Altered IkBa expression promotes NF-kB activation in monocytes fromprimary Sjogren’s syndrome patients

Aims: To study the importance of IkBa in NF-kB signal transduction, we analysed the IkBa expression in monocytes from Sjo¨gren’s syndrome (SS) patients versus healthy controls. Methods: Monocytes were obtained from the peripheral blood of 30SSpatients and 23 healthy subjects. IkBaexpressionwas studied by semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), real-time PCR, immunoblotting, flow cytometry and enzyme linked immunosorbent assay (ELISA). Results: Analysis of the gene and protein expression profiles of SS monocytes revealed a down-regulation of IkBa, and in all the Sjo¨gren’s syndrome cases examined, serum IkBa levels were significantly decreased in comparison with controls. Conclusions: Our findings clearly demonstrate changes in the levels of IkBa in SS monocytes, suggesting that the attenuated expression of IkBa could contribute to the deregulation of NF-kB pathways in the SS pathogenesis. Decreased expression of IkBa may specifically amplify cytokines production and inflammatory response linked to Sjo¨gren’s syndrome.