Does targeting the interleukin 23–helper T cell 17 pathway represent a targeted treatment option for pityriasis rubra pilaris?
In this case report, gene expression analyses of lesional skin samples taken from 3 patients with pityriasis rubra pilaris revealed a preferential helper T cell 17 expression profile. Analyses of samples from 1 patient performed before and during anti–interleukins 12 and 23 treatment with ustekinumab showed that expression levels of helper T cell 17 cytokines, but not of tumor necrosis factor or interferon-γ, paralleled clinical and histologic improvements.
This report identifies a role of the interleukin 23–helper T cell 17 axis in pityriasis rubra pilaris and provides a rationale for targeting this pathway as a treatment option for refractory pityriasis rubra pilaris.
Treatment of pityriasis rubra pilaris (PRP) is solely based on its resemblance to psoriasis rather than any knowledge of its pathomechanism. Insight into pathogenic mediators of inflammation is essential for targeted and valid treatment options that could replace previous serendipitous therapeutic approaches in refractory PRP.
To determine whether blockade of the interleukin 23–helper T cell 17 (IL-23–TH17) pathway with ustekinumab represents an efficacious and, based on its proinflammatory cytokine profile, targeted treatment option in PRP.
Design, Setting, and Participants
In this case report, a patient with PRP received outpatient treatment at a university hospital department of dermatology with ustekinumab according to the dosing regimen approved for psoriasis. Lesional skin biopsy samples were taken from this patient and 2 others with refractory PRP. Messenger RNA (mRNA) expression of proinflammatory innate and T-cell–derived cytokines were measured and compared with skin samples from patients with psoriasis and healthy donors. From 1 patient, lesional skin samples were taken before ustekinumab treatment and 4 and 28 weeks after treatment initiation. Follow-up was completed after 6 months.
Subcutaneous ustekinumab, 45 mg, at weeks 0 and 4 and quarterly thereafter.
Main Outcomes and Measures
The primary outcome was to determine the changes in expression of proinflammatory innate and T-cell–derived cytokines during ustekinumab therapy. The secondary objective was to evaluate the clinical and histopathologic phenotype in relation to the mRNA expression profile of proinflammatory cytokines.
In lesional PRP skin samples from a single patient, upregulated expression levels were found for most proinflammatory innate cytokines, including tumor necrosis factor (TNF), IL-6, IL-12, IL-23, and IL-1β. Among adaptive T-cell cytokines, an increase of TH1 cytokines and, in particular, TH17 cytokines IL-17A, IL-17F, and IL-22 was seen in PRP. The patient with PRP who received ustekinumab showed regression of skin lesions after 2 weeks and almost complete resolution after 1 month. Clinical and histopathologic improvement paralleled the expression levels of TH17 cytokines but not of interferon-γ and TNF, which lagged behind the amelioration.
Conclusions and Relevance
In this case report, a role of the IL-23–TH17-axis in PRP was identified, suggesting a shared pathogenic inflammatory pathway with psoriasis, despite evident clinical and histopathologic differences. In addition, this report provides a rationale for targeting the IL-23–TH17-pathway as a treatment option for refractory PRP.
Feldmeyer L, Mylonas A, Demaria O, et al. Interleukin 23–Helper T Cell 17 Axis as a Treatment Target for Pityriasis Rubra Pilaris. JAMA Dermatol. 2017;153(4):304–308. doi:10.1001/jamadermatol.2016.5384
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