A Report on the Safety of Acitretin Use in Renal Failure Patients on Hemodialysis.

Acitretin, commonly used for severe psoriasis and keratinocyte carcinoma chemoprevention in high-risk patients, is contraindicated in patients with end stage renal disease on hemodialysis. However, these patients often lack medication choices and in certain clinical scenarios, the benefits of acitretin may outweigh the potential risks. We identified 24 end stage renal disease patients on HD taking acitretin from Duke and Vanderbilt University Medical Centers. While adverse effects were common, patients did not frequently discontinue the medication due to them. We also found no association between acitretin with hospital admissions or mortality. We lastly found statistically significant increases in ALP and total bilirubin when on acitretin and dialysis compared to baseline. However, there was no dose-dependency or temporal association with acitretin or hemodialysis initiation. Based off these preliminary findings, we find that acitretin may safely be used in patients receiving HD with close monitoring of ALP and bilirubin.

Systematic Review of Intralesional Therapies for Cutaneous Warts.

Intralesional therapies are used for recalcitrant warts, but no Food and Drug Administration-approved treatment exists nor is there consensus regarding the most efficacious therapy. Therefore, this systematic review aims to summarize efficacy and adverse events reported in 62 randomized controlled trials (RCTs) of intralesional therapies for cutaneous warts. The most studied intralesional therapies included measles, mumps, rubella (MMR) vaccine (n = 24 studies), purified protein derivative (PPD) (n = 19 studies), vitamin D3 (n = 15 studies), and Candida antigen (n = 14 studies). Most studies included adult and pediatric patients or adults alone, with only 4 studies on pediatric patients alone. MMR vaccine was the most studied treatment (n = 853 patients). MMR had a complete response rate of 27-90%. The next most common treatment, PPD, had a complete response rate of 45-87%. Other treatments included Candida antigen and vitamin D3, with complete response rates of 25-84% and 40-96%, respectively. The most frequent side effects were injection-site reactions and flu-like symptoms. This systematic review represents a useful summary of intralesional therapy RCTs for clinician reference. This study also highlights the lack of large multi-institutional RCTs, despite many patients being treated for this widespread problem.

A case of trichodysplasia spinulosa related to ruxolitinib treated successfully with oral acitretin.

Trichodysplasia spinulosa (TS) is a rare disease that affects immunocompromised patients, characterized by hair-like growths caused by TS-associated polyomavirus infection. Little is known about specific immunosuppressive drugs that can precipitate the condition. We report a case of TS presenting after initiating the oral Janus-associated kinase inhibitor (JAKi) ruxolitinib. A 67-year-old female with a history of allogeneic bone marrow transplant requiring immunosuppression with tacrolimus, prednisone and, more recently, ruxolitinib 5 mg twice daily due to Graft versus Host Disease presented to the clinic with a facial rash. The clinical and histopathological findings in the setting of immunosuppression were consistent with TS. Initial treatments were ineffective, but oral acitretin showed significant improvement after 3 months. Due to the close temporal relationship between the initiation of ruxolitinib and the development of TS, this case suggests that JAKis may contribute to TS development by suppressing the JAK-signal transducer and activator of the transcription pathway's antiviral functions.

Gene Expression Profiles in Cutaneous Oncology.

Skin cancer is highly curable under most circumstances; however, locally advanced or metastatic disease historically has poor outcomes and limited treatment options. Treatment has recently been advanced by the discovery of pertinent genes influencing pathogenesis and further revolutionized by the advent of specific gene expression profiles (GEPs). GEPs have been developed to help refine current diagnostic and prognostic strategies used in skin cancer with the goal to ultimately help guide management and treatment modalities to improve patient care. This article provides a high-level review of diagnostic and prognostic GEPs that have been developed specifically for squamous cell carcinoma and melanoma.

Cutaneous Squamous Cell Carcinoma Arising in Immunosuppressed Patients: A Systematic Review of Tumor Profiling Studies.

As solid organ transplantation becomes more prevalent, more individuals are living as members of the immunosuppressed population with an elevated risk for cutaneous squamous cell carcinoma (cSCC). Although great progress has been made in understanding the pathogenesis of cSCC in general, little is known about the drivers of tumorigenesis in immunosuppressed patients and organ-transplant recipients, specifically. This systematic review sought to synthesize information regarding the genetic and epigenetic alterations as well as changes in protein and mRNA expression that place this growing population at risk for cSCC, influence treatment response, and promote tumor aggressiveness. This review will provide investigators with a framework to identify future areas of investigation and clinicians with additional insight into how to best manage these patients.

