Antibodies to M-type phospholipase A2 receptor (PLA2R) in membranous lupus nephritis.

BACKGROUND: Antibodies to M-type phospholipase A2 receptor (a-PLA2R) have been identified in most patients with idiopathic membranous nephropathy, but the prevalence in membranous lupus nephritis (MLN) is still unclear. The objective of this study was to assess the prevalence of a-PLA2R antibodies in a large cohort of patients with lupus nephritis. METHODS: a-PLA2R antibodies were measured by ELISA in serum from patients with systemic lupus erythematosus ( n = 190), of whom 37 had a biopsy-proven MLN. Positive samples were confirmed by commercial ELISA kit, Western blot and immunohistochemistry in renal tissue. RESULTS: A total of 10 from 190 patients (5.3%) with systemic lupus erythematosus had circulating a-PLA2R measured by in-house ELISA assay. The antibodies were detected in 7 patients with MLN (18.9%) and 3 patients with non-renal lupus disease (3.2%). PLA2R staining was detected in the kidney biopsy of 5 of the 7 (71.4%) patients with MLN. a-PLA2R levels were associated with active disease but not proteinuria levels. Presence of a-PLA2R antibodies at baseline was associated with worse remission rates and longer time to remission compared to those patients serologically negative. CONCLUSIONS: a-PLA2R antibodies can be detected with low prevalence in MLN patients, but their detection is associated with a worse renal prognosis.

DUSP23 is over-expressed and linked to the expression of DNMTs in CD4+ T cells from systemic lupus erythematosus patients.

We evaluated the transcriptional expression of dual-specificity protein phosphatase 23 (DUSP23) in CD4+ T cells from 30 systemic lupus erythematosus (SLE) patients and 30 healthy controls. DUSP23 mRNA levels were considerably higher in the patient group: 1490 ± 1713 versus 294·1 ± 204·2. No association was found between DUSP23 mRNA expression and the presence of typical serological and clinical parameters associated with SLE. Meaningful statistical values were obtained in the patient group between the levels of DUSP23 and integrin subunit alpha L (ITGAL), perforin 1 (PRF1) and CD40L. Similarly, transcript levels of different DNA methylation-related enzymes [DNA methylation-related enzymes (DNMT1, DNMT3A, DNMT3B, MBD2, and MBD4)] were also correlated positively with the expression of DUSP23. In an attempt to counteract the hypomethylation status of the promoters of certain genes known to be over-expressed in SLE, it is possible that DUSP23 acts as a negative regulatory mechanism which ultimately silences the transcription of these epigenetically regulated genes by triggering an increase in the expression of different DNMTs.

Microarray study reveals a transforming growth factor-ß-dependent mechanism of fibrosis in discoid lupus erythematosus.

BACKGROUND: Discoid lupus erythematosus (DLE) is characterized by scarring lesions that develop and perpetuate fibrotic lesions. These are not observed in subacute cutaneous lupus erythematosus (SCLE). The pathophysiological basis of this is currently unknown. OBJECTIVES: To identify contradistinctive signalling pathways and cellular signatures between the two type of lupus, with a focus on the molecular mechanisms leading to fibrosis. METHODS: We conducted a gene expression microarray analysis in lesional and nonlesional skin biopsy specimens of patients with DLE (n = 10) and SCLE (n = 10). Confirmatory reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry were performed on selected transcripts in a new cohort of paraffin-embedded skin biopsies (n = 20). Changes over time of a group of selected inflammatory and fibrotic genes were also evaluated in a second biopsy taken 12 weeks later. In vitro functional studies were performed in primary isolated fibroblasts. RESULTS: Compared with nonlesional skin, DLE samples expressed a distinctive T-cell gene signature. DLE samples displayed a significant CD4 T-cell enrichment with an imbalance towards T helper 1 cytokine predominance and a relative increased forkhead box (FOX)P3 response. RT-qPCR and immunochemical analysis over time showed a progressive increment of fibrotic markers and persistent FOXP3 recruitment. Ex vivo upregulation of SERPINE1, MMP9, TGFBR1, phosphorylated SMAD3 and TGFB1 suggested a transforming growth factor (TGF)-ß-dependent mechanism of fibrosis in DLE, also confirmed by the results observed following in vitro stimulation with TGF-ß. CONCLUSIONS: These results highlight major pathogenic pathways in DLE and provide novel molecular targets for the development of new therapies. The data suggest the existence of a TGF-ß-dependent pathway inducing fibrosis in DLE.

