Clinical significance of serum soluble IL-2R levels in patients with adult T cell leukaemia (ATL) and HTLV-1 carriers.

The levels of soluble IL-2Ralpha (sIL-2Ralpha) in serum were measured in HTLV-1 carriers and ATL patients in order to evaluate their possible correlation with clinical status. Mean sIL-2R levels in ATL patients were found to be 9704 U/ml for the acute/lymphoma type, 1961 U/ml for the chronic type and 788 U/ml for the smouldering type. The level for asymptomatic HTLV-1 carriers was 475 U/ml, and 165 U/ml for healthy young adult HTLV-1- controls. The serial measurement of sIL-2R in ATL patients, healthy HTLV-1 carriers, and HTLV-1 carriers with diseases other than ATL showed a good correlation between serum levels of sIL-2R and the pathophysiological status of disease. Furthermore, an increase in the sIL-2Ralpha level in serum indicated the exacerbation of HTLV-1 infection and autoimmune diseases. The measurement of sIL-2Ralpha levels is therefore a very useful parameter for determining disease status.