Occurrence of thrombotic thrombocytopenic purpura in a systemic lupus erythematosus patient with antiphospholipid antibodies in association with a decreased activity of von Willebrand factor-cleaving protease

Beta2-glycoprotein I Expression in Lupus Nephritis Patients with Antiphospholipid-associated Nephropathy

OBJECTIVE

Antiphospholipid-associated nephropathy (aPLN) is a severe condition in patients with lupus nephritis (LN). aPLN should be distinguished from other reasons for renal ischemia. The most important cofactor of antiphospholipid antibodies (aPL), β2-glycoprotein I (β2GPI), was shown in vitro to bind endothelial cells and to induce a procoagulant phenotype. The objectives of this study were to investigate whether β2GPI expression was involved in patients with LN with aPLN and to determine its specificity.

METHODS

We retrospectively investigated β2GPI expression in 231 renal biopsy specimens of patients with LN. Data from biopsy reports and clinical information were collected. Immunohistochemical staining for β2GPI expression was performed.

RESULTS

Histological aPLN was detected in 88 patients with LN (38.1%). The LN with aPLN consisted of 43 patients (18.6%). Expression of β2GPI was detected in endothelial cells in 14 (32.6%) in renal arteries or arterioles, 11 (25.6%) in glomerular or peritubular capillaries, and a total of 15 (34.9%) of the 43 patients with LN with aPLN. It was mainly expressed in the endothelial cells in patients with LN with aPLN (p < 0.05). The specificity of β2GPI expression in patients with LN with aPLN was 97.5%.

CONCLUSION

Expression of β2GPI may be involved in the formation of aPLN in patients with LN. This expression in endothelial cells in kidney tissue may be considered a useful marker for aPLN.

Catastrophic APS in the context of other thrombotic microangiopathies

The catastrophic antiphospholipid syndrome (CAPS) is a rare disease that affects 1 % of cases with antiphospholipid syndrome (APS). CAPS can mimic or overlap with different thrombotic diseases; many patients present with a microthrombotic storm or thrombotic microangiopathic hemolytic anemia (TMHA). Thus, the differential diagnosis of CAPS includes thrombotic thrombocytopenic purpura (TTP), typical and atypical hemolytic uremic syndrome (HUS), systemic infections, malignancies, pregnancy-related disorders, malignant hypertension, heparin-induced thrombocytopenia, and drug-induced thrombotic microangiopathies. Antiphospholipid antibody (aPL) positivity has been proposed as the clue in this differential diagnosis; however, aPL can also occur in healthy people and in those with infections or malignancies. Thus, the differential diagnosis of an aPL-positive patient presenting with a microthrombotic storm is broad; the workup should include a special attention to signs of infection and disseminated malignant disease, assessing the funduscopic signs of malignant hypertension, testing ADAMTS13 activity and anti-heparin-platelet factor 4 (HPF4) antibodies, and searching previous exposure to certain drugs. This article aims to review the main diseases included in the differential diagnosis of CAPS in the context of other thrombotic microangiopathies.

Clinical characteristics and prognosis of diffuse proliferative lupus nephritis with thrombotic microangiopathy

We retrospectively analyzed the clinicopathologic characteristics and prognosis of 33 patients with diffuse proliferative lupus nephritis (class IV LN) complicated with thrombotic microangiopathy (TMA). Eighty-one percent of patients had renal dysfunction (mean Scr 3.1 ± 2.0 mg/dl), among whom 42.4% needed acute hemodialysis. Nephrotic proteinuria, gross hematuria and hypertension were presented in 57.6%, 24.2% and 93.9% of the patients. Microangiopathic hemolytic anemia, serum anti-dsDNA and anticardiolipin antibodies were found in 60.6%, 75.8% and 33.3% of the patients. Renal biopsy showed IV-G in 75.8%, class IV with class V in 21.2%, and IV-S in 1.23% of the patients. Glomerular segmental necrosis, microthrombi, crescents and arteriolar thrombosis were found in 51.5%, 69.7%, 60.6% and 60.7% of the patients, respectively. The follow up was 1 to 101 months (median 13 months). Only 50% of patients showed response to treatment. Three patients died, 10 developed end-stage renal failure (ESRF). The 5-year patient and renal survival rate was 69.2% and 46.7%, respectively. Major risks for ESRF included: a need for acute dialysis on admission, no response to the treatment and high renal chronic index. The results showed that class IV lupus nephritis with TMA has high mortality and low renal survival.

