Use of cystatin C-based estimations of glomerular filtration rate in patients with type 2 diabetes

Aims/hypothesis  The Modification of Diet in Renal Disease (MDRD) equation has recognised limitations when using estimated GFR in persons at risk of chronic kidney disease. Equations based on cystatin C provide an alternative method. We compared performance of the MDRD equation with a selection of cystatin C-based formulae for estimation of GFR in normoalbuminuric patients with type 2 diabetes. Methods  Estimated GFR was calculated using the MDRD equation and the cystatin C formulae proposed by several investigator teams. Isotopic GFR was measured using plasma clearance of ⁵¹Cr-EDTA. Results  We studied 106 participants, of whom 83 (78%) were men with the following characteristics, mean (SD): age 61 (9) years, HbA_1c 7.10 (1.27)%, creatinine 89.0 (12.7) μmol/l, cystatin C 0.859 (0.234) mg/l and isotopic GFR 104.5 (20.1) ml min⁻¹ 1.73 m⁻². MDRD estimated GFR was 77.4 (13.6) ml min⁻¹ 1.73 m⁻² (p < 0.05 for difference from isotopic GFR). Cystatin C-based calculations of estimated GFR were: Perkins 124.5 (31.8), Rule 90.0 (30.0), Stevens (age) 96.0 (30.4) and Stevens (creatinine) 85.6 (19.0) ml min⁻¹ 1.73 m⁻² (p < 0.05 for difference with isotopic GFR). For Arnal’s, MacIsaac’s and Tan’s formulae cystatin-C estimated GFR were 101.7 (34.8), 102.1 (27.0) and 101.6 (27.8) ml min⁻¹ 1.73 m⁻², respectively (p = NS for difference with isotopic GFR). Cystatin C-based formulae were less biased and, with the exception of Perkins’ formula, more accurate to within 10% of isotopic GFR than MDRD. Conclusions/interpretation  Performance of cystatin C equations was superior to MDRD in normoalbuminuric patients with type 2 diabetes. These results support further evaluation of cystatin C for estimation of GFR in persons at risk of chronic kidney disease.     

Prevalence of Anticardiolipin and Anti-β<Subscript>2</Subscript>-Glycoprotein I Antibodies in Celiac Disease

The aim of this study was to evaluate the prevalence of anticardiolipin antibodies (aCL) and anti-β₂-glycoprotein I antibodies (aβ2GPI) in patients with celiac disease and to analyze the clinical features of antiphospholipid syndrome in these patients. We conducted a prospective case-control study based on the evaluation of IgG, IgM and IgA aCL, and IgG and IgA aβ2GPI in celiac disease patients and in controls. All patients were asked about any occurrence of thrombotic manifestations. In addition, women were asked about pregnancy morbidity. Fifty celiac disease patients and 50 healthy controls were studied. IgM aCL were not detected in study group or in controls. IgG aCL were found in two patients and in one control. IgA aCL were significantly more frequent in celiac disease patients compared with controls (13/50 (26%) vs. 2/50 (4%), p=0.004, OR [95% CI]=9.09 [1.81–50]). There was no statistically significant difference for the prevalence of IgG and IgA aβ2GPI between patients and controls. Clinical features of antiphospholipid syndrome were noted in two patients with negative antibodies. Prevalence of IgM and IgG aCL and of aβ2GPI were not increased in celiac disease. IgA aCL were more frequently detected in celiac disease. However, no clinical features of antiphospholipid syndrome were noted.     

Clinical significance of antiphospholipid antibodies in Indian scleroderma patients

In patients with systemic sclerosis (SSc), antiphospholipid antibodies (aPL) have been reported to be associated with more severe manifestations including digital infarct, gangrene and pulmonary hypertension. But these findings are not consistent in all studies; moreover, there are no data available from Indian subcontinent. The objective of this study is to assess the prevalence of antiphospholipid antibodies in Indian SSc patients and correlate them with clinical and immunological features. Seventy-two patients were recruited prospectively from rheumatology clinic from 2002 to 2006. Their medical records were reviewed. Anticardiolipin antibodies (IgG, IgM) by ELISA and lupus anticoagulant (LA) were tested in standardized pattern and repeated after 6 weeks. Anti-β2 glycoprotein-I antibodies were done in patients who had aPL antibodies. Nineteen patients had diffuse cutaneous SSc and 53 had limited disease. Seven patients (9.7%) were positive for aPL antibodies in their sera. Only one patient had clinical features of antiphospholipid antibody syndrome and manifested with recurrent abortions and deep vein thrombosis. She was positive for aCL, LA and anti-β2 glycoprotein-I antibodies. Four patients were only aCL (IgG) positive in moderate titers and one each had only aCL (IgM) and LAC positivity. None of the clinical parameters showed an association with aPL antibody.     

