SEB Stimulation Induces Functional Pathogenic Features in Th17 Cells from Psoriasis Patients

Case Report: Coexistence of bullous pemphigoid and psoriasis: Therapeutic challenge and IL17A-targeted parallel treatment strategy

Autoimmune blistering diseases of the skin have all been reported in patients with psoriasis, bullous pemphigoid (BP) being the most frequently observed. The pathophysiologic triggers for BP in psoriatic patients are unclear. Recent observational studies have suggested that chronic psoriatic inflammation may cause pathological changes to the basement membrane zone, thus inducing autoimmunity against BP antigens through cross reactivity and “epitope spreading.” The coexistence of BP and psoriasis poses challenging therapeutic dilemmas related to the incompatibility of their standard treatments. Considering the probable common immunologic mechanisms in the pathogenesis of these inflammatory skin disorders, a suitable treatment regimen should be applied for their parallel control. We report three patients, who developed BP in the course of preceding long-lasting psoriasis. Secukinumab was administered as first-line treatment with promising therapeutic effect for both skin disorders and long-term disease control in two of the cases. In the third case, parallel disease control was initially achieved with methotrexate. A few years later, secukinumab was used for the treatment of a relapse of both dermatoses but worsening of BP was observed and methotrexate was reintroduced. Our experience on the therapeutic potential of secukinumab in BP is supported by the data in the literature. Recently, it was demonstrated that the proinflammatory cytokine IL17A has a functional role in the process of skin inflammation in BP, similarly to psoriasis. IL17A inhibition has emerged as a promising therapeutic strategy in patients with extensive or refractory BP but paradoxical development of BP after secukinumab treatment for psoriasis has also been described. This controversy emphasizes the need for further investigation into the development of optimal treatment strategies and recommendations.

Association of Pathogenic Th17 Cells with the Disease Severity and Its Potential Implication for Biological Treatment Selection in Psoriasis Patients

Psoriasis is an inflammatory autoimmune disease characterized by cutaneous lesions in plaques. It has been proposed that the immune response has a key role in the disease progression. Particularly, the Th17 cells through IL-17 can contribute to maintain the inflammatory process. The pathogenic Th17 phenotype has been described in human diseases and associated with high severity in inflammatory experimental models. However, it is not clear if the pathogenic phenotype could be present in the skin and peripheral blood as well as its possible association to severity in psoriasis. In the lesional skin, we found high infiltration of Th17 cells and the pathogenic phenotype, finding a correlation between the frequency of Th17 cells and the Psoriasis Area and Severity Index (PASI) score. In peripheral blood, we observed a pool of Th17 lymphocytes with potential to acquire pathogenic features. Interestingly, the percentage of pathogenic Th17 cells (CD4⁺ RORγt⁺ IFN-γ⁺) correlates with disease severity. Moreover, we distinguished three groups of patients based on their IL-17/IFN-γ production by Th17 lymphocytes, which seems to be related with a dynamic or stable potential to express these cytokines. Remarkably, we evaluated the cytokine production by Th17 cells as an immunological marker for the adequate selection of biologic therapy. We found that patients analyzed by this immunological approach and treated with antibodies against IL-17 and TNFα showed great improvement depicted by reduction in PASI and Dermatology Life Quality Index (DLQI) score as well as the percentage of Body Surface Area (BSA). Altogether, our results highlight the importance of the assessment of the pathogenic phenotype in Th17 cells as an immune personalized analysis with the potential to support the therapy choice in the clinical practice.