Recent evidence demonstrates that hyperprolactinemia was found in active systemic lupus erythematosus (SLE). This indicates prolactin (PRL) is an important immunoregulator and may play a role in the pathogenesis of SLE. However, study of the prevalence and the clinical significance of hyperprolactinemia in SLE and other rheumatic disease has rarely been carried out.
From January 1995 to January 1996, 79 individuals were enrolled in this study. PRL levels of 30 cases of SLE were compared with those in 29 rheumatoid arthritis (RA) and 20 normal healthy volunteers. Moreover, a correlation between levels of PRL and SLE disease activity index (SLEDAI) in SLE patients was studied.
The mean value of serum PRL level in SLE patients (19.35 +/- 11.33 ng/dl) was significantly higher than in RA patients (12.33 +/- 8.30 nd/dl, p < 0.05). The difference was more pronounced between SLE patients and healthy individuals (12.01 +/- 7.53 ng/dl, p < 0.01). However, patients with RA had no significant difference from the control group. Analysis made between SLEDAI and PRL levels in SLE patients revealed no significant correlation (r = 0.537, p = 0.07). Furthermore, no significant correlation was found between antinuclear antibody (ANA), C3, C4, anti-DNA and hyperprolactinemia.
This study has shown that hyperprolactinemia is prevalent in random SLE patients, but not in RA patients. The elevated PRL levels seem not to be associated with disease activity and ANA positivity.