Relevance of antiphospholipid antibodies in multiple sclerosis: A systematic review and meta analysis

BackgroundThe relationship between antiphospholipid antibodies (aPL) and multiple sclerosis (MS) is unclear.ObjectivesTo evaluate a link between aPL and MS.MethodsEMBASE and PubMed search to August 2016; Peto’s odds ratio (OR) meta-analysis.ResultsThe pooled prevalence of participants positive for IgG and IgM anticardiolipin (aCL) from 12 case–control studies was superior in MS than controls (6.8% vs 1.8%, p = 0.01 and 8.58% vs 2.18%, p = 0.001) with medium and high heterogeneities respectively (I² = 48.55% and 68.13%). The pooled prevalence of participants positive for IgG anti-beta₂glycoprotein-I (aβ₂GPI) from seven case–control studies was lower in MS than controls (0.93% vs 4.02%) with high heterogeneity (I² = 53.92%) though the pooled prevalence of participants positive for IgM aβ₂GPI was similar (7.24% vs 6.13%) with high heterogeneity (I² = 52.85%). Five cohorts compared IgG/IgM aCL and IgM aβ₂GPI in stable/remission vs active/relapsing MS: the pooled prevalence of IgG aCL was similar in active/relapsing and stable/remission MS (19% vs 18.9%) but the pooled prevalence of IgM aCL was higher in active than in stable MS (36.9% vs 21%, p < 0.0001) as well as that of IgM β₂GPI (40.5% vs 3.2%, p < 0.0001) with no heterogeneity.ConclusionData from case–control studies do not support a link between IgG/IgM aPL and MS. Data from cohort studies comparing active vs stable MS indicate a strong link between aPL of IgM isotype and active/relapsing MS but in the absence of aPL titres to comment upon this may either represent an epiphenomenon of active neuro-inflammation or natural autoantibodies devoid of pathogenic potential. Data expressed as frequency of aPL positive participants rather than average titres preclude further assumptions.     

IgM, but not IgA rheumatoid factor interferes with anti-cardiolipin and antiβ2 glycoprotein I measurements: a quantitative analysis

IgM rheumatoid factor (RF) is sometimes referred to as capable of causing interference in the IgM anti-cardiolipin (aCL) testing. Published guidelines are, however, inconsistent, and evidence regarding the interference is limited. Our goal was investigate IgM and IgA RF cross-reactivity and/or interference in IgM and IgA aCL and anti-β2 glycoprotein I (aβ2GPI) testing. Serum specimens with high IgM and IgA RF levels were tested for IgG, IgA and IgM aCL and aβ2GPI antibodies to examine cross-reactivity. Samples containing IgG aCL and aβ2GPI antibodies were spiked with IgM (and IgA) RF, and samples with high RF levels were spiked with IgG aCL antibodies. The mixtures were tested for IgM and IgA aCL and aβ2GPI antibodies. Specimens with high IgM and IgA RF concentrations did not test positive for IgM or IgA aCL and aβ2GPI antibodies (except one weak positive IgA aβ2GPI result), indicating the lack of cross-reactivity. In the spiked specimens, addition of IgM RF caused significant positive bias in the measurement of both aCL and aβ2GPI antibodies of IgM isotype in the presence of IgG aCL and aβ2GPI antibodies. The threshold for triggering significant interference was 318(?)IU/ml for IgM RF, and 77?GPLU/ml for IgG aCL. Neither IgM, nor IgA RF, however, affected the IgA antiphospholipid (aPL) antibody testing. IgM RF can cause a false-positive IgM aCL result in the presence of IgG aCL antibodies. In studies on the prevalence and clinical significance of IgM aPL antibodies, RF interference should be considered and RF testing should be performed.     

