Rheumatoid arthritis in Kenya. II. Serological observations

Sera from 48 Kenyan Africans with rheumatoid arthritis, 43 patients with other diseases, and 98 blood donors were tested for the presence of rheumatoid factor by latex fixation tests using human European, human African, and rabbit immunoglobulin, and a sheep cell haemagglutination test. In the patients with rheumatoid arthritis the frequency of rheumatoid factor was comparable to that reported in series from Europe and the USA, thus differing from the findings in West Africa. In the control patients and blood donors a high frequency of positive tests for rheumatoid factor was found; a similar result has been obtained from population studies in other African countries. Broadly similar results were obtained with each of the latex tests, and these were found to be less specific for rheumatoid arthritis than the sheep cell haemagglutination test.