Studies on the frequency and pathogenesis of liver involvement in rheumatoid arthritis

A systematic prospective survey of 100 outpatients with rheumatoid arthritis revealed that 45 had biochemical evidence of liver disease. In most cases this was due to increases in total serum alkaline phosphatase (ALP) and/or gammaglutamyl transpeptidase (GGT). Examination of serum ALP isoenzyme profiles in 50 of the patients showed that the liver isoenzyme was the sole or major component in 44 patients, including many with normal total ALP levels. 18% had raised serum liver ALP together with raised GGT, suggestive of an underlying hepatobiliary lesion. No correlation could be detected between raised serum levels of liver enzymes and the age or sex of the patient, duration or severity of arthritis, and drug or alcohol history. However, there was a significant correlation between raised serum ALP and lacrimal or salivary gland dysfunction. It is suggested that immunological mechanisms may be involved in the development of hepatic abnormalities in rheumatoid arthritis.