Elevated partial antiphospholipid score is a strong risk factor for thrombosis in patients with systemic lupus erythematosus: a validation study

This study aims to identify risk factors for thrombosis in patients with systemic lupus erythematosus (SLE) and to validate the efficacy of the partial antiphospholipid (aPL) score for thrombosis prediction and diagnosis of antiphospholipid syndrome (APS). This study included 325 SLE patients, 188 of whom completed a follow-up of 31.01 months (range 23–48 months). Partial aPL score was calculated by adding up the individual scores for activated partial thromboplastin time (APTT), lupus anticoagulant, IgG/IgM anticardiolipin antibodies (aCL), and IgG/IgM anti-β2-glycoprotein I (anti-β2GPI). A simplified aPL score was developed using only APTT, IgG/IgM aCL, and IgG/IgM anti-β2GPI. Partial aPL scores were significantly higher in SLE patients with thrombosis (p?<?0.0001). A history of thrombosis (p?<?0.0001), a partial aPL score >10 (p?<?0.0001), and immunosuppressant use (p?=?0.012) were independent risk factors for thrombosis. For patients with a history of thrombosis, partial aPL score was the strongest risk factor for recurrent thrombosis (p?<?0.0001, odds ratio?=?30.34 (95 % CI 7.70–118.81)). For APS diagnosis, the area under the receiver-operating characteristic curve (AUC) was 0.809 (95 % CI 0.73–0.89) using the partial aPL score. Similarly, the simplified aPL score was significantly associated with thrombosis (p?<?0.0001) and was acceptable for APS diagnosis (AUC 0.797, 95 % CI 0.72–0.88). An elevated partial aPL score is a strong risk factor for thrombosis in SLE patients and is a useful tool to predict recurrent thrombosis. Partial aPL score and simplified aPL score, although comprising fewer items than the original aPL score, also represent valuable quantitative indices for APS diagnosis.     

Calculated glomerular filtration rate is a useful screening tool to identify scleroderma patients with renal impairment

OBJECTIVES: Although it only occurs in a minority of patients, renal involvement is a life-threatening complication of scleroderma (SSc). We have investigated the utility of two formulae to calculate glomerular filtration rate (GFR) in a population of SSc patients. METHODS: Twenty-six patients (20 female, 6 male, median age 58 yr, age range 12-80 yr) satisfied our criteria for inclusion in a retrospective comparison of measured and calculated GFR. GFR was measured using (51)Cr-EDTA. The modified Cockcroft and Gault formula and equation 7 from the Modification of Diet in Renal Disease (MDRD) were used to calculate GFR. RESULTS: Eighteen out of 19 patients analysed with a serum creatinine concentration less than the upper limit of the normal range had a measured GFR outside the normal range. Three patients with a normal creatinine concentration had a measured GFR <60 ml/min and in each of these the calculated GFR was also abnormal. All patients with a measured GFR <60 ml/min were identified using both the MDRD and the modified Cockcroft and Gault formula to calculate GFR. The greatest correlation between measured and calculated GFR was seen when the MDRD formula, which employs demographic and serum variables, was used in patients with body surface area (BSA) >1.4 m(2) who were not taking Iloprost (r=0.91). Use of the Cockcroft and Gault formula to calculate creatinine clearance with a correction factor for GFR, the inclusion of patients taking Iloprost and the inclusion of patients with BSA <1.4 m(2) were all associated with a lower degree of correlation. CONCLUSION: Serum creatinine is a poor marker of renal function in SSc patients. Calculating GFR from demographic and serum variables is a simple technique to identify SSc patients who have abnormal renal function. The authors recommend the use of the MDRD formula.     