Sequence analysis of TMEM173 exon 5 in patients with systemic autoimmune diseases.

BACKGROUND: Overactivation of the interferon pathways has been demonstrated in patients suffering from different systemic autoimmune diseases (SADs). Genetic associations have been described for many genes involved in these pathways. Gain-of-function mutations in the TMEM173 gene have recently been reported in patients with autoinflammatory diseases that share some clinical features with SADs. METHODS: We aimed at detecting the reported three mutations of transmembrane protein 173 (TMEM173) exon 5 in 100 patients suffering from: systemic lupus erythematosus (SLE) (n = 22), primary antiphospholipid syndrome (PAPS) (n = 20), systemic sclerosis (SSc) (n = 20), dermatomyositis (DM) (n = 20), and vasculitis (n = 18). Samples from 19 healthy controls were also included. Sequence analyses were performed from the derived TMEM173 exon 5 PCR fragment amplified from DNA obtained from whole blood. RESULTS: Neither mutations nor single nucleotide polymorphisms (SNPs) in the exon 5 of the TMEM173 gene were detected. Just the rs7380272 SNP, located in the intronic region upstream exon 5, was detected in some patients and controls. The allele frequency of this SNP, though, was not statistically different between the patients groups and the control group. CONCLUSIONS: Our study demonstrates the lack of association between the presence of SADs and mutations in exon 5 of the TMEM173 gene. SADs are complex multifactorial diseases in which not just one but probably many different genetic alterations may coexist. Although we cannot rule out the possibility that other variations may exist in other regions of this gene, we think that studies must be directed towards the analysis of other genes which, as TMEM173, also code for nucleic acid sensors that activate the nucleic-acid induced type I IFN pathway.

Long-Term Safety and Efficacy of Epratuzumab in the Treatment of Moderate-to- Severe Systemic Lupus Erythematosus: Results From an Open-Label Extension Study.

OBJECTIVE: The primary objective was to assess the long-term safety of repeated courses of epratuzumab therapy in patients with moderate-to-severe systemic lupus erythematosus. Secondary objectives were to assess long-term efficacy and health-related quality of life (HRQOL). METHODS: Eligible patients from the 12-week, phase IIb, randomized, placebo-controlled EMBLEM study enrolled into the open-label extension (OLE) study, SL0008. In the SL0008 study, patients received 1,200 mg epratuzumab infusions at weeks 0 and 2 of repeating 12-week cycles, plus standard of care. Safety measures included treatment-emergent adverse events (TEAEs) and serious TEAEs. Efficacy measures included combined treatment response, the British Isles Lupus Assessment Group score, the Systemic Lupus Erythematosus Disease Activity Index score, and the physician's and patient's global assessment of disease activity. Total daily corticosteroid dose and HRQOL (by the Short Form 36 health survey) were also assessed. RESULTS: A total of 113 of the 203 patients (55.7%) who entered the SL0008 study continued epratuzumab therapy until study closure (total cumulative exposure: 381.3 patient-years, median exposure: 845 days, and maximum exposure: 1,185 days/approximately 3.2 years). TEAEs were reported in 192 patients (94.6%); most common were infections and infestations (68.0%, 138 patients). Serious TEAEs were reported in 51 patients (25.1%), and 14 patients (6.9%) had serious infections. In patients treated for 108 weeks (n = 116), the median corticosteroid dose was reduced from 10.0 mg/day at OLE screening to 5.0 mg/day at week 108. Improvements in efficacy and HRQOL measures in EMBLEM were maintained in the OLE, while placebo patients exhibited similar improvements in disease activity upon a switch to epratuzumab. CONCLUSION: Open-label epratuzumab treatment was well tolerated for up to 3.2 years, and associated with sustained improvements in disease activity and HRQOL, while steroids were reduced.

Prevalence of HHV-8 in systemic autoimmune diseases.

