Complement-fixing antibrain antibodies in multiple sclerosis. A preliminary report

The role of complement in neurological and neuropsychiatric diseases

The complement system is a major component of innate immunity and a potent driver of inflammation. It has key roles in host defense against pathogens but can also contribute to pathology by driving inflammation and cell damage in diverse diseases. Complement has emerged as an important factor in the pathogenesis of numerous diseases of the CNS and PNS, including infectious, autoimmune and degenerative disorders, and is increasingly implicated in neuropsychiatric disease. Establishing the roles and relevance of complement in disease pathogenesis has become ever more important in recent years as new drugs targeting the complement system have reached the clinic, and the potential for using complement analytes as disease biomarkers has been recognized. In this brief review, the author summarizes the evidence implicating complement in these diseases and outlines ways in which this new understanding can be used to aid diagnosis and improve outcome.

Effectors of demyelination and remyelination in the CNS: implications for multiple sclerosis

Most of the research on multiple sclerosis (MS) has focused on the early events that trigger demyelination and subsequent remyelination. Less attention has been given to the factors that directly mediate the demyelination that is the hallmark of the disease. Effector cells or molecules are those factors directly responsible for mediating the damage in the disease. Similarly, there are effector molecules that are critical for remyelination in the central nervous system (CNS). By understanding those effector molecules in demyelination and remyelination that directly influence the pathologic process, we should be able to generate specific therapies with the greatest potential for benefiting MS patients. This review focuses on effector cells and molecules that are critical for demyelination and remyelination in MS but also in experimental models of the disease including experimental autoimmune encephalomyelitis (EAE), virus-induced models of demyelination (Theiler's virus, murine hepatitis virus), and toxic models of demyelination (lysolecithin, ethidium bromide, and cuprizone). These are models in which the effector molecules for demyelination and remyelination have been most precisely evaluated.

The significance of abnormal immune responses in patients with multiple sclerosis

Early diagnosis of multiple sclerosis (MS) may be assisted by tests for the abnormal immune responses of the central nervous system (CNS) including oligoclonal IgG bands in the cerebrospinal fluid (CSF), increased CNS IgG synthesis, increased CNS antibody synthesis against multiple viruses and increased numbers of enlarged lymphoid cells in the CSF. Alterations in immunological responses are important in the pathogenesis of MS. Further studies are needed, however, to identify the antigen(s) and/or antibodies responsible for oligoclonal IgG in the CSF of MS patients. Also, the cause(s) for the other immunological abnormalities with diagnostic importance need to be identified. The increased synthesis of antibodies against multiple unrelated viruses suggests generalized alteration in the immune regulatory system. The etiology of MS might be multifactorial involving abnormal immunological responses, possibly precipitated by infectious agents acquired during childhood by genetically susceptible individuals. The immunological responses including alterations in myelin basic protein concentration, antimyelin antibody and immune complex activities in CSF, and in vitro stimulation, suppression and migration inhibition of blood lymphocytes appear to correlate with stage of MS and severity of CNS damage. Some of the tests may become useful in estimating the prognosis of the disease. Longitudinal studies are needed to clarify the sensitivity of the diagnostic and prognostic immunological tests and etiological significance of these abnormalities in MS.

Multiple specificities of antibrain antibodies in multiple sclerosis and chronic myelopathy

The presence of complement-fixing antibodies against brain antigens was tested in paired serum and cerebrospinal fluid (CSF) samples from 60 multiple sclerosis (MS) patients, 15 patients with chronic myelopathy of undetermined cause (CM) and 60 control patients. Six MS sera, 34 MS CSF, 4 CM sera, 3 CM CSF, 4 control sera and 1 control CSF gave positive reactions either with a lipid extract or a saline extract of normal human brain. The proportion of anticomplementary CSF was significantly higher in the MS group than in the control group (15% vs 0%, P less than 0.01). The reactivity of a large number of individual positive samples was further investigated. Seven antibody specificities were discerned in the MS samples. Most samples reacted with non-lipid antigens, the dominating being a heat-labile, nonlipid component associated with CNS myelin. Antibodies to cerebroside and sulfatide were detected in a few patients. A number of samples reacted with cholesterol in combination with a variety of lipids. Positive samples from the CM patients exhibited a similar heterogeneity. In the control group positive reactions were seen in one patient with systemic lupus erythematosus (SLE), two patients with rheumatoid arthritis (RA), and one with a spinal meningioma. The reaction patterns of these patients were different from those commonly seen in MS patients. The complement-fixing antibrain antibodies in MS CSF are usually of IgG class (Ryberg 1976). This applies also to the positive MS sera in this study. The distribution of the antibodies between serum and CSF indicated, in several cases, an intrathecal synthesis. All of a number of human brains, including one MS brain, contained all 6 antigens (haptens) reactive in saline extracts. Antibodies to tissues outside the CNS were rarely detected in MS patients. The varied humoral autoimmune response in MS might reflect a heterogeneity in the MS patients, the disease itself or its causative agent.

Complement-fixing antibrain antibodies in multiple sclerosis. Comparison of their occurrence in cerebrospinal fluid and serum

Cerebrospinal fluid (CSF) and serum samples from 40 multiple sclerosis (MS) patients and 48 control patients were examined by a microcomplement fixation test for the presence of antibodies against saline extracts of human brain. When tested with an IgG content standardized in 100 mg per 100 ml, 13 of the MS CSF and one of the corresponding MS sera were positive, whereas none of the control specimens were positive. The antibody was shown to be highly organ specific when tested against extracts of myocard, spleen, kidney and peripheral nerve. Chromatographic experiments showed the antibody to belong to the IgG class. It was concluded that the antibody was probably synthesized intrathecally in 12 and extrathecally in one MS patient.