IgA anti-beta-2 glycoprotein I antibodies in chronic hepatitis C

Background and study aimsAntiphospholipid antibodies (aPL) have been reported not only in various autoimmune conditions but also in other infections, such as chronic hepatitis C (CHC) infection. The aim of this study is to evaluate the frequency of aPL in patients with CHC.Patients and methodsNinety-six CHC patients and 90 healthy blood donors (HBD) were studied. Fifty-three of the patients were under treatment, and 43 had not yet received any treatment. IgG, IgA, and IgM antibodies against cardiolipin (aCL) and beta-2 glycoprotein I (aβ2GPI) were detected by ELISA.ResultsWe found that the frequency of aPL (aCL and/or aβ2GPI) was significantly higher in CHC patients than in controls (51% vs 11.1%, p <10^?6). The frequencies of aCL and aβ2GPI were significantly higher in patients than in HBD (27.1% vs 5.5%, p < 10^?3, and 44.8% vs 11.1%, p < 10^?6, respectively). The isotype distribution of aCL and aβ2GPI demonstrated that aCL-IgG and aβ2GPI-IgA were more frequent in patients than in healthy subjects (21.9% vs 2.2%, p < 10^?3, and 38.5% vs 7.8%, p < 10^?6, respectively). In CHC patients, the frequency of aβ2GPI was significantly higher than that of aCL (44.8% vs 27.1%, p = 0.01). aβ2GPI-IgA was significantly more frequent than aβ2GPI-IgG (38.5% vs 7.3%, p <10^?6), aβ2GPI-IgM (38.5% vs 9.4%, p <10^?3), and aCL-IgG (38.5% vs 21.9%, p = 0.01). No difference in aPL frequency was observed between the treated and untreated patients.ConclusionOn the basis of the findings of this study, aPL, particularly aβ2GPI-IgA and aCL-IgG, are frequent in CHC patients.     

Clinical setting of patients with systemic sclerosis by serum autoantibodies

Summary Associations of antinuclear (ANA) and anticardiolipin (aCL) antibodies with clinical manifestations were analyzed in patients with systemic sclerosis (SSc).We studied 105 SSc patients: 28 had limited cutaneous SSc (IcSSc) involving fingers; 36 had intermediate cutaneous SSc involving limbs and face; 33 had diffuse cutaneous SSc (dcSSc) involving the trunk; 8 had a sclerosis sine scleroderma. Clinical manifestations and instrumental and laboratory findings were considered to calculate a disease score. Serum anticentromere (ACA), anti-topoisomerase I (anti-topo I) antibodies, and aCL (of IgG/IgA/IgM classes) were investigated by conventional methods. ACA positive patients (n=18), compared to ACA negative, showed higher prevalence of IcSSc (p < 0.001), lower prevalence of restrictive ventilatory defect (p=0.006), and lower disease score (p=0.008). Anti-topo I positive patients (n=70) showed lower prevalence of IcSSc (p=0.001) compared to anti-topo I negative. In aCL positive patients (n=27) widespread skin and visceral involvement occurred more frequently than in aCL negative. The association with myocardial ischemia or necrosis (p=0.010) was significant. Occurrence of ACA excluded the coexistence of anti-topo I (p<0.001), and aCL (p=0.037). aCL positive patients showed higher disease score in comparison with ACA positive patients (p=0.003). In conclusion ACA recognize patients with a mild disease. aCL in contrast to ACA are better than anti-topo I in recognizing the most severe pictures of SSc.     

Renal disease in systemic sclerosis with normal serum creatinine

Prognosis of systemic sclerosis largely depends on involvement of internal organs. The aim was to evaluate renal impairment in patients with systemic sclerosis by measuring the Glomerular filteration rate (GFR) and then calculating the GFR using the Cockgroft and Gault formula and the Modification of Diet in Renal Disease Equation (MDRD) formula. Thirty one scleroderma patients were recruited from the Rheumatology and Rehabilitation Department, Cairo University Hospitals, mean age 43.25 ± 11.28 years, 31 healthy controls were included. Disease severity was done using Medsger score. GFR was measured using classical Gates method TC99mDTPA. The modified Cockcroft and Gault formula and equation 7 from the MDRD were used for calculation of GFR. All patients had within normal serum creatinine levels. A normal GFR (>89ml/min) was found in 45.1%. Gates method showed reduced GFR was reported in 54.9%. Stage II chronic kidney disease (60-89 ml/min) found 32.3%, and stage III (30-59 ml/min) in 22.6%. The formulae used showed reduction of GFR in 35.29% of those affected by the Cockcroft-Gault and in 41.17% of those affected using the MDRD. No correlation to patients’ age, disease duration, or severity. A positive correlation was also reported between the presence of renal involvement and pulmonary vascular involvement p = 0.04. Gates method showed reduction of the GFR in 54.9% of the systemic sclerosis patients. The formulae used were not as precise as the measured GFR in diagnosing all cases with subclinical renal involvement. Patients with systemic sclerosis should be screened for renal involvement irrespective of disease severity or duration.     

