Testing for antiphospholipid antibody (aPL) specificities in retrospective "normal" cerebral spinal fluid (CSF)

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). In contrast, CSF from autopsy confirmed AD subjects contained little or no redox-reactive aPL autoantibodies. Tests using an in vitro rat synaptosome model showed that the oxidized CSF autoantibodies from a normal individual can cause ERK1/2 phosphorylation at a level consistent with reports of pathogenic changes found in brain tissues from AD patients. The decrease or absence of redox-reactive antibodies in CSF from Alzheimer's patients suggests that these antibodies may have been previously unmasked by the oxidative conditions that exist in the CNS in AD patients. These unmasked autoantibodies could then bind to neuronal tissues and possibly participate in the initial cascade leading to the dementia in Alzheimer's. To our knowledge, this is the first description of resident autoantibodies with the potential to cause brain cell damage documented in CSF without a breech in the blood-brain barrier. The untimely and inappropriate physiological unmasking of these redox-reactive autoantibodies in AD patients CSF may represent a valuable biomarker for diagnosis and progression of this and perhaps other neurodegenerative diseases which also have oxidative stress components. These novel autoantibody observations may stimulate thoughts about additional therapeutic approaches and warrant similar studies for other neurodegenerative diseases.

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. This finding is consistent with a recent report of antiphospholipid antibodies found in the cerebrospinal fluid of adults with acute psychosis.

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. Five CSF samples had aPL specificities not found in the patient's serum suggesting the possibility of intrathecal synthesis. Specificity and isotype discordance between CSF and blood aPL in these psychiatric patients implicates a central nervous system independent autoimmune process that may have an underlying association with the pathophysiology of their diseases.

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. Simultaneous masking and unmasking of different autoantibodies in a given patient's serum or plasma is evidence that immune complexes are not the source of redox-reactive autoantibodies. We propose that a mechanism responsible for unmasking-masking antibody specificities requires nitrosylation of tyrosine residues in the hypervariable or complementarity determining regions of the antibodies' antigen-binding sites. Other laboratories, selected by us for their respective expertise, have studied our redox-reacted and control serum and/or antibody preparations and have found an expanding array of autoantibody specificities. The gathering data suggest that certain autoimmune diseases may involve redox disorders rather than a failure to deplete, suppress, tolerate or divert self-directed B cell activity. The persistence and fluctuation of redox-reactive autoantibodies suggest that they are manifestations of an as yet undefined natural selective pressure on the evolution of the immunological system. We propose that they are the "contrivances" suggested by Paul Ehrlich more than a hundred years ago, and that these antibodies perform important physiological and pathophysiological functions.