Elevated soluble interleukin-2 receptor levels in serum of human immunodeficiency virus infected populations.

Soluble interleukin-2 receptor (SIL-2R) levels in sera were quantitated in asymptomatic intravenous drug abusers (IVDA) and in patients with lymphadenopathy or AIDS. The mean SIL-2R level in serum of normal controls was 158 +/- 19 compared to 368 +/- 35 U/ml in serum of HIV-seronegative asymptomatic IVDA. The mean SIL-2R in serum of HIV-seropositive asymptomatic IVDA was 609 +/- 85 U/ml and in patients with lymphadenopathy was 745 +/- 79 U/ml. In addition, AIDS patients with Pneumocystis carinii pneumonia, Kaposi's sarcoma, or both had elevated mean levels of SIL-2R values with a broad range. This elevated level of SIL-2R may reflect excessive cell surface IL-2R expansion by the infected cells.