Inherited macrothrombocytopenias on the rise.

In this issue of Blood, Manchev et al describe a consanguineous family with severe macrothrombocytopenia and bleeding symptoms where exome sequencing revealed a homozygous missense mutation in the PRKACG gene (p.74Ile>Met) encoding the γ-catalytic subunit of cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA).

Interferon-α induces altered transitional B cell signaling and function in Systemic Lupus Erythematosus.

Previous studies suggest that the B cells of patients with Systemic Lupus Erythematosus (SLE) are hyper-responsive to BCR crosslinking; however, it has been unclear whether this is the result of altered B cell signaling or differences in various B cell subpopulations in SLE patients as compared to healthy controls. Here we have developed a novel Phosflow technique that permits examination of cell signaling in distinct B cell subpopulations stratified based upon developmental stage and cell surface IgM levels, which we use to show that the naïve B cells of SLE patients are hyper-responsive to IgM receptor crosslinking, resulting in increased SYK phosphorylation. We further demonstrate that this hyper-responsiveness is most marked in the transitional B cell subset and that it is associated with altered function, resulting in decreased apoptosis and increased proliferation of these cells. Examination of repeated samples from the same patients revealed that the hyper-responsiveness fluctuated over time, suggesting that it may be mediated by pro-inflammatory factors rather than genetic variations between patients. In support of this concept, incubation of healthy control B cells with IFN-α or SLE plasma induced the hyper-responsive phenotype, which was blocked by anti-IFN-α antibody. Furthermore, no obvious correlation was seen between genetic variants that are proposed to alter BCR signaling and the increased SYK phosphorylation. The findings suggest that pro-inflammatory factors, in particular Type I IFNs, modulate B cell function in SLE in a way that could contribute to the breach of tolerance in this condition.

Anti-nucleosome antibodies outperform traditional biomarkers as longitudinal indicators of disease activity in systemic lupus erythematosus.

OBJECTIVE: The aim of this study was to determine whether anti-nucleosome antibodies function as activity-specific biomarkers in SLE. METHODS: Fifty-one patients were recruited and followed prospectively with periodic clinical and biochemical assessments over a 14-month period. Disease activity was determined by the SLEDAI-2K. Anti-nucleosome antibody levels were measured by an ELISA and its utility as an activity-specific biomarker as compared with that of anti-dsDNA antibodies and C3 was assessed both at baseline and in longitudinal analysis. RESULTS: Anti-nucleosome antibodies were significantly elevated in SLE patients vs controls and showed a moderate positive correlation with disease activity. The utility of anti-nucleosome antibodies in identifying patients with active disease in a cross-sectional analysis was comparable to that of anti-dsDNA antibodies and C3. Analysis of variance demonstrated that the level of anti-nucleosome antibodies and C3 varied significantly with changes in disease activity over time. Changes in clinical state were not mirrored by changes in anti-dsDNA antibodies. In time-dependent analysis, anti-nucleosome antibodies showed a better fit over time than anti-dsDNA antibodies and C3. In pairwise comparisons, C3 and anti-nucleosome antibodies outperformed other models, including the conventional pairing of C3 and anti-dsDNA antibodies, however, no biomarker alone or as a group accurately predicted impending remissions or exacerbations. CONCLUSION: Anti-nucleosome antibodies demonstrate greater fidelity as a biomarker for changes in SLE disease activity than traditional biomarkers, supporting the routine monitoring of this antibody in clinical practice.

Abnormal megakaryocyte development and platelet function in Nbeal2(-/-) mice.

Gray platelet syndrome (GPS) is an inherited bleeding disorder associated with macrothrombocytopenia and α-granule-deficient platelets. GPS has been linked to loss of function mutations in NEABL2 (neurobeachin-like 2), and we describe here a murine GPS model, the Nbeal2(-/-) mouse. As in GPS, Nbeal2(-/-) mice exhibit splenomegaly, macrothrombocytopenia, and a deficiency of platelet α-granules and their cargo, including von Willebrand factor (VWF), thrombospondin-1, and platelet factor 4. The platelet α-granule membrane protein P-selectin is expressed at 48% of wild-type levels and externalized upon platelet activation. The presence of P-selectin and normal levels of VPS33B and VPS16B in Nbeal2(-/-) platelets suggests that NBEAL2 acts independently of VPS33B/VPS16B at a later stage of α-granule biogenesis. Impaired Nbeal2(-/-) platelet function was shown by flow cytometry, platelet aggregometry, bleeding assays, and intravital imaging of laser-induced arterial thrombus formation. Microscopic analysis detected marked abnormalities in Nbeal2(-/-) bone marrow megakaryocytes, which when cultured showed delayed maturation, decreased survival, decreased ploidy, and developmental abnormalities, including abnormal extracellular distribution of VWF. Our results confirm that α-granule secretion plays a significant role in platelet function, and they also indicate that abnormal α-granule formation in Nbeal2(-/-) mice has deleterious effects on megakaryocyte survival, development, and platelet production.

