Serology - Rheumatoid Factor

Research has shown that both environmental and genetic factors can affect the production of RF with various biological properties. Although they may be found in all immunoglobulin classes, the RF most frequently detected is the IgM type; present in about 75% of adult patients with RA and about 10% of children with juvenile RA. RF have also been observed in the serum of patients with lupus erythematosus, hepatitis, liver cirrhosis, syphilis and various other conditions; but the RF titre is much lower than in RA.