RT-PCR and in situ hybridization were observed during dialyzer reuse. Results Every plasma cytokine level was decreased during reuse compared with first use dialyzer, but no significant difference was found between them. The levels of gene expression of IL-1?、TNF-? and IL-6 were different from the first use significantly. Conclusion If effective dialysis volumn was maintained, formaldehyde as disinfectant on reprocessing the dialyzer may amilorate membrane bio-compatibility. It would be benificial to decrease appearance of long term hemodialysis -related complications.