Abstract
We examined soluble IL-2R in sera of patients with SLE by ELISA using two monoclonal anti IL-2R antibodies. When we examined sera of forty patients with SLE, soluble IL-2R in sera of them significantly increased as compared with normal controls, (SLE; 337.8±188.2U/ml, Normal control; 150.0±35.0U/ml). Sixteen patients (40%) had high titer of soluble IL-2R (more than mean+2 S. D. of normal controls). And then we investigated the clinical findings of patients with high titer of soluble IL-2R. Although in these patients, the peripheral pattern of anti nuclear antibody and pericarditis appeared more frequently than patients with normal titer of soluble IL-2R, there was no significance in anti DNA antibody, CH 50, renal involvement (proteinuria, urine cast), skin involvement, pleuritis, central nervous system involvement, hematological findings. It is known that soluble IL-2R appeared in the culture supernatant of normal peripheral blood lymphocyte stimulated by mitogen (PHA, anti OKT 3 etc.) or in sera of patients with adult T cell leukemia, it is said that soluble IL-2R relate to activated T cells. On the other hand, although it was reported that activated T cells appeared in peripheral blood lymphocytes of patients with SLE, the fact that many patients with SLE had soluble IL-2R in our examination may relate to activated T cells. And therefore, we confirmed them by using various activated T cell marker (HLA-DR positive T cell, HLA-DP positive T cell, IL-2R positive T cell). The patients with high titer of soluble of IL-2R tended to have high positive rate of HLA-DP positive T cells, HLA-DR positive T cells, but not so much IL-2R positive T cell. This results suggest the existence of activated T cells and the relationship between soluble IL-2R and activated T cells. It is said that patients with SLE have T cells abnormality (ex. the decrease of mitogen response, auto mixed lymphocyte reaction, IL-2 production, IL-2 response) and activated T cells, and it is suggested that these abnormality related to the pathogenesis of SLE. Our results confirm the existence of activated T cells, in patients with SLE and suggest the possibility that soluble IL-2R could be used as the marker of activated T cells or the new barometer of disease activity, although it is not clear how activated T cells relate to pathogenesis or clinical findings of SLE. And, although the immunological role of soluble IL-2R is not clear, it may be one of clue in the investigation of pathogenesis of SLE.