BACKGROUND: Epidemiological data suggest that some viruses may be linked to the development of autoimmunity. OBJECTIVES: The objective of this work was to determine the presence of HHV-8 viral DNA in whole blood from patients suffering from different systemic autoimmune diseases (SAD). We also aimed at testing the prevalence of patients showing antibodies against an HHV-8 orfK8.1 peptide. STUDY DESIGN: Two hundred and eighty SAD patients and 50 healthy blood donor controls were included. Molecular analyses were performed by nested PCR from DNA obtained from whole blood and an enzyme immunoassay was developed in order to test for the presence of antibodies directed against a synthetic peptide derived from the HHV-8 orfK8.1 protein. RESULTS: Only 2 out of the 280 samples analyzed yielded the specific HHV-8 PCR product. Antibodies against orfK8.1 were detected in 2 SLE patients, 1 patient suffering from Sjögren's syndrome and 2 patients with vasculitis. CONCLUSIONS: We conclude that HHV-8 is usually not present in blood neither from autoimmune patients nor from healthy controls. Furthermore, HHV-8 antibodies against the HHV-8 orfK8.1 peptide were rarely detected. It leads us to infer that HHV-8 is not involved on the development of these disorders. It does not rule out the possibility that other environmental and microbiological triggers may account for their etiopathogenesis.

Increased myo-inositol in parietal white and gray matter as a biomarker of poor prognosis in neuropsychiatric lupus: a case report.

Neuropsychiatric manifestations can be a serious complication of systemic lupus erythematosus, affecting nearly 56% of these patients. Frequently, acceptable clinical outcome is observed in neurolupus with immunosuppressive therapy. Different metabolites identified with MR spectroscopy may be associated with modifications in the natural history of this disease, specifically in the central nervous system. We report a case of neurolupus with progressive neurologic impairment despite aggressive immunosuppressive treatment. We describe clinical features, laboratory and MRI results, as well as characteristic findings on MR spectroscopy. Serial MRI identified atrophy of the left temporal lobe. MR spectroscopy showed an increase of myo-inositol/creatine ratio intensity, accompanied by a decrease of N-acetylaspartate/creatine ratio in both parietal white and gray matter. During follow-up, the patient developed progressive cognitive deficiency despite the intensification of therapy. Neurolupus manifestations are common and immunosuppressive treatment often avoids severe complications. Characteristic findings on MR spectroscopy may be useful for clinicians to determine poor prognosis and resistance to therapy.

Acquired haemophilia A. First line treatment with calcineurin inhibitors and steroid pulses: a 10-year follow-up study.

Acquired haemophilia A (AH) is defined as the presence of autoantibodies or inhibitors against factor VIII (FVIII) with a clinical bleeding onset that can be life-threatening. Immunosuppressant therapy must be initiated rapidly to eradicate the inhibitor. Current treatments based on steroids plus cyclophosphamide or rituximab are quite effective, but with significant side-effects. Based on previous described AH cases treated with cyclosporine, with a good side-effect profile, we aimed at assessing prospectively a first-line calcineurin inhibitor based immunosuppressive therapy. We included a total of 11 patients affected with AH. Once diagnosed, pulse steroids and calcineurin inhibitors were started. Time to achieve sustained response (SR), defined as testing negative for inhibitor and with stable FVIII level >50%, immunosuppressant side-effects, and relapse of AH were evaluated. Eight patients received cyclosporine and three patients received tacrolimus. SR was achieved in 10 of 11 patients (90.9%) in a median time of 3 weeks (range 2-8 weeks), and none of them relapsed during a median follow-up time of 14 months (range 4-120). One major side-effect appeared (posterior encephalopathy) that forced to discontinue cyclosporine. Overall 5-year survival rate was 54.5%, with a total of five patients dying during the follow-up (mortality rate of 45.5%). These five patients had achieved SR and died because of complications of basal morbidities and/or senescence, not related to AH (bleeding) or to immunosuppressant's (infection) side-effects. Combination therapy of calcineurin inhibitors and pulse steroids seems clinically effective as a first-line treatment of AH.

Anti-ganglioside antibodies in patients with systemic lupus erythematosus and neurological manifestations.

