Promotion of lymphocyte blastogenesis by hemodialysate of chronic renal failure

Effects of hemodialysate of patients with chronic renal failure (CRF) on blastogenesis of human peripheral blood lymphocytes in the presence of concanavalin A or phytohemagglutinin was investigated. Hemodialysates from 11 CRF patients significantly promoted lymphocyte blastogenesis when compared with control dialysis fluids (p less than 0.01). The strongest activity (39% promotion of the lymphocyte blastogenesis) was observed with a hemodialysate obtained at 0.5 h after beginning dialysis. The activity decreased thereafter. On the contrary, the blastogenesis-promoting activity in plasma decreased significantly after hemodialysis (p less than 0.01, n = 11). To further confirm the presence of low-molecular-weight factor(s) in CRF, ultrafiltration of plasma obtained from CRF and healthy subjects was conducted using a membrane filter with a molecular cutoff of 3,000 D. The filtrate of CRF plasma significantly promoted lymphocyte blastogenesis when compared to that of healthy subjects (p less than 0.01). Heat treatment (100 degrees C, 40 min) did not abolish the activity of the hemodialysate. None of the drugs taken by the patients nor creatinine accumulated in CRF promoted the lymphocyte blastogenesis. Chromatographic analysis of a hemodialysate demonstrated several peaks which were absent in the control dialysis fluid. These results showed the presence of a novel lymphocyte-stimulating factor(s) in CRF, which is heat stable and has a low molecular weight (less than 3,000 D).