB and SF NK and CD4+ T cells expressed the KIR3DL2 receptor compared with controls. In ERA, KIR3DL2 expression was increased in PB and SF CD4 T cells (and SF NK cells) compared with RA controls. KIR3DL2+ NK cells had an activated phenotype, and were protected from apoptosis by culture with a cell line expressing B27₂. SpA PB mononuclear NK cells from SpA patients showed greater cytotoxicity than those from controls.

Conclusion

KIR3DL2 expression on NK cells and CD4 lymphocytes is increased in SpA and ERA. These cells are activated and may have a pathogenic role.

     

CD4+,CD28− T cells in rheumatoid arthritis patients combine features of the innate and adaptive immune systems

Objective

To determine whether CD4+,CD28− T cells, which are expanded in patients with rheumatoid arthritis (RA), express receptors that typically regulate the function of natural killer (NK) cells.

Methods

Expression of the NK cell surface molecules CD158, p70, CD94, CD161, and CD8α on T cell subsets was determined by multicolor flow cytometric analysis of peripheral blood mononuclear cells from 36 RA patients. Expression of CD161 on tissue‐infiltrating CD4 T cells was determined by 2‐color immunohistochemistry analysis of synovial tissue samples.

Results

Killer cell–inhibitory receptors (KIR) and killer cell–activating receptors (KAR) were exclusively expressed on CD4+,CD28− T cells, with the CD158b molecule being the most frequently detected isoform. A coordinated mechanism inducing KIR/KAR expression was suggested by similarities in the expression of CD158b on CD4 and CD8 T cells. CD4+,CD28− T cells were also positive for CD8‐αα homodimers, another characteristic shared with NK cells. Of the C‐type lectin NK cell receptors (NK receptors), CD94 was consistently absent, but CD161 was found on a CD4 T cell population that is significantly expanded in RA patients (P = 0.01). Involvement in disease of NK receptor–expressing CD4 T cells was suggested by the presence of CD4+,CD161+ T cells in follicular microstructures typical of rheumatoid synovitis.

Conclusion

Patients with RA have an expanded and unusual subset of CD4 T cells that infiltrates the tissue lesions and is characterized by a deficiency of CD28, the expression of CD8‐αα homodimers, and the expression of several types of HLA class I–recognizing NK receptors. CD4 T cells bearing NK receptors can bridge functions of the innate and adaptive immune systems, such as responsiveness to specific antigen, rapid release of interferon‐γ, cytotoxicity, independence from classic costimulatory pathways, and integration of multiple activating and inhibitory signals to control effector functions.

     

Stratification of pedigrees multiplex for systemic lupus erythematosus and for self‐reported rheumatoid arthritis detects a systemic lupus erythematosus susceptibility gene (SLER1) at 5p15.3

Objective

Arthritis is a common manifestation in systemic lupus erythematosus (SLE), appearing in ∼85% of patients. Often, the polyarthritis at presentation of SLE cannot be distinguished from rheumatoid arthritis (RA) by physical examination or history. Indeed, physicians initially tell many SLE patients that they have RA (one source of “self‐reported RA”), only to have SLE established later. In addition, RA aggregates in families with an SLE proband. We predicted that pedigrees multiplex for both SLE and for self‐reported RA would better isolate particular genetic effects. If this proved to be true, we would then use the increased genetic homogeneity to more easily reveal genetic linkage.

Methods

From a collection of 160 pedigrees multiplex for SLE, we selected 36 pedigrees that also contained ≥2 members with self‐reported RA (19 pedigrees were African American, 14 were European American, and 3 were of other ethnic origin). Data from a genome scan of 307 microsatellite markers were evaluated for SLE linkage by contemporary genetic epidemiologic techniques.

Results

The most significant evidence of linkage to SLE was obtained at 5p15.3 in the European American pedigrees by both parametric (logarithm of odds [LOD] score 6.2, P = 9.3 × 10⁻⁸) and nonparametric (LOD score 6.9, P = 1.7 × 10⁻⁸) methods. The best‐fitting model for this putative SLE gene in this region was a recessive gene with a population frequency of 5% and with 50% penetrance in females and 15% penetrance in males at virtually 100% homogeneity.

Conclusion

For a genetically complex disease phenotype, an unusually powerful linkage has been found with SLE at 5p15.3 in European American pedigrees multiplex for SLE and for self‐reported RA. This result predicts the presence of a gene at the top of chromosome 5 in this subset of patients that is important for the pathogenesis of SLE.

