Macrophage-mediated complications after stem cell transplantation

Area of Science:

• Immunology
• Hematology
• Transplantation Medicine

Background:

• Hematopoietic stem cell transplantation (HSCT) success hinges on managing complications, particularly graft versus host disease (GVHD).
• Accurate pathological diagnosis of HSCT complications, especially GVHD, can be challenging.
• Macrophages are increasingly recognized for their significant roles in post-HSCT complications.

Purpose of the Study:

• To review the multifaceted roles of macrophages in various complications following HSCT.
• To explore the origins (recipient vs. donor) and functions of macrophages in different pathological conditions post-HSCT.
• To assess the potential of macrophages as diagnostic or prognostic markers in HSCT complications.

Main Methods:

• Review of existing literature focusing on macrophage involvement in HSCT complications.
• Analysis of studies investigating macrophage populations in skin GVHD-like lesions.
• Examination of research on macrophages in intestinal transplantation-associated microangiopathy (i-TAM) and cryptogenic organizing pneumonitis.

Main Results:

• Residual recipient macrophages are crucial for engraftment and rejection early post-HSCT, with hemophagocytosis indicating activation.
• Increased macrophage numbers in skin lesions correlate with better overall survival, suggesting a predictive role for skin GVHD-like conditions.
• Activated recipient macrophages are key in i-TAM pathogenesis, while donor-derived macrophages are implicated in cryptogenic organizing pneumonitis.

Conclusions:

• Macrophages, both recipient and donor-derived, exhibit distinct roles in HSCT complications.
• Macrophages represent promising predictive markers for specific HSCT-related conditions, such as skin GVHD-like lesions.
• Understanding macrophage dynamics is vital for improving HSCT outcomes and managing post-transplant complications.