Yue-Ying Gu

Analysis of gene expression profiles in human systemic lupus erythematosus using oligonucleotide microarray

Epidemiologic studies suggest a strong genetic component for susceptibility to systemic lupus erythematosus (SLE). To investigate the genetic mechanism of pathogenesis of SLE, we studied the difference in gene expression of peripheral blood cells between 10 SLE patients and 18 healthy controls using oligonucleotide microarray. When gene expression for patients was compared to the mean of normal controls, among the 3002 target genes, 61 genes were identified with greater than a two-fold change difference in expression level. Of these genes, 24 were upregulated and 37 downregulated in at least half of the patients. By the Welchs ANOVA/Welchs t-test, all these 61 genes were significantly different (P<0.05) between SLE patients and normal controls. Among these genes with differential expression, IFN-ω and Ly6E (TSA-1/Sca-2) may play an important role in the mechanism of SLE pathogenesis. TSA-1 antigens may represent an important alternative pathway for T-cell activation that may be involved in IFN-mediated immunomodulation. Hierarchical clustering showed that patient samples were clearly separated from controls based on their gene expression profile. These results demonstrate that high-density oligonucleotide microarray has the potential to explore the mechanism of pathogenesis of systemic lupus erythematosus.

Pulmonary hypertension in systemic lupus erythematosus.

Abstract A prospective echocardiographic and clinical study was performed on 84 Chinese patients with systemic lupus erythematosus (SLE) and 99 controls to investigate the prevalence and the mechanism of pulmonary hypertension (PH) in SLE. Comparison between Doppler estimation and catheterization measurement was made in 12 cases to validate the predictive method. Compared to normal subjects, lupus patients had significantly increased sys-tolic pulmonary artery pressure (SPAP) (29.59±12.52 vs 19.64±5.82, P<0.001), mean pulmonary artery pressure (MPAP) (15.11±7.36 vs 10.21±4.72, P<0.001) and total pulmonary resistance (TPR) (315.85±190.65 vs 220.37± 55.92, P<0.001). Nine of the 84 patients presented PH, defined as SPAP >30 mmHg and MPAP >20 mmHg. Pulmonary hypertensive patients had higher serum endothelin (ET) than non-pulmonary hypertensive patients, were more commonly in active stages, and presented Raynauds phenomenon and rheumatoid factors. ET level was correlated with echocardiographic pulmonary pressure. Pulmonary hypertension commonly occurs in Chinese patients with SLE (11%), and it correlates with the lupus activity and the elevation of serum endothelin.

Adult clinically amyopathic dermatomyositis with rapid progressive interstitial lung disease : a retrospective cohort study

The aim of the study was to investigate the characteristics of adult clinically amyopathic dermatomyositis (CADM) with rapid progressive interstitial lung disease (ILD). Hospitalized patients with dermatomyositis (DM) and polymyositis (PM) between 1998 and 2005 in the Shanghai Renji Hospital were retrospectively studied. One hundred and forty-five patients were classified into CADM, classic DM or PM according to the modified Sontheimer’s definition or Bohan–Peter’s classification criteria. They were further stratified based on the presence or absence of clinical ILD. The Kaplan–Meier survival analysis and COX regression were performed. The predictive factors for ILD and other clinical properties of CADM-ILD were explored. The presence of clinical ILD was a significant risk factor for the poor outcome of DM/PM (OR = 4.237, CI 95%: 1.239–14.49, p = 0.021). Other risk factors are the presence of rashes and elevated urea nitrogen. Patients with DM/PM complicated by ILD had different clinical courses. Patients with CADM-ILD showed a rapidly progressive pattern with 6-month survival rate of 40.8%. The DM-ILD manifested a progressive pattern with a 5-year survival rate of 54%, while PM-ILD was chronic with 5- and 10-year survival rate of 72.4% and 60.3%, respectively. Better preserved muscle strength, elevated erythrocyte sedimentation rate, and hypoalbuminemia may herald ILD in DM/PM. Patients with CADM-ILD who later died had lower PO2, higher lactate dehydrogenase, and prominent arthritis/arthralgia compared with those who survived. The presence of antinuclear antibody seems to be protective. Rapid progressive CADM-ILD is refractory to conventional treatment. ILD is a common complication in over 40% of our hospitalized DM/PM cohort and is also a prominent prognostic indicator. CADM is a special phenotype of DM/PM. CADM-ILD, which is usually rapidly progressive and fatal, requires further investigation.

