To describe the relationship between the two mechanisms involved in sIL6R generation in rheumatoid arthritis (RA).
RA patients were selected from a group of subjects genotyped for the rs8192284 SNP, located at the proteolytic cleavage site of IL-6R. sIL6R and protease levels (ADAM17) were measured and the contribution of alternative splicing in the generation of sIL-6R was evaluated through qRT-PCR.
Increased sIL-6R plasma levels and expression of spliced isoform generating sIL-6R are genotype dependent. ADAM17 concentrations were independent of the genotype studied.
Alternative splicing and proteolytic cleavage participate in sIL-6R generation in RA. The rs8192284 polymorphism determines the sIL-6R plasma level through differential proteolytic rupture controlled by ADAM17.