Hyperhomocysteinemia is common in patients with antiphospholipid syndrome and may contribute to expression of major thrombotic events

Hematological manifestations of antiphospholipid syndrome: Going beyond thrombosis

Thrombotic complications are a hallmark of antiphospholipid syndrome (APS). These vascular - arterial, venous, and/or small vessel - complications are well described and known to hematologists and healthcare providers caring for patients with this disease. In this review, we shed light on other hematological manifestations of the disease, including bleeding, thrombocytopenia, autoimmune hemolytic anemia, and thrombotic microangiopathy syndromes. While these manifestations are not bona fide clinical criteria for the diagnosis of APS, they frequently interact and contribute to the complexity of clinical management of APS.

Clinical characteristics and prognosis of patients with isolated thrombotic vs. obstetric antiphospholipid syndrome: a prospective cohort study

BACKGROUND

Several studies suggested that thrombotic and obstetric antiphospholipid syndromes could be independent identities, but few have systematically compared their clinical characteristics and prognosis.

OBJECTIVE

The objective of this study is to identify key differences between thrombotic APS (tAPS) and obstetric APS (oAPS).

METHODS

This single-center, prospective study included consecutive patients with primary antiphospholipid syndrome (APS) receiving treatment at the Peking Union Medical College Hospital during a period from 2013 to 2020.

RESULTS

Screening of the database yielded a total of 244 women with positive antiphospholipid antibody (aPL). Among the 105 women with primary APS, 39 (37.14%) had isolated tAPS (ItAPS), 44 (41.90%) had isolated oAPS (IoAPS), and 9 (8.57%) had both tAPS and tAPS+oAPS. In comparison to those with IoAPS, patients with ItAPS had older age (41.92 ± 11.97 vs. 33.16 ± 4.22 years, P < 0.01), higher rate of cardiovascular risk (at least one positive of coronary heart disease, hypertension, obesity, diabetes, and hyperlipidemia) (41.03% vs. 6.82%, P < 0.01), and higher frequency of thrombocytopenia (43.59% vs. 20.45%, P < 0.05). Antibody profiles were generally similar among the groups, but isolated anti-β2GPI positivity was more common in patients with IoAPS (52.27% vs. 17.94% for ItAPS, P = 0.01). Triple aPL positivity was more common in patients with both tAPS and oAPS (66.67% vs. 46.15% for ItAPS vs. 25% for IoAPS, P = 0.022). Blood homocysteine was higher in patients with ItAPS (11.20 vs. 9.90 μmol/L for IoAPS, P < 0.05), but there were no differences in inflammatory markers or complements. Recurrence rate of thrombosis was higher in patients with ItAPS (33.33% vs. 2.27% for IoAPS, P ≤ 0.001) with a mean follow-up of 61 months.

CONCLUSION

Despite generally similar antibody and biochemical profiles, patients with ItAPS had much higher risk of recurrent thrombosis than IoAPS, supporting distinct mechanisms of pathogenesis.

Impact of hypertension and hyperhomocysteinemia on arterial thrombosis in primary antiphospholipid syndrome

The aim of this study was to evaluate traditional risk factors for coronary artery disease (CAD), homocysteine, anti-oxidized low-density lipoprotein (anti-oxLDL), anti-lipoprotein lipase (anti-LPL) and endothelin-1 (ET-1) in patients with primary anti-phospholipid syndrome (APS), furthermore verify possible association among these variables and arterial thrombosis. Thirty-eight women with primary APS and 30 age-and-sex-matched controls were evaluated. Patients presented higher-LDL and triglycerides levels and lower-HDL levels than controls. Anti-LPL antibodies were not detected in both groups. The mean number of risk factors was higher in patients than in controls ( P = 0.030). Anti-oxLDL antibodies, homocysteine and ET-1 mean levels were similar between groups, but abnormal homocysteine levels were found only among primary APS patients ( P = 0.031). Hypertension and the presence of at least one risk factor for CAD were more prevalent in patients with arterial involvement than those without. Homocysteine levels and mean number of risk factors for CAD were significantly higher in patients with arterial thrombosis than controls. In a multivariate analysis hypertension was the only independently associated with arterial thrombosis (OR 14.8, 95% CI = 2.1—100.0, P = 0.006). This study showed that in primary APS patients other risk factors besides anti-phospholipid antibodies contribute for the occurrence of arterial events and the most important factor was hypertension. Lupus (2007) 16, 782—787.

