Immunohistochemical expression of M1 and M2 macrophages in oral lichen planus and oral squamous cell carcinoma using CD68 and CD163: A comparative study.

BACKGROUND

Macrophages are essential cellular elements of innate and adaptive immunity and one of the most common cell types in chronic inflammatory conditions such as oral lichen planus (OLP) and oral squamous cell carcinoma (OSCC). However, the roles of M1 and M2 macrophages in the pathogenesis of erosive OLP (E-OLP) which has the highest malignant potential remain unclear.

OBJECTIVE

To evaluate and compare the immunohistochemical expression of M1 and M2 macrophages in OLP and OSCC.

MATERIALS AND

METHODS

Paraffin-embedded tissue sections of 20 OLP (9 erosive, 11 non-erosive) and 30 OSCC (16 well, 8 moderate, and 6 poorly differentiated) cases were subjected to immunohistochemical staining for CD68 (M1) and CD163 (M2). The slides were examined for distribution, intensity, and localisation of CD68 and CD163 expression. Quantitative assessment of the staining was done with the help of Image Pro Plus software. Statistical analysis using Fisher exact test for qualitative assessment and Student t-test and one-way ANOVA for quantitative analysis were done.

RESULTS

Although there was an increase in the density of CD68+ and CD163+ macrophages in E-OLP, a statistically significant difference was not observed between the subgroups of OLP. However, the density of CD68 and CD163-positive macrophages was relatively higher in moderately differentiated OSCC with no statistically significant difference. However, the staining pattern, intensity, and localisation between CD68 and CD163 in OLP and OSCC showed significant difference.

CONCLUSION

An increase in the density of CD68+ and CD163+ macrophages in E-OLP may be associated with the pathogenesis of OLP into malignant transformation.