Clinical and diagnostic potential of regulatory T cell markers: From bench to bedside

Regulatory T (Treg) cells are heterogeneous immune cell populations residing in the thymus and peripheral lymphatic tissues. This immune cell plays a central and critical role in maintaining immune tolerance against undesirable immune responses. Treg cells' phenotypic heterogeneity caused by different pathological conditions makes their identification and differentiation from non-suppressive T cells difficult. On the other hand, using nonspecific markers and variable isolation panels leads to undesirable outcomes. There are a variety of markers to identify functional Treg cells, including CD25, FOXP3, and CTLA-4, as well as the epigenetic signature of forkhead box P3 (FOXP3), which can be used for both natural and induced Treg cells. Phenotypic heterogeneity is a major concern in Treg purification when using nonspecific markers, which can be addressed by utilizing suitable isolation panels designed for different purposes. This review presents a clinical framework for Treg detection and isolation, focusing on Treg markers such as CD25, FOXP3, CTLA-4, CD127, GPA-33, and TSDR demethylation to design Treg isolation panels suitable for different Treg therapy purposes. The current review also highlights new reliable Treg markers applicable for different purposes.

Automated summary

Regulatory T (Treg) cells are heterogeneous immune cell populations essential for maintaining immune tolerance. Phenotypic heterogeneity caused by different pathological conditions makes identification and differentiation challenging. Utilizing suitable isolation panels designed for different purposes is crucial for addressing the issue of Treg purification.