multiplexed-immunofluorescence-analysis-quantification-intratumoral

Multiplexed Immunofluorescence Analysis and Quantification of Intratumoral PD-1+ Tim-3+ CD8+ T Cells

Immune cells are important components of the tumor microenvironment and influence tumor growth and evolution at all stages of carcinogenesis. Notably, it ...

Université Paris Diderot Paris 7

In survival analysis, assessing the existence of potential centre effects on the baseline hazard or on the effect of fixed covariates on the baseline hazard, such as treatment-by-centre interaction, is a frequent clinical concern in multicentre studies. Survival models with random effects on the baseline hazard and/or on the effect of the covariates of interest have been largely applied, for instance, to investigate potential centre effects. We aimed to develop a procedure to routinely test for multiple random effects in survival analyses. We propose a statistic and a permutation approach to test whether all or a subset of components of the variance-covariance matrix of random effects are non-zero in a mixed-effects Cox model framework. Performances of the proposed permutation tests are examined under different null hypotheses corresponding to the different components of the variance-covariance matrix, i.e., to the different random effects considered on the baseline hazard and/or on the covariates effects. Several alternative hypotheses are evaluated using simulations. The results indicate that the permutation tests have valid type I error rates under the null and achieve satisfactory power under all alternatives. The procedure is applied to two European cohorts of haematological stem cell transplants in acute leukaemia to investigate the heterogeneity across centres in leukaemia-free survival and the potential heterogeneity in prognostic factors effects across centres.

Investigating covariate-by-centre interaction in survival data.

Inhibitory receptors expressed by T cells mediate tolerance to tumor antigens, with coexpression of these receptors exacerbating this dysfunctional state. Using the VectraR automated multiparametric immunofluorescence technique, we quantified intratumoral CD8+ T cells coexpressing the inhibitory receptors PD-1 and Tim-3 from patients with renal cell carcinoma (RCC). A second validation cohort measured the same parameters by cytometry. The percentage of tumor-infiltrating CD8+ T cells coexpressing PD-1 and Tim-3 correlated with an aggressive phenotype and a larger tumor size at diagnosis. Coexpression of PD-1 and Tim-3 above the median conferred a higher risk of relapse and a poorer 36-month overall survival. Notably, other CD8+T-cell subsets did not exert a similar effect on overall survival. Moreover, only the PD-1+Tim-3+ subset of CD8+ T cells exhibited impaired function after stimulation. Our findings establish intratumoral Tim-3+PD1+CD8+ T cells as critical mediators of an aggressive phenotype in RCC. Use of the Vectra tool may be useful to identify similarly critical prognostic and predictive biomarkers in other tumor types and their response to immunotherapy. Cancer Res; 77(5); 1075-82. ©2016 AACR.

Lucie Biard

Université Paris Diderot Paris 7

Multiplexed Immunofluorescence Analysis and Quantification of Intratumoral PD-1⁺ Tim-3⁺ CD8⁺ T Cells