Raised IgG antiglobulin factors in Still's disease.

Still's disease (juvenile chronic polyarthritis) differs markedly from adult rheumatoid arthritis in the relative incidence of rheumatoid factor. The sheep cell agglutination test was found to be positive in only 11 to 13 per cent. of Still's disease patients compared with 70 to 80 per cent. of affected adults (Bywaters, Carter, and Scott, 1959; Laaksonen, 1966). Similarly, using the sensitive agglutination test with human FII coated erythrocytes, only 26 per cent. of definite cases of Still's disease gave titres of 1: 200 or more in contrast with an incidence of 87 per cent. in cases of classical and definite rheumatoid arthritis (Zutshi, Ansell, Bywaters, Epstein, Holborrow, and Reading, 1969). Since antibodies of the IgM class tend to be particularly effective in agglutination reactions, it is likely that the conventional tests for rheumatoid factor minimize any possible contribution from antiglobulin factors in other immunoglobulin classes. Accordingly, we have recently developed a technique for the quantitative assessment of antiglobulin factors in the IgG, IgM, and IgA classes (Torrigiani and Roitt, 1967). The method depends upon the adsorption of antiglobulins on to insoluble crosslinked rabbit y-globulin, their subsequent elution from this complex, and estimation by single radial immunodiffusion using specific anti-immunoglobulin antisera. It was found that in addition to IgM antiglobulin factors, IgA antibodies were present in 50 per cent. and IgG antiglobulins in 100 per cent. of sero-positive adult rheumatoid arthritis patients. In the present investigation we have looked for antiglobulin factors in the sera of children with Still's disease using this quantitative technique.