INTRODUCTION: Anti-ganglioside antibodies (AGA) have been associated with several peripheral neuropathies, such as Miller-Fisher syndrome, Guillain-Barré syndrome and multifocal motor neuropathy. They have also been studied in patients with systemic lupus erythematosus (SLE), focusing on neuropsychiatric manifestations and peripheral neuropathy, but the results are contradictory. OBJECTIVE: To study the presence of AGA in a large cohort of patients with SLE and neuropsychiatric manifestations. PATIENTS AND METHODS: Serum from 65 consecutive patients with SLE and neuropsychiatric manifestations, collected from 1985 to 2009, was tested for the presence of AGA antibodies (GM1, GM2, GM3, asialo-GM1 GD1a, GD1b, GD3, GT1b, GQ1b) using a standard enzyme-linked immunosorbent assay ELISA test (INCAT 1999) and thin layer chromatography (TLC). RESULTS: Positive results for asialo-GM1 (IgM) were found in 10 patients, 6 were positive for asialo-GM1 (IgM and IgG), and 4 were positive for other AGA such as GM1, GM2, GM3, GD1b, GT1b, GD3, (mainly IgM). CONCLUSIONS: Clinical and statistical studies showed no correlation between AGA and neuropsychiatric manifestations of SLE. Although some patients showed reactivity to AGA, these antibodies are not a useful marker of neuropsychiatric manifestations in SLE patients.

Beta2-glycoprotein I gene polymorphisms Val247Leu and Trp316Ser in Spanish patients with primary antiphospholipid syndrome.

The significance of beta2-glycoprotein I (ß2GPI) polymorphisms in the production of anti-ß2GPI and other antiphospholipid autoantibodies (aPL) and in the pathogenesis of primary antiphospholipid syndrome (PAPS) is not well understood. We performed a study comparing the distribution of polymorphisms at codons 247 (Val247Leu) and 316 (Trp316Ser) of the ß2GPI gene in a Caucasian Spanish population of PAPS patients and healthy controls, and then making correlations with the development of anti-ß2GPI antibodies and other aPL and associated clinical manifestations. A total of 57 PAPS patients and 100 control subjects were included. In the analysis of Val247Leu polymorphism, alleles (V and L) and genotypes (V/V, V/L, L/L) were similarly distributed in PAPS patients and controls (P = 0.66 and P = 0.22, respectively). Regarding Trp316Ser polymorphism, we found a higher percentage of patients with respect to controls expressing S allele (11.4 vs. 5%, P = 0.02) and T/S genotype (22.8 vs. 10%, P = 0.02). However, when we compared T/T and T/S genotypes in PAPS patients, we found no differences regarding generation of anti-ß2GPI, other aPL and clinical manifestations favoring any genotype. Our findings suggest that among Spanish Caucasians, polymorphisms at codon 247 (Val247Leu) do not seem to influence PAPS pathogenesis. On the contrary, polymorphisms at codon 316 (Trp316Ser), by means of an increased S allele and T/S genotype presence in Spanish Caucasian patients, might play a role in the pathogenic development of PAPS, although mechanism would not involve an increased production of anti-ß2GPI and other aPL.

Thalidomide in the treatment of refractory cutaneous lupus erythematosus: prognostic factors of clinical outcome.

