Predominance of CD27-PD-1- Effector Memory T Cells Re-Expressing CD45RA Characterizes Treatment-Resistant Severe Alopecia Areata

This study investigates the characteristics of treatment-resistant severe alopecia areata, focusing on the role of CD27-PD-1- effector memory T cells re-expressing CD45RA. Rapidly progressive alopecia areata (RP-AA) is characterized by sudden and extensive hair loss, often treated with intravenous corticosteroid pulse therapy (IV-PT), which targets CD8+ T cells. However, treatment responses vary, and early predictive factors are needed. The study highlights that an increase in CD8+ effector memory T cells re-expressing CD45RA correlates with the intractability of severe alopecia areata, suggesting these cells as potential markers for predicting treatment resistance.