Pityriasis Rubra Pilaris Transcriptomics Implicate T Helper 17 Signaling and Correlate with Response to Ixekizumab, with Distinct Gene Expression Profiles in Nonresponders

Severe pityriasis rubra pilaris complicated with Kaposi's varicelliform eruption and cutaneous MRSA infection case report

A 62-year-old woman presented to our hospital with erythroderma affecting 100 % of body surface area, skin scaling and a body temperature of 37.3o C. The lesions initially appeared on her scalp 6 months prior, then psoriasis was diagnosed. Topical corticosteroids were prescribed, which were ineffective. After 2 months the rash spread to the rest of the body, accompanied by nail changes and hair loss. The patient was subsequently admitted to the local hospital, where following clinical evaluation, oral methotrexate 10 mg once weekly was initiated for 6 weeks. Despite the administered treatment the patient's health and skin condition deteriorated, manifesting with an appearance of new lesions. By the time of admission to our hospital erythroderma affecting 100 % of body surface area covered with wide skin scales and punched-out erosions on the torso, lower eyelid ectropion, loss of scalp hair and thickened yellow nail plates were observed. Skin biopsy revealed histological changes consistent with pityriasis rubra pilaris diagnosis. Polymerase chain reaction test from erosions confirmed the presence of herpes simplex virus 1/2 and culture results identified methicillin-resistant Staphylococcus aureus. Given the considerations of pityriasis rubra pilaris, hematologic disorders and paraneoplastic syndrome, a comprehensive work-up for haematological and oncological disorders was conducted, which yielded no significant findings. The patient was treated with intravenous corticosteroids, antibiotics, and antiviral drugs. Isotretinoin was initiated following the histological confirmation of pityriasis rubra pilaris. By the time of discharge, the patient's condition improved. During a follow-up visit 43 weeks after the initiation of isotretinoin, the skin was almost clear. The described case highlights the rare possibility of developing Kaposi's varicelliform eruption in patients with pityriasis rubra pilaris and demonstrates that isotretinoin is a safe and effective treatment option for this condition.

Targeting IL-1 controls refractory pityriasis rubra pilaris

Pityriasis rubra pilaris (PRP) is a rare inflammatory skin disease with a poorly understood pathogenesis. Through a molecularly driven precision medicine approach and an extensive mechanistic pathway analysis in PRP skin samples, compared to psoriasis, atopic dermatitis, healed PRP, and healthy controls, we identified IL-1β as a key mediator, orchestrating an NF-κB-mediated IL-1β-CCL20 axis, including activation of CARD14 and NOD2. Treatment of three patients with the IL-1 antagonists anakinra and canakinumab resulted in rapid clinical improvement and reversal of the PRP-associated molecular signature with a 50% improvement in skin lesions after 2 to 3 weeks. This transcriptional signature was consistent with in vitro stimulation of keratinocytes with IL-1β. With the central role of IL-1β underscoring its potential as a therapeutic target, our findings propose a redefinition of PRP as an autoinflammatory keratinization disorder. Further clinical trials are needed to validate the efficacy of IL-1β antagonists in PRP.

Guselkumab for Pityriasis Rubra Pilaris and Dysregulation of IL-23/IL-17 and NFkB Signaling: A Nonrandomized Trial

Importance

There is no US Food and Drug Administration-approved treatment for pityriasis rubra pilaris (PRP), and it is common for patients to fail to experience improvement with several systemic options. Involvement of interleukin (IL) 23 suggests a potential therapeutic target.

Objective

To determine whether guselkumab, an IL-23p19 inhibitor, provides clinical improvement for participants with PRP and better understand gene and protein dysregulation in PRP.

Design, Setting, and Participants

This single-arm, investigator-initiated nonrandomized trial was conducted from October 2019 to August 2022 at a single-center academic university with participants from 8 states in the US. In total, 14 adults with moderate to severe PRP were enrolled; 12 completed the trial. Age-matched and sex-matched healthy controls provided skin and blood for proteomic and transcriptomic studies. The primary outcome was observed at 24 weeks, and additional follow-up occurred at 36 weeks.

Intervention

Guselkumab is a fully human immunoglobulin G1 λ monoclonal antibody that selectively binds and inhibits the p19 subunit of IL-23. Subcutaneous injections were given at the US Food and Drug Administration-approved dosing schedule for psoriasis over a 24-week period.

Main Outcomes and Measures

The primary outcome was the mean change in the Psoriasis Area Severity Index (PASI) score at week 24. Secondary outcomes included pruritus, Dermatology Life Quality Index score, clinical response at week 36, and association with transcriptomics and proteomics expression.

Results

A per-protocol analysis was performed for the cohort of 4 female and 8 male patients who had a mean (SD) age of 56.5 (18.7) years. The mean improvement in PASI score, pruritus, and Dermatology Life Quality Index score was 61.8% (P < .001), 62.3% (P = .001), and 60.2% (P < .001), respectively. Nine participants (75%) achieved a 50% improvement in PASI. Among these clinical responders, at week 36, 8 of 9 achieved PASI75, and 6 of 9 achieved PASI90. No participants had pathogenic CARD14 gene variations. There was 1 serious adverse event that was not associated with the study drug. Proteomics and gene expression profiles identified dysregulation of a predominance of inflammatory pathways (such as T helper 17 and nuclear factor κ B) in participants with PRP who later responded well to treatment with guselkumab and stronger dysregulation of keratinocyte development pathways in individuals who did not respond to guselkumab.

Conclusion and Relevance

The results of this nonrandomized trial suggest that guselkumab has efficacy in treating refractory moderate to severe adult PRP.

Trial Registration

ClinicalTrials.gov Identifier: NCT03975153.

Pityriasis Rubra Pilaris: An Updated Review of Clinical Presentation, Etiopathogenesis, and Treatment Options

Pityriasis rubra pilaris (PRP) is a rare papulosquamous reaction pattern with a significant impact on quality of life. Type I PRP is the most common PRP variant, presenting as erythematous papules emerging in a follicular distribution and later coalescing into plaques with characteristic islands of sparing; histologically, an alternating pattern of orthokeratosis and parakeratosis is considered the hallmark of PRP (checkerboard hyperkeratosis). Other PRP variants (types II-V) differ in their age of onset and clinical presentation. Type VI PRP is a rare PRP subtype associated with human immunodeficiency virus infection and is occasionally associated with diseases of the follicular occlusion tetrad. Caspase recruitment domain family, member 14 (CARD14)-associated papulosquamous eruption and facial discoid dermatitis are newly described disease states that have an important clinical overlap with PRP, creating shared conundrums with respect to diagnosis and treatment. The etiology inciting PRP often remains uncertain; PRP has been suggested to be associated with infection, malignancy, or drug/vaccine administration in some cases, although these are based on case reports and causality has not been established. Type V PRP is often due to inborn CARD14 mutations. Furthermore, recent literature has identified interleukin-23/T-helper-17 cell axis dysregulation to be a major mediator of PRP pathogenesis, paving the way for mechanism-directed therapy. At present, high-dose isotretinoin, ixekizumab, and secukinumab are systemic agents supported by single-arm prospective studies; numerous other agents have also been trialed for PRP, with variable success rates. Here, we discuss updates on clinical manifestations, present new insights into etiopathogenesis, and offer a survey of recently described therapeutic options.