Treatment options for patients who have antiphospholipid syndromes

The antiphospholipid thrombosis syndrome, associated with anticardiolipin (aCL) or subgroup antibodies, can be divided into one of six subgroups (I-VI). There is little overlap (about 10% or less) between these subtypes, and patients usually conveniently fit into only one of these clinical types. Although there appears to be no correlation with the type, or titer, of aCL antibody and type of syndrome, the subclassification of thrombosis and aCL antibody patients into these groups is important from the therapy standpoint. This article also reviews the clinical presentations associated with each of these six subgroups.

The clinical spectrum of antiphospholipid syndrome

Antiphospholipid syndrome (APS) is a disorder characterized by a wide variety of clinical manifestations. Virtually any organ system or tissue may be affected by the consequences of large- or small-vessel thrombosis. There is a broad spectrum of disease among individuals with antiphospholipid antibodies (aPL). Patients may exhibit clinical features suggesting APS but not fulfill the International Criteria for a "definite" diagnosis. Seronegative APS patients demonstrate typical idiopathic thromboses but aPL are not initially detected. Patients defined with definite APS demonstrate nearly identical sites of venous and arterial thrombosis, regardless of the presence or absence of systemic lupus erythematosus. Microangiopathic APS may present with isolated tissue and organ injury or as the overwhelming "thrombotic storm" observed in catastrophic APS.

Catastrophic antiphospholipid syndrome

Antiphospholipid syndrome (APS) is a thrombotic disorder associated with autoantibodies that target membrane phospholipids and phospholipid-binding proteins, which regulate coagulation. APS is usually characterized by major arterial or venous occlusions, pregnancy complications, or both. In 1992, Asherson described an unusual variant of APS termed the catastrophic antiphospholipid syndrome (also known as Asherson's syndrome), the hallmark of which is rapid multiorgan failure caused by widespread small-vessel thrombi. Empiric treatments have improved the prognosis of patients, but half still die from thrombotic diathesis, even though those who survive the acute stages frequently remain well. Given the persistently high mortality rate, efforts have been underway to facilitate early diagnosis, institute effective treatments in a timely manner and to better understand the cause (or causes) of this extreme condition in order to improve outcomes.

New subsets of the antiphospholipid syndrome in 2006: "PRE-APS" (probable APS) and microangiopathic antiphospholipid syndromes ("MAPS")

The concept of "probable" antiphospholipid syndrome (APS) is almost identical with several conditions which may presage the development of the APS with its major complications of large vessel thromboses resulting in deep vein occlusions in the lower limbs (DVT) particularly and strokes. These conditions comprising livedo reticularis, chorea, thrombocytopenia, fetal loss and valve lesions. These conditions, comprising livedo reticularis, chorea, thrombocytopenia, fetal loss and valve lesions may be followed, often years later by diagnosable APS. The issue whether these patients should be more aggressively treated on presentation in order to prevent the thrombotic complications. A new subset of the APS is proposed viz. microangiopathic antiphospholipid syndrome ("MAPS") comprising those patients presenting with thrombotic microangiopathy and demonstrable antiphospholipid antibodies who may share common although not identical provoking factors (e.g. infections, drugs), clinical manifestations and haematological manifestations (severe thrombocytopenia, hemolytic anaemia) and treatments viz. plasma exchange. Patients without large vessel occlusions may be included in the MAPS subset. These conditions include thrombotic thrombocytopenic purpura (TTP), hemolytic-uremic syndrome (HUS), and the HELLP syndrome. Patients with catastrophic antiphospholipid syndrome (CAPS) who do not demonstrate large vessel occlusions also fall into this group. Disseminated intravascular coagulation (DIC) has also been reported with demonstrable antiphospholipid antibodies and also manifests severe thrombocytopenia and small vessel occlusions. It may cause problems in differential diagnosis.

