Prolactin and interleukin 6 in prepubertal girls with juvenile chronic arthritis.

Objective: To evaluate prolactin (PRL) serum levels in prepubertal girls affected with 2 different subtypes of pauciarticular onset juvenile chronic arthritis (JCA) and with previous acute postinfectious arthritis in remission (AA), and to correlate the relationship of PRL versus interleukin 6 (IL-6) serum levels.

Methods: Eleven girls with antinuclear antibody (ANA) positive early onset pauciarticular JCA, 8 with ANA negative late onset pauciarticular JCA of various forms (considered to have spondyloarthropathy, SpA), and 7 who had had AA were evaluated for serum concentrations of PRL, IL-6, and thyroid hormones and presence of uveitis. All were prepubertal and without clinical or biological signs of disease activity.

Results: Mean serum concentrations of PRL were significantly increased in ANA positive (8.9 +/- 4.0 ng/ml) patients and in patients with SpA (7.8 +/- 2.4 ng/ml) compared to those of AA patients (4.4 +/- 0.3 ng/ml) (p = 0.01 and p = 0.025, respectively) and to controls. Both ANA positive and SpA patients showed increased mean serum concentrations of IL-6 in comparison with AA patients and controls. Significant correlation between PRL and IL-6 concentrations (r = 0.604, p = 0.002) was observed from the whole series.

Conclusion: We found a direct correlation between serum levels of PRL and IL-6 in both ANA positive JCA patients and in ANA negative SpA patients; thus, hyperprolactinemia correlates better with the chronic course of the disease than with ANA positivity.