Association of autoantibodies to heat-shock protein 60 with arterial vascular events in patients with antiphospholipid antibodies.

OBJECTIVE: Anti-heat shock protein 60 autoantibodies (anti-Hsp60) are associated with cardiovascular disease and are known to affect endothelial cells in vitro, and we have recently shown that anti-Hsp60 promote thrombosis in a murine model of arterial injury. Based on those findings, we undertook the present study to investigate the hypothesis that the presence of anti-Hsp60, alone or in combination with other thrombogenic risk factors, is associated with an elevated risk of vascular events. METHODS: The study population was derived from 3 ongoing cohort studies: 2 independent systemic lupus erythematosus (SLE) registries and 1 cohort comprising SLE patients and non-SLE patients. Data from a total of 402 participants were captured; 199 of these participants had had confirmed vascular events (arterial vascular events in 102, venous vascular events in 76, and both arterial and venous vascular events in 21). Anti-Hsp60 were detected by enzyme-linked immunoassay, and association with vascular events was assessed by regression analysis. RESULTS: Multiple regression analysis revealed that arterial vascular events were associated with male sex, age, and hypertension. Analyses of the vascular events according to their origin showed an association of anti-Hsp60 with arterial vascular events (odds ratio 2.26 [95% confidence interval 1.13-4.52]), but not with venous vascular events. Anti-Hsp60 increased the risk of arterial vascular events (odds ratio 5.54 [95% confidence interval 1.89-16.25]) in antiphospholipid antibody (aPL)-positive, but not aPL-negative, individuals. CONCLUSION: We demonstrate that anti-Hsp60 are associated with an increased risk of arterial vascular events, but not venous vascular events, in aPL-positive individuals. These data suggest that anti-Hsp60 may serve as a useful biomarker to distinguish risk of arterial and venous vascular events in patients with aPL.

Glomerular filtration rate predicts arterial events in women with systemic lupus erythematosus.

OBJECTIVES: To determine whether renal function predicts the development of cardiovascular disease and other arterial vascular events in patients with SLE. METHOD: An inception cohort of 437 females was studied. Baseline estimated glomerular filtration rate (eGFR) was calculated using serum creatinine and the abbreviated Modification of Diet in Renal Disease Study Group formula. Arterial events including myocardial infarction, angina, transient ischaemic attacks, cerebral vascular accidents and other arterial events were documented at up to 15 years since the first visit. Disease activity was determined using SLEDAI. Patients were classified into those with or without arterial events and further into events that occurred within or after 3 years since the first visit (events <3 years, events ≥3 years). The association between eGFR and risks of arterial events was investigated using the Cox proportional hazards model. RESULTS: There was a total of 58 arterial events of which 51.9% were events ≥ 3 years. Patients with arterial events had a significantly lower baseline eGFR and were significantly older than those without arterial events. Furthermore, baseline eGFR was significantly lower in events <3 years compared with events ≥ 3 years. Baseline eGFR, age and baseline SLEDAI were significantly associated with the risks of arterial events [eGFR: hazard ratio (HR) = 0.986; age: HR = 1.032; SLEDAI: HR = 1.041]. CONCLUSION: Lower baseline eGFR, older age and higher SLEDAI score were significantly associated with increasing odds of developing arterial events at an earlier stage of SLE.

Fatigue severity in anti-nuclear antibody-positive individuals does not correlate with pro-inflammatory cytokine levels or predict imminent progression to symptomatic disease.

