Immunohistochemical investigation of activated macrophages markers in middle ear cholesteatoma

Introduction 

The pathogenesis of cholesteatoma is characterized by bone destruction of the middle ear, inner ear and skull base. The only treatment for cholesteatoma is currently the surgical removal. Although various infiltrating inflammatory and immune cells are involved in the pathogenesis of cholesteatoma, a leading role is played by macrophages. The activation of the macrophages by various stimuli leads to their polarization into the classically activated (M1) or alternatively activated (M2) phenotype. The distinct involvement of the different activation phenotypes of macrophages has been demonstrated in various inflammatory diseases. This observation implies that the investigation of the various macrophage profiles of cholesteatoma can be of therapeutic significance.

Material and Methods 

The macrophages in cholesteatoma specimens were immunohistochemically characterized by an antibody combination of an M1 macrophage marker (CD80), an M2 macrophage marker (CD163) and a pan-macrophage marker (CD68). The immunohistochemical findings were correlated with the clinical presentation.

Results 

M2 macrophages were more abundant than M1 macrophages in the perimatrix of the cholesteatome specimens. The relative ratio of M1 to M2 macrophages in the cholesteatoma specimens correlated with the extent of preoperative ossicular erosion.

Conclusion 

The investigation of the polarization and functions of macrophages in various clinical presentations of cholesteatoma is of great interest in order to prevent the associated destructive inflammation and bone erosion. It is hoped that the results will contribute to the development of pharmaceutical treatment approaches and therefore to the expansion of the range of therapies of cholesteatoma.

Conflict of Interest

The author declares that there is no conflict of interest.

Publication History

Article published online:
24 May 2022