HC-IgA antibodies of different specificities are normally present in serum: quantitation by ELISA and relationship to the major Ig classes.
Enzyme-linked immunosorbent assays (ELISA) were developed for direct measurement of protein HC-IgA complexes (HC-IgA) in serum with antibody specificity for rabbit IgG (rheumatoid factor (RF) activity), lipopolysaccharide from Yersinia enterocolitica serotype O:3 (Y3) and tetanus toxoid (TT). About 80% of patients with rheumatoid arthritis had increased concentrations of HC-IgA-RF. The values were correlated with the concentrations of IgA-RF and IgM-RF. HC-IgA anti-Y3 was measured in 45 sera with anti-Y3 antibodies of IgM, IgG and IgA class. The HC-IgA anti-Y3 levels were correlated with those of anti-Y3 of IgG and IgM class, but not of IgA class. For HC-IgA anti-Y3, the closest correlation was that with the specific IgM antibody concentration, rs = 0.63 (p less than 0.001). In 25 normal sera, significant correlations were observed between HC-IgA anti-TT and specific antibodies of IgG and IgA class, but not of IgM class. In 107 sera containing IgA M-components, the total concentration of HC-IgA correlated poorly with both protein HC and with IgA concentrations. It was concluded that specific HC-IgA antibodies are normal constituents of serum, and that their concentrations are not directly related to the serum content of specific IgA antibodies.
Department of Medical Microbiology, University of Lund, Sweden.
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Truedsson
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Karypidis
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Eberhardt
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Grubb
D000510:Alpha-Globulins / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis*; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D046911:Macromolecular Substances; D012217:Rheumatoid Factor / Q000032:analysis; D013745:Tetanus Toxoid / Q000276:immunology; D015008:Yersinia enterocolitica / Q000276:immunology
D000510:Alpha-Globulins; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D046911:Macromolecular Substances; D013745:Tetanus Toxoid; C016001:alpha-1-microglobulin; D012217:Rheumatoid Factor