Polymorphism of the prolactin extrapituitary promoter in psoriatic arthritis

Excerpt

Psoriatic arthritis is characterized as seronegative arthritis that affects patients suffering from psoriasis [1]. Aetiology of this condition is still not clear and therapeutic approaches are not always successful. However, good response to bromocriptine therapy decreasing prolactin levels in patients with psoriatic arthritis has been demonstrated in some reports [2, 3]. Prolactin acts as a cytokine and plays a role in pathogenesis of systemic autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus [4, 5]. Moreover, high serum prolactin levels were observed in group of patients with psoriasis and link between keratinocytes hyperproliferation and prolactin has been proposed [6]. The peptide hormone prolactin is produced from pituitary lactotrophs and extrapituitary tissues such as lymphocytes as well. Extrapituitary PRL production is regulated by an alternative promoter located 5.8 kb upstream from the pituitary one [7, 8]. A functional single nucleotide polymorphism (SNP) G/T at the position −1149 of this extrapituitary promoter has been observed and in lymphocytes higher PRL mRNA expression found to be connected with G allele [9]. In our work we studied −1149G/T SNP PRL in group of 83 Czech patients with psoriatic arthritis (PsA). …