No abstract

T cells are crucial mediators of the skin damage in psoriasis. We here show that interleukin-21 (IL-21), a T cell-derived cytokine, is highly expressed in the skin of individuals with psoriasis, stimulates human keratinocytes to proliferate and causes epidermal hyperplasia when injected intradermally into mice. In the human psoriasis xenograft mouse model, blockade of IL-21 activity resolves inflammation and reduces keratinocyte proliferation. Blocking IL-21 may represent a new therapeutic strategy in psoriasis.

Management of psoriasis in elderly patients can be challenging, because of the impairment of immune system efficiency and the presence of comorbidities that contra-indicate systemic therapies. We studied the safety and efficacy of systemic traditional and biological treatments in 187 consecutive psoriatic patients aged > 65 years. At week 12 of therapy, Psoriasis Area and Severity Index 75 was achieved by 49%, 27%, 46% and 31% of patients who received methotrexate, acitretin, cyclosporine or PUVA, and 64.1%, 64.7%, 93.3%, 57.1% and 100% of patients who received etanercept, adalimumab, infliximab, efalizumab and ustekinumab. The rate of adverse events was 0.12, 0.32, 1.4 and 0.5 per patient-year in the methotrexate, acitretin, cyclosporine and PUVA groups and 0.11, 0.35, 0.19, 0.3 and 0.26 in the etanercept, adalimumab, infliximab, efalizumab and ustekinumab groups. Traditional drugs were less effective than biologics in our elderly population. Etanercept was associated with a lower rate of adverse events compared with other treatments.

Based on data available in the literature and the clinical experience of the authors, this article suggests the optimal approach to drug monitoring and antidrug antibody assay and the most effective use of biologic immunotherapies in this setting. Immunogenicity should be taken into account in the adoption of therapeutic choices in psoriatic patients, such as anti-TNFα agent intensification, or switching to another anti-TNFα agent or a drug with a different mechanism of action.

Since targeted biologic treatments have been introduced for the treatment of plaque-type psoriasis and psoriatic arthritis, switching between different medications has become necessary in selected patients, particularly after treatment failures. To evaluate the efficacy and safety of etanercept treatment in adult patients with psoriasis after failure to respond to other previous therapies. In particular, the differences in efficacy profiles after switching from traditional (cyclosporine [ciclosporin], methotrexate, retinoids, fumaric acid esters, psoralen plus UVA therapy, corticosteroids) or biologic (infliximab, efalizumab) treatments were analyzed. The study included 124 patients affected by plaque-type psoriasis who received etanercept administered subcutaneously at a dosage of 50 mg twice weekly for 12 weeks, followed by 25 mg twice weekly for an additional 12 weeks, and 110 patients affected by psoriatic arthritis who were treated with etanercept 25 mg twice weekly in a continuous regimen, after a 12-week period of treatment with etanercept 50 mg twice weekly. Efficacy results were consistent in both groups of patients (plaque-type psoriasis and psoriatic arthritis), as expressed by the percentage of patients who achieved Psoriasis Area and Severity Index (PASI) 50 and PASI 75 scores. Among psoriatic arthritis patients, the mean pain Visual Analog Scale (VAS) score showed a substantial reduction during the treatment course, from 67.2 at week 0 to 15.8 at week 24. After 24 weeks, among patients with plaque-type psoriasis who had not previously received biologic therapies, 89.9% of patients achieved PASI 50 and 75.3% achieved PASI 75, while among patients who had received biologic therapies, 69.6% of patients achieved PASI 50 and 65.2% achieved PASI 75. In addition, 92.3% of patients with psoriatic arthritis who had not previously received biologic therapies achieved PASI 50 and 73.8% achieved PASI 75, while among patients who had received biologic therapies, 45.8% of patients achieved PASI 50 and 29.2% achieved PASI 75. Our study demonstrated that etanercept was more effective in those patients who had not previously received other biologic therapies than in those who had. The results of the present study indicate that etanercept may represent a valid, effective, and well tolerated therapeutic alternative even after failure to respond to traditional and other biologic therapies.