Abstract： This study performed to investigate the differences of plasma gene expression profiles between primary biliary cirrhosis(PBC)patients and healthy controls,and the effect of tryptase Alpha/Beta 1(TPSAB1)on the proliferation of naive CD4+T cells derived from peripheral blood mononuclear cell(PBMC)in patients with PBC.The plasma samples of three PBC patients and three healthy controls were analyzed by microarray;Immune cell isolation kits were used to isolate natural killer(NK)cells,B cells,naive CD4+T and naive CD8+T cells from PBMC;The expression level of TPSAB1 in NK cells,B cells,naive CD4+T cells and naive CD8+T cells were analyzed by qRT-PCR;The expression of TPSAB1 in CD4+T cells was analyzed by Western blotting after interference by short hairpin RNA(shRNA)targeting TPSAB1.WST-1 proliferation kit and 5-Ethynyl-2'-deoxyuridine(EdU)staining assay were used to detect the proliferation of naive CD4+T cells after CD3/CD28 stimulation in vitro.The apoptosis of CD4+T cells was measured by flow cytometry.Enzyme linked immunosorbent assay(ELISA)was used to determine interferon-γ(IFN-γ),interleukin-4(IL-22),and IL-17 secretion in TPSAB1 knock-down CD4+T cells.Data showed that the expression level of TPSAB1 in NK cells and naive CD4+T cells from PBC patients were significantly higher than those of healthy control group.Naive CD4+T cells from PBC patients showed enhanced proliferative capacity after CD3/CD28 stimulation compared with controls.However,there was no difference in apoptosis between the two groups.The levels of IL-22,IL-17 and IFN-γ were significantly increased in PBC patients.Compared with the control group,knockdown of TPSAB1 inhibited the proliferation ability of naive CD4+T cells under CD3/CD28 stimulation.At the same time,the levels of IL-22,IL-17 and IFN-γ were decreased.In conclusion,inhibition of TPSAB1 protein expression can block the proliferation of naive CD4+T cells,suggesting that TPSAB1 may be a new target for the treatment of PBC.