Profile(Japanese)
My research focuses on cutaneous immunology, particularly autoimmune diseases, hair follicle immunology, atopic dermatitis, and psoriasis, encompassing both basic and clinical investigations.
From 2002 to 2004, I trained in the laboratory of Ralf Paus, a leading authority in hair follicle biology and immunology, at University of Hamburg (February 2002 to January 2004). During this period, I further advanced my research on hair follicle immunology, focusing on immune tolerance in the perifollicular environment and the role of stress hormones. I demonstrated that the hair follicle represents an immune-privileged site characterized by reduced expression of MHC class I molecules, and that collapse of this immune privilege triggers autoimmune hair loss such as alopecia areata. These findings were published (Ito et al., *Am J Pathol*, 2004) and have since been widely cited, contributing to the establishment of a fundamental concept in alopecia areata pathogenesis.
After returning to Japan, I resumed clinical practice in a specialized alopecia clinic and have consistently aimed to translate research findings into regional clinical care. As part of this effort, I investigated the role of plasmacytoid dendritic cells in the pathogenesis of alopecia areata (Ito et al., *Allergology International*, 2019). This work suggested that viral infections may act as triggers for disease onset, providing a rationale for patient education and lifestyle guidance.
In pursuit of novel therapeutic strategies, I explored CCR5 inhibition as a potential target. Using the C3H/HeJ mouse model, I demonstrated that blockade of Th1/Tc1 cell trafficking with anti-CCR5 antibodies ameliorates alopecia (J Cutan Allergy Immunol, 2019). These basic research findings have contributed to the conceptual framework underlying the development of JAK inhibitors targeting IFN-γ signaling. Subsequently, international multicenter clinical trials—including those involving Hamamatsu University School of Medicine—were conducted, leading to regulatory approvals and expanded indications for these therapies in 2022 and 2023.
In addition, I supervised Dr. Kageyama in analyzing cytokine balance in alopecia areata associated with atopic dermatitis, which was published in *International Journal of Molecular Sciences*. More recently, I have focused on elucidating the pathogenesis of chronic, treatment-resistant alopecia areata. In this context, I identified the involvement of tissue-resident memory T cells, highlighting a disease mechanism that should be considered in therapeutic decision-making.
Our institution is among the most active centers in Japan in the use of JAK inhibitors for alopecia areata. We maintain collaborative research partnerships and advisory roles with multiple pharmaceutical companies, aiming to contribute to basic research, drug development, and clinical trials.
Moving forward, I will continue to investigate the mechanisms underlying refractory alopecia areata and explore novel therapeutic targets.