     

Epstein‐Barr virus load in the peripheral blood of patients with rheumatoid arthritis: Accurate quantification using real‐time polymerase chain reaction

Objective

To determine whether patients with rheumatoid arthritis (RA) have elevated Epstein‐Barr virus (EBV) load in their peripheral blood mononuclear cells (PBMCs) and whether it is correlated with the HLA–DR genes they express, we developed an accurate EBV DNA quantitative assay using real‐time polymerase chain reaction (PCR) with fluorescent probes.

Methods

We studied the EBV DNA load in the PBMCs of 84 patients with RA, 69 normal controls, and 22 patients with rheumatic conditions other than RA. A 214‐bp segment from the long internal repeat of EBV was amplified from 500 ng of PBMC DNA (150,000 cells) and quantified by real‐time PCR with fluorescent probes.

Results

We demonstrated that in patients with RA, the EBV DNA load in PBMCs is increased almost 10‐fold compared with that in normal controls. The EBV load is stable over time and is not obviously influenced by disease‐modifying antirheumatic drugs or HLA–DR.

Conclusion

Patients with RA have elevated EBV load in their peripheral blood.

     

Coexpression of CD177 and membrane proteinase 3 on neutrophils in antineutrophil cytoplasmic autoantibody–associated systemic vasculitis: Anti–proteinase 3–mediated neutrophil activation is independent of the role of CD177‐expressing neutrophils

Objective

Wegener's granulomatosis (WG) is strongly associated with antineutrophil cytoplasmic autoantibodies (ANCAs) directed against proteinase 3 (PR3). Recent studies have shown that membrane‐bound PR3 (mPR3) is differentially expressed and colocalizes with CD177/NB1 on circulating neutrophils. We undertook this study to assess the differential expression of CD177 on neutrophils from patients with ANCA‐associated systemic vasculitis (ASV) in comparison with patients with systemic lupus erythematosus (SLE), patients with rheumatoid arthritis (RA), and healthy individuals, and to investigate whether colocalization of mPR3 and CD177 affects anti‐PR3–mediated neutrophil activation.

Methods

Expression of CD177 and mPR3 was analyzed by flow cytometry on isolated neutrophils from patients with ASV (n = 53), those with SLE (n = 30), those with RA (n = 26), and healthy controls (n = 31). Neutrophil activation mediated by anti‐PR3 antibodies was assessed by measuring the oxidative burst with a dihydrorhodamine assay.

Results

Percentages of CD177‐expressing neutrophils were significantly higher in patients with ASV and those with SLE than in healthy controls. In 3 healthy donors, CD177 expression was not detected. After priming with tumor necrosis factor α, neutrophils remained negative for CD177 while mPR3 expression was induced. Neutrophils from CD177‐negative donors or CD177− neutrophils sorted from donors with bimodal expression were susceptible to anti‐PR3–mediated oxidative burst. Variation in the extent of anti‐PR3–mediated neutrophil activation among different donors occurred independent of the percentage of CD177‐expressing neutrophils.

Conclusion

Membrane expression of CD177 on circulating neutrophils is increased in patients with ASV and in those with SLE, but not in RA patients. However, primed neutrophils from CD177‐negative individuals also express mPR3 and are susceptible to anti‐PR3–mediated oxidative burst, suggesting that recruitment of CD177‐independent mPR3 is involved in anti‐PR3–induced neutrophil activation.

     

Coordinate overexpression of interferon‐α–induced genes in systemic lupus erythematosus

Objective

To study the contribution of interferon‐α (IFNα) and IFNγ to the IFN gene expression signature that has been observed in microarray screens of peripheral blood mononuclear cells (PBMCs) from patients with systemic lupus erythematosus (SLE).

Methods

Quantitative real‐time polymerase chain reaction analysis of healthy control PBMCs was used to determine the relative induction of a panel of IFN‐inducible genes (IFIGs) by IFNα and IFNγ. PBMCs from 77 SLE patients were compared with those from 22 disease controls and 28 healthy donors for expression of IFIGs.

Results

Expression of IFNα‐inducible genes was significantly higher in SLE PBMCs than in those from disease controls or healthy donors. The level of expression of all IFIGs in PBMCs from SLE patients with IFNα pathway activation correlated highly with the inherent responsiveness of those genes to IFNα, suggesting coordinate activation of that cytokine pathway. Expression of genes preferentially induced by IFNγ was not significantly increased in SLE PBMCs compared with control PBMCs. IFNα‐regulated gene‐inducing activity was detected in some SLE plasma samples.

