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.
Truedsson
L
L
Department of Medical Microbiology, University of Lund, Sweden.
Karypidis
A H
AH
Eberhardt
K
K
Grubb
A
A
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