Haptoglobin. A potential reporter molecule for glycosylation changes in disease.

The acute-phase protein, haptoglobin, is elevated in many diseases; however, its glycosylation also changes, and the type of change observed can vary with disease. Increased fucosylation is a common finding, and the fucose-specific lectin, lotus tetragonolobus, can be used to differentiate different diseases (eg inflammatory conditions, liver diseases), and to monitor disease activity in cancer. Changes in N-acetyl neuraminic acid and N-acetylglucosamine suggest that particular carbohydrate structures predominate in certain diseases. Because haptoglobin glycosylation provides a record of previous intracellular events, it will help to improve our understanding of pathological processes and provide potential clinical markers for the future.