Conclusion

The coordinate activation of IFNα‐induced genes is a characteristic of PBMCs from many SLE patients, supporting the hypothesis that IFNα is the predominant stimulus for IFIG expression in lupus.

     

Association of the PD‐1.3A allele of the PDCD1 gene in patients with rheumatoid arthritis negative for rheumatoid factor and the shared epitope

Objective

To study the frequency of allele A of polymorphism PD‐1.3 of the PDCD1 gene in patients with rheumatoid arthritis (RA) and its subsets, based on the presence of rheumatoid factor (RF) and the shared epitope (SE) alleles.

Methods

A total of 1,175 patients with RA and 3,404 controls were genotyped for the PD‐1.3 A/G polymorphism, which previously was identified as being involved in susceptibility to systemic lupus erythematosus (SLE) in patients of European descent.

Results

We first detected a trend for association of allele A of the single‐nucleotide polymorphism PD‐1.3 with RA (P = 0.053, odds ratio [OR] 1.18, 95% confidence interval [95% CI] 0.99–1.41). To further clarify the nature of this association, patients with RA were divided into 4 groups according to the presence of RF and the SE alleles. Association was found only in the group of patients negative for both RF and the SE alleles (P = 0.0054 [corrected P = 0.015], OR 1.75, 95% CI 1.15–2.65).

Conclusion

Patients negative for both RF and the SE alleles showed association with the same allele that we previously identified as being involved in susceptibility to SLE. These results provide the first evidence of the involvement of the human PDCD1 gene in arthritis.

     

The association of a nonsynonymous single‐nucleotide polymorphism in TNFAIP3 with systemic lupus erythematosus and rheumatoid arthritis in the Japanese population

Objective

Genome‐wide association (GWA) studies in systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) in Caucasian populations have independently identified risk variants in and near the tumor necrosis factor α (TNFα)–induced protein 3 gene (TNFAIP3), which is crucial for the regulation of TNF‐mediated signaling and Toll‐like receptor signaling. The aim of this study was to assess the role of TNFAIP3 in the development of SLE and RA in Japanese subjects.

Methods

We selected 2 single‐nucleotide polymorphisms (SNPs) from previous GWA studies. Rs2230926 is a nonsynonymous SNP in TNFAIP3 and is associated with SLE, while rs10499194 is an intergenic SNP associated with RA. We then performed 2 independent sets of SLE case–control comparisons (717 patients and 1,362 control subjects) and 3 sets of RA case–control comparisons (3,446 patients and 2,344 control subjects) using Japanese subjects. We genotyped SNPs using TaqMan assays.

Results

We observed a significant association between rs2230926 and an increased risk of SLE and RA in the Japanese population (for SLE, odds ratio [OR] 1.92, 95% confidence interval [95% CI] 1.53–2.41, P = 1.9 × 10⁻⁸; for RA, OR 1.35, 95% CI 1.18–1.56, P = 2.6 × 10⁻⁵). The intergenic SNP rs10499194 was also associated with SLE and RA, while the risk allele for RA in Caucasians was protective against the diseases in our population.

Conclusion

We demonstrated a significant association between the nonsynonymous variant in TNFAIP3 and the risk for SLE and RA in the Japanese population. TNFAIP3, similar to STAT4 and IRF5, may be a common genetic risk factor for SLE and RA that is shared between the Caucasian and Japanese populations.

     

Expression and occupancy of BAFF‐R on B cells in systemic lupus erythematosus

Objective

To determine whether receptors for B lymphocyte stimulator (BLyS) are altered on B cells of patients with systemic lupus erythematosus (SLE).

Methods

Total available receptors for BLyS were measured by analysis of binding of recombinant soluble BLyS to peripheral blood B cells in 36 SLE patients, 29 healthy controls, and 10 disease controls. Antibodies to the receptors BAFF‐R, BCMA, and TACI were used to define expression of the individual BLyS receptors on subsets of B cells in blood, spleen, and tonsils. Two different antibodies to BAFF‐R, which were differentially sensitive to BAFF‐R occupancy, were used to compare BAFF‐R on B cells in an additional 20 healthy subjects and 25 SLE patients. Assays of B cell survival after stimulation in vitro were used to determine the sensitivity of B cells to exogenous BLyS.

