EXPRESSION OF IL-2R, IL-4R, IL-6R ON PERIPHERAL-BLOOD LYMPHOCYTES IN SYSTEMIC LUPUS-ERYTHEMATOSUS AND CORRELATION WITH DISEASE-ACTIVITY - APROSPECTIVE-STUDY

Aims-To study the expression of interleukin-2 receptor (IL-2R), interl eukin-4 receptor (IL-4R) and interleukin-6 receptor (IL-6R) on periphe ral blood lymphocytes (PBL) in patients with systemic lupus erythemato sus (SLE); to correlate the level of expression of these receptors wit h SLE disease activity. Methods-Peripheral blood lymphocytes were stud ied by a high sensitivity flow cytometry technique using monoclonal an tibodies directed against CD25 (IL-2R alpha chain), CD122 (IL-2R beta chain), CD124 (IL-4R), and CD126 (IL-6R). SLE disease activity was sco red using the SLE Disease Activity Index, C3 and C3, concentrations, a nti-dsDNA level, and absolute lymphocyte count. Results-Compared with normal controls, PBL from. patients with SLE had a higher percentage o f CD25+ cells (median 20.8% v 16.5%) and a lower percentage of CD122cells (median 13.1% v 22.4%). The difference in CD122+ cells was great er in the CD122(weak) population than the CD122(strong) (natural kille r cell) population. The percentages of CD124+ and CD126+ PBLs in patie nts with SLE and controls were similar. On CD25+ cells, the relative a ntigenic level of the IL-2R alpha chain was significantly higher in pa tients with SLE (median 2.01 v 1.81). The relative antigenic levels of CD122+, CD124+ and CD126+ cells were similar in patients and controls . Neither the percentages nor the relative antigenic levels of all of these cytokine receptors were correlated with any of the parameters of disease activity. Conclusion-Lymphocyte activation in patients with S LE was evident from the increase in CD25 expression on PBL, with a rec iprocal decrease in CD122 expression. As tile expression of IL-2R, IL- 4R, IL-6R did not correlate with disease activity, it seems that these cytokine/receptor systems do not play a direct role in disease activa tion in SLE.