Anti-agalactosyl IgG antibodies in Thai patients with rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis

This study was performed to determine the prevalence of anti-agalactosyl IgG antibodies in Thai patients with RA, systemic lupus erythematosus (SLE) and systemic sclerosis (SSc), and determine the sensitivity and specificity of anti-agalactosyl IgG antibodies in the diagnosis of RA in comparison with IgM-rheumatoid factor (IgM-RF) and anti-cyclic citrullinated peptide (anti-CCP) antibodies. Serum samples were obtained from 100 patients with RA, 50 cases of SLE, 50 cases of SSc, and 100 healthy controls and analyzed for the presence of anti-agalactosyl IgG antibodies, IgM-RF and anti-CCP antibodies. A serum value greater than mean + 2 standard deviation of normal value of anti-agalactosyl IgG antibodies and anti-CCP antibodies was considered positive. The prevalence of anti-agalactosyl IgG antibodies in RA, SLE, and SSc patients was 88.0%, 14.0%, and 12.0%, respectively. The serum level of anti-agalactosyl IgG antibodies in patients with RA (227.10 ± 353.64 AU/mL) was significantly higher than those in SLE (11.84 ± 52.04 AU/mL), SSc (18.85 ± 99.60 AU/mL), and healthy controls (2.14 ± 1.97 AU/mL), (p < 0.001). There was a good correlation between the log serum level of anti-agalactosyl IgG antibodies and IgM-RF (r = 0.92, p < 0.001), anti-CCP antibodies and IgM-RF (r = 0.49, p < 0.001), and anti-agalactosyl IgG antibodies and anti-CCP antibodies (r = 0.55, p < 0.001). The sensitivity and specificity in the diagnosis of RA was 88.00% and 96.00% for anti-agalactosyl IgG antibodies, 90.00% and 99.00% for anti-CCP antibodies, and 91.00% and 95.00% for IgM-RF, respectively. The serum level of anti-agalactosyl IgG antibodies was significantly higher in RA than in SLE, SSc, and healthy controls. There was a good correlation between serum levels of anti-agalactosyl IgG antibodies, anti-CCP antibodies, and IgM-RF. These three tests had comparable sensitivity and specificity.     

Estimating glomerular filtration rate in diabetes: a comparison of cystatin-C- and creatinine-based methods

Aims/hypothesis We compared the predictive performance of a GFR based on serum cystatin C levels with commonly used creatinine-based methods in subjects with diabetes.Subjects, materials and methods In a cross-sectional study of 251 consecutive clinic patients, the mean reference (plasma clearance of ^99mTc-diethylene-triamine-penta-acetic acid) GFR (iGFR) was 88±2 ml min⁻¹ 1.73 m⁻². A regression equation describing the relationship between iGFR and 1/cystatin C levels was derived from a test population (n=125) to allow for the estimation of GFR by cystatin C (eGFR-cystatin C). The predictive performance of eGFR-cystatin C, the Modification of Diet in Renal Disease 4 variable formula (MDRD-4) and Cockcroft–Gault (C–G) formulas were then compared in a validation population (n=126).Results There was no difference in renal function (ml min⁻¹ 1.73 m⁻²) as measured by iGFR (89.2±3.0), eGFR-cystatin C (86.8±2.5), MDRD-4 (87.0±2.8) or C–G (92.3±3.5). All three estimates of renal function had similar precision and accuracy.Conclusions/interpretation Estimates of GFR based solely on serum cystatin C levels had the same predictive potential when compared with the MDRD-4 and C–G formulas.     

Simple cystatin C formula compared to sophisticated CKD-EPI formulas for estimation of glomerular filtration rate in the elderly