BACKGROUND: Although thalidomide has been shown to be effective in patients with refractory cutaneous lupus erythematosus (CLE), its use is still hampered by its potential severe side-effects and the current restricted availability. OBJECTIVES: To evaluate prospectively the clinical efficacy and safety of low-dose thalidomide in an observational study and to establish prognostic factors of clinical outcome. METHODS: Sixty consecutive patients with refractory CLE were treated with thalidomide (100 mg daily). Clinical response was assessed by the CLE Disease Area and Severity Index (CLASI). Clinical and immunological parameters were evaluated during treatment. RESULTS: Patients were followed for up to 8 years (range 2-18). One patient discontinued treatment because of side-effects. Of the 59 remaining patients, 58 (98%) achieved clinical response, already noticeable at 2 weeks following treatment. Complete response occurred in 50 patients (85%). Clinical relapse was frequent (70%) and usually occurred 5 months after withdrawal or reduction of thalidomide. Subacute CLE (SCLE) was the predicting factor of long-term remission after therapy discontinuation [odds ratio (OR) 30, 95% confidence interval (CI) 5·82-154·63], whereas discoid lupus erythematosus (DLE) was predictive of relapse (OR 5·71, 95% CI 1·36-24·06). Eleven patients (18%) reported paraesthesia; in five of the 11, nerve conduction studies confirmed a sensory polyneuropathy. Neurological symptoms resolved in 12 months (range 6-18) after thalidomide withdrawal. Two patients, heavy smokers and without antiphospholipid antibodies, had a cerebral ischaemic event. CONCLUSIONS: Low-dose thalidomide is an effective treatment for refractory CLE, but its benefits need to be balanced against the potential adverse effects. Whereas DLE forms tended to relapse and required a long-term maintenance dose of thalidomide, SCLE forms showed a sustained remission after withdrawal.

The PTPN22*R620W polymorphism does not confer genetic susceptibility to antiphospholipid syndrome in the Spanish population.

In this work, we proposed to determine the association of the PTPN22*R620W SNP with primary antiphospholipid syndrome (PAPS) in a case-control association study of Spanish Caucasian individuals. A total of 81 PAPS patients were compared with 81 blood-donor healthy control subjects. PTPN22 SNP (R620W) genotyping was performed by using a polymerase chain reaction-restricted fragment length polymorphism assay. No statistically significant differences were found between control subjects and PAPS patients for the PTPN22*R620W genotypes (P = 0.214). No statistically significant differences were found according to either the presence or absence of antiphospholipid antibodies or the clinical manifestations associated to PAPS. Our results indicate that this functional PTPN22*R620W polymorphism is not associated to PAPS; it seems not to be a risk factor in our Spanish population. The effect of the PTPN22 SNP on clinical manifestations and presence of antiphospholipid antibodies in APS warrants further investigations.

Echocardiography at diagnosis of antiphospholipid syndrome provides prognostic information on valvular disease evolution and identifies two subtypes of patients.

The evolution of valvular disease in antiphospholipid syndrome (APS) is barely known. In order to evaluate whether the presence or absence of valvular disease at the time of diagnosis of APS, assessed by an initial echocardiogram, predicts its subsequent evolution, we performed a prospective cohort study. We included 53 patients with APS. An initial transthoracic echocardiogram was performed on patients at the time of diagnosis of APS. Serial echocardiograms were conducted along a 12-year follow-up. Final echocardiograms were used for comparative purposes. We started with 29 patients (54%) with and 24 (45%) without valvulopathy at initial echo. At the final echocardiogram, 27 of 29 patients with initial valvulopathy continued to have valvular disease (a 93% observed likelihood), and 22 of 24 patients without initial valvulopathy demonstrated an absence of valvular disease (a 91% observed likelihood). Patients with valvulopathy in comparison with those without presented more arterial thrombotic events (69% vs. 20%, P < 0.001), atherosclerotic risk factors (62% vs. 29%, P = 0.01), livedo (48% vs. 16%, P = 0.01) and migraine (41% vs. 12%, P = 0.02). We have identified two subtypes of APS patients with and without valvulopathy by defining differential clinical features and with little crossover in valvular involvement over a long follow-up period, giving a high prognostic value to the initial echocardiographic assessment.

DNase 1 activity in patients with systemic lupus erythematosus: relationship with epidemiological, clinical, immunological and therapeutical features.