Results

Total available receptors for BLyS were decreased in patients with SLE, independent of changes of subsets in the blood in these patients. The decrease correlated with changes in disease activity. Although total surface BAFF‐R was not significantly different between healthy controls and SLE patients, BAFF‐R was occupied in SLE patients. B cells from these patients were less responsive to exogenous BLyS.

Conclusion

BAFF‐R is consistently occupied on blood B cells in SLE. Occupancy of BAFF‐R on blood B cells is likely to contribute to disease mechanisms in SLE and could serve as a biomarker of disease activity. Targeting BLyS as a therapeutic strategy will require overcoming the persistent binding of BLyS to BAFF‐R.

     

Association of autoantibodies to glucose‐6‐phosphate isomerase with extraarticular complications in rheumatoid arthritis

Objective

In the K/BxN mouse model, autoantibodies against glucose‐6‐phosphate isomerase (GPI) cause arthritis. The relevance of this model for human disease remains a subject of controversy. We set out to determine whether GPI autoantibodies occur in patients with rheumatoid arthritis (RA) and, if so, at what stage of the RA.

Methods

Using an enzyme‐linked immunosorbent assay, serum from 131 RA patients and 28 healthy controls was tested for autoantibodies against recombinant human GPI. Patients were grouped according to disease duration and presence of rheumatoid nodules, rheumatoid vasculitis, and Felty's syndrome, which are extraarticular complications of RA.

Results

Elevated levels of autoantibodies against GPI were present in 5% of patients with uncomplicated RA and 4% of controls. In RA complicated by extraarticular manifestations, anti‐GPI antibodies were observed in 18% of patients with rheumatoid nodules, 45% of patients with rheumatoid vasculitis, and 92% of patients with Felty's syndrome.

Conclusion

In patients with RA, autoantibodies to GPI are associated with the occurrence of extraarticular complications.

     

Dysregulated expression of CXCR4/CXCL12 in subsets of patients with systemic lupus erythematosus

Objective

CXCR4 is a chemokine with multiple effects on the immune system. In murine lupus models, we demonstrated that monocytes, neutrophils, and B cells overexpressed CXCR4 and that its ligand, CXCL12, was up‐regulated in diseased kidneys. We undertook this study to determine whether CXCR4 expression was increased in peripheral blood leukocytes from patients with systemic lupus erythematosus (SLE) and whether CXCL12 expression was increased in kidneys from patients with SLE.

Methods

Peripheral blood leukocytes from 31 SLE patients, 8 normal controls, and 9 patients with rheumatoid arthritis were prospectively analyzed by flow cytometry for CXCR4 expression. Biopsy samples (n = 14) from patients with lupus nephritis (LN) were immunostained with anti‐CXCL12 antibody.

Results

CD19+ B cells and CD4+ T cells from SLE patients displayed a >2‐fold increase (P = 0.0001) and >3‐fold increase (P < 0.0001), respectively, in median CXCR4 expression compared with that in controls (n = 7–8). Moreover, CXCR4 expression on B cells was 1.61‐fold higher in patients with SLE Disease Activity Index (SLEDAI) scores >10 (n = 8) than in patients with SLEDAI scores ≤10 (n = 16) (P = 0.0008), 1.71‐fold higher in patients with class IV LN (n = 5) than in patients with other classes of LN (n = 7) (P = 0.02), and 1.40‐fold higher in patients with active neuropsychiatric SLE (NPSLE) (n = 6) than in patients with inactive NPSLE (n = 18) (P = 0.01). CXCL12 was significantly up‐regulated in the tubules and glomeruli of kidneys in patients with LN (n = 14), with the percentage of positive cells correlating positively with the severity of LN.

Conclusion

CXCR4 appears to be up‐regulated in multiple leukocyte subsets in SLE patients. The heightened expression of CXCR4 on B cells in active NPSLE and of CXCL12 in nephritic kidneys suggests that the CXCR4/CXCL12 axis might be a potential therapeutic target for SLE patients with kidney and/or central nervous system involvement.

     

Protein phosphorylation and kinome profiling reveal altered regulation of multiple signaling pathways in B lymphocytes from patients with systemic lupus erythematosus

Objective

The cause of B lymphocyte hyperactivity and autoantibody production in systemic lupus erythematosus (SLE) remains unclear. Previously, we identified abnormalities in the level and translocation of signaling molecules in B cells in SLE patients. The present study was undertaken to examine the extent of signaling abnormalities that relate to altered B cell responses in SLE.

