Lack of association between hyperprolactinemia and soluble IL-2 receptor levels in systemic lupus erythematosus.

Abstract

The aim of the study was to evaluate the association between hyperprolactinemia and T lymphocyte activation through the soluble IL-2 receptor (sIL-2R) in systemic lupus erythematosus (SLE) patients. Seventy SLE patients, 18 of them with hyperprolactinemia (HPRL), were compared with 18 normoprolactinemic (NPRL) patients and 10 age-matched healthy blood-bank donor women. Patients were evaluated by means of the SLE activity index (SLEDAI). Total serum IgG and sIL-2R levels were determined by an ELISA assay. Differences between sIL-2R and IgG serum levels in patients and controls were examined by Kruskal-Wallis analysis and a Spearman r correlation to determine the association between sIL-2R, IgG and prolactin (PRL) levels. IgG and sIL-2R serum levels did not differ significantly between HPRL and NPRL patients: 1827.3 (1428-2226) vs 2028.8 (1586-2467) mg/dl and 882.2 (511-1254) vs 740.1 (534-946.4) U/ml, respectively (confidence interval 95%). In the total SLE group, sIL-2R and IgG serum levels were positively associated (P = 0.0009), however, this was not the case for sIL-2R and PRL (P > 0.49). We did not demonstrate an association between HPRL and lymphocyte activation measured through serum sIL-2R in female patients with SLE.