IL-10 synthesis and secretion by peripheral blood mononuclear cells in haemodialysis patients

Purpose of study. IL-10 may explain the paradox between immunodeficiency and oversecretion of cytokines in chronic haemodialysis (HD) patients. We analysed the secretion of IL-10 by PBMC and the expression of IL-10 mRNA in 10 long-term HD patients (108-276 months), 10 short-term HD patients (3-18 months), and 10 healthy controls. Results. Spontaneous IL-10 secretion was higher in HD patients than in controls (15 pg/ml vs 2 pg/ml, P=0.004). It was detected in 13 of 20 patients and in 1 of 10 controls (P=0.01). IL-10 mRNA expression was also higher in HD patients than in controls. Spontaneous secretions of IL-10 and IL-6 were positively correlated in patients. IL-10 secretion in response to LPS was higher than the upper limit of control range in 4 of 10 long-term HD patients and in no short-term HD patients (P=0.04). IL-10 mRNA expression was also higher in long-term than in shortterm HD patients. Conclusions. This study demonstrates that IL-10 is spontaneously synthesized and secreted in HD patients, supporting an immunomodulating role in this setting. The greater IL-10-producing capacity in long-term HD patients indicates a chronic effect of haemodialysis on PBMC responsiveness.