IL-17 A expression negatively correlates with γδ T-Cell density in human psoriasis lesions: a novel implication for disease pathogenesis

Abstract

Background

Psoriasis, an inflammatory autoimmune disease, arises from intricate interactions between the immune system and epithelium. Recent reports have suggested new roles for gamma delta (γδ) T-cells in addition to immune surveillance, however, it remains to be determined whether the mechanisms identified in psoriasis murine models have a similar role in humans. The aim of the present study was to investigate the relationship between IL-17 A mRNA expression levels and γδ T-cell frequency in human psoriatic lesions, and to clarify the potential role of γδ T-cells in psoriasis pathogenesis.

Methods

The study involved 20 patients diagnosed with psoriasis and 16 control subjects. Expression of the IL-17 A gene was measured in formalin-fixed paraffin-embedded (FFPE) tissues by RT-PCR method. TCRγδ⁺ immunofluorescence staining was performed to measure the distribution of γδ T-cells in the same samples.

Results

In psoriatic lesion biopsies, TCRγδ⁺ T-cell percentage was found higher than the control samples. Additionally, psoriasis patients exhibited elevated levels of IL-17 A gene expression. In addition, this study showed a weak negative correlation between the proportion of γδ T-cells and IL-17 A mRNA expression in psoriatic skin samples.

Conclusion

A weak negative correlation between IL-17 A mRNA levels and γδ T-cell presence in human psoriasis lesions highlighting the novel effector functions of these cells in psoriasis pathogenesis.