Urinary imidazoles in rheumatoid arthritis.

This is a study of a small group of patients with rheumatoid arthritis, in whom the urine excretion of imidazole compounds was examined by Figlu assay and chromatography of 12-hour urine collections following 15 g. histidine load, and by assay of 4 amino-imidazole-5 carboxamide (AIC) in 12hour urines with and without histidine load. Gough, McCarthy, Read, Mollin, and Waters (1964) found low serum folate in one-third of cases with rheumatoid arthritis and a raised Figlu excretion in three quarters of these. This, they thought, was biochemical evidence of folic acid deficiency. 33 per cent. of their cases had serum folates of less than 4 ng. per ml., but many other patients with folates between 3 and 7 ng. per ml. had a positive Figlu result. Abnormalities of liver function in rheumatoid arthritis are known but perhaps not well recognized. Darby (1956) found abnormal bromosulphophtalein tests in 23 per cent. cases of rheumatoid disease and urine coproporphyrin was elevated in 31 per cent. cases. Proliferation of reticulo-endothelial tissue is recognized in rheumatoid disease and accounts for lymph gland enlargement, splenic enlargement, Kuppfer cell hyperplasia, and sometimes reticulum cell hyperplasia in the bone marrow (Wardle and Attan, 1967).