AIM:To study the levels of membrane interleukin-2 receptor(mIL-2R)and T cell subsets in peripheral bloodmononuclear cells(PBMC)from patients with hepatitis Cand their role in the pathogenesis of hepatitis C.METHODS:The levels of mIL-2R and T cells subsets in PBMCwere detected by biotin-streptaUvidin(BSA)technique beforeand after stimulation with PHA in 203 patients with hepatitis Cwith HCV-RNA(+),anti-HCV(+),anti-HCV(-).RESULTS:The total expressive levels of mlL-2R before andafter stimulation with PHA(0.03±0.01,0.03±0.02,0.04±0.02,0.36±0.03),and T cell subsets in PBMC(0.62±0.06,0.37±0.05,0.35±0.07)were all lower in patients withhepatitis C than those in normal controls(0.66±0.07,0.41±0.06,0.31±0.05,P<0.01).Among the patients,thelevels of mlL-2R were lower in silence than those in situationof PHA inducting(P<0.0]).However,the levels of mlL-2Rwere similar in acute hepatitis C to that in chronic hepatitis C(P>0.05).The levels of CD_3~+,CD_4~+,CD_4~+/CD_8~+were lowerand CD_8~+was higher in patients with acute and chronichepatitis C with anti-HCV(+)than those in normal controls(0.62±0.06,0.37±0.05,0.35±0.07,1.18±0.30,0.61±0.07,0.37±0.05,1.39±0.33,0.31±0.05,P<0.05-P<0.01).CONCLUSION: The cellular immunity is obviously changed in patients with hepatitis C. The levels of mlL-2R and activation of T cells are closely associated with chronicity of hepatitis C. AIM: To study the levels of membrane interleukin-2 receptor (mIL-2R) and T cell subsets in peripheral blood mononuclear cells (PBMC) from patients with hepatitis Cand their role in the pathogenesis of hepatitis C. METHODS: The levels of mIL-2R and T cells subsets in PBMCwere detected by biotin-streptaUvidin (BSA) technique before and after stimulation with PHA in 203 patients with hepatitis C with HCV-RNA (+), anti-HCV total expressive levels of mlL-2R before and after stimulation with PHA (0.03 ± 0.01,0.03 ± 0.02,0.04 ± 0.02,0.36 ± 0.03), and T cell subsets in PBMCs (0.62 ± 0.06,0.37 ± 0.05,0.35 ± 0.07) were all lower in patients with hepatpatitis C than those in normal controls (0.66 ± 0.07, 0.41 ± 0.06, 0.31 ± 0.05, P <0.01) .Among the patients, thelevels of mlL-2R were lower in silence than those in situationof PHA inducting <0.0]). However, the levels of mlL-2Rwere similar in acute hepatitis C to that in chronic hepatitis C (P> 0.05). The levels of CD_3 ~ +, CD_4 ~ +, CD_4 ~ + / CD_8 ~ + were lowerand CD_8 ~ + was higher in patients with acute and chronic hepatitis C with anti-HCV (+) than those in normal controls (0.62 ± 0.06,0.37 ± 0.05,0.35 ± 0.07,1.18 ± 0.30,0.61 ± 0.07,0.37 ± 0.05,1.39 ± 0.33,0.31 ± 0.05, P <0.05-P <0.01) .CONCLUSION: The cellular immunity is obviously changed in patients with hepatitis C. The levels of mlL-2R and activation of T cells are closely associated with chronicity of hepatitis C.