Serum-soluble interleukin 2 receptor in psoriasis. Failure to reflect clinical improvement

Interleukin 2 (IL-2) is a T-cell growth factor produced by activated T cells. The cellular receptor for IL-2 is also expressed on activated T cells and one of its component molecules can be shed from the cell and measured as a soluble protein (sIL-2R). Blood levels of sIL-2R can be used to monitor in vivo immune activation and have been shown to correlate with clinical disease activity in conditions such as rheumatoid arthritis and atopic eczema. The present study shows that serum sIL-2R levels are raised in patients with chronic plaque psoriasis. These elevated serum levels were maintained during successful treatment of the skin lesions with topical tar preparations. This is in contrast to atopic eczema where serum sIL-2R levels fall with treatment and may indicate that topical treatment of psoriasis does not correct the underlying state of immune activation, even when resolution of the skin plaques is achieved.