First detection of macrophages in seroma fluid

Objective: Seroma formation is a common complication following mastectomy. This study investigates macrophage polarization and its role in seroma formation using biomaterials from the SerMa pilot study. Macrophage polarization into M1 (CD86+) or M2 (CD163+, CD206+) subtypes plays an important role in cancer progression, with M1 being associated with a favorable prognosis and M2 with a worse prognosis.

Materials and Methods: Seroma fluid (SFl) cells were measured by flow cytometry to determine macrophage presence and polarization status. Additionally, patient serum and SFl were used to determine their potential to differentiate the human monocyte cell line THP1 into macrophages.

Results: Seroma fluids: Our measurements successfully detected macrophages in SFl, identifying macrophages in approximately 10% of all cells. We observed a significantly higher amount of M2 (CD163+, CD206+) macrophages compared to M1 (CD86+) macrophages.

THP-1 stimulation: Each macrophage subpopulation (CD86+(M1), CD163+, CD206+(M2)) was significantly increased in SFl-treated cells compared to serum.

Conclusion: For the first time, macrophages were detected in SFl, with higher levels of CD163+(M2) cells than CD86+(M1) macrophages. This is in line with our previously presented data on the detection of macrophages in tumors and especially in the surrounding adipose tissue, which may be associated with a worse prognosis. We successfully differentiated THP-1 derived macrophages into M1 or M2 after exposure to SFl or serum. The percentage of all macrophage subpopulations was significantly increased, most pronounced in SFl-stimulated cells. Further research is needed to explore the interplay between macrophages, seroma formation and prognosis.

Publikationsverlauf

Artikel online veröffentlicht:
04. Juni 2025