FII haemagglutination test for serum antigammaglobulin factors in Still's disease.

The nosological status of Still's disease (juvenile chronic polyarthritis) in relation to adult rheumatoid arthritis has been widely debated; one of the major differences is the markedly lower frequency of rheumatoid factor in the former even at low titres. Bywaters, Carter, and Scott (1959) reported that only 13-4 per cent. of 142 patients had a positive Waaler-Rose or differential agglutination test (DAT) of 1: 16 or more on initial testing. Cassidy and Valkenburg (1967), using the human erythrocyte agglutination test and the latex-fixation test, showed 22 per cent. of 110 patients with juvenile rheumatoid arthritis of onset before the age of 15 years to be positive by one or other test. In the largest published series, Laaksonen (1966) showed that the latex-fixation test was positive in 29 5 per cent. of 363 cases and the Waaler-Rose in 112 per cent. of 384 cases; and, further, that positivity in either test was more common in cases in which the age at onset was over 6 years.