Hidradenitis Suppurativa: Host-Microbe and Immune Pathogenesis Underlie Important Future Directions.

Hidradenitis suppurativa (HS) is an inflammatory disease of the skin with a chronic, relapsing-remitting course. The pathogenesis of the disease is poorly understood and involves multiple factors, including genetics, environment, host-microbe interactions, and immune dysregulation. In particular, the composition of the cutaneous microbiome shifts as the disease progresses, although it is unclear whether this is a primary or secondary process. Trials with immunomodulatory therapy elucidate the role of specific immune pathways and cytokine signaling in disease mechanism, such as TNF-α, IL-1ß, IL-12, IL-17, IL-23, and complement. Future studies should continue examining the causes of and contributing factors to microbial changes and immune dysregulation in HS pathogenesis.

Single-Cell RNA Sequencing Reveals Cellular and Transcriptional Changes Associated With M1 Macrophage Polarization in Hidradenitis Suppurativa.

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease characterized by recurrent abscesses, nodules, and sinus tracts in areas of high hair follicle and sweat gland density. These sinus tracts can present with purulent drainage and scar formation. Dysregulation of multiple immune pathways drives the complexity of HS pathogenesis and may account for the heterogeneity of treatment response in HS patients. Using transcriptomic approaches, including single-cell sequencing and protein analysis, we here characterize the innate inflammatory landscape of HS lesions. We identified a shared upregulation of genes involved in interferon (IFN) and antimicrobial defense signaling through transcriptomic overlap analysis of differentially expressed genes (DEGs) in datasets from HS skin, diabetic foot ulcers (DFUs), and the inflammatory stage of normal healing wounds. Overlap analysis between HS- and DFU-specific DEGs revealed an enrichment of gene signatures associated with monocyte/macrophage functions. Single-cell RNA sequencing further revealed monocytes/macrophages with polarization toward a pro-inflammatory M1-like phenotype and increased effector function, including antiviral immunity, phagocytosis, respiratory burst, and antibody-dependent cellular cytotoxicity. Specifically, we identified the STAT1/IFN-signaling axis and the associated IFN-stimulated genes as central players in monocyte/macrophage dysregulation. Our data indicate that monocytes/macrophages are a potential pivotal player in HS pathogenesis and their pathways may serve as therapeutic targets and biomarkers in HS treatment.

ENTPD1 (CD39) Expression Inhibits UVR-Induced DNA Damage Repair through Purinergic Signaling and Is Associated with Metastasis in Human Cutaneous Squamous Cell Carcinoma.

UVR and immunosuppression are major risk factors for cutaneous squamous cell carcinoma (cSCC). Regulatory T cells promote cSCC carcinogenesis, and in other solid tumors, infiltrating regulatory T cells and CD8+ T cells express ectonucleoside triphosphate diphosphohydrolase 1 (ENTPD1) (also known as CD39), an ectoenzyme that catalyzes the rate-limiting step in converting extracellular adenosine triphosphate (ATP) to extracellular adenosine (ADO). We previously showed that extracellular purine nucleotides influence DNA damage repair. In this study, we investigate whether DNA damage repair is modulated through purinergic signaling in cSCC. We found increased ENTPD1 expression on T cells within cSCCs when compared with the expression on T cells from blood or nonlesional skin, and accordingly, concentrations of derivative extracellular adenosine diphosphate (ADP), adenosine monophosphate (AMP), and ADO are increased in tumors compared with those in normal skin. Importantly, ENTPD1 expression is significantly higher in human cSCCs that metastasize than in those that are nonmetastatic. We also identify in a mouse model that ENTPD1 expression is induced by UVR in an IL-27-dependent manner. Finally, increased extracellular ADO is shown to downregulate the expression of NAP1L2, a nucleosome assembly protein we show to be important for DNA damage repair secondary to UVR. Together, these data suggest a role for ENTPD1 expression on skin-resident T cells to regulate DNA damage repair through purinergic signaling to promote skin carcinogenesis and metastasis.