Antiphospholipid autoantibodies as blood biomarkers for detection of early stage Alzheimer's disease.

A robust blood biomarker is urgently needed to facilitate early prognosis for those at risk for Alzheimer's disease (AD). Redox reactive autoantibodies (R-RAAs) represent a novel family of antibodies detectable only after exposure of cerebrospinal fluid (CSF), serum, plasma or immunoglobulin fractions to oxidizing agents. We have previously reported that R-RAA antiphospholipid antibodies (aPLs) are significantly decreased in the CSF and serum of AD patients compared to healthy controls (HCs).

Autoantibody potential of cancer therapeutic monoclonal antibodies.

We and others have reported that multiple autoantibodies are unmasked in human polyclonal antibody preparations after exposure to physiological oxidizing agents (hemin) or electromotive force. We now have asked if oxidation unmasks autoantibody reactivities in monoclonal antibodies (mAb). To do this, we have studied 9 FDA approved mAb used therapeutically, including 4 chimeric, 4 humanized and 1 chemically modified chimeric Fab that were exposed to the physiological oxidizing agent hemin at 36 degrees C for 20 hr.

Phosphatidylethanolamine at the luminal endothelial surface--implications for hemostasis and thrombotic autoimmunity.

Objective: Accumulating evidence suggests that phosphatidylethanolamine (PE) is physically present at the luminal endothelial surface, where it tentatively functions as a critical anticoagulant. The goal of the current investigation was 3-fold: to characterize the distribution profile of PE at the luminal endothelial surface; to examine the immunoreactivity to the vascular endothelium by anti-PE (aPE) sera from patients presenting with thrombosis; and to discuss the potential mechanism of PE upregulation by endothelial cells.

Methods: The rat aortic arch was selected as major conduit vessel under significant hemodynamic burden.

Redox-reactive antiphospholipid antibody differences between serum from Alzheimer's patients and age-matched controls.

There is no universally acceptable inclusive laboratory biomarker for the diagnosis and staging of neurodegenerative diseases, for example, Alzheimer's. There is an abnormal increase of oxidative stress in the central nervous system (CNS) of Alzheimer's patients that causes oxidation of proteins, lipids and DNA. We have published that the antiphospholipid (aPL) autoantibodies that are members of the redox-reactive autoantibody (R-RAA) family, are significantly decreased or absent in the cerebrospinal fluids of autopsy-confirmed Alzheimer's disease (AD) patients.

Redox-reactive autoantibodies: biochemistry, characterization, and specificities.

Oxidation-reduction (redox) reactions can "unmask" autoantibody activity in blood and other body fluids from normal, healthy individuals. These "unmasked" autoantibodies are similar if not identical to autoantibodies associated with autoimmune diseases. The agents responsible for this unmasking are physiological oxidants such as hemin and likely other naturally occurring molecules in the body that contain transitional metals available for participation in redox reactions.

Anti-phospholipid antibodies in cerebrospinal fluid but not serum from a boy with psychosis.

A 12-year-old African American boy with mental retardation and Asperger's disorder presented with acute psychosis. Antiphospholipid antibody testing with enzyme-linked immunosorbent assay showed increased levels of immunoglobulin G anticardiolipin antibodies in the cerebrospinal fluid, but not in the serum. Although antiphospholipid antibodies have been reported in the serum of patients with thrombotic and neurologic disorders, there are only a few reports of these antibodies in cerebrospinal fluid.

Antiphospholipid antibodies in blood and cerebrospinal fluids of patients with psychosis.

Antiphospholipid antibodies (aPL) have been reported in the cerebrospinal fluids (CSF) of neurology patients but no CSF studies with psychiatric patients exist. We tested serum from 100 hospitalized psychotic patients having hallucinations and/or delusions for aPL. Patients with positive serum aPL findings were asked to submit CSF for aPL testing.

Redox-reactive autoantibodies in cerebrospinal fluids.

The oxidative stress associated with increased transitional metal concentrations in neurodegenerative diseases served as the impetus for our testing the status of redox-reactive autoantibodies in the cerebrospinal fluids from autopsy-confirmed Alzheimer's patients. Here we describe a novel family of autoantibodies capable of recognizing autoantigens subsequent to in vitro oxidation-reduction (redox) reactions in the blood and spinal fluids of all normal individuals tested. Redox autoantibodies are not detected in conventional immunoassays, thereby differentiating them from natural and hidden autoantibodies described by others.

Redox-reactive autoantibodies in Alzheimer's patients' cerebrospinal fluids: preliminary studies.

Oxidation of cerebrospinal fluid (CSF) causes differential unmasking of autoantibodies in control CSF vs. that obtained from postmortem CSF samples from autopsy confirmed Alzheimer's disease (AD) cases. This study demonstrates that normal CSF from both living patients and from non-demented autopsy cases contains redox-reactive autoantibodies with specificities that include antiphospholipid antibodies (aPL).

Fatal hemorrhagic diathesis associated with mild factor IX deficiency in pl/J mice.

Surgical implantation of devices into the abdomen of PL/J mice was associated with fatal hemorrhage at 9 to 11 d after surgery. Coagulation profiles were evaluated to determine the underlying cause of this effect. The mean activated partial thromboplastin time (aPTT) of untreated PL/J mice was significantly higher than that of BALB/cByJ and C57BL/6J strains.

Redox-reactive autoantibodies: detection and physiological relevance.

We recently described a hitherto unrecognized family of autoantibodies that become unmasked (detectable) subsequent to oxidation-reduction (redox) reactions. These masked redox-reactive autoantibodies are not detectable by using conventional immunoassays. Additional experimentation has demonstrated that autoantibodies in the blood of patients with autoimmune diseases can be masked (become undetectable) by exposure to oxidizing agents.

Autoantibodies unmasked by redox reactions.

Blood from healthy donors was found to contain a variety of autoantibodies after being cultured overnight in commercial blood culture bottles. Paradoxically some autoantibodies in the blood of patients with autoimmune diseases were no longer detectable when similarly cultured. By a process of elimination it was revealed that hemin was responsible for the conversion of antibody-negative blood to antibody-positive blood, as well as for the conversion of antibody-positive blood to antibody-negative blood.

The appearance and disappearance of antiphospholipid autoantibodies subsequent to oxidation--reduction reactions.

The mechanisms that cause the appearance of autoantibodies are not understood. Compared to normal antibody production, factors responsible for autoantibody synthesis are more complex; they are thought to disrupt the normal mechanisms proposed to eliminate or down-regulate self-antibodies or to interfere with anti-self-receptor editing. Data presented show that autoantibodies exist in the blood of all normal individuals.

Antiphospholipid antibodies: discovery, definitions, detection and disease.

Antiphospholipid antibodies (aPL) are immunoglobulins of IgG, IgM and IgA isotypes that target phospholipid (PL) and/or PL-binding plasma proteins. Detection of aPL in the laboratory is done currently by both immunoassays and functional coagulation tests. Convention defines aPL specificity in immunoassays according to the particular PL substrate present, for example aPS represents antiphosphatidylserine antibodies.

Frequency and specificities of antiphospholipid antibodies (aPL) in volunteer blood donors.

In the State of Indiana, blood donors are screened by a written questionnaire prior to donation to identify potential exposures to infectious diseases and to assess medications. The potential donor is not asked about aPL-related events. Animal experiments have shown, however, that passive transfer of aPL can produce aPL-associated pathology in the recipient.