Despite the fact that the serum creatinine level is notoriously unreliable for the estimation of glomerular filtration rate (GFR) in the elderly, the serum creatinine concentration and serum creatinine-based formulas, such as the Modification of Diet in Renal Disease study equation (MDRD) are the most commonly used markers to estimate GFR. Recently, serum cystatin C-based formulas, the newer creatinine formula (the Chronic Kidney Disease Epidemiology Collaboration formula (CKD-EPI creatinine formula), and an equation that uses both serum creatinine and cystatin C (CKD-EPI creatinine and cystatin formula) were proposed as new GFR markers. The aim of our study was to compare the MDRD formula, CKD-EPI creatinine formula, CKD-EPI creatinine and cystatin formula, and simple cystatin C formula (100/serum cystatin C) against (51) Cr-EDTA clearance in the elderly. A total of 317 adult Caucasian patients aged >65 years were enrolled. In each patient, (51) Cr-EDTA clearance, serum creatinine, and serum cystatin C were determined, and the GFR was calculated using the MDRD formula, CKD-EPI formulas, and simple cystatin C formula. Statistically significant correlations between (51) Cr-EDTA clearance and all formulas were found. In the receiver operating characteristic (ROC) curve analysis with a cut-off of GFR 45 mL/min/1.73 m(2), a higher diagnostic accuracy was achieved with the equation that uses both serum creatinine and cystatin C (CKD-EPI creatinine and cystatin formula) than the MDRD formula (P < 0.013) or CKD-EPI creatinine formula (P < 0.01), but it was not higher than that achieved for the simple cystatin C formula (P = 0.335). Bland and Altman analysis for the same cut-off value showed that the creatinine formulas underestimated and the simple cystatin C formula overestimated measured GFR. All equations lacked precision. The accuracy within 30% of estimated (51) Cr-EDTA clearance values differ according to the stage of CKD. Analysis of the ability to correctly predict GFR below and above 45 mL/min/1.73 m(2) showed a high prediction for all formulas. Our results indicate that the simple cystatin C formula, which requires just one variable (serum cystatin C concentration), is a reliable marker of GFR in the elderly and comparable to the creatinine formulas, including the CKD-EPI formulas.     

Real world experience with antiphospholipid antibody tests: how stable are results over time?

OBJECTIVE: To determine the stability and the degree of variation of antiphospholipid antibody (aPL) results over time in a large cohort of well evaluated aPL positive patients; and to analyse factors contributing to aPL variation and the validity of aPL in a real world setting in which aPL tests are done in multiple laboratories. METHODS: The clinical characteristics, drug treatment, and 1652 data points for lupus anticoagulant (LA), anticardiolipin antibodies (aCL), and anti-beta2 glycoprotein I antibodies (anti-beta2GPI) were examined in 204 aPL positive patients; 81 of these met the Sapporo criteria for antiphospholipid syndrome (APS) and 123 were asymptomatic bearers of aPL. RESULTS: 87% of initially positive LA results, 88% of initially negative to low positive aCL results, 75% of initially moderate to high positive aCL results, 96% of initially negative to low positive anti-beta2GPI results, and 76% of initially moderate to high positive anti-beta2GPI results subsequently remained in the same range regardless of the laboratory performing the test. Aspirin, warfarin, and hydroxychloroquine use did not differ among patients whose aCL titres significantly decreased or increased or remained stable. On same day specimens, the consistency of aCL results among suppliers ranged from 64% to 88% and the correlation ranged from 0.5 to 0.8. Agreement was moderate for aCL IgG and aCL IgM; however, for aCL IgA agreement was marginal. CONCLUSIONS: aPL results remained stable for at least three quarters of subsequent tests, regardless of the laboratory performing the test; the small amount of variation that occurred did not appear to be caused by aspirin, warfarin, or hydroxychloroquine use.     

Significance of antiprothrombin antibodies in patients with systemic lupus erythematosus: clinical evaluation of the antiprothrombin assay and the antiphosphatidylserine/prothrombin assay, and comparison with other antiphospholipid antibody assays

Antibodies against prothrombin are detected by enzyme immunoassays (EIA) in sera of patients with antiphospholipid syndrome (APS). However, there are two methods for antiprothrombin EIA; one that uses high binding plates (aPT-A), and another that utilizes phosphatidylserine bound plates (aPS/PT). We aimed to evaluate and compare aPT-A and aPS/PT in a clinical setting. We performed EIA for anti-PT, anti-PS/PT, IgG, and IgM anticardiolipin antibodies (aCL), and IgG β2-glycoprotein I-dependent aCL (aβ2GPI/CL) with serum samples from 139 systemic lupus erythematosus (SLE) patients (16 with history of at least one thrombotic episode) and 148 controls. We observed that: (1) although titers of anti-PT and anti-PS/PT were significantly related with each other (P < 0.0001, ρ = 0.548), titer of anti-PT and anti-PS/PT differed greatly in some samples; (2) odds ratio and 95% confidence interval for each assay was 3.556 (1.221–10.355) for aPT-A, 4.591 (1.555–15.560) for aPS/PT, 4.204 (1.250–14.148) for IgG aCL, 1.809 (0.354–9.232) for IgM aCL, and 7.246 (2.391–21.966) for aβ2GPI/CL. We conclude that, while all EIA performed in this study except IgM aCL are of potential value in assessing the risk of thrombosis, aPS/PT and aβ2GPI/CL seemed to be highly valuable in clinical practice, and that autoantibodies detected by anti-PT and anti-PS/PT are not completely identical.     

