Increased excretion of two sialic acid‐containing trisaccharides in the urine of patients with rheumatoid arthritis

Abstract

The urinary excretion of sialic acid-containing trisaccharides in patients with active rheumatoid arthritis was studied. Sialyl-lactose and sialyl-N-acetyllactosamine were identified and their excretion patterns studied by TLC and gas chromatography. The urinary output of sialyl-lactose was greater in patients with active rheumatoid arthritis (48.2 .+-. 6.1 mg/24 h, SEM [standard error of the mean], n = 6) than in healthy subjects (19.8 .+-. 3.7 mg/24 h, SEM, n = 5; P < 0.01). The excretion of sialyl-N-acetyllactosamine was also higher in the rheumatoid group (18.5 .+-. 2.1 mg/24 h, SEM, n = 6), than in the controls (11.1 .+-. 1.2 mg/24 h, SEM, n = 5; P < 0.05). The qualitative excretion patterns of the sialyl-oligosaccharide fraction were similar for the 2 groups as judged from TLC. Correlating the results with the clinical state of the patients with rheumatoid arthritis suggests that the urinary level of the sialyl-oligosaccharides reflects the activity of the disease. A proposed mechanism for the increased excretion of sialic acid-containing trisaccharides in rheumatoid arthritis is presented.