Thrombotic thrombocytopenic purpura associated with systemic lupus erythematosus

Thrombotic thrombocytopenic purpura (TTP) occurring in patients with systemic lupus erythematosus (SLE) is rare and can be difficult to diagnose because of overlapping features of the two disorders. The aim of this study is to further characterize this uncommon association in terms of presenting features, diagnostic difficulties and treatment outcome. This is the largest series from a single centre with 6 patients diagnosed over a 6-year period. Two thirds of the patients had a simultaneous diagnosis of TTP and SLE. Half of the patients had a positive Coombs test along with clear features of TTP. Five patients received plasmapheresis as initial treatment while 1 patient received plasma infusions only. Four out of 5 patients responded to plasmapheresis and only 1 patient required cytotoxic therapy. TTP in association with SLE appears to be underdiagnosed and a positive Coombs test is not against the diagnosis of TTP in this setting. Most of the patients respond well to plasmapheresis. In case of a poor response, cytotoxic drugs should be considered early.

Thrombotic microangiopathic haemolytic anaemia and antiphospholipid antibodies

OBJECTIVE

To analyse the clinical and laboratory features of patients with thrombotic microangiopathic haemolytic anaemia (TMHA) associated with antiphospholipid antibodies (aPL).

METHODS

A computer assisted (PubMed) search of the literature was performed to identify all cases of TMHA associated with aPL from 1983 to December 2002.

RESULTS

46 patients (36 female) with a mean (SD) age at presentation of TMHA of 34 (15) years were reviewed. Twenty eight (61%) patients had primary antiphospholipid syndrome (APS). TMHA was the first clinical manifestation of APS in 26 (57%) patients. The clinical presentations were haemolytic-uraemic syndrome (26%), catastrophic APS (23%), acute renal failure (15%), malignant hypertension (13%), thrombotic thrombocytopenic purpura (13%), and HELLP (haemolysis, elevated liver enzymes, and low platelet count in association with eclampsia) syndrome (4%). Lupus anticoagulant was detected in 86% of the episodes of TMHA, and positive anticardiolipin antibodies titres in 89%. Steroids were the most common treatment (69% of episodes), followed by plasma exchange (PE) (62%), anticoagulant or antithrombotic agents (48%), immunosuppressive agents (29%), and immunoglobulins (12%). Recovery occurred in only 10/29 (34%) episodes treated with steroids, and in 19/27 (70%) episodes treated with PE. Death occurred in 10/46 (22%) patients.

CONCLUSIONS

The results emphasise the need for systematic screening for aPL in all patients with clinical and laboratory features of TMHA. The existence of TMHA in association with an APS forces one to rule out the presence of the catastrophic variant of this syndrome. PE is indicated as a first line of treatment for all patients with TMHA associated with aPL.

Von Willebrand factor

The adhesive protein von Willebrand factor contributes to platelet function by mediating the initiation and progression of thrombus formation at sites of vascular injury. In the last 2 years, there has been considerable progress in explaining the biologic properties of von Willebrand factor. The three-dimensional structure of specific domains has been explained, with the demonstration of distinct conformational changes in the A1 domain caused by single amino acid substitutions associated with enhanced binding to platelets. The structural and functional properties of the interaction between the von Willebrand factor A1 domain and glycoprotein Ibalpha have also been elucidated in greater detail, bringing researchers closer to understanding how this adhesive bond can oppose the fluid dynamic effects of rapidly flowing blood to initiate thrombus formation and, concurrently, contribute to platelet activation. Because hemodynamic forces greatly influence platelet responses to vascular injury in stenosed and partially occluded arteries, a detailed description of how von Willebrand factor interacts with tissues and platelets may help in the design of more specific therapeutic inhibitors of arterial thrombosis. Moreover, enlightening findings have been obtained on the link between regulation of von Willebrand factor multimer size and microvascular thrombosis. This progress in basic research has provided critical information to define with greater precision the role of von Willebrand factor in vascular biology and pathology.