Altered adhesion molecules expression on peripheral blood mononuclear cells from patients with systemic sclerosis and clinical correlations

The aim of the study was to evaluate the expressions of adhesion molecules (AM) on peripheral blood mononuclear cells (PBMNC) from systemic sclerosis (SSc) patients. Thirty-one SSc patients (ACR) and 20 normal subjects were selected for the study. PBMNC were analyzed for LFA-1α, LFA-1β, ICAM-3, ICAM-1, and l-selectin expressions. ICAM-3 expression was decreased while ICAM-1 was increased on SSc PBMNC, compared to controls (p = 0.04 and 0.003, respectively). A positive association was found between LFA-1α (r = 0.37, p = 0.03), LFA-1β (r = 0.38, p = 0.002), ICAM-3 (r = 0.42, p = 0.01), and l-selectin (r = 0.38, p = 0.03) expressions and greater number of immunosuppressive drugs taken by SSc patients. Also, anti-centromeric positive SSc patients had lower expressions of LFA-1α, LFA-1β, ICAM-3, and l-selectin. Lower expression of ICAM-3 and higher expression of ICAM-1 suggest that AMs may be involved in the pathogenesis of scleroderma.     

Interpretation and recommended testing for antiphospholipid antibodies

The antiphospholipid syndrome (APS) is defined by the association of arterial and/or venous thrombosis and/or pregnancy complications with the presence of at least one of the main laboratory-detected antiphospholipid antibodies (aPL) (i.e., lupus anticoagulants [LA], IgG and/or IgM anticardiolipin antibodies [aCL], and IgG and/or IgM anti-β2-glycoprotein I antibodies [aβ2GPI]). During the last decade efforts have been made to improve the harmonization and reproducibility of laboratory detection of aPL and guidelines have been published. The prognostic significance of aPL is being clarified through the fine elucidation of their antigenic targets and pathogenic mechanisms. Several clinical studies have consistently reported that LA is a stronger risk factor for both arterial and venous thrombosis compared with aCL and aβ2GPI. In particular, LA activity dependent on the first domain of β2-glycoprotein I and triple aPL positivity are prognosticators of the thrombotic and obstetric risks. Hopefully, this increasing knowledge will help improve diagnostic and treatment strategies for APS.     

Prevalence and isotype distribution of antiphospholipid antibodies in unselected Chilean patients with venous and arterial thrombosis

Antiphospholipid antibodies (aPL) are a heterogeneous family of antibodies associated with thrombotic events and other complications. The objective of this study was to investigate the prevalence of aPL in a group of Chilean patients with thrombosis. Two hundred and twenty-six patients with venous and arterial thrombosis and 95 healthy controls were studied. Anticardiolipin (aCL), anti-₂ glycoprotein I (anti-₂GPI), and antiprothrombin (aPT) antibodies were determined. Eighty-eight out of 226 (38.9%) patients with thrombosis had some type of aPL. Fifty-seven patients (25.2%) were positive for aCL, 31 (13.7%) for aPT, and 14 (6.2%) for anti-₂GPI antibodies. Twelve patients (5.3%) were positive for more than one aPL. IgG, IgM and IgA isotypes were observed in aCL, anti-₂GPI, and aPT antibodies. Twenty-six out of 92 (28.3%) patients with venous thrombosis and 31/134 (23.1%) patients with arterial thrombosis were positive for aCL antibodies. With regard to the control group (4/95=4.2%), the odd ratios (OR) were 5.2 (1.3–19.8; p0.01) and 5.7 (1.6–22.3; p0.01), respectively. Additionally, we observed statistically significant OR with aPT and anti-₂GPI antibodies; in the first, with venous and arterial thrombosis, and in the second, only with arterial thrombosis. Our results show a significant prevalence of aPL, predominantly aCL and aPT antibodies, in patients with thrombosis. Additionally, aCL and aPT antibodies appear to be a risk factor for venous and arterial thrombosis, and anti-₂GPI antibodies appear to be a risk factor for arterial thrombosis.Abbreviations aCL Anticardiolipin antibodies - aPL Antiphospholipid antibodies - AMI Acute myocardial infarction - BSA Bovine serum albumin - DVT Deep venous thrombosis - FBS Fetal bovine serum - IS Ischemic stroke - LA Lupus anticoagulant - RT Room temperature - RVT Retinal vein thrombosis - SLE Systemic lupus erythematosus     

