Distribution of serum levels of sCD40 in healthy donors, haemodialysis (HD), CAPD, chronic renal failure (CRF), tumour and chronic inflammatory bowel disease (CIBD) patients. The sCD40 serum levels of healthy donors were just above the detection limit, whereas sCD40 serum levels were highly elevated in all uraemic patients. Tumour and CIBD patients showed only weak elevations of sCD40.