Distinct Variations in Gene Expression and Cell Composition across Lichen Planus Subtypes

Abstract

Lichen planus (LP) is a highly prevalent inflammatory skin disease. While various clinical subtypes have been defined, detailed comparisons of these variants are lacking. This study aimed to elucidate differences in gene expression and cellular composition across LP subtypes. Lesional skin biopsies from 28 LP patients (classical, oral, genital, and lichen planopilaris) and seven non-diseased skin controls (NDC) were analyzed. Gene expression profiling of 730 inflammation-related genes was conducted using NanoString. Immune cell compositions were assessed by multiplex immunohistochemistry. Gene expression profiles revealed unique inflammatory signatures for each LP subtype. Lichen planopilaris exhibited the most divergence, with downregulated gene expression and upregulation of complement pathway genes (C5-7), along with elevated M2 macrophages. Oral and genital LP demonstrated similar profiles with strong upregulation of TNF-related and Toll-like receptor-associated genes. Oral LP showed the highest upregulation of cytotoxicity-associated genes, as well as high numbers of CD8+ IL-17A+ (Tc17) cells (8.02%). Interferon gene signatures were strongly upregulated in oral and classical LP. The study highlights distinct differences in inflammatory gene expression and cell composition across LP subtypes, emphasizing the need for tailored therapeutic approaches.

Keywords: NanoString; immune cell infiltrate; lichen planus; lichen planus subtypes; multiplex immunohistochemistry.

Figure 1

Clear distinction of different lichen planus subtypes and healthy skin in gene expression analysis. NanoString technology was applied to compare the expression of 730 inflammation-related genes across lesional skin samples from 5 classical lichen planus (LP), 4 genital LP, 3 oral LP, and 5 lichen planopilaris patients and 3 healthy skin (NDC) samples. Heatmap showing hierarchical clustering of different LP subtypes and NDC.

Figure 2

Pathway-specific differences in gene expression across different lichen planus subtypes. NanoString technology was applied to compare the expression of different immune−related genes across lesional skin samples from 5 classical lichen planus (LP), 4 genital LP, 3 oral LP, and 5 lichen planopilaris patients and 3 healthy skin samples. Heatmaps showing genes related to complement pathway (A), TNF−related genes (B), Toll−like receptor (TLR)−related genes (C), and cytotoxicity−related genes (D).

Figure 3

Multiplex immunohistochemical analysis reveals different cell-type compositions among lichen planus subtypes. Cellular composition among different subtypes of lichen planus (LP) was investigated by multiplex immunohistochemistry using the Akoya system. Two different antibody panels (T-cell panel: CD8, FoxP3, IL17A, Granzyme B, PanCK, CD4; macrophage panel: pSTAT1, MPO, c−Maf, PanCK, CD68) were developed for staining. (A) Visualization by application of Opal fluorescent dyes. (B) The non−metric multidimensional scaling (NMDS) visualization highlights the intrinsic differences in cell-type composition between the various subtypes of LP.

Figure 4

Significant differences in cell-type composition across different lichen planus subtypes. Cellular composition across different lichen planus (LP) subtypes, including 4 cases of healthy skin, 6 cases of classical LP, 4 cases of genital LP, 3 cases of oral LP, and 3 cases of lichen planopilaris, was assessed by multiplex immunohistochemistry using the Akoya system. The frequency of CD4+ T cells, CD8+ T cells, regulatory T cells (Tregs), cytotoxic cells (Granzyme B+), Th17 cells (IL−17A), keratinocytes, M1 and M2 macrophages, total macrophages, neutrophilic granulocytes, and other cells was assessed. (A) shows the cell−type composition of all samples, (B) represents individual testing of cell types in the dermis, with data being transformed using the centered−log−ratio transformation. (C) Statistical analysis of differences between the groups was performed using Fisher’s exact test.

Figure 4

Significant differences in cell-type composition across different lichen planus subtypes. Cellular composition across different lichen planus (LP) subtypes, including 4 cases of healthy skin, 6 cases of classical LP, 4 cases of genital LP, 3 cases of oral LP, and 3 cases of lichen planopilaris, was assessed by multiplex immunohistochemistry using the Akoya system. The frequency of CD4+ T cells, CD8+ T cells, regulatory T cells (Tregs), cytotoxic cells (Granzyme B+), Th17 cells (IL−17A), keratinocytes, M1 and M2 macrophages, total macrophages, neutrophilic granulocytes, and other cells was assessed. (A) shows the cell−type composition of all samples, (B) represents individual testing of cell types in the dermis, with data being transformed using the centered−log−ratio transformation. (C) Statistical analysis of differences between the groups was performed using Fisher’s exact test.