Interleukin-10 family cytokines: key regulators and novel therapeutic targets for respiratory diseases.

Respiratory disorders such as asthma, chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS), pulmonary fibrosis, and infectious conditions including COVID-19 and tuberculosis continue to rank among the foremost causes of illness and death worldwide. Although vaccines, antimicrobial treatments, and anti-inflammatory agents have improved disease management, their overall impact remains limited because of the intricate regulation of immune responses at epithelial surfaces. Within this context, the interleukin-10 (IL-10) cytokine family (comprising IL-10, IL-19, IL-20, IL-22, IL-24, and IL-26) has been identified as a key immunological axis in the respiratory tract. These cytokines possess structural homology and predominantly transmit signals through heterodimeric class II receptors via the JAK-STAT cascade. However, their functions are far from uniform: IL-10 primarily exerts suppressive effects on inflammation, whereas IL-19, IL-20, IL-24, and IL-26 are commonly associated with tissue injury, chronic inflammation, and airway remodeling. IL-22 occupies an intermediate role, promoting epithelial regeneration under certain conditions but aggravating inflammation or tumorigenesis in others. This article reviews recent findings on the IL-10 family in a range of respiratory diseases, emphasizing their context-dependent activity, value as potential biomarkers, and relevance as therapeutic targets. A clearer understanding of how protective versus pathogenic signals are balanced within this cytokine network is essential for designing targeted interventions that preserve host defense while restoring airway integrity.