Antiphospholipid antibodies in patients with lupus nephritis

Anti-Phosphatidylethanolamine and Anti-Phosphatidylserine Antibodies—Association with Renal Involvement, Atherosclerosis, Cardiovascular Manifestations, Raynaud Phenomenon and Disease Activity in Polish Patients with Systemic Lupus Erythematosus

Objective. To evaluate the association between anti-phosphatidylethanolamine (aPE) and anti-phosphatidylserine (aPS) antibodies and cardiovascular risk, organ involvement and disease activity in systemic lupus erythematosus (SLE) patients. Methods. We studied 93 SLE patients and 30 controls. We analyzed levels of anti-phospholipid antibodies, including aPS and aPE, the profiles of antinuclear, anti-neutrophil cytoplasmic (ANCA) and anti-endothelial antibodies, carotid intima-media thickness (cITM) and atherosclerotic plaque presence, ankle-brachial and high resistance indices, atherosclerotic risk factors, organ manifestations and treatment. Results. Levels of aPS and aPE were significantly higher in SLE patients in comparison with the controls (p = 0.038 and p = 0.044, respectively). aPS was associated with the risk of Raynaud’s phenomenon (p = 0.021) development. aPE increased the risk of renal involvement (p = 0.049), cerebral stroke (p = 0.050), high vlues of cIMT (p = 0.041) development as well as occurrence of selected serological markers associated with activity of the disease such as anti-double stranded DNA (p = 0.021). The long duration of regular smoking (p = 0.021) and the high number of cigarettes/day (p = 0.015) were significantly associated with the risk of aPE occurrence. Conclusions. Patients with aPS and aPE are at risk of vascular involvement. Especially the presence of aPE may significantly increase the risk of thrombotic complications development in SLE patients without classical serological markers of APS. Finally, aPE might be used as a marker of disease activity and risk of renal injury development in this patient group. The classical atherosclerotic markers including lipid indices play an important role in complex analysis of cardiovascular risk in lupus patients and enable to identify patients at the highest risk and implement effective preventive, diagnostic and therapeutic procedures.

Antiphospholipid antibody profiles in lupus nephritis with glomerular microthrombosis: a prospective study of 124 cases

Introduction

Glomerular microthrombosis (GMT) is a common vascular change in patients with lupus nephritis (LN). The mechanism underlying GMT is largely unknown. Although several studies have reported the association of antiphospholipid antibodies (aPL) with GMT, the relation between GMT and aPL remains controversial. Previous studies have demonstrated that some aPL could bind to several hemostatic and fibrinolytic proteases that share homologous enzymatic domains. Of the protease-reactive aPL, some can inhibit the anticoagulant activity of activated protein C and the fibrinolytic function of plasmin, and hinder the antithrombin inactivation of thrombin. The purpose of this study was to investigate the prevalence of GMT in LN patients and examine the relation between the aPL profiles (including some protease-reactive aPL) and GMT.

Methods

Renal biopsy specimens were examined for the presence of glomerular microthrombi. Plasma samples from 25 LN patients with GMT (LN-GMT group) and 99 LN patients without GMT (LN-non-GMT group) were tested for lupus anticoagulant and antibodies against cardiolipin, β2 glycoprotein I, plasmin, thrombin, tissue plasminogen activator, and annexin II.

Results

The prevalence of GMT in LN patients was 20.2%. Compared with the LN-non-GMT group, the LN-GMT group had an elevated systemic lupus erythematosus disease activity index; elevated renal tissue injury activity and chronicity indices; elevated serum creatinine, blood urea nitrogen, and proteinuria levels; a lower serum C3 level and much intense glomerular C3, C1q staining; and a higher frequency of hypertension (P < 0.05 for all). Additionally, the detection rate of lupus anticoagulant, immunoglobulin G (IgG) anti-β2 glycoprotein I and anti-thrombin antibodies were higher in the LN-GMT group than in the LN-non-GMT group (P < 0.05 for all). No statistical differences were found in the detection rates of IgG anti-cardiolipin, plasmin, tissue plasminogen activator, or annexin II antibodies (P > 0.05 for all). No detectable difference in IgM autoantibodies to the above antigens was observed between the two groups.

Conclusions

GMT occurs in approximately 20.2% of LN patients. Patients with GMT have severer renal tissue injuries and poorer renal functions than patients without GMT. The lupus anticoagulant and antibodies against β2 glycoprotein I and thrombin may play a role in GMT.

Apolipoprotein H promoter polymorphisms in relation to lupus and lupus-related phenotypes

OBJECTIVE

Sequence variation in gene promoters is often associated with disease risk. We tested the hypothesis that common promoter variation in the APOH gene (encoding for ss(2)-glycoprotein I) is associated with systemic lupus erythematosus (SLE) risk and SLE-related clinical phenotypes in a Caucasian cohort.

METHODS

We used a case-control design and genotyped 345 women with SLE and 454 healthy control women for 8 APOH promoter single-nucleotide polymorphisms (SNP; -1284C>G, -1219G>A, -1190G>C, -759A>G, -700C>A, -643T>C, -38G>A, and -32C>A).Association analyses were performed on single SNP and haplotypes. Haplotype analyses were performed using EH (Estimate Haplotype-frequencies) and Haploview programs. In vitro reporter gene assay was performed in COS-1 cells. Electrophoretic mobility shift assay (EMSA) was performed using HepG2 nuclear cells.

RESULTS

Overall haplotype distribution of the APOH promoter SNP was significantly different between cases and controls (p = 0.009). The -643C allele was found to be protective against carotid plaque formation (adjusted OR 0.37, p = 0.013) among patients with SLE. The -643C allele was associated with a ~2-fold decrease in promoter activity as compared to wild-type -643T allele (mean +/- standard deviation: 3.94 +/- 0.05 vs 6.99 +/- 0.68, p = 0.016). EMSA showed that the -643T>C SNP harbors a binding site for a nuclear factor. The -1219G>A SNP showed a significant association with the risk of lupus nephritis (age-adjusted OR 0.36, p = 0.016).

CONCLUSION

Our data indicate that APOH promoter variants may be involved in the etiology of SLE, especially the risk for autoimmune-mediated cardiovascular disease.

Antiphospholipid syndrome and the kidneys

OBJECTIVES

To study the relationship between antiphospholipid antibodies and kidney diseases.

METHODS

We reviewed the medical literature from 1968 to 2005 using MEDLINE and the keywords antiphospholipid syndrome, anticardiolipin antibodies, lupus anticoagulant, hypertension, renal artery stenosis, renal vascular thrombosis, thrombotic microangiopathy, and glomerulonephritis.

RESULTS

The renal manifestations of the antiphospholipid syndrome may result from thrombosis occurring at any location within the renal vasculature, that is, in the renal artery trunk or branches, intraparenchymal arteries and arterioles, glomerular capillaries, and the renal veins. The spectrum of these manifestations includes renal artery stenosis and/or malignant hypertension, renal infarction, renal vein thrombosis, thrombotic microangiopathy, increased allograft vascular thrombosis, and reduced survival of renal allografts. More recently nonthrombotic conditions like glomerulonephritis have also been reported.

CONCLUSION

The kidney appears to be a major target organ in both primary and secondary APS. Early detection of renal involvement may improve the prognosis of these patients.