[The IL-6 soluble receptors in hemodialyzed patients]

Pro-inflammatory cytokines, in addition to their role in host defence, can be considered a disease mediator; therefore, a reduction in cytokine synthesis or its effects is becoming a target of many diseases. Interleukin-6 (IL-6) is a pro-inflammatory cytokine that could play a role in several clinical problems related to dialysis treatment. Biological activities of IL-6 could be modulated by two soluble circulating receptors, namely sIL-6R and sgp130. sIL-6R can enhance the inflammatory effects of IL-6 and; therefore, is an "agonistically" acting molecule. On the contrary, sgp130 efficiently binds the IL-6/sIL-6R complex with "antagonistic" effects. In this study we evaluated sgp130 release by peripheral blood mononuclear cells (PBMC) harvested from 10 healthy controls (CON) and 11 end-stage renal disease (ESRD) patients undergoing renal dialysis therapy RDT) with cellulosic hemophan membrane (HD). We also evaluated gp130 gene expression by reverse transcriptase polymerase chain reaction (RT-PCR). gp130 is the membrane bound receptor of IL-6 that could be proteolytically cleaved to generate soluble sgp130. Our results demonstrated that HD. at basal conditions, showed a higher release of sgp130 as compared with CON. We also demonstrated by RT-PCR at basal conditions a higher gene expression of gp130 in HD, as compared with CON. These results took place in the absence of any mitogenic stimulation and suggest that in HD patients an inflammatory subclinical status increases sgp130 release. The results obtained after lipopolysaccharide (LPS) stimulation confirm the role of inflammation on the increased release of sgp130 in HD patients.