Intrathecal activation as a typical immune response within the central nervous system in angiostrongyliasis.

Angiostrongylus cantonensis is a zoonotic pathogen that occasionally causes human angiostrongyliasis; its main clinical manifestation is eosinophilic meningitis. This report defines the concept of intrathecal activation of complement as evidence of intrathecal synthesis of major immunoglobulins during this disease. Details are presented of the activation of complement system components in cerebrospinal fluid, and their application to our understanding of this tropical disease, which is emerging in the Western hemisphere. Intrathecal synthesis of at least one of the major immunoglobulins and a wide spectrum of patterns may be observed. Although intrathecal synthesis of C3c is always present, C4 intrathecal synthesis does not occur in every patient. The diversity of intrathecal synthesis and activation of the different complement pathways enables their division into three variant groups (A, B, and C). Variant group A includes the classical and/or lectin pathway and involves two or more major immunoglobulins with C3 and C4 intrathecal synthesis. Variant group B involves C4 in cerebrospinal fluid that comes from blood in the intrathecal activation of the classical pathway. Variant group C includes the alternative pathway.

Complement protein isoforms in CSF as possible biomarkers for neurodegenerative disease.

It has been suggested that the activation of the complement system is involved in the pathogenesis of several neurodegenerative diseases including Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS). Here, the CSF expression levels of complement proteins C3b, C4b, factor B, and factor H were compared between normal subjects and patients diagnosed with AD, PD, MS, and neurosyphilis. The CSF proteins were initially separated using two-dimensional gel electrophoresis, which allowed the comparison of some of the individual complement isoforms. Patients with AD, PD, and MS all showed more than one complement isoform with a significant change (p < 0.05) in CSF expression level compared to normal subjects. PD patients were found to have the greatest number of significantly changed isoforms, all showing a decreased expression level in PD CSF. The complement isoforms examined were able to distinguish between some, but not all, of the diseases studied. The data suggest that when investigating a protein as a possible biomarker, it may be useful to compare individual protein isoform expression levels in addition to the more commonly measured total protein expression level.