Tissue-resident memory T cells in the kidney

Abstract

The identification of tissue-resident memory T cells (TRM cells) has significantly improved our understanding of immunity. In the last decade, studies have demonstrated that TRM cells are induced after an acute T-cell response, remain in peripheral organs for several years, and contribute to both an efficient host defense and autoimmune disease. TRM cells are found in the kidneys of healthy individuals and patients with various kidney diseases. A better understanding of these cells and their therapeutic targeting might provide new treatment options for infections, autoimmune diseases, graft rejection, and cancer. In this review, we address the definition, phenotype, and developmental mechanisms of TRM cells. Then, we further discuss the current understanding of TRM cells in kidney diseases, such as infection, autoimmune disease, cancer, and graft rejection after transplantation.

Tissue-resident memory T cells in renal autoimmune diseases

“…Tissue-resident memory T cells (T RM cells) are a recently identified lymphocyte subset that resides in peripheral organs for long time periods ( 1 , 2 ). These cells have been detected and analyzed in numerous non-lymphoid tissues, especially barrier-organs.…”

“…Mice studies have proven that T RM cells have superior effector functions including rapid chemokine and cytokine production. Hence, together with circulating memory T cells (e.g., effector memory T cells and central memory T cells), T RM cells are critical for efficient pathogen clearance, providing an antigen-specific immediate frontline defense in peripheral organs ( 1 , 2 ).…”

“…The kidney is a non-barrier organ, but still frequently gets challenged by diverse pathogens, including bacteria, viruses, and fungi, which drive renal T RM cell generation ( Figure 1A ) ( 2 , 5 , 11 – 14 ). Due to limited access, exploring precise immune cell populations of healthy human kidneys had been challenging.…”

“…Due to limited access, exploring precise immune cell populations of healthy human kidneys had been challenging. In the last few years, however, detailed analysis of the immune landscape in healthy renal tissue has been implemented using flow cytometry and single-cell RNA sequencing (scRNA-seq) ( 2 , 5 , 8 , 15 – 17 ). In particular, the combined analysis of mRNA expression and cell surface marker via cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) has provided a completely new insight into cell heterogeneity.…”

Heterogeneity of tissue-resident immunity across organs and in health and disease

“…In other organs in adults, tissue-resident immunity seems to be better understood, for example, in the kidneys. Thus, Asada et al propose therapeutic options resulting from the insights on resident immune cells in the kidneys available to date, which include emerging treatment options for kidney infections, autoimmune diseases, graft rejection, and cancer [ 4 ]. In the liver, memory T cells with a profile of tissue residency have been identified.…”