Serum interleukin-2 receptor in systemic lupus erythematosus and rheumatoid arthritis.

Interleukin-2 receptor (IL-2R) is expressed on activated lymphocyte after stimulation with antigen or interleukin-2 (IL-2), meanwhile soluble form of the receptor is released. Using enzyme-linked immunosorbent assay, serum IL-2R levels were determined in 34 healthy controls, 61 patients with systemic lupus erythematosus (SLE) and 32 patients with rheumatoid arthritis (RA), yielding mean +/- SD values of 355 +/- 89, 807 +/- 453 and 567 +/- 210 U/ml respectively. In both SLE and RA patients, the active disease group had more markedly elevated serum IL-2R levels compared with those of the inactive group. In patients with SLE, elevated serum IL-2R is associated with lymphopenia, renal disorders, decreased C3 level and increased anti-DNA, thus make it a good parameter to monitor disease activity in SLE.