BACKGROUND: Fatigue is a common symptom of systemic autoimmune rheumatic disease (SARD). Patients with SARD have a protracted pre-clinical phase during which progressive immunologic derangements occur culminating in disease. In this study, we sought to determine when fatigue develops and whether its presence correlates with inflammatory factors or predicts disease progression. METHODS: Anti-nuclear antibody (ANA)-negative healthy controls (HCs) and ANA-positive participants with no criteria, at least one clinical criteria (undifferentiated connective tissue disease, UCTD), or meeting SARD classification criteria were recruited. Fatigue was assessed using a modified version of the FACIT-F questionnaire and the presence of fibromyalgia determined using a questionnaire based on the modified 2010 ACR criteria. Peripheral blood expression of five IFN-induced genes was quantified by NanoString and the levels of IL-1ß, IL-6, or TNF-α by ELISA. RESULTS: Fatigue was as prevalent and severe in individuals lacking SARD criteria as it was in UCTD and SARD. Overall, ~ 1/3 of ANA+ subjects met fibromyalgia criteria, with no differences between sub-groups. Although fatigue was more severe in these individuals, those lacking fibromyalgia remained significantly more fatigued than ANA- HC. However, even in these subjects, fatigue correlated with the widespread pain index and symptom severity scores on the fibromyalgia questionnaire. Fatigue was not associated with elevated cytokine levels in any of the ANA+ sub-groups and did not predict imminent disease progression. CONCLUSIONS: Fatigue is common in ANA+ individuals lacking sufficient criteria for a SARD diagnosis, correlates with fibromyalgia-related symptoms, and is not associated with inflammation or predictive of disease progression.

The presence of anti-nuclear antibodies alone is associated with changes in B cell activation and T follicular helper cells similar to those in systemic autoimmune rheumatic disease.

BACKGROUND: Diagnosis of systemic autoimmune rheumatic diseases (SARD) relies on the presence of hallmark anti-nuclear antibodies (ANA), many of which can be detected years before clinical manifestations. However, ANAs are also seen in healthy individuals, most of whom will not develop SARD. Here, we examined a unique cohort of asymptomatic ANA+ individuals to determine whether they share any of the cellular immunologic features seen in SARD. METHODS: Healthy ANA- controls and ANA+ (ANA ≥1:160 by immunofluorescence) participants with no SARD criteria, with at least one criterion (undifferentiated connective tissue disease (UCTD)), or meeting SARD classification criteria were recruited. Peripheral blood cellular immunological changes were assessed by flow cytometry and transcript levels of BAFF, interferon (IFN)-induced and plasma cell-expressed genes were quantified by NanoString. RESULTS: A number of the immunologic abnormalities seen in SARD, including changes in peripheral B (switched memory) and T (iNKT, T regulatory, activated memory T follicular helper) subsets and B cell activation, were also seen in asymptomatic ANA+ subjects and those with UCTD. The extent of these immunologic changes correlated with ANA titer or the number of different specific ANAs produced. Principal component analysis of the cellular data indicated that a significant proportion of asymptomatic ANA+ subjects and subjects with UCTD clustered  with patients with early SARD, rather than ANA- healthy controls. CONCLUSIONS: ANA production is associated with altered T and B cell activation even in asymptomatic individuals. Some of the currently accepted cellular features of SARD may be associated with ANA production rather than the immunologic events that cause symptoms in SARD.

Identification of a neutrophil-related gene expression signature that is enriched in adult systemic lupus erythematosus patients with active nephritis: Clinical/pathologic associations and etiologic mechanisms.

Both a lack of biomarkers and relatively ineffective treatments constitute impediments to management of lupus nephritis (LN). Here we used gene expression microarrays to contrast the transcriptomic profiles of active SLE patients with and without LN to identify potential biomarkers for this condition. RNA isolated from whole peripheral blood of active SLE patients was used for transcriptomic profiling and the data analyzed by linear modeling, with corrections for multiple testing. Results were validated in a second cohort of SLE patients, using NanoString technology. The majority of genes demonstrating altered transcript abundance between patients with and without LN were neutrophil-related. Findings in the validation cohort confirmed this observation and showed that levels of RNA abundance in renal remission were similar to active patients without LN. In secondary analyses, RNA abundance correlated with disease activity, hematuria and proteinuria, but not renal biopsy changes. As abundance levels of the individual transcripts correlated strongly with each other, a composite neutrophil score was generated by summing all levels before examining additional correlations. There was a modest correlation between the neutrophil score and the blood neutrophil count, which was largely driven by the dose of glucocorticosteroids and not the proportion of low density and/or activated neutrophils. Analysis of longitudinal data revealed no correlation between baseline neutrophil score or changes over the first year of follow-up with subsequent renal flare or treatment outcomes, respectively. The findings argue that although the neutrophil score is associated with LN, its clinical utility as a biomarker may be limited.

