Objective To discuss a convenient and pragmatic method of fitting and optimizing standard curve for determining concentration of serum hepatitis B virus large surface protein(HBV-LP).MethodsEnzyme-linked immunosorbent assay(ELISA)was used to measure the absorbance of standard preparation of HBV-LP.Concentration and absorbance of standard preparation of HBV-LP was carried out curve fitting with 4-parameter formula model and linear model and log-linear model and quadratic polynomial model and cubic polynomial model and S model by program solution of Excel,respectively.The most standard curve for determining concentration of serum HBV-LP was determined with coefficient of determination of regression model.ResultsThe scatterplot of standard preparation of HBV-LP submited nonlinear tendency.There were all significance to regression equation of 4-parameter formula model and linear model and log-linear model and quadratic polynomial model and cubic polynomial model and S model(P

Objective To investigate the expression of T cell immunoreceptor with Ig and immunoreceptor tyrosine-based inhibitory domains (TIGIT) on peripheral CD4+ T and CD8+ T cells from patients with rheumatoid arthritis (RA) and its significance in order to clarify its role in the development of RA.Methods Peripheral blood samples were collected from 81 patients with RA and 33 healthy controls (HC).Expression of TIGIT on the surface of peripheral blood leukocytes was detected by flow cytometry.Differences in TIGIT expression between RA and HC groups were comparatively analyzed.Correlations of TIGIT expression on CD4+ T and CD8+ T cells with several laboratory indexes were analyzed.All data were statistically analyzed.Results (1) The percentage of TIGIT-expressing CD3+ T cells in patients with RA was significantly higher than that in HC (P<0.01).Moreover, the median fluorescence intensity (MFI) of TIGIT on CD3+ T cells was significantly elevated in patients with RA as compared with that in HC (P<0.01).No significant difference in the expression of TIGIT on B cells, monocytes or neutrophils was observed between RA and HC groups.(2) The percentages of TIGIT-expressing CD4+ T and CD8+ T cells were significantly elevated in patients with RA as compared with those in HC (P<0.01).Moreover, the MFI of TIGIT on CD4+ T and CD8+ T cells were significantly elevated in patients with RA as compared with those in HC (P<0.01).(3) The percentages of both TIGIT-expressing CD4+ T cells and TIGIT-expressing CD8+ T cells in patients with RA were positively correlated with erythrocyte sedimentation rate (ESR) (rs=0.355, P<0.01;rs=0.277, P=0.013).(4) The percentages of both TIGIT-expressing CD4+ T cells and TIGIT-expressing CD8+ T cells in patients with RA were positively correlated with rheumatoid factor (RF) (rs=0.265, P=0.017;rs=0.366, P<0.01).The MFI of TIGIT on CD4+ T cells was positively correlated with RF in RA group (rs=0.226, P=0.043).The percentage of TIGIT-expressing CD4+ T cells was positively correlated with anti-cyclic citrullinated peptide (anti-CCP) antibody in patients with RA who were positive for anti-CCP antibody (rs=0.324, P=0.012).(5) The percentage of TIGIT-expressing CD4+ T cells as well as the MFI of TIGIT on CD4+ T cells in patients with RA was positively correlated with Disease Activity Score-28 (DAS28) (r=0.232, P=0.038;r=0.343, P<0.010).Conclusion The expression of TIGIT on T cells is elevated in patients with RA and correlated with inflammatory markers, antibody production and disease activity.