T follicular helper cells in cancer, tertiary lymphoid structures, and beyond

Peripheral immunophenotyping reveals lymphocyte stimulation in healthy women living with hereditary breast and ovarian cancer syndrome

Germline pathogenic variants in BRCA1 and BRCA2 (gpath(BRCA1/2)) represent genetic susceptibility for hereditary breast and ovarian cancer syndrome. Tumor-immune interactions are key contributors to breast cancer pathogenesis. Although earlier studies confirmed pro-tumorigenic immunological alterations in breast cancer patients, data are lacking in healthy carriers of gpath(BRCA1/2). Peripheral blood mononuclear cells of 66 women with or without germline predisposition or breast cancer were studied with a mass cytometry panel that identified 4 immune subpopulations of altered frequencies between healthy controls and healthy gpath(BRCA1) carriers, while no difference was observed in healthy gpath(BRCA2) carriers compared to controls. Moreover, 3 (one IgD-CD27+CD95+ B cell subpopulation and two CD45RA-CCR7+CD38+ CD4+ T cell subpopulations) out of these 4 subpopulations were also elevated in triple-negative breast cancer patients compared to controls. Our results reveal an activated peripheral immune phenotype in healthy carriers of gpath(BRCA1) that needs to be further elucidated to be leveraged in risk-reducing strategies.

The immunology of type 1 diabetes

Following the seminal discovery of insulin a century ago, treatment of individuals with type 1 diabetes (T1D) has been largely restricted to efforts to monitor and treat metabolic glucose dysregulation. The recent regulatory approval of the first immunotherapy that targets T cells as a means to delay the autoimmune destruction of pancreatic β-cells highlights the critical role of the immune system in disease pathogenesis and tends to pave the way for other immune-targeted interventions for T1D. Improving the efficacy of such interventions across the natural history of the disease will probably require a more detailed understanding of the immunobiology of T1D, as well as technologies to monitor residual β-cell mass and function. Here we provide an overview of the immune mechanisms that underpin the pathogenesis of T1D, with a particular emphasis on T cells.

Increased circulating regulatory T cells and decreased follicular T helper cells are associated with colorectal carcinogenesis

Objective

Colorectal cancer (CRC) is the third most prevalent cancer worldwide and is associated with high morbidity and mortality rates. Colorectal carcinogenesis occurs via the conventional adenoma-to-carcinoma and serrated pathways. Conventional T helper (Th) and innate lymphoid cells (ILCs) play vital roles in maintaining intestinal homeostasis. However, the contribution of these two major lymphoid cell populations and their associated cytokines to CRC development is unclear. Therefore, we aimed to analyze peripheral lymphocyte profiles during colorectal carcinogenesis.

Methods

We collected 86 blood samples concurrently, and pathologists confirmed the presence of various pathological conditions (i.e., HPs, adenoma, and carcinoma) using hematoxylin and eosin staining. Ten healthy donors were recruited as healthy controls (HCs) from the physical examination center. We performed flow cytometry on peripheral blood mononuclear cells collected from patients with various pathological conditions and the HCs, and cytokines (interleukin-2, interleukin-4, interleukin-5, interleukin-13, interleukin-17A, interleukin-17F, interleukin-22, interferon-γ, and tumor necrosis factor-α) were quantified. We also analyzed the published single-cell RNA sequence data derived from tissue samples from different stages of colorectal carcinogenesis.

Results

The cytokine response in peripheral CD4+ T cells was upregulated during the carcinoma process. The frequency of peripheral regulatory T cells (Tregs) increased in the adenoma and carcinoma stages. While the T follicular helper (Tfh) cell proportion was downregulated in the adenoma and carcinoma processes. Thus, Th cell subsets, especially Tregs and Tfh cells, were involved in colonic diseases. Moreover, the immunological profile characteristics in the HPs were clarified.

Conclusion

We comprehensively analyzed circulating ILCs and adaptive T-cell lymphocyte subtypes in colorectal carcinoma progression. Our results show the immunological profile characteristics and support the involvement of Th subsets, especially Treg and Tfh cell populations, in colonic diseases. These findings significantly enhance our understanding of the immune mechanisms underlying CRC and its precancerous lesions. Further investigation of the Treg and Tfh cells' function in colorectal disease development will provide potential therapeutic targets for monitoring and preventing CRC development.