The main objective of this study is to determine the relationship between the activity of DNase1 and the clinical and immunological features in patients with systemic lupus erythematosus (SLE). A total of 66 patients (8 men and 58 women) diagnosed with SLE according to the American College of Rheumatology (ACR) SLE classification criteria were included in the study. Sixty-two sera from healthy blood donors were also included as controls. Epidemiological, clinical, immunological and therapeutical features for each patient were obtained. Disease activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). DNase1 activity was determined by using a radial enzyme diffusion method. Statistical analysis was performed using SPSS 12.0 software, with significant P value <0.05. Dnase1 activity was lower in patients with SLE than in the control group: 13.69 +/- 8.52 mug/mL vs 24.75 +/- 12.32 mug/mL, respectively (P < 0.005). No statistical relationship was found between DNase1 activity and disease evolution time, hypertension, presence of absolute or relative proteinuria, SLEDAI, new clinical manifestations, anti-Ro antibodies, anti-La antibodies, anti-RNP antibodies, anti-DNA antibodies, anti-cardiolipin antibodies, lupus anticoagulant, or with the treatment pattern received by the patients. Although important differences in DNase1 activity were found between patients with or without anti-Sm antibodies, they did not reach statistical significance. DNase1 activity was significantly lower in patients with SLE. Nevertheless, we did not find further relationships with any other of the epidemiological, clinical, immunological or therapeutical variables considered.

Anti-PDGFR-alpha antibodies measured by non-bioactivity assays are not specific for systemic sclerosis.

OBJECTIVE: To evaluate the presence of anti-PDGFR-alpha antibodies by immunological methods in patients with systemic sclerosis (SSc). METHODS: Fifty-eight women diagnosed with SSc and 36 healthy women controls were included. IgG anti-PDGFR-alpha were measured by ELISA and immunoblot. Associations with clinical and immunological findings were also studied. RESULTS: Non-significant differences were detected between patients with SSc and controls: median value 0.287 (range 0-2.06) versus median value 0.226 (range 0-2.94), respectively (p = 0.583). No correlation between the presence of anti-PDGFR-alpha antibodies and clinical and serological features was found. Serum samples from patients with SSc and healthy people who had high titres of anti-PDGFR-alpha antibodies by ELISA recognised the same band corresponding to PDGFR-alpha by immunoblot. CONCLUSION: Although anti-PDGFR-alpha antibodies seem to be disease-specific when determined by bioactivity assays, these antibodies are also detected in normal subjects when immunological methods are used. Thus, anti-PDGFR-alpha antibodies may arise from natural autoantibodies. Possibly, SSc autoantibodies recognise a different epitope on the PDGFR-alpha molecule which triggers its stimulatory effect when analysed by functional assays. Alternatively, naturally occurring autoantibodies may even become pathogenic after affinity maturation and class switching in genetically susceptible subjects.

Activation of the signal transducer and activator of transcription-1 in diffuse proliferative lupus nephritis.

Difuse proliferative lupus nephritis (DPLN) is the most common and severe form of lupus nephritis. A predominance of IFN-gamma-producing T cells in both peripheral and renal tissues of patients with DPLN has been identified which suggests an important role for cell-mediated immunity in the pathogenesis of this complication in SLE. The biological effects of IFN-gamma rely mainly on the activity of the transcription factor called signal transducer and activator of transcription (STAT)-1. To assess the IFN-gamma/STAT-1 pathway in DPLN, we examined the expression of STAT-1 in renal biopsies from 15 DPLN patients by immunohistochemical staining with an anti-STAT-1 antibody. The expression of STAT-1 in renal tissues was correlated with several clinical and laboratory findings in these DNPN patients.STAT-1 was activated in the tubular cells in all DPLN patients. Seven of 15 DPLN biopsies (46.7%) showed positive cells in glomeruli. Five of these seven DPLN biopsies (71.4%) with positive glomerular cells showed a serum creatinine >1.5 mg/mL at the time the biopsy was carried out whereas only one of eight DPLN biopsy specimens (12.5%) without positive glomerular cells, showed a serum creatinine >1.5 mg/mL (P = 0.041). Moreover, the percentage of DPLN patients with a worse renal outcome in those who showed expression of STAT-1 in glomerulari were higher in comparison to those without STAT-1 expression (P = 0.041). Our results show that STAT-1 is activated in DPLN suggesting that biological effects of IFN-gamma in renal tissues depend, at least in part, on the activation of STAT-1.

Opposed independent effects and epistasis in the complex association of IRF5 to SLE.