Development, Sensibility, and Validity of a Systemic Autoimmune Rheumatic Disease Case Ascertainment Tool.

OBJECTIVE: Case ascertainment through self-report is a convenient but often inaccurate method to collect information. The purposes of this study were to develop, assess the sensibility, and validate a tool to identify cases of systemic autoimmune rheumatic diseases (SARD) in the outpatient setting. METHODS: The SARD tool was administered to subjects sampled from specialty clinics. Determinants of sensibility - comprehensibility, feasibility, validity, and acceptability - were evaluated using a numeric rating scale from 1-7. Comprehensibility was evaluated using the Flesch Reading Ease and the Flesch-Kincaid Grade Level. Self-reported diagnoses were validated against medical records using Cohen's κ statistic. RESULTS: There were 141 participants [systemic lupus erythematosus (SLE), systemic sclerosis (SSc), rheumatoid arthritis, Sjögren syndrome (SS), inflammatory myositis (polymyositis/dermatomyositis; PM/DM), and controls] who completed the questionnaire. The Flesch Reading Ease score was 77.1 and the Flesch-Kincaid Grade Level was 4.4. Respondents endorsed (mean ± SD) comprehensibility (6.12 ± 0.92), feasibility (5.94 ± 0.81), validity (5.35 ± 1.10), and acceptability (3.10 ± 2.03). The SARD tool had a sensitivity of 0.91 (95% CI 0.88-0.94) and a specificity of 0.99 (95% CI 0.96-1.00). The agreement between the SARD tool and medical record was κ = 0.82 (95% CI 0.77-0.88). Subgroup analysis by SARD found κ coefficients for SLE to be κ = 0.88 (95% CI 0.79-0.97), SSc κ = 1.0 (95% CI 1.0-1.0), PM/DM κ = 0.72 (95% CI 0.49-0.95), and SS κ = 0.85 (95% CI 0.71-0.99). The screening questions had sensitivity ranging from 0.96 to 1.0 and specificity ranging from 0.88 to 1.0. CONCLUSION: This SARD case ascertainment tool has demonstrable sensibility and validity. The use of both screening and confirmatory questions confers added accuracy.

Presence of an interferon signature in individuals who are anti-nuclear antibody positive lacking a systemic autoimmune rheumatic disease diagnosis.

BACKGROUND: Elevated levels of type I interferons (IFNs) are a characteristic feature of the systemic autoimmune rheumatic diseases (SARDs) and are thought to play an important pathogenic role. However, it is unknown whether these elevations are seen in anti-nuclear antibody-positive (ANA+) individuals who lack sufficient criteria for a SARD diagnosis. We examined IFN-induced gene expression in asymptomatic ANA+ individuals and patients with undifferentiated connective tissue disease (UCTD) to address this question. METHODS: Healthy ANA- control subjects and ANA+ titre (≥1:160 by immunofluorescence) participants meeting no criteria, meeting at least one criterion (UCTD) or meeting SARD classification criteria were recruited. Whole peripheral blood IFN-induced and BAFF gene expression were quantified using NanoString technology. The normalized levels of five IFN-induced genes were summed to produce an IFN5 score. RESULTS: The mean IFN5 scores were increased in all ANA+ participant subsets as compared with healthy control subjects. We found that 36.8% of asymptomatic ANA+ and 50% of UCTD participants had IFN5 scores >2 SD above the mean for healthy control subjects. In all ANA+ subsets, the IFN5 score correlated with the presence of anti-Ro/La antibodies. In the asymptomatic ANA+ subset, this score also correlated with the ANA titre, whereas in the other ANA+ subsets, it correlated with the number of different ANA specificities. Development of new SARD criteria was seen in individuals with normal and high IFN5 scores. CONCLUSIONS: An IFN signature is seen in a significant proportion of ANA+ individuals and appears to be associated with ANA titre and type of autoantibodies, rather than with the presence or development of clinical SARD symptoms.

