Objective:To investigate the effects of a novel extracorporeal blood purification therapy-coupled plasma filtration adsorption(CPFA) on the function of monocytes in the multiple organ dysfunction syndromes(MODS) patients with severe infection. Methods:This study was a pospective,pilot,crossover clinical trial. A total of seven patients diagnosed MODS with severe infection were selected in this study. Patients were randomly allocated to both 10 hrs of coupled plasma filtration adsorption plus hemodialysis(CPFA,treatment A) and 10 hrs of high volume hemo- filtration(HVHF,treatment B) with 12 h interval in random order,that was to say each patient receiving A+B or B+A randomly. Plasma monocyte HLA-DR expression and leukocyte TNF--琢 production(both spontaneous and lipopolysaccharide stimulating) were tested before and after the treatment. TNF--琢 production from normal human monocytes(THP-1 cell) incubated with patients’ plasma obtained at 0,5,10 h of the treatment was also measured. Results:①The blood monocyte HLA-DR expression(%) increased after CPFA(84.32 ± 4.63 vs. 73.65 ± 11.52,P = 0.037) but no change after HVHV(P > 0.05).②Spontaneous and lipopolysaccharide inducing TNF--琢 production from patients’ whole blood increased over time with CPFA(P < 0.05). This increase was negative in HVHF group(P > 0.05). ③Patients’ serum suppressed production of TNF-a by cultured monocytes(THP-1). This suppression effect decreased over time with CPFA(P < 0.05). However,no significant difference was seen in HVHF group(P > 0.05). Conclusion:CPFA was superior to HVHF in improving the antigen presentation ability of monocyte and restoring leukocyte responsiveness to lipopolysaccharide. These findings suggest a potential role for CPFA in the treatment of MODS.