Background: In female patients with systemic lupus erythematosus (SLE), we identified estrogen receptor ERa, ERb and ERa variant transcripts in peripheral blood mononuclear cells (PBMC). Exon 1 and 2 of ERa gene was subjected to mutation analysis to assess whether possible nucleotide alterations are linked to the disease.
Methods: The whole coding sequence of ERa was analysed by reverse transcription polymerase chain reaction (RT-PCR) and cDNA sequencing in PBMC prepared from 19 SLE patients and 12 healthy females. ERa exon 1 and exon 2 were subjected to mutation analysis using DNA isolated from whole blood of 21 SLE patients and 29 healthy females. The aminoterminal coding sequence of ERb was also analysed by RT-PCR.
Results: Wild type ERa and ERa splicing variants with deletions in exons 2, 5 and 7 were detected both in healthy individuals and in SLE patients, with no qualitative difference in their expression among the two populations. In ERa exon 1, the polymorphisms identified codon 10 and codon 87, both in patients and in healthy individuals who were not associated with the disease. No other mutations were present in ERa exon 1 or ERa exon 2 in all subjects studied. ERb was expressed in both populations.
Conclusion: PBMC of SLE patients express wild type ERa, ERb and the same ERa variants as do healthy individuals. Genetic alterations in exon 1 and exon 2 of the ERa gene are not linked with SLE disease.