A discrete cluster of urinary biomarkers discriminates between active systemic lupus erythematosus patients with and without glomerulonephritis.

BACKGROUND: Management of lupus nephritis (LN) would be greatly aided by the discovery of biomarkers that accurately reflect changes in disease activity. Here, we used a proteomics approach to identify potential urinary biomarkers associated with LN. METHODS: Urine was obtained from 60 LN patients with paired renal biopsies, 25 active non-LN SLE patients, and 24 healthy controls. Using Luminex, 128 analytes were quantified and normalized to urinary creatinine levels. Data were analyzed by linear modeling and non-parametric statistics, with corrections for multiple comparisons. A second cohort of 33 active LN, 16 active non-LN, and 30 remission LN SLE patients was used to validate the results. RESULTS: Forty-four analytes were identified that were significantly increased in active LN as compared to active non-LN. This included a number of unique proteins (e.g., TIMP-1, PAI-1, PF4, vWF, and IL-15) as well as known candidate LN biomarkers (e.g., adiponectin, sVCAM-1, and IL-6), that differed markedly (>4-fold) between active LN and non-LN, all of which were confirmed in the validation cohort and normalized in remission LN patients. These proteins demonstrated an enhanced ability to discriminate between active LN and non-LN patients over several previously reported biomarkers. Ten proteins were found to significantly correlate with the activity score on renal biopsy, eight of which strongly discriminated between active proliferative and non-proliferative/chronic renal lesions. CONCLUSIONS: A number of promising urinary biomarkers that correlate with the presence of active renal disease and/or renal biopsy changes were identified and appear to outperform many of the existing proposed biomarkers.

Lack of Interferon and Proinflammatory Cyto/chemokines in Serologically Active Clinically Quiescent Systemic Lupus Erythematosus.

OBJECTIVE: Serologically active clinically quiescent (SACQ) patients with systemic lupus erythematosus (SLE) remain clinically quiescent for prolonged periods despite anti-dsDNA antibodies and/or low complements, indicating the presence of immune complexes. The immune mechanisms leading to this quiescence are unknown. However, in addition to activating complement, immune complex uptake by various cells leads to the production of interferon (IFN)-α and other proinflammatory factors that are also involved in tissue damage. Here we investigate whether production of these factors is reduced in SACQ patients. METHODS: The levels of 5 IFN-induced genes and 19 cyto/chemokines were measured in SACQ patients and were compared with those in serologically and clinically active (SACA) and serologically and clinically quiescent (SQCQ) patients. SACQ and SQCQ were defined as ≥ 2 years without clinical activity, with/without persistent serologic activity, respectively, and off corticosteroids/immunosuppressives. SACA was defined as disease activity compelling immunosuppression. Levels of OAS1, IFIT1, MX1, LY6E, and ISG15 were measured by quantitative real-time polymerase chain reaction (PCR) and a composite score (IFN-5) derived from this. Plasma cyto/chemokines were measured by Luminex assay. Nonparametric univariate and logistic regression analyses were conducted. RESULTS: There were no differences in gene expression or cyto/chemokine levels between SACQ and SQCQ patients. The SACQ IFN-5 score was significantly lower than that of SACA (p = 0.003) and was driven by SACQ status, not by autoantibody profile or disease duration. Levels of granulocyte-macrophage colony-stimulating factor, interleukin (IL) 6, IL-10, IFN-γ-inducible protein 10, monocyte chemoattractant protein 1, and tumor necrosis factor-α were significantly lower in SACQ than SACA. CONCLUSION: The levels of proinflammatory factors in SACQ mirror those of SQCQ patients, indicating reduced production of these factors despite the presence of immune complexes.

Germline mutations in ETV6 are associated with thrombocytopenia, red cell macrocytosis and predisposition to lymphoblastic leukemia.

