Correlation between stromal Th and Tc lymphocytes and PD-L1 expression in early breast cancer tumors

INTRODUCTION

Prognostic and predictive value of PD-L1 as a biomarker in breast cancer remains controversial. While some studies suggest its association with negative prognostic parameters, others reported a highly significant association between PD-L1 expression and tumor-infiltrating lymphocytes, which are known to be an independent favorable prognostic factor. The aim of present study is to examine the relationship between immune response markers and PD-L1 expression in early breast cancer.

MATERIAL AND METHODS

Immunohistochemical expression of PD-L1, along with density and composition of stromal lymphocytic infiltrate and peritumoral lymphoid aggregates was analyzed in 95 samples of invasive breast cancer.

RESULTS

A strong positive correlation between PD-L1 expression and the density of stromal lymphocytic infiltrate and peritumoral lymphoid aggregates was identified and a cut-off value of 53% coverage of tumor stroma by lymphocytes, with which PD-L1 positivity can be predicted with excellent diagnostic accuracy, was determined for the first time using statistical methods. Additionally, PD-L1 positivity was observed significantly more often in tumors with higher absolute number of both CD4 and CD8 T-lymphocytes in the stromal infiltrate. No significant correlation with molecular subtype of breast cancer was found.

CONCLUSIONS

Our results indicate that the density of stromal lymphocytic infiltrate might be a better predictor of PD-L1 positivity in early breast cancer than the molecular subtype and that the key to the optimization of PD-L1 as a biomarker in breast cancer lies in its interpretation in the context of other immune response markers.

Chronic activation of 4-1BB signaling induces granuloma development in tumor-draining lymph nodes that is detrimental to subsequent CD8+ T cell responses

The antitumor capabilities of agonistic anti-4-1BB mAbs have made them an attractive target for tumor immunotherapy. However, the adverse side effects associated with agonist antibodies have hindered their clinical development. Here, we aimed to study the immune-related adverse events of repeated doses and long-term use of agonistic anti-4-1BB mAbs. We show that chronic activation of 4-1BB signals induced the accumulation of IFN-γ-producing PD-1⁺CD8⁺ T cells in the secondary lymphoid organs of tumor-bearing mice by increasing the number of dividing CD8⁺ T cells, which was beneficial for suppressing tumor growth in the early phase of anti-4-1BB induction. However, repeated exposure to anti-4-1BB mAbs led to granuloma development in tumor-draining lymph nodes (TDLNs) of mice due to recruitment and accumulation of macrophages via the CD8⁺ T cell-IFN-γ axis. This was accompanied by excessive lymph node swelling, which impaired the sequential activation of CD8⁺ T cells. Our data provide insights into the immune-related adverse events of long-term agonist 4-1BB antibody dosing, which should be considered during the clinical development of immunomodulating therapy.

Increased expression of CD8 marker on T-cells in COVID-19 patients. Blood Cells Mol Dis. 2020;83:102437. [PMID: 32325421 PMCID: PMC7194879 DOI: 10.1016/j.bcmd.2020.102437]

BACKGROUND

Cell-mediated immunity including T-cells (T helper and cytotoxic) plays an essential role in efficient antiviral responses against coronavirus disease-2019 (COVID-19). Therefore, in this study, we evaluated the ratio and expression of CD4 and CD8 markers in COVID-19 patients to clarify the immune characterizations of CD4 and CD8 T-cells in COVID-19 patients.

METHODS

Peripheral blood samples of 25 COVID-19 patients and 25 normal individuals with similar age and sex as the control group were collected. White blood cells, platelets, and lymphocytes were counted and CD4 and CD8 T lymphocytes were evaluated by flow cytometry.

RESULTS

The number of white blood cells, lymphocytes, and platelets were reduced significantly in COVID-19 patients (P < 0.05). The difference in CD4:CD8 ratio, CD4 T-cell frequency, CD8 T-cell frequency, and CD4 mean fluorescence intensity (MFI) was not significant between COVID-19 patients and healthy individuals (P > 0.05); however, the CD8 MFI increased significantly in COVID-19 infected patients (P < 0.05).

CONCLUSION

Although, there is no significant difference in the ratio of CD4 to CD8 between two groups, the expression level of CD8 in COVID-19 patients was significantly higher than the normal individuals. This result suggested that the cellular immune responses triggered by COVID-19 infection were developed through overexpression of CD8 and hyperactivation of cytotoxic T lymphocytes.