Inflammatory state in a subject is assayed by determining the level of expression of A3 adenosine receptor (A3AR) in white blood cells (WBC), e.g. circulating WBCs, from the subject. A high level of expression of A3AR is indicative of an inflammatory state in the subject. This assay can be used for determining whether a patient known to have an inflammatory state should be treated with an A3AR agonist to reduce the inflammatory state. The patient will be so treated only if the level of A3AR in the WBC of the subject is above a predefined threshold, which is about twice the level of A3AR in WBC of healthy subjects. The inflammatory state may particularly be rheumatoid arthritis or uveitis.
