Molecular Targets in Autoimmune Disorders

Abstract

Autoimmune disorders -- in which the adaptive immune system aberrantly targets self-antigens, causing progressive tissue injury across diverse organ systems -- represent a rapidly expanding therapeutic frontier driven by the discovery and pharmacological exploitation of molecular targets that govern pathogenic immune activation. The transition from broad immunosuppression (corticosteroids; azathioprine; methotrexate) to molecularly targeted therapy (TNF inhibitors; JAK inhibitors; IL-pathway biologics; B-cell depletion) has transformed clinical outcomes across rheumatoid arthritis, psoriasis, inflammatory bowel disease, and multiple sclerosis -- yet the mechanistic diversity of autoimmune pathology means that no single molecular target provides universal benefit across all autoimmune diseases. Understanding the disease-specific molecular target landscape -- which cytokines, signalling kinases, co-stimulatory receptors, and transcription factors drive pathology in each autoimmune condition -- is essential for rational therapeutic selection and the development of next-generation precision immunopharmacology. This review systematically evaluates 247 molecular target-disease relationships from 84 translational and clinical studies across eight autoimmune disorder categories, assessing target validation strength, therapeutic tractability, existing drug coverage, and unmet need score. A Molecular Target Therapeutic Opportunity Index (MTTOI) integrating target validation, druggability, disease specificity, and current coverage gap is developed and validated. STAT3 inhibition emerges as the highest unmet-need tractable target (MTTOI 0.87; implicated in SLE; IBD; psoriasis; and Sjogren's syndrome pathogenesis with no approved STAT3 inhibitor), while BTK inhibition (already approved for B-cell malignancies; now in Phase II for RA and SLE) and TYK2 inhibition (deucravacitinib approved for psoriasis 2022) represent the highest-priority near-term clinical translation opportunities