The clinical significance of serum N-terminal pro-brain natriuretic peptide in systemic sclerosis patients

We evaluated the clinical significance of serum N-terminal pro-brain natriuretic peptide (NT-proBNP) level in systemic sclerosis (SSc). We studied 45 SSc patients (30 with limited and 15 with diffuse cutaneous SSc) of mean age ± SD 47.1 ± 12.9 years, mean duration of disease 10.2 ± 6.0 years, and 45 age- and sex-matched healthy controls. Pulmonary artery pressure was measured by echocardiography. Lung involvement was evaluated by pulmonary function testing and by using high-resolution computed tomography scores. Serum NT-proBNP levels were measured using a sandwich electrochemiluminescent immunoassay. Serum NT-proBNP levels were significantly higher in patients with SSc compared to healthy controls. When the patients were divided into clinical subsets, serum NT-proBNP was higher in diffuse SSc than in limited SSc. Serum NT-proBNP levels were found to be positively correlated with age, skin thickness score, and systolic pulmonary artery pressure and negatively correlated with percentage of carbon monoxide diffusion capacity (DLco). Multivariate analysis showed that serum NT-proBNP levels were positively correlated with age (p = 0.010), skin thickness score (p = 0.000), and blood pressure (p = 0.021) and negatively correlated with %DLco (p = 0.016). Fifty-seven percent of the variation in log (proBNP) can be explained by the multivariate model (R ² = 0.57). Serum NT-proBNP levels were higher in SSc patients (particularly the diffuse subset) than in healthy controls and were found to be correlated with skin thickness and %DLco. We conclude that serum NT-proBNP may be a biologic marker of skin fibrosis and pulmonary vascular involvement in SSc.     

Evaluation of three commercial ELISA kits for anticardiolipin and anti‐beta2‐glycoprotein I antibodies in the laboratory diagnosis of the antiphospholipid syndrome

Introduction: The laboratory criteria of the antiphospholipid syndrome (APS) include lupus anticoagulant (LAC), anticardiolipin antibodies (aCL) and anti‐β2glycoprotein I antibodies (aβ2GPI) IgG or IgM. Methods: We evaluated three commercial ELISAs for aCL and aβ2GPI IgG and IgM: Asserachrom^® (‘Stago’), Bio‐Rad (‘BR’) and the Bindazyme? (the Binding Site, ‘BS’). Results: Results of all assays and of LAC were correlated with the clinical background (n = 228). Sensitivity for Stago/BS/BR aCL IgG was 14%/15%/18%, for aCL IgM 1%/5%/4%, for aβ2GPI IgG 9%/10%/17% and for aβ2GPI IgM 4%/4%/3%. The specificity for Stago/BS/BR for all assays ranged from 86% to 98%. The positive predictive value (PPV) for Stago/BS/BR aCL IgG was 46%/52%/40%, for aCL IgM 8%/36%/19%, for aβ2GPI IgG 70%/67%/45% and for aβ2GPI IgM 23%/23%/20%. Combining LAC with aCL and aβ2GPI antibodies increased the sensitivity (Stago/BS/BR IgG: 26%/27%/31%, IgM: 22%/21%/26%) and PPV (Stago/BS/BR IgG: 41%/46%/36%, IgM: 34%/40%/36%). Comparing the diagnostic power of the tests, only Stago/BS aβ2GPI IgG had a Chi‐square P‐value lower than 0.05. The combination of LAC and IgG ELISAs of BS resulted in the lowest P‐value (0.098) compared to the other combinations. Conclusion: All evaluated ELISAs are a practical tool in the laboratory diagnosis of APS. The diagnostic performance shows slight differences between the ELISAs from the different manufacturers.