Methods

B lymphocytes from 88 SLE patients and 72 healthy controls were isolated from blood by negative selection. Protein tyrosine phosphorylation and cellular kinase levels were analyzed by Western blotting, flow cytometry, and a kinome array protocol. Changes in protein phosphorylation were determined in ex vivo B cells and following B cell receptor engagement.

Results

Differences in tyrosine phosphorylation in B cells from patients with SLE, compared with matched controls, were demonstrated. Further, the kinome array analysis identified changes in the activation of key kinases, i.e., the activity of phosphatidylinositol 3‐kinase, which regulates survival and differentiation, was up‐regulated and the activity of Rac and Rho kinases, which regulate the cytoskeleton and migration, was increased. In contrast, the activity of ATR, which regulates the cell cycle, was down‐regulated in SLE patients compared with controls. Differences in signaling pathways were seen in all SLE B lymphocyte subsets that manifested phenotypic features of immature, mature, and memory cells.

Conclusion

This study revealed dysregulation in multiple signaling pathways that control key responses in B cells of SLE patients. Data generated in this study provide a molecular basis for further analysis of the altered B lymphocyte responses in SLE.

     

Participatory patient–physician communication and morbidity in patients with systemic lupus erythematosus

Objective

To examine associations between active patient–physician communication and measures of morbidity in patients with systemic lupus erythematosus (SLE).

Methods

Audiotapes of routine visits between 79 women with SLE and their rheumatologists were coded for active patient participation and the degree of patient‐centered communication of the physician, using a validated coding scheme. Measures of SLE activity, functional disability, and permanent organ damage were recorded at the same visit. Permanent organ damage was reassessed in 68 patients after a median of 4.7 years.

Results

Patients who participated more actively in their visits had less permanent organ damage, as measured by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index, and tended to accrue less organ damage over time. There were no associations between either active patient participation or physicians' patient‐centered communication scores and measures of SLE activity or functional disability.

Conclusions

Patients with SLE who participated more actively in their visits had less permanent organ damage, suggesting that involving patients more in their care may decrease morbidity.

     

Unmet demands for health care among patients with rheumatoid arthritis: Indications for underuse?

Objective

To assess the prevalence of unmet health care demands among rheumatoid arthritis (RA) patients, and to determine if these unmet demands indicate underuse.

Methods

A total of 679 patients with RA participated in a questionnaire survey and clinical examination. Unmet health care demands and health care use were assessed for orthopedic care, allied health care, home care, and psychosocial care. Indications for underuse were determined by comparing health outcomes of patients with unmet health care demands and of health care users.

Results

Of the 679 patients, 28.7% had an unmet demand for 1 of the 4 services: 13.4% for allied health care, 9.7% for orthopedic care, 9.4% for home care, and 6.2% for psychosocial care. Underuse of allied health care, home care and psychosocial care was observed.

Conclusion

Unmet demands for health care are frequent among RA patients. Most unmet demands indicate underuse. Health care professionals should therefore be more responsive to the demands of patients.

     

Remnants of secondarily necrotic cells fuel inflammation in systemic lupus erythematosus

Objective

Patients with systemic lupus erythematosus (SLE) are often characterized by cellular as well as humoral deficiencies in the recognition and phagocytosis of dead and dying cells. The aim of this study was to investigate whether the remnants of apoptotic cells are involved in the induction of inflammatory cytokines in blood‐borne phagocytes.

Methods

We used ex vivo phagocytosis assays comprising cellular and humoral components and phagocytosis assays with isolated granulocytes and monocytes to study the phagocytosis of secondarily necrotic cell–derived material (SNEC). Cytokines were measured by multiplex bead array technology.

Results

We confirmed the impaired uptake of various particulate targets, including immunoglobulin‐opsonized beads, by granulocytes and monocytes from patients with SLE compared with healthy control subjects. Surprisingly, blood‐borne phagocytes from two‐thirds of the patients with SLE took up SNEC, which was rarely phagocytosed by phagocytes from healthy control subjects or patients with rheumatoid arthritis. Supplementation of healthy donor blood with IgG fractions derived from patients with SLE transferred the capability to take up SNEC to the phagocytes of healthy donors. Phagocytosis‐promoting immune globulins also induced secretion of huge amounts of cytokines by blood‐borne phagocytes following uptake of SNEC.

Conclusion

Opsonization of SNEC by autoantibodies from patients with SLE fosters its uptake by blood‐borne monocytes and granulocytes. Autoantibody‐mediated phagocytosis of SNEC is accompanied by secretion of inflammatory cytokines, fueling the inflammation that contributes to the perpetuation of autoimmunity in SLE.