Enhanced serum prolactin (PRL) in patients with systemic lupus erythematosus: PRL levels are related to the disease activity

Recent accumulated evidence suggests that prolactin (PRL) is an important immunomodulator and plays a part in the pathogenesis of systemic lupus erythematosus (SLE). The current study assessed the frequency of hyperprolactinaemia in patients with SLE and its association with defined clinical manifestations or serological abnormalities. PRL levels were analysed in 60 patients with SLE including a follow-up of 20 patients, 18 patients with rheumatic autoimmune diseases other than SLE (AID) and in 47 normal healthy subjects (NHS) using ELISA. Clinical manifestations and disease activity (ECLAM) were recorded. Autoantibodies (anti-dsDNA, anti-CL) were determined by standard techniques. In all, 28.3% of the patients with SLE had raised serum PRL. Their PRL levels (17.4 ± 15.1 ng/ml, P < 0.0001) and those of patients with AID (13.1 ± 10.3 ng/ml, P < 0.001) were significantly higher compared to NHS (6.3 ± 3.2 ng/ml). Anti-dsDNA (r_s = 0.3, P = 0.04) and anti-CL antibody titres (IgG; r_s = 0.3, P = 0.03) correlated with PRL level. Furthermore, elevated erythrocyte sedimentation rate (ESR), anaemia, decrease in C3, fatigue, fever and renal involvement were associated with hyperprolactinaemia. These results were confirmed by follow-up examinations. Moderate hyperprolactinaemia is present in a subset of patients with SLE and serum PRL correlates with clinical and serological disease activity.