Objective: To study prospectively the serum prolactin concentrations among patients with systemic lupus erythematosus and their possible relationship to disease activity and manifestations.
Methods: Serum prolactin levels were measured by radioimmunoassay in 38 patients with systemic lupus erythematosus and 22 age matched controls. Patients with known secondary causes for hyperprolactinaemia, such as pregnancy, lactation, prolactinoma and taking medications known to induce prolactin secretion, were excluded from the study. Demographic, clinical and laboratory features of the patients were obtained. Patients were divided into two subgroups according to their disease activity. Mean prolactin levels from both groups were compared using student test, and prolactin from patients with systemic lupus erythematosus was correlated with variables of disease activity, including the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI).
Results: Mean prolactin levels were higher in patients with systemic lupus erythematosus (15.4) than healthy controls (9.83); however, the difference did not reach statistical significance (p=). Hyperprolactinemia was found in 24 patients with systemic lupus erythematosus and 5 controls. The frequency of hyperprolactinaemia in systemic lupus erythematosus group was higher than healthy controls. No significant difference in mean prolactin levels was found between patients with active versus inactive disease (18.9 vs 18.5).
Conclusion: Hyperprolactinaemia occurred significantly in patients with systemic lupus erythematosus, but did not correlate with disease activity.