Characterization of DNA and RNA in circulating immunocomplexes in multiple sclerosis, amyotrophic lateral sclerosis and normal controls

Serum IgG to brain microvascular endothelial cells in multiple sclerosis

Serum IgG to brain microvascular endothelial cells (BMECs) were assessed in the sera from 50 patients with definite multiple sclerosis, 24 patients with other inflammatory and non-inflammatory neurological diseases and 30 healthy individuals. Standard indirect immunofluorescence on BMEC culture was used as the bioassay system. Positive immunostaining was found in the sera (1:5 to 1:50 dilution) from 0/15 inactive relapsing remitting (RR), 12/16 active RR (p = 0.0001), 1/8 relapsing progressive (RP) and 0/11 primary progressive (PP) patients. No specific binding was detected when sera from neurologic and healthy controls were used. The specificity of the immune reaction for brain endothelium was established by the absence of staining on human umbilical vein endothelial cell and brain pericyte cultures. Gadolinium (Gd)-enhanced magnetic resonance imaging of the brain and spinal cord was performed in 36 MS patients within a 10-day interval from serum collection. Anti-brain endothelium antibodies were found in 9/12 patients with, and in 1/24 patients without Gd-enhanced lesions (p = 0.00002). Regardless of a pathogenetic role in the blood-brain barrier breakdown, serum IgG to BMECs may be a marker of disease activity in RR and RP MS and a factor differentiating RR/RP and PP MS.

Detection and isolation of immune complexes in multiple sclerosis cerebrospinal fluid

Immune complexes were studied in the cerebrospinal fluid (CSF) of 20 multiple sclerosis (MS) and 20 other neurological disease (OND) patients using polyethylene glycol precipitation; ten samples from each group were also examined using gel chromatography followed by ELISA. Polyethylene glycol detected predominantly IgG and IgM complexes in 13 of 20 MS samples and four of 20 OND samples. Intact MS complexes ranged in size from 230 to 340 kDa and contained 64 and 53 kDa antigens. Gel chromatography detected IgA complexes in eight of ten MS samples and one of ten OND samples; these complexes appeared to consist of polymeric IgA rather than true antigen. Chromatography detected IgG complexes in nine of ten MS and four of ten OND samples. Intact MS complexes ranged from 240 to 320 kDa and contained 200 and 150 kDa antigens. This study suggests that immune complexes are a very frequent finding in the CSF of MS patients and are in sufficient quantity to visualize on gel electrophoresis.