Prognostic factors of lupus myelopathy

Myelopathy is a rare but severe neurological manifestation of systemic lupus erythematosus (SLE) with a high morbidity. The factors that contribute to prognosis are unknown. In this study, 14 patients with lupus myelopathy (LM) from our centre were retrospectively studied. Another 23 patients with other neuropsychiatric SLE (NPSLE) features were enrolled as a comparison group. The morbidity of LM was evaluated by the ASIA Impairment Scale. The clinical and serological characteristics and prognostic factors for LM were investigated. The age, gender, duration of SLE, non-CNS disease activity and autoantibody profile in patients with LM was not different in the NPSLE cohort. A relatively low prevalence of anti–phospholipid antibodies (aPL) in LM sera compared to NPSLE (28.6% vs 52.2%, P = 0.19) was observed. Longitudinal lesion detected by magnetic resonance imaging (MRI) was identified in 33.3% of patients with LM, whereas 50% showed focal speckle-like lesions. The morbidity of LM is 50%. Muscle strength of grade 3 or higher on admission was a strong indicator for a better prognosis (P = 0.006), whereas other parameters including longitudinal lesion, sensory deficit level, disease activity and aPL did not discriminate good from poor outcome in LM. Early aggressive immunosuppressive therapy (within 2 weeks of onset of myelopathy) tend to associate with a favourable outcome (P = 0.07).

Clinical features, prognostic and risk factors of central nervous system infections in patients with systemic lupus erythematosus.

The purpose of this study is to describe the etiology, characteristics and outcomes of central nervous system (CNS) infections in patients with systemic lupus erythematosus (SLE), while also identifying prognostic and risk factors. Thirty-eight SLE patients with CNS infections were identified from review of all charts of patients with SLE hospitalized from January 1995 to June 2005. These patients were divided into 3 groups, i.e., Mycobacterium tuberculosis (TB), non-TB bacterial and fungal infection groups. Of the 38 SLE cases with CNS infections, TB was identified in 19 patients, Listeria monocytogenes in 3 patients, Klebsiella pneumoniae in 1 patient, Staphylococcus aureus in 1 patient, Gram’s stain positive bacteria in 1 patient, Cryptococcus neoformans in 12 patients, and Aspergillus fumigatus in 1 patient. The rate of unfavorable outcome in patients with fungal infection was lower than in patients with TB (P=0.028) and non-TB bacterial CNS infections (P=0.046). SLE patients with TB or fungal CNS infections had a more insidious or atypical clinical presentation. Compared to SLE patients without CNS infections, those with CNS infections were more likely to have low serum albumin levels (P=0.048) and have been receiving higher doses of prednisolone at the onset of CNS infection (P=0.015) or higher mean doses of prednisolone within the previous year (P=0.039). In conclusion, low levels of serum albumin and higher doses of received prednisolone are important risk factors for the development of CNS infections in SLE patients.

Anti-α-Internexin Autoantibody from Neuropsychiatric Lupus Induce Cognitive Damage via Inhibiting Axonal Elongation and Promote Neuron Apoptosis

Background Neuropsychiatric systemic lupus erythematosus (NPSLE) is a major complication for lupus patients, which often leads to cognitive disturbances and memory loss and contributes to a significant patient morbidity and mortality. The presence of anti-neuronal autoantibodies (aAbs) has been identified; as examples, anti-NMDA receptors and anti-Ribsomal P aAbs have been linked to certain pathophysiological features of NPSLE. Methods and Findings In the current study, we used a proteomic approach to identify an intermediate neurofilament alpha-internexin (INA) as a pathogenetically relevant autoantigen in NPSLE. The significance of this finding was then validated in an expanded of a cohort of NPSLE patients (n = 67) and controls (n = 270) by demonstrating that high titers of anti-INA aAb was found in both the serum and cerebrospinal fluid (CSF) of ∼50% NPSLE. Subsequently, a murine model was developed by INA immunization that resulted in pronounced cognitive dysfunction that mimicked features of NPSLE. Histopathology in affected animals displayed cortical and hippocampal neuron apoptosis. In vitro studies further demonstrated that anti-INA Ab mediated neuronal damage via inhibiting axonal elongation and eventually driving the cells to apoptosis. Conclusions Taken together, this study identified a novel anti-neurofilament aAb in NPSLE, and established a hitherto undescribed mechanism of aAb-mediated neuron damage that could have relevance to the pathophysiology of NPSLE.

