Recent perspectives on macrophage memory: types, mechanisms, and characteristics in pulmonary diseases

Innate immunity has long been viewed as lacking memory capabilities. However, an increasing number of studies are challenging this conventional immunological paradigm. In recent years, innate immune memory has been recognized as an essential component of immune defense, allowing organisms to mount either enhanced or diminished responses to previously encountered stimuli. Increasing evidence suggests that innate immune memory may underlie various lung diseases. In this regard, elucidating the mechanisms of innate immune memory in pulmonary diseases not only aids in understanding the underlying pathophysiology of pulmonary disorders but also holds significant implications for therapeutic interventions. Macrophages, as a central element of the lung’s innate immune system, represent one of the most extensively investigated cell types in terms of innate immune memory. In this review, we first outline the origin and maintenance of lung macrophage homeostasis, alongside the conceptual framework, classifications, and mechanistic underpinnings of macrophage immune memory. Subsequently, we focus on summarizing the distinctive features of macrophage immune memory across diverse lung diseases, including infections, tumors, transplantation, and other immune-related conditions. Finally, we propose potential therapeutic strategies to manage various lung diseases through modulating macrophage immune memory. We hope that these advancements in immunology will uncover novel pharmacological targets and provide valuable theoretical support for researchers to understand the pathogeneses and develop effective treatment strategies.