We measured the levels of colony-stimulating factors (G-CSF, M-CSF and GM-CSF) and several cytokines in paired sera obtained from 51 patients (33 males and 18 females; mean age: 53 years) on long-term haemodialysis (HD). The mean pre-HD G-CSF level was 22.7 +/- 21.7 pg/ml and the post-HD level was 40.3 +/- 54.4 pg/ml. The mean pre-HD M-CSF level was 2.4 times higher than normal at 1287 +/- 380 U/ml, and it increased to 1644 +/- 456 U/ml after HD (r = 0.83). GM-CSF was not detectable in any of the serum samples. IL-1 beta was detectable in 38 pre-HD sera at a mean level of 57.1 +/- 21.8 pg/ml, but was rarely detected after HD. TNF-alpha was not usually detected. When the CSF levels were divided by the product of the serum total protein concentration and body weight, the post-HD value for G-CSF was almost always greater than the pre-HD value and there was an improved pre-post correlation (r = 0.69). In the transformed pairs of M-CSF level, the post-HD value did not differ much from the pre-HD value, and a strong pre-post correlation was noted (r = 0.94). These results suggest that the serum G-CSF level is not affected by chronic renal failure, although HD may induce an increase of G-CSF. In the case of M-CSF, however, impaired renal metabolism and/or excretion may increase the serum concentration, but it is not modulated by haemodialysis.(ABSTRACT TRUNCATED AT 250 WORDS)