Genetic variation in the interferon regulatory factor 5 (IRF5) gene affects systemic lupus erythematosus (SLE) susceptibility. However, association is complex and incompletely defined. We obtained fourteen European sample collections with a total of 1383 SLE patients and 1614 controls to better define the role of the different IRF5 variants. Eleven polymorphisms were studied, including nine tag single nucleotide polymorphisms (SNPs) and two extra functional polymorphisms. Two tag SNPs showed independent and opposed associations: susceptibility (rs10488631, P<10(-17)) and protection (rs729302, P<10(-6)). Haplotype analyses showed that the susceptibility haplotype, identified by the minor allele of rs10488631, can be due to epistasis between three IRF5 functional polymorphisms. These polymorphisms determine increased mRNA expression, a splice variant with a different exon 1 and a longer proline-rich region in exon 6. This result is striking as none of the three polymorphisms had an independent effect on their own. Protection was independent of these polymorphisms and seemed to reside in the 5' side of the gene. In conclusion, our results help to understand the role of the IRF5 locus in SLE susceptibility by clearly separating protection from susceptibility as caused by independent polymorphisms. In addition, we have found evidence for epistasis between known functional polymorphisms for the susceptibility effect.

Antinuclear antibody testing in pleural fluid for the diagnosis of lupus pleuritis.

We sought to determine whether measuring antinuclear antibodies (ANA) and their specificities [dsDNA, extractable nuclear antigens (ENA)] on pleural fluid may contribute to the differential diagnosis of pleural effusions. ANA were tested by indirect immunofluorescence on Hep-2 cells in the pleural fluid of 266 patients with effusions of different etiologies, including 15 lupus pleuritis. The cutoff value for diagnostic use was set at 1:160. Pleural fluid analysis of specific autoantibodies, such as anti-dsDNA and anti-ENA, was also performed if a positive ANA test was obtained. All patients with lupus pleurisy and 16 of 251 (6.4%) patients with pleural effusions secondary to other causes were ANA positive. Fifty-six percent of the positive ANAs in non-lupus pleural fluids were due to neoplasms. The pleural fluid ANA titers were low (< or = 1:80) or absent in two patients with systemic lupus erythematosus (SLE) and effusions due to other factors. Whereas ANA staining patterns in pleural fluid did not help to discriminate lupus pleuritis from non-lupus etiologies, the absence of pleural fluid anti-dsDNA or anti-ENA favored the latter. ANAs in pleural fluid provided no additional diagnostic information beyond that obtained by the measurement in serum and, therefore, these tests need not be routinely performed on pleural fluid samples. However, in patients with SLE and a pleural effusion of uncertain etiology, lack of ANAs or specific autoantibodies in pleural fluid argues against the diagnosis of lupus pleuritis.

Multiplex family-based study in systemic lupus erythematosus: association between the R620W polymorphism of PTPN22 and the FcgammaRIIa (CD32A) R131 allele.

A functional polymorphism in PTPN22, a gene encoding a phosphatase involved in T-cell signaling, has been associated with autoimmunity. We checked for the prevalence of the PTPN22 R620W polymorphism in multiplex families affected with systemic lupus erythematosus (SLE) and other autoimmune diseases. Its association with other polymorphisms in mannose binding lectin (MBL) and FcgammaRIIa (CD32A) genes was also studied. Deoxyribonucleic acid samples were obtained from 233 Spanish individuals who belonged to 21 families in which at least two members had been diagnosed with some autoimmune disease, mainly SLE. A healthy control population was also included (n= 129). Genotyping for the R620W single-nucleotide polymorphism (SNP) was performed by restriction fragment length polymorphism analysis of polymerase chain reaction products. Allele frequency for the T allele was slightly higher in the families with autoimmune disease, especially when considering the affected individuals (0.094 vs 0.062). Actually, 18.8% affected family members vs 11.6% controls had the polymorphism (P= 0.179). Nineteen percent of affected individuals had both the PTPN22 T and the CD32A R131 alleles, whereas only 8.5% unaffected relatives had both susceptibility alleles simultaneously [P= 0.031, odds ratios 2.508 (95% confidence interval 1.066-5.896)]. The tendency toward finding the T allele more frequently in members affected with some particular autoimmune disorder suggests that this SNP may confer susceptibility to autoimmunity. The fact that more affected than unaffected relatives carried both the T and the R131 alleles simultaneously leads us to think about the existence of a combinatorial effect between genes that could help define individuals prone to autoimmune diseases.