Homocysteine, antiphospholipid antibodies and risk of thrombosis in patients with systemic lupus erythematosus

Cardiovascular disease is a major cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Antiphospholipid syndrome (APS) is one of the most important causes of thrombosis in SLE. In addition, an association between hyperhomocysteinemia and increased cardiovascular risk has also been reported. Our aim is to analyse the association of thrombosis with plasma total homocysteine (ptHcy), antiphospholipid antibodies (aPL) and other vascular risk factors in SLE patients. Fasting plasma levels of ptHcy, vitamin B12, folate, total cholesterol and creatinine were measured in 117 SLE patients. Clinical and immunological data were obtained from our prospective computerized database. aPL-positivity was defined according to Sapporo criteria. There was no association between aPL and ptHcy. ptHcy was higher in patients with arterial (median 13.02 versus 10.16 mmol/L, P = 0.010) but not venous thrombosis. In the subgroup analysis, this association was only seen in aPL-negative patients. In logistic regression, aPL (OR 6.60, 95% CI 1.86-23.34) and ptHcy (OR 1.10, 95% CI 1.01-1.19) were independently associated with arterial thrombosis. However, when hypertension, smoking and plasma total cholesterol were added to the model, only aPL (OR 7.38, 95% CI 2.02-26.91) and hypertension (OR 7.70, 95% CI 2.33-25.39), but not ptHcy, remained independently related to arterial events. aPL was the only variable independently related to venous thrombosis (OR 7.68, 95% CI 1.60-36.86). ptHcy concentrations are higher in SLE patients with arterial thrombosis. No interaction between homocysteine and aPL was found. Raised ptHcy may be a marker of increased vascular risk in aPL-negative SLE patients. The role of homocysteine as a marker of vascular risk may depend on the presence of traditional risk factors, although a modest intrinsic effect cannot be entirely excluded.

Hyperhomocysteinemia Relates to the Subtype of Antiphospholipid Antibodies in Non-SLE Patients

Abnormal increases of antiphospholipid antibody and plasma homocysteine levels are recently emerging as nonlipidic risk factors for cerebral atherogenesis and thrombosis. Both antiphospholipid antibody and homocysteine share many similar bioeffects in hemostasis, but their interaction is still inconsistent. In this study, we examined the relation between the plasma homocysteine level and lupus anticoagulant, anticardiolipin antibody, and anti-β2-glycoprotein I antibody in patients with noncardiac cerebral ischemia. Systemic lupus erythrematosus patients were excluded. The results showed a higher frequency of moderate hyperhomocysteinemia in patients with an abnormal increase of lupus anticoagulant only. Neither the serum folate and cobalamin levels nor methylenetetrahydrofolate reductase allele mutation contributes to this result. Accordingly, homocysteine interacts with lupus anticoagulant to promote cerebral atherosclerosis and ischemia. The role of vasculopathic or prothrombotic autoantibody generation in response to specific pathological change such as hyperhomocysteinemia warrants further investigation.

Acute adrenal failure associated with primary antiphospholipid syndrome and homozygosity for MTHFR C677T

A 47-year-old woman with a recent clinical diagnosis of acute cholecystitis developed acute adrenal failure. Initial computed tomograms of the abdomen showed bilateral adrenal swelling which evolved into bilateral adrenal hemorrhage on repeat examination a few days later. Laboratory investigations revealed a previously undiagnosed primary antiphospholipid syndrome and homozygosity for the MTHFR C677T mutation with hyperhomocysteinemia. This case highlights the protean clinical manifestations of adrenal vascular accidents and the need for a thorough search for underlying prothrombotic states in this setting.

Hyperhomocysteinemia and Smoking in Primary Antiphospholipid Syndrome

The thrombotic tendency in antiphospholipid syndrome (APS) shares several pathways with atherosclerosis. Atherothrombosis (atherosclerosis superimposed with thromboses) is influenced by nonmodifiable and some modifiable risk factors (smoking, obesity, physical inactivity, alcohol abuse, hyperhomocysteinemia). Therefore, we investigated the association among clinical and serological features of patients with primary APS and potentially modifiable risk factors for the development of atherothrombosis. Also, we compared the analyzed parameters with those in control subjects. Homocysteine concentrations were detected by HPLC (high performance liquid chromatography), while antiphospholipid antibodies were detected by ELISA. Smokers had elevated levels of homocysteine (χ2= 6.22, p < 0.05). Independently of patients' age, the association between increased levels of homocysteine and history of myocardial infarctions was found (χ2= 4.61, p < 0.05). Hyperhomocysteinemia and smoking are the most important modifiable risk factors for atherothrombosis in primary APS.

Reticulate keloidal purpura associated with transient antiphospholipid antibodies and hyperhomocysteinaemia

A 66-year-old woman presented with a reticulate pattern of purpuric, keloidal scarring affecting her lower legs and necrosis of her left thumb and little finger as sequelae of an episode of staphylococcal septicaemia. Her premorbid past history includes three miscarriages, three episodes of pulmonary embolism and an internal iliac vein thrombosis. Skin biopsy specimens showed keloidal scar tissue in the dermis but no evidence of thrombosis or vasculitis. Blood tests demonstrated moderate hyperhomocysteinaemia. Elevated levels of anticardiolipin antibodies were found on one occasion but this was not detected on initial or repeat testing.

What is antiphospholipid syndrome?

