Reduction in IgG galactose in juvenile and adult onset rheumatoid arthritis measured by a lectin binding method and its relation to rheumatoid factor

Article Abstract:

Most proteins that function outside of cells are actually glycoproteins and have chains of various types of sugars attached along intervals of the protein structure. Antibodies (immunoglobulins, Igs) are one type of extracellular protein that are glycosylated, and in patients with adult-onset rheumatoid arthritis, IgGs (antibodies of the G subclass) frequently are missing the galactose which usually ends the sugar chains. This difference from the normal glycoprotein structure of antibodies may be enough to trigger production of new antibodies against the structure. In fact, patients with rheumatoid arthritis have blood levels of rheumatoid factor, autoantibodies (antibodies made against the body's own molecules) against a segment of IgGs. Similar abnormalities in glycosylation (sugar attachment) of antibodies have been found in patients with juvenile-onset rheumatoid arthritis. These changes were identified by classical, laborious laboratory methods. To better understand the significance of altered glycosylation of antibodies, a new method using lectins (proteins that bind sugars) was used to study galactose-deficient Igs, or G(o), in 17 children with active juvenile chronic arthritis. Results were compared with those from 13 patients with adult-onset rheumatoid arthritis, 10 patients with systemic lupus erythematosus, and 12 adult and 13 juvenile healthy control subjects. Raised levels of rheumatoid factor (of the IgM subclass) were almost exclusively found in patients with adult-onset rheumatoid arthritis. Patients with juvenile- or adult-onset rheumatoid arthritis had significantly higher levels of G(o) than did healthy subjects, after adjusting for age. G(o) levels did not correlate with rheumatoid factor levels. Total levels of IgG correlated significantly with G(o) levels and with laboratory tests indicating the presence of acute inflammatory disease. Further study is needed of the implications of these findings. (Consumer Summary produced by Reliance Medical Information, Inc.)

Analysis, Measurement, Oligosaccharides, Rheumatoid arthritis in children, Juvenile rheumatoid arthritis, Galactose metabolism

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Detection of enterovirus specific RNA sequences in muscle biopsy specimens from patients with adult onset myositis

Article Abstract:

Polymyositis, the inflammation of skeletal muscle, is characterized by weakening of muscle in the limbs, neck, shoulders, and back, and commonly affects the muscles of the chest wall, pharynx, and diaphragm. The cause of polymyositis is not known, but the disease has been classified as an autoimmune disorder, in which immune factors attack body tissues. Studies have also shown that polymyositis may be associated with enteroviral infection. A genetic indicator called a subgenomic cDNA probe was used to detect the presence of genetic components of enteroviruses in muscle biopsy samples from patients with long-term adult myositis. Virus-specific ribonucleic acid (RNA) sequences, which are genetic elements of the enterovirus, were detected in the muscle biopsy samples of 6 out of 13 patients with idiopathic (unknown cause) polymyositis or dermatomyositis (inflammation of skin and muscle). Patients with muscle disorders other than myositis had no evidence of viral-specific RNA. Viral antigens (components of the virus capable of activating the immune system) were not detected in any muscle biopsy specimens. The results suggest that patients with myositis have a persistent enteroviral infection. Reasons why viral antigens could not be detected in these patients are discussed. (Consumer Summary produced by Reliance Medical Information, Inc.)

Diagnosis, Causes of, Genetic aspects, DNA probes, Muscles, Muscle diseases, Muscular diseases, Myositis, Enteroviruses, Biopsy, Enterovirus diseases, Enterovirus infections

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Expression of public idiotypes in patients with Lyme arthritis

Article Abstract:

The expression of idiotypes may contribute to the cause of arthritis in patients suffering from Lyme disease. Idiotypes are structures on the surface of immunoglobulins, or antibodies, that are found in patients suffering from different rheumatic autoimmune disorders. A study compared the expression of idiotypes in 12 patients with Lyme disease over an average of six years to that in patients with systemic lupus erythematosus and in healthy individuals. Lyme disease patients had significantly higher expression of immunoglobulin M or immunoglobulin G idiotypes 16/6 and BEG2 than lupus erythematosus patients or healthy individuals. Expression of immunoglobulin A idiotype 16/6 was significantly higher only during episodes of arthritis in patients with Lyme disease and increased with the severity of the episode of arthritis.

Lyme disease, Arthritis, Immunoglobulin idiotypes

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