Evaluation of risk factors that contribute to high prevalence of premature atherosclerosis in Chinese premenopausal systemic lupus erythematosus patients.

Objective:To evaluate the prevalence of atherosclerosis in Chinese premenopausal women with systemic lupus erythematosus (SLE) and study possible associations between traditional and nontraditional risk factors with premature atherosclerosis. Methods:We evaluated 111 premenopausal women with SLE and 40 healthy controls without clinical cardiovascular disease. B-mode ultrasound was used to measure carotid plaque and intima-media wall thickness (IMT). The frequency of risk factors for atherosclerosis in patients and controls was compared, and the relationship between the patients’ clinical characteristics and carotid plaque was examined. At the same time, we used B-mode ultrasound to measure flow-mediated dilation (FMD) and nitroglycerin-mediated dilation (NMD) in the brachial artery to assess for difference in endothelial function between SLE patients and controls. Results:Carotid plaque was more frequent in patients with lupus (16 of 111 patients) than in control subjects (0 of 40 subjects) (P = 0.007). The mean IMT was significantly higher in patients than in controls. Compared with controls, SLE patients were found to have a significantly higher prevalence of hypertension (P = 0.001), hypercholesterolemia (P = 0.022), and hypertriglyceridemia (P < 0.001). As compared with patients without plaque, patients with plaque were significantly older, had longer disease duration, higher body mass index, raised blood pressure, shorter prothrombin time, raised C-reactive protein, higher Systemic Lupus International Collaborating Clinics damage index score, higher cumulative prednisone dose, used less hydroxychloroquine, had higher mean IMT, lower FMD, and NMD. In logistic regression analysis, older age, higher body mass index, and higher Systemic Lupus International Collaborating Clinics damage index score were independently related to the presence of plaque. Using multiple regression analysis, we found SLE (P = 0.003) to be significantly associated with impaired FMD. Conclusion:In our Chinese SLE group, patients presented a higher prevalence of carotid atherosclerosis plaque than healthy controls. SLE patients have significant endothelial dysfunction. We found that risk factors identified in other SLE populations were associated with atherosclerosis in our Chinese group.

Interferon-induced protein IFIT4 is associated with systemic lupus erythematosus and promotes differentiation of monocytes into dendritic cell-like cells

IntroductionUsing oligonucleotide microarray, many IFN-inducible genes have been found to be highly expressed in peripheral blood mononuclear cells (PBMCs) from most patients with systemic lupus erythematosus (SLE). Among these IFN-inducible genes, IFN-induced protein with tetratricopeptide repeats 4 (IFIT4) is a novel gene whose function is unknown.MethodsIn this study we examined the role played by IFIT4 in monocyte differentiation and the correlation between IFIT4 expression and the clinical manifestation of SLE. To this end, we used plasmid transfection, flow cytometry, mixed leucocyte responses, ELISA, quantitative RT-PCR and Western blotting.ResultsWe found that both IFIT4 mRNA and protein expression levels were significantly higher in PBMCs and monocytes from SLE patients than in those from healthy control individuals. IFIT4 expression was positively correlated with antinuclear antibodies, anti-double-stranded DNA, and anti-Sm auto-immune antibodies in SLE. Patients with SLE exhibiting higher expression of IFIT4 had a higher prevalence of leucopenia, thrombocytopenia and C3/C4 decrease. IFIT4 protein was localized exclusively to the cytoplasm, and it was significantly upregulated by IFN-α in normal PBMCs. To determine the role played by IFIT4 in monocyte differentiation, the monocytic cell line THP-1 was transfected with pEGFP-IFIT4 expression plasmid and stimulated with granulocyte-macrophage colony-stimulating factor/IL-4 to generate IFIT4-primed dendritic cell-like cells (DCLCs). IFIT4-primed DCLCs acquired morphological characteristics of dendritic cells more quickly, with greater resemblance to dendritic cells, as compared with DCLCs primed with pEGFP-C1 control plasmid trasfection. Furthermore, they exhibited higher expressions of CD40, CD86, CD80, HLA-DR and CD83, along with lower expression of CD14; increased IL-12 secretion; and an increased ability to stimulate T-cell proliferation. In addition, IFIT4-primed DCLCs enhanced IFN-γ secretion (about 2.4-fold) by T cells compared with controls.ConclusionOur findings suggest that IFIT4 might play roles in promoting monocyte differentiation into DCLCs and in directing DCLCs to modulate T-helper-1 cell differentiation; these actions might contribute to the autoimmunity and pathogenesis of SLE.

