The mononuclear phagocyte and immunoregulatory effector (M-PIRE) system: evolving concepts

Area of Science:

• Immunology
• Cell Biology
• Pathology

Background:

• Macrophages exhibit phagocytic activity, with recent discoveries revealing additional roles in antigen presentation and immunoregulatory protein synthesis.
• Current pathological classifications and diagnostic approaches for histiocytic disorders are outdated, failing to incorporate recent findings on this cell system.
• The term 'mononuclear phagocyte system' is obsolete due to its limited scope, not encompassing the full spectrum of functions.

Purpose of the Study:

• To propose a new nomenclature, the mononuclear phagocyte and immunoregulatory effector (M-PIRE) system, to accurately reflect the diverse functions of these cells.
• To provide a conceptual overview of the M-PIRE system, including its cellular components, origin, functions, and relevance to disease states.
• To highlight the need for revising pathological concepts and diagnostic strategies based on the updated understanding of this cell system.

Main Methods:

• Literature review and synthesis of recent evidence on the functions and cell types within the mononuclear phagocyte and immunoregulatory effector system.
• Conceptual analysis of cell origins, transitional forms, and functional roles within the proposed M-PIRE system.
• Comparative analysis of existing nomenclature with proposed M-PIRE designation based on scientific evidence.

Main Results:

• The M-PIRE system comprises diverse cells, including precursor cells, histiocytes, dendritic cells, and Langerhans cells, found throughout the body.
• Evidence suggests a common origin for macrophages and dendritic cells, with potential for cell type transitions.
• The M-PIRE system plays a pivotal and multifaceted role in immunity, necessitating a revised understanding in pathology.

Conclusions:

• The designation M-PIRE system accurately represents the complex and varied roles of these cells in immunity and beyond phagocytosis.
• Revising nomenclature and disease classification is essential for pathology practice to align with current scientific understanding.
• Further research into the origin, transitions, and disease implications of the M-PIRE system is warranted.