The description of antiphospholipid syndrome (APS) is vascular thrombosis and/or pregnancy morbidity occurring in persons with antiphospholipid antibodies (aPL). However, because of an unclear etiopathogenesis and the heterogeneous nature of aPL and of aPL-related clinical manifestations, a single, unambiguous definition of APS does not exist. In this paper, we describe a structured approach to APS, discuss the controversies, and offer descriptions of APS that include: an autoimmune systemic disease with a spectrum of (mostly thrombotic) clinical manifestations, an overdiagnosed disease when aPL is present but has no proven direct causative role in the clinical manifestations, and a disease of controversies that requires clarification of etiology and mechanisms and risk-stratified controlled clinical studies.

Homocysteine levels in women with antiphospholipid syndrome and normal fertile controls

OBJECTIVE

Recent studies have identified hyperhomocysteinemia as a risk factor for both recurrent pregnancy loss and thrombosis. Antiphospholipid syndrome, an autoimmune disorder, is also characterized by recurrent pregnancy loss and thrombosis. Thus, our purpose was to determine if hyperhomocysteinemia is more common in patients with APS than normal fertile controls.

METHODS

Plasma, sera and whole blood were obtained from two groups of women: (1) 22 with well-characterized antiphospholipid syndrome; and (2) 41 healthy fertile controls. Levels of fasting homocysteine, vitamin B16, vitamin B12, folate and the incidence of the C677/T mutation of the methylene tetrahydrofolate reductase genotype (C677T/MTHFR) were determined.

RESULTS

The proportion of individuals with hyperhomocysteinemia and fasting plasma homocysteine levels were similar in women with APS and controls. Levels of vitamin B6, vitamin B12, folate and the incidence of C677/MTHFR were also similar in the two groups.

CONCLUSION

Hyperhomocyteinemia and the C677T/MTHFR mutation are not common in women with antiphospholipid syndrome. Abnormal homocysteine metabolism is unlikely to play a major role in the pathogenesis of antiphospholipid syndrome.

Antiphospholipid syndrome: genetic review

The possibility of a genetic predisposition to develop the antiphospholipid syndrome (APS) and to produce anticardiolipin antibodies and lupus anticoagulant has been addressed by family studies and by population studies. Various studies suggest a familial occurrence of anticardiolipin antibodies and lupus anticoagulant, with or without clinical evidence of APS. This familial tendency could be genetically determined. Multiple human leukocyte antigen-DR or -DQ associations with antiphospholipid antibodies have been described. Genetic studies of beta(2)-glycoprotein-1(GP1) polymorphisms have been determined and valine/leucine polymorphism could be a genetic risk for having anti-beta(2)-GP1 antibodies and APS. Compared with polymorphism of beta(2)-GP1 as a genetic risk factor for APS, beta(2)-GP1 deficiency is not associated with thrombosis and patients with APS usually have normal or somewhat elevated levels of beta(2)-GP1. The antigen specificity of antiphospholipid antibodies and the pathophysiology of thrombosis in APS are highly heterogeneous and multifactorial.

Antiphospholipid antibodies as a risk factor for atherosclerotic events in renal transplant recipients

BACKGROUND

Epidemiologic studies reported that antiphospholipid antibodies (APAs) were independent predictors of atherosclerotic events. We recently reported a high prevalence of APAs in renal transplant recipients. Nevertheless, the role of APAs on atherosclerotic events has not been prospectively studied in this high-risk population.

METHODS

Participants in the study were 324 consecutive renal transplant recipients. Patients were enrolled between January 1996 and May 1998 and followed up until June 2002.

RESULTS

The patients were followed for a mean duration of 62 +/- 26 months. Eighty seven (26.8%) patients exhibited APAs. We found a slight, but significant, correlation between total plasma homocysteine (tHcy) concentration and anticardiolipin (ACA) titers (r = 0.26; P = 0.036). Fifty six athersclerotic events (17.2%) occurred in 54 patients. Atherosclerotic events occurred more frequently in patients with APAs (33% vs. 9%; P = 0.0003) and ACAs levels were higher in patients who experienced atherosclerotic events (23.7 +/- 13.1 IU vs. 13.9 +/- 9.4 IU; P = 0.003). APAs were associated with an increased risk of atherosclerotic events (RR, 2.82; 95% CI, 1.17 to 5.31). Cox regression analysis also revealed that age above the median (RR, 5.21; 95% CI, 1.67 to 17.13), a previous history of cardiovascular disease (RR, 3.54; 95% CI, 1.57 to 10.43), hyperhomocysteinemia (RR, 4.01; 95% CI, 1.22 to 14.61), and current smoking (RR, 2.17; 95% CI, 1.01 to 6.72) were risk factors for atherosclerotic events.

CONCLUSION

The presence of APAs is an independent cardiovascular risk factor in renal transplant recipients. Prevention trials are necessary to assess the efficacy and safety of anticoagulation therapy in transplant patients with APAs.