Some familial platelet disorders are associated with predisposition to leukemia, myelodysplastic syndrome (MDS) or dyserythropoietic anemia. We identified a family with autosomal dominant thrombocytopenia, high erythrocyte mean corpuscular volume (MCV) and two occurrences of B cell-precursor acute lymphoblastic leukemia (ALL). Whole-exome sequencing identified a heterozygous single-nucleotide change in ETV6 (ets variant 6), c.641C>T, encoding a p.Pro214Leu substitution in the central domain, segregating with thrombocytopenia and elevated MCV. A screen of 23 families with similar phenotypes identified 2 with ETV6 mutations. One family also had a mutation encoding p.Pro214Leu and one individual with ALL. The other family had a c.1252A>G transition producing a p.Arg418Gly substitution in the DNA-binding domain, with alternative splicing and exon skipping. Functional characterization of these mutations showed aberrant cellular localization of mutant and endogenous ETV6, decreased transcriptional repression and altered megakaryocyte maturation. Our findings underscore a key role for ETV6 in platelet formation and leukemia predisposition.

T cell and dendritic cell abnormalities synergize to expand pro-inflammatory T cell subsets leading to fatal autoimmunity in B6.NZBc1 lupus-prone mice.

We have previously shown that B6 congenic mice with a New Zealand Black chromosome 1 (c1) 96-100 cM interval produce anti-nuclear Abs and that at least two additional genetic loci are required to convert this subclinical disease to fatal glomerulonephritis in mice with a c1 70-100 cM interval (c1(70-100)). Here we show that the number of T follicular helper and IL-21-, IFN-γ-, and IL-17-secreting CD4(+) T cells parallels disease severity and the number of susceptibility loci in these mice. Immunization of pre-autoimmune mice with OVA recapitulated these differences. Differentiation of naïve T cells in-vitro under polarizing conditions and in-vivo following adoptive transfer of OVA-specific TCR transgenic cells into c1(70-100) or B6 recipient mice, revealed T cell functional defects leading to increased differentiation of IFN-γ- and IL-17-producing cells in the 96-100 cM and 88-96 cM intervals, respectively. However, in-vivo enhanced differentiation of pro-inflammatory T cell subsets was predominantly restricted to c1(70-100) recipient mice, which demonstrated altered dendritic cell function, with increased production of IL-6 and IL-12. The data provide support for the role of pro-inflammatory T cells in the conversion of subclinical disease to fatal autoimmunity and highlight the importance of synergistic interactions between individual susceptibility loci in this process.

Development and assessment of users' satisfaction with the systemic lupus erythematosus disease activity index 2000 responder index-50 website.

OBJECTIVE: To describe the development of the Systemic Lupus Erythematosus Disease Activity Index 2000 Responder Index-50 (S2K RI-50) Website (www.s2k-ri-50.com) and to assess satisfaction with its training and examination modules among rheumatologists and rheumatology fellows. METHODS: The development of the Website occurred in 3 phases. The first was a deployment phase that consisted of preparing the site map along with its content. The content included the S2K RI-50 training manual, the tests and corresponding question bank, and the online adaptive training module, along with the extensive site testing. The second phase included the participation of rheumatologists and trainees who completed the Website modules. The third was a quality assurance phase in which an online survey was developed to determine the satisfaction level of its users. Further modifications were implemented per participants' recommendations. RESULTS: The site has been online since it was registered in September 2010. Fourteen rheumatologists and rheumatology trainees from different centers reviewed and completed the material contained in the Website. The survey revealed acceptance among rheumatologists for the Website's content, design, and presentation. The Website was rated as user-friendly and useful in familiarizing investigators with the S2K RI-50. After completion of the training and examination modules, participants reported a suitable level of preparation to implement the S2K RI-50 in clinical trials and research settings in a timely manner. CONCLUSION: The Website includes training and examination modules that familiarize rheumatologists with the S2K RI-50 and assesses their competence to use the index. This prepares them for the use of the S2K RI-50 in clinical trials and research settings.

Increased expression of B cell activation factor supports the abnormal expansion of transitional B cells in systemic lupus erythematosus.

