Microneedle-mediated expansion of skin-resident regulatory T cells for management of autoimmune skin diseases

Project Summary/Abstract Disorders in the regulatory arm of the adaptive immune system can result in autoimmune skin diseases (ASDs) such as Alopecia Areata (AA). Janus Kinase (JAK) inhibitors are the only FDA-approved approach for severe AA, yet their immunosuppressive nature carries the risk of heightened susceptibility to infections and malignancies. These systemic side effects deter their use for patients with focal or mild-to-moderate AA as the risks outweigh the benefits. Moreover, they only offer temporary symptom relief, largely due to their suppression of regulatory T cells (Tregs), which may explain the high relapse rates (>80%) observed clinically after therapy discontinuation. Tregs are critical for maintaining immune tolerance, even more in the context of AA, where the depletion of skin-specific Tregs has been demonstrated to trigger inflammation in the hair follicles (HFs) and alopecia. Hence, localized therapies that selectively expand Tregs, instead of suppressing them, are urgently needed. The LybraPatch©, a hydrogel-based microneedle (MN) patch, offers a revolutionary solution by delivering Treg-expanding cytokines, IL-2 and CCL22, directly at the site of autoimmunity. This targeted approach minimizes systemic exposure while restoring immune homeostasis. We have demonstrated in a murine model of immune-mediated AA that the LybraPatch promotes significant Treg expansion and reduction of pro- inflammatory cues, leading to hair regrowth and reversal of the symptoms for weeks beyond treatment discontinuation without inducing systemic immunosuppression. In order to advance towards IND-enabling studies, it is now essential to further define the optimal IL-2 dosage ensuring selective Treg expansion without activating pro-inflammatory effector T cells (Teffs) since IL-2 can lead to their synchronous activation if delivered in higher dosages. Here, we first aim to define the maximum tolerated dosage (MTD) of IL-2 leading to systemic Treg expansion in a murine model of AA via pharmacokinetic (PK) analyses. Specifically, the local and systemic concentration of IL-2 will be measured following the administration of the patch. Next, we will perform pharmacodynamic (PD) studies to evaluate the effects of various IL-2 doses on the skin’s immune environment, focusing on Treg expansion and Teff activation using flow cytometry. By the conclusion of this work, we will establish the precise IL-2 dosing parameters and therapeutic window that balance safety and efficacy, establishing a data package to support our upcoming IND-enabling studies. Our work will address a critical gap in ASD treatment landscape for focal patients (accounting for more than 90% of all patients) that still lack FDA approved treatments. The LybraPatch promises to offer a localized, minimally invasive therapy that targets the root cause of immune dysregulation while avoiding systemic risks. This work lays the foundation for safer and more effective treatments, advancing the clinical translation of localized immunomodulatory strategies for ASDs.