Platelet serotonin release in rheumatoid arthritis: a study in food-intolerant patients.

Serotonin and 5-hydroxyindoleacetic acid levels in platelet-rich plasma were determined in serial samples obtained before and up to 6 h after food-challenge in 7 patients showing inflammation of the joints after ingestion of certain foods. Exacerbation of arthritis was associated with a fall in serotonin levels and a subsequent increase in 5-hydroxyindoleacetic acid. These data suggest that serotonin may be released from platelets during food challenges and that platelet serotonin release may contribute to joint inflammation.