Antiglobulin factors in sera from patients with rheumatoid arthritis and normal subjects. Quantitative estimation in different immunoglobulin classes.

Abstract

The conventional tests for rheumatoid factor depend upon the agglutination of particles such as red cells or latex, coated with immunoglobulin-G. Since antibodies of the IgM class tend to be particularly effective in agglutination reactions, it is likely that the rheumatoid factor tests minimize any possible contribution from antiglobulin factors in other immunoglobulin classes. However, if the rheumatoid factors represent an immunological response of the patient to slightly altered autologous IgG, one would also expect to find antiglobulin factors in the IgG and IgA classes. In order to investigate this possibility we have developed a method which identifies the immunoglobulin class of the antiglobulin and also allows a quantitative assessment to be made. The method depends upon the absorption of antiglobulins on to insoluble cross-linked rabbit y-globulin, their subsequent elution from this complex, and estimation by the immunoplate technique using specific anti-immunoglobulin antisera incorporated into the gel. A preliminary account of these studies has been revorted (Torrigiani and Roitt, 1965a).Material and Methods Sera 27 sera from patients with rheumatoid arthritis all containing rheumatoid factors reacting with rabbit IgG in the sheep cell agglutination test (SCAT) were used.As controls, 21 sera from normal blood donors and four cord bloods were tested. All sera were stored at -20°C. and spun at 4,000 r.p.m. before use.

Igm and igg anti‐f(ab )2 antibodies in rheumatoid arthritis and systemic lupus erythematosus

“…While IgM RF long had been considered to be present in greater quantity than IgG RF sera, recently reported data suggest that the levels of both IgM and IgG RF are significantly higher in RA than in normal sera (8,10,22,23) and, in fact, that there is more IgG RF than IgM RF in RA sera (10). It would appear that the distribution patterns of anti-F(ab')2 antibodies and RF are similar.…”

“…Our RIA was designed to overcome interference of endogenous RF, a problem inherent in direct tests for class specific antibodies (1 [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The data obtained by our RIA suggest some similarity in isotype patterns of anti-F(ab')z antibody and R F when sera of patients with RA are compared with sera of patients with systemic lupus erythematosus (SLE) or with sera of normal donors.…”

Serum and synovial fluid IgG, IgA and IgM antigammaglobulins in rheumatoid arthritis

“…The presence of RF, as measured by agglutination tests and presumed to r e p resent IgM antibodies, has been associated with an unremitting disease course (17, 18), the occurrence of subcutaneous nodules (17-19), limited functional capacity (17, 18), radiologic evidence of joint destruction (18, 20), and diminished serum (20,21) and synovial fluid (20,22) complement levels. IgG and IgA antigammaglobulins, however, have not been clearly associated with these clinical manifestations of RA (11,15).…”

“…Later RF were reco<gnized among lower molecular weight proteins (6)(7)(8)(9) and as intermediate complexes (6,7,9). Subsequently RF were identified among YG and yA globulins (10)(11)(12)(13)(14)(15)(16). The presence of RF, as measured by agglutination tests and presumed to r e p resent IgM antibodies, has been associated with an unremitting disease course (17, 18), the occurrence of subcutaneous nodules (17-19), limited functional capacity (17, 18), radiologic evidence of joint destruction (18, 20), and diminished serum (20,21) and synovial fluid (20,22) complement levels.…”

“…IgG and IgA antigammaglobulins, however, have not been clearly associated with these clinical manifestations of RA (11, 15).…”