When more regulatory T cells do not mean better control

Bang et al. Allergology International. 2026;75(3):488-499.

Co-corresponding author collaboration

This study was conducted with Dong Hun Lee and the co-corresponding authors listed below.

Yong-Hee Kim
- Department of Basic Research, PB Immune Therapeutics Inc, Seoul, Republic of Korea
- Transplantation Research Institute, Seoul National University Medical Research Center, Seoul, Republic of Korea
Hyun Je Kim
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
- Interdisciplinary Program in Artificial Intelligence (IPAI), Seoul National University, Seoul, Republic of Korea
- Genomic Medicine Institute, Medical Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Dermatology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
Dong Hun Lee / EASI Lab PI
- Institute of Human-Environment Interface Biology, Medical Research Center, Seoul National University, Seoul, Republic of Korea
- Department of Dermatology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea

Names and affiliations are as published in the article.

01 / The question

The question

Do expanded regulatory T cells in atopic dermatitis retain effective suppression, or do they contain distinct functional states?

02 / How we tested it

How we tested it

PBMCs from 48 people with AD and 48 controls were profiled using 39-parameter CyTOF and clustering. Reanalysis of public PBMC and skin scRNA-seq was combined with in vitro OX40⁺ Treg suppression assays and tissue immunofluorescence.

How the evidence connects

CyTOF, functional assays and skin immunofluorescence were performed in this collaborative study; scRNA-seq evidence came from public-data reanalysis. Functional assays involved 5 HC and 3 AD donors, and skin immunofluorescence involved 7 participants per group.

03 / What the study found

What the study found

A Treg population with high OX40 and CRTH2 expression was associated with disease severity. OX40⁺ Tregs from AD donors showed lower suppressive capacity than the corresponding OX40⁺ population from controls, with enrichment also supported in skin.

04 / Interpreting the evidence

Interpreting the evidence

The main cohort was Korean and the functional assays involved few donors. In vitro findings do not fully reproduce the skin microenvironment, and the study does not establish prediction of responses to OX40-targeted treatment.

Figures from the paper

Complete Figure 6a–f: complementary evidence from public skin scRNA-seq and tissue immunofluorescence. CyTOF and suppression assays are not shown in this figure.

Original Figure 6a–f: FOXP3 UMAP, Treg frequencies and TNFRSF4 analysis in public skin single-cell data; DAPI/CD4/FOXP3/OX40 skin immunofluorescence in controls and AD, with quantification. Scale bars: 40 μm. — **Fig. 6a–f (complete figure) · Bang et al. · Allergology International (2026)**
Public skin single-cell data and tissue immunofluorescence provide complementary evidence for OX40⁺ regulatory T cells in atopic dermatitis. Shown: the complete original Figure 6.
© 2026 Japanese Society of Allergology. Published by Elsevier B.V. CC BY-NC-ND 4.0. CC BY-NC-ND 4.0 · Publication

The next question

A question to explore together

Could longitudinal sampling of skin and blood reveal how changes in OX40⁺ Treg states relate to clinical response?

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