Increased expression of the type I interferon-inducible gene, lymphocyte antigen 6 complex locus E, in peripheral blood cells is predictive of lupus activity in a large cohort of Chinese lupus patients:

Several studies by microarray analysis and real-time polymerase chain reaction (RT-PCR) reveal that type I interferon-inducible genes (IFIGs) are implicated in systemic lupus erythematosus (SLE). To find a potential clinical biomarker capable of monitoring lupus disease activity clinically, quantitative RT-PCR was used to identify transcript expression levels of 13 type I IFIGs in peripheral blood cells in 144 patients with SLE, 27 non-SLE patients and 60 healthy controls and then analyse connections between gene expression and disease activity. The expression levels of five type I IFIGs (LY6E, OAS3, IFIT4, OAS1 and OAS2) were significantly higher in the SLE group than in the healthy and non-SLE controls. LY6E gene that had highest expression was chosen to analyse the association of expression level with clinical features. Compared to low LY6E expression group, SLE patients with high LY6E expression had higher SLEDAI-2K score, increased 24 h urine protein and lower blood C3 complement. Active SLE patients had more elevated LY6E expression than stable patients. And LY6E expression levels in patients with SLE were strongly correlated with their SLEDAI-2K scores. Our results indicate that increased expression of LY6E gene in peripheral blood cells in patients with SLE is correlated with lupus activity and may be a useful, noninvasive biomarker for assessing SLE disease activity.

Some Plasmin-Induced Antibodies Bind to Cardiolipin, Display Lupus Anticoagulant Activity and Induce Fetal Loss in Mice

The combined presence of anti-phospholipid Ab (aPL), thrombosis, and/or fetal loss is recognized as the antiphospholipid syndrome (APS). aPL include anti-cardiolipin Ab (aCL) and/or lupus anticoagulants (LAC, detected as Ig that prolong certain in vitro phospholipid (PL)-restricted blood clotting tests); both aCL and LAC are the diagnostic Ab for APS. Studies show that aPL represent a heterogeneous group of Ab, which recognize various PL, PL-binding plasma proteins, and/or PL-protein complexes. Recently, we found that five of seven patient-derived IgG monoclonal aCL react with thrombin, activated protein C, and plasmin. All three proteins are trypsin-like serine proteases (SP), and are highly homologous in their catalytic domains. Importantly, among these SP autoantigens, the reactive aCL bind to plasmin with the highest affinity, suggesting that plasmin may serve as a major driving autoantigen for some aCL in ∼30% of APS patients who are positive for IgG anti-plasmin Ab. To test this hypothesis, we immunized BALB/c mice with human plasmin and analyzed immune sera for aCL activity and reactivity with relevant SP. We found that some immune sera displayed aCL activity and/or bound to test SP. Subsequently, eight mAb were obtained and studied. The results revealed that one mAb displayed the aCL and the LAC activities and induced fetal loss when injected into pregnant mice. Immunohistological analyses of placentas revealed extensive deposits of activated C3 components. Combined, these data demonstrate that plasmin may serve as a driving Ag for some pathogenic aPL.