OBJECTIVE: To examine the relationship between interferon-α (IFN-α) and dysregulation of B cell activation factor (BAFF) and specific B cell phenotypes in systemic lupus erythematosus (SLE). METHODS: Four-color flow cytometry was used to examine the peripheral B cell populations in patients with SLE. RNA was isolated from the peripheral blood of 87 patients and BAFF expression was determined by quantitative polymerase chain reaction (PCR) and normalized to GAPDH. The expression levels of 5 IFN-responsive genes (LY6E, OAS1, IFIT1, ISG15, and MX1) were determined by quantitative PCR and totaled to generate a global IFN score. The correlations were examined between peripheral B cell populations (including transitional, pregerminal, plasmablasts, and memory) and the expression of BAFF and the global IFN score. RESULTS: Examination of the peripheral B cell populations in SLE demonstrated a relative expansion of the transitional B cell and plasmablast compartment and a reduction in the memory B cell population. Expressions of BAFF and global IFN score were elevated in patients with SLE compared to healthy controls. A strong positive correlation was noted between BAFF expression and the relative proportion of late transitional (T2) B cells. The proportions of more mature B cell phenotypes did not correlate with BAFF expression. The global IFN score was strongly associated with the level of BAFF expression and moderately correlated with the proportion of late transitional B cells. CONCLUSION: The findings suggest that elevated BAFF expression supports expansion of the T2 B cell compartment and contributes to a breach in tolerance in patients with SLE.

Healthcare cost and loss of productivity in a Canadian population of patients with and without lupus nephritis.

OBJECTIVE: To compare the healthcare cost and loss of productivity in patients with systemic lupus erythematosus (SLE) with (LN) and without lupus nephritis (lupus nephritis-negative, LNN). METHOD: Patients were classified into those with active (ALN and ALNN) and inactive disease (ILN and ILNN). Patients reported on visits to healthcare professionals and use of diagnostic tests, medications, assistive devices, alternative treatments, hospital emergency visits, surgical procedures, and hospitalizations as well as loss of productivity in the 4 weeks preceding enrollment. RESULTS: Enrollment was 141 patients, 79 with LN and 62 LNN. Patients with LN were more likely to visit rheumatologists and nephrologists, undergo diagnostic tests, and had higher costs for medications than patients who were LNN. The annual healthcare cost averaged $CAN 12,597 ± 9946 for patients with LN and $10,585 ± 13,149 for patients who were LNN, a difference of $2012 (95% CI -$2075, $6100). Patients with ALN had more diagnostic tests and surgical procedures, contributing to a significantly higher annual direct cost ($14,224 ± 10,265) compared to patients with ILN ($9142 ± 8419) and a difference of $5082 (95% CI $591, $9573). The healthcare cost was not different between patients with ALNN and patients with ILNN. In patients with LN and patients who were LNN, < 50% were employed and on average missed 6.5-9 days of work per month. The loss of productivity was significantly higher for caregivers of patients with LN than caregivers of patients who were LNN. CONCLUSION: Healthcare cost and loss of productivity were similar between patients with LN and patients who were LNN; the loss of productivity for caregivers is higher for patients with LN; and the healthcare cost is greater in ALN than in ILN.

Altered expression of TNF-alpha signaling pathway proteins in systemic lupus erythematosus.

OBJECTIVE: To investigate the expression of tumor necrosis factor receptors (TNFR1 and TNFR2) and adapter proteins (TRADD, RIP, and TRAF2) in peripheral blood mononuclear cell (PBMC) subsets from patients with systemic lupus erythematosus (SLE). METHODS: PBMC were isolated from 45 SLE patients and 25 controls, and stained with labeled antibodies that enabled identification of various T cell, B cell, and monocyte subpopulations. Expression of TNF-related signaling molecules was measured by staining with labeled antibodies either directly or following fixation and permeabilization. Apoptosis was quantified using an anti-active caspase 3 antibody. RNA expression of TNF-related signaling molecules was assessed by quantitative RT-PCR and serum levels of TNF-alpha by ELISA. RESULTS: SLE patients had increased levels of TNFR1, TNFR2, and TRAF2, together with decreased levels of RIP, on various B, CD4+ T, and CD8+ T cell subsets as compared to controls. This altered expression was seen in both naive and memory subpopulations, and reflected altered staining of the whole population rather than a subset of cells that were activated. The levels of these molecules were not significantly correlated with serum TNF-alpha levels or their RNA expression in whole peripheral blood. TNFR1 and TNFR2 expression was negatively correlated with disease activity. There was no association between the proportion of apoptotic cells in any of the subpopulations and serum TNF-alpha levels or expression of TNF-related signaling molecules. CONCLUSION: Patients with SLE had altered expression of TNF-related signaling molecules, suggesting that there may be an imbalance in TNF-alpha signaling favoring cellular activation as opposed to proapoptotic pathways.