Lymphocyte subpopulations in patients with acne vulgaris

DNA methylation profiling and integrative multi-omics analysis of skin samples reveal important contribution of epigenetics and immune response in the pathogenesis of acne vulgaris

The regulatory effect of DNA methylation on the pathogenesis of acne vulgaris is completely unknown. Herein we analyzed the DNA methylation profile in skin samples of acne vulgaris and further integrated it with gene expression profiles and single-cell RNA-sequencing data. Finally, 31,134 differentially methylated sites and 770 differentially methylated and expressed genes (DMEGs) were identified. The multi-omics analysis suggested the importance of DNA methylation in inflammation and immunity in acne. And DMEGs were verified in an external dataset and were closely related to early inflammatory acne. Additionally, we conducted experiments to verify the mRNA expression and DNA methylation level of DMEGs. This study supports the significant contribution of epigenetics to the pathogenesis of acne vulgaris and may provide new ideas for the molecular mechanisms of and potential therapeutic strategies for acne vulgaris.

Transcriptomics Analysis Indicates Trifarotene Reverses Acne-Related Gene Expression Changes

Background and Objectives: Trifarotene is a topical retinoid selective for retinoic acid receptor gamma that was recently approved for treatment of acne vulgaris. We performed a gene expression analysis to identify the molecular and cellular impact of trifarotene treatment on acne papules. Methods: In this open-label prospective study, subjects with moderate inflammatory acne of the back were treated with trifarotene 0.005% or vehicle cream on dedicated areas for 27 days, and 4 biopsies were collected from each subject (1 from skin without a visible acne lesion and three at the site of an acne papule: one baseline, one after vehicle treatment, and one after trifarotene treatment). Large scale gene expression profiling of the biopsies was performed using Affymetrix technology, treatment-specific gene expression profiles were generated using statistical modeling, and pathway analysis was performed. Using single-cell RNAseq data, in silico deconvolution of transcriptomics data was performed to identify cellular signatures. Results: We discovered a unique set of 67 genes modulated by trifarotene that are primarily involved in cellular migration, inflammation, and extracellular matrix reorganization. Changes in cellular expression were similar in both trifarotene-treated and spontaneously-resolving lesions. However, only trifarotene treatment impacted SPP1⁺ macrophages, a subset of highly proliferative macrophages recently identified in fibrotic tissue. Conclusions: These results show that trifarotene has a novel action in acne treatment by affecting epidermal and immune components of acne pathogenesis.

Detection of Propionibacterium acnes polypeptides which have stimulated an immune response in acne patients but not in normal individuals

Patient and normal volunteer sera were used as probes in two-dimensional PAGE of P. acnes culture supernatant fluid and cell extracts to determine whether specific P. acnes polypeptides were associated with the immune reaction in acne. Eight polypeptides, M(r) 20 to 131 x 10(3), pI 4.7 to 6.5 in the cell extract, and 7 polypeptides M(r) 10 to 24 kD, pI 4.8 to 7.5 in the culture supernatant fluid were specifically highlighted by patient sera and not volunteer sera. These polypeptides were not related to described extracellular enzymes of P. acnes. It is possible that these polypeptides are involved in the induction of acne.

Serum hormone levels in men with severe acne

In order to evaluate the hormonal milieu in young men with severe acne, we measured serum estradiol (E2), total testosterone (T), free testosterone (FT), dihydrotestosterone (DHT), dehydroepiandrosterone sulfate (DHEA-S), and sex hormone binding globulin (SHBG) levels in sixteen male patients aged 20-30 years with severe acne, including twelve cases of nodular-cystic acne, and in seventeen age-matched normal controls. There were no significant differences in the serum levels of T, FT, DHT, DHEA-S, or SHBG between the patients and the controls, but serum E2 was significantly higher in the patient population. Thus, the hemodynamics of serum androgens in male patients with acne do not seem to differ significantly from that of normal controls. Elevated E2 levels might affect the inflammatory response of acne vulgaris through the release of thymic hormones, as reported in the literature.

A histological and immunocytochemical study of early acne lesions

We examined 69 biopsies of acne lesions known to be 6, 24 or 72 h old and found that the lymphocyte was the predominant cell at 6 and 24 h. The helper:suppressor T cell ratio in the inflammatory infiltrate was 2.8:1. Polymorphonuclear leukocytes were increasingly seen at 24 and 72 h and were associated with disruption of the duct. We hypothesize that this early lymphocytic infiltrate represents a cell mediated immune response to an antigen within the duct lumen.

IgG subclasses in acne vulgaris

IgG subclasses were measured in male patients with very low grade or severe acne. No IgG subclass deficiencies were found. Patients with severe acne had a significant increase in total IgG attributable to their exposure to antigens which stimulate the production of antibodies in the IgG2 and IgG3 subclasses.