Characterization of CD45RO+ Memory T Lymphocytes in Keloid Disease

Abstract

Background

Memory T cells, a highly effective subset of T lymphocytes, have been reported to be involved in many inflammatory skin disorders. However, the potential role of memory T cells in keloid disease (KD) remains unclear.

Objectives

Due to their important role in regulating inflammation, we investigated the characteristics of CD45RO⁺ memory T cells (mT) in KD.

Methods

Primary cutaneous cells were isolated from keloid scars and normal skin by enzymic digestion. Combined with peripheral blood mononuclear cells (PBMCs) isolated from a related blood sample, flow cytometry was applied to identify the phenotypic and functional abnormalities of memory T cells in KD.

Results

We observed that the majority of T lymphocytes in keloid scars had the memory phenotype, and a greater number of the CD8⁺ mT in keloid scars produced lower levels of TNF-α. This abnormal cytokine production was even more distinct in FOXP3^-CD8^- mT, with lower TNF-α production and enhanced IFN-γ production. Furthermore, FOXP3⁺CD8^- mT in keloid scars were abnormal, including showing reduced CD25 and CTLA-4 expression and IL-10 production. In addition, a significant decrease in the number of CD4⁺CD25^highFOXP3⁺ regulatory T cells was identified in patients with multiple keloid scars. We also found that there was significantly increased infiltration of CD103⁺CD8⁺ mT in keloid scars.

Conclusions

Our findings preliminarily elucidate the abnormalities of CD45RO⁺ memory T cells in keloid scars and provide early evidence that a disrupted T cell response contributes to the progression of KD.

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