Circadian rhytm of serum interleukin-6 in rheumatoid arthritis
1994 (English)In: Annals of the Rheumatic Diseases, ISSN 0003-4967, Vol. 53, no 8, 521-4 p.Article in journal (Refereed) Published
OBJECTIVES--To test the hypothesis of a diurnal variation in circulating levels of interleukin-6 (IL-6) and/or tumour necrosis factor-alpha (TNF-alpha) in rheumatoid arthritis and other inflammatory connective tissue diseases. METHODS--Serum levels of IL-6 and TNF-alpha were measured at three hour intervals from 7:30 to 22:30 in 48 patients with different rheumatic diseases as well as ten healthy controls. In four of the patients with rheumatoid arthritis, serum IL-6 levels were measured before and after one week of treatment with prednisolone 15-20 mg daily. RESULTS--IL-6 and TNF-alpha could not be detected in serum from healthy controls. However, serum IL-6 levels were substantially increased in patients with rheumatoid arthritis. Furthermore, patients with rheumatoid arthritis showed a statistically significant circadian variation in levels of IL-6. Peak values appeared in the morning and low values in the afternoon and evening. In contrast, levels were low and stable in other connective tissue diseases. Levels of TNF-alpha were low in patients with rheumatoid arthritis and high in patients with other connective tissue diseases, but without circadian rhythm. After treatment with prednisolone, levels of serum IL-6 decreased significantly, but the circadian rhythm remained. CONCLUSIONS--The circadian rhythm of circulating IL-6 might correspond to the circadian rhythm of symptoms in rheumatoid arthritis. The diurnal variation of IL-6, and possibly other cytokines, might explain the conflicting results previously reported on the inter-relationship between circulating IL-6 levels and disease activity in rheumatoid arthritis.
Place, publisher, year, edition, pages
1994. Vol. 53, no 8, 521-4 p.
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-90243PubMedID: 7944637OAI: oai:DiVA.org:uu-90243DiVA: diva2:162535