C.E.M. Griffiths

Pathogenesis and clinical features of psoriasis

Psoriasis, a papulosquamous skin disease, was originally thought of as a disorder primarily of epidermal keratinocytes, but is now recognised as one of the commonest immune-mediated disorders. Tumour necrosis factor alpha, dendritic cells, and T-cells all contribute substantially to its pathogenesis. In early-onset psoriasis (beginning before age 40 years), carriage of HLA-Cw6 and environmental triggers, such as beta-haemolytic streptococcal infections, are major determinants of disease expression. Moreover, at least nine chromosomal psoriasis susceptibility loci have been identified. Several clinical phenotypes of psoriasis are recognised, with chronic plaque (psoriasis vulgaris) accounting for 90% of cases. Comorbidities of psoriasis are attracting interest, and include impairment of quality of life and associated depressive illness, cardiovascular disease, and a seronegative arthritis known as psoriatic arthritis. A more complete understanding of underlying pathomechanisms is leading to new treatments, which will be discussed in the second part of this Series.

Infliximab induction and maintenance therapy for moderate-to-severe psoriasis : a phase III, multicentre, double-blind trial

BACKGROUND Tumour necrosis factor alpha (TNFalpha) is thought to play a part in the pathogenesis of psoriasis. We assessed the efficacy and safety of continuous treatment with infliximab, a monoclonal antibody that binds to and neutralises the activity of TNFalpha, in patients with psoriasis. METHODS In this phase III, multicentre, double-blind trial, 378 patients with moderate-to-severe plaque psoriasis were allocated in a 4:1 ratio to receive infusions of either infliximab 5 mg/kg or placebo at weeks 0, 2, and 6, then every 8 weeks to week 46. At week 24, placebo-treated patients crossed over to infliximab treatment. Skin and nail signs of psoriasis were assessed using the psoriasis area and severity index (PASI) and nail psoriasis severity index (NAPSI), respectively. The primary endpoint, analysed on an intention-to-treat-basis, was the proportion of patients achieving at least a 75% improvement in PASI from baseline to week 10. FINDINGS At week 10, 80% (242/301) of patients treated with infliximab achieved at least a 75% improvement from their baseline PASI (PASI 75) and 57% (172/301) achieved at least a 90% improvement (PASI 90), compared with 3% and 1% in the placebo group, respectively (p<0.0001). At week 24, PASI 75 (82% for infliximab vs 4% for placebo) and PASI 90 (58%vs 1%) were maintained (p<0.0001). At week 50, 61% achieved PASI 75 and 45% achieved PASI 90 in the infliximab group. Infliximab was generally well tolerated in most patients. INTERPRETATION Infliximab is effective in both an induction and maintenance regimen for the treatment of moderate-to-severe psoriasis, with a high percentage of patients achieving sustained PASI 75 and PASI 90 improvement through 1 year.

Global epidemiology of psoriasis: a systematic review of incidence and prevalence.

The worldwide incidence and prevalence of psoriasis is poorly understood. To better understand this, we performed a systematic review of published population-based studies on the incidence and prevalence of psoriasis. Three electronic databases were searched from their inception dates to July 2011. A total of 385 papers were critically appraised; 53 studies reported on the prevalence and incidence of psoriasis in the general population. The prevalence in children ranged from 0% (Taiwan) to 2.1% (Italy), and in adults it varied from 0.91% (United States) to 8.5% (Norway). In children, the incidence estimate reported (United States) was 40.8/100,000 person-years. In adults, it varied from 78.9/100,000 person-years (United States) to 230/100,000 person-years (Italy). The data indicated that the occurrence of psoriasis varied according to age and geographic region, being more frequent in countries more distant from the equator. Prevalence estimates also varied in relation to demographic characteristics in that studies confined to adults reported higher estimates of psoriasis compared with those involving all age groups. Studies on the prevalence and incidence of psoriasis have contributed to a better understanding of the burden of the disease. However, further research is required to fill existing gaps in understanding the epidemiology of psoriasis and trends in incidence over time.

Comparison of Ustekinumab and Etanercept for Moderate-to-Severe Psoriasis

BACKGROUND Biologic agents offer a range of new therapeutic options for patients with psoriasis; however, the relative benefit-risk profiles of such therapies are not well known. We compared two biologic agents, ustekinumab (an interleukin-12 and interleukin-23 blocker) and etanercept (an inhibitor of tumor necrosis factor alpha), for the treatment of psoriasis. METHODS We randomly assigned 903 patients with moderate-to-severe psoriasis to receive subcutaneous injections of either 45 or 90 mg of ustekinumab (at weeks 0 and 4) or high-dose etanercept (50 mg twice weekly for 12 weeks). The primary end point was the proportion of patients with at least 75% improvement in the psoriasis area-and-severity index (PASI) at week 12; a secondary end point was the proportion with cleared or minimal disease on the basis of the physicians global assessment. Assessors were unaware of the treatment assignments. The efficacy and safety of a crossover from etanercept to ustekinumab were evaluated after week 12. RESULTS There was at least 75% improvement in the PASI at week 12 in 67.5% of patients who received 45 mg of ustekinumab and 73.8% of patients who received 90 mg, as compared with 56.8% of those who received etanercept (P=0.01 and P<0.001, respectively). Similarly, 65.1% of patients who received 45 mg of ustekinumab and 70.6% of patients who received 90 mg of ustekinumab had cleared or minimal disease according to the physicians global assessment, as compared with 49.0% of those who received etanercept (P<0.001 for both comparisons). Among patients who did not have a response to etanercept, 48.9% had at least 75% improvement in the PASI within 12 weeks after crossover to ustekinumab. One or more adverse events occurred through week 12 in 66.0% of patients who received 45 mg of ustekinumab and 69.2% of patients who received 90 mg of ustekinumab and in 70.0% who received etanercept; 1.9%, 1.2%, and 1.2%, respectively, had serious adverse events. Safety patterns were similar before and after crossover from etanercept to ustekinumab. CONCLUSIONS The efficacy of ustekinumab at a dose of 45 or 90 mg was superior to that of high-dose etanercept over a 12-week period in patients with psoriasis. (ClinicalTrials.gov number, NCT00454584.)

A global phase III randomized controlled trial of etanercept in psoriasis: safety, efficacy, and effect of dose reduction

Background  In previous studies, etanercept significantly improved plaque psoriasis and was well tolerated.

European S3‐Guidelines on the systemic treatment of psoriasis vulgaris

Of the 131 studies on monotherapy or combination therapy assessed, 56 studies on the different forms of phototherapy fulfilled the criteria for inclusion in the guidelines. Approximately three-quarters of all patients treated with phototherapy attained at least a PASI 75 response after 4 to 6 weeks, and clearance was frequently achieved (levels of evidence 2 and 3). Phototherapy represents a safe and very effective treatment option for moderate to severe forms of psoriasis vulgaris. The onset of clinical effects occurs within 2 weeks. Of the unwanted side effects, UV erythema from overexposure is by far the most common and is observed frequently. With repeated or long-term use, the consequences of high, cumulative UV doses (such as premature aging of the skin) must be taken into consideration. In addition, carcinogenic risk is associated with oral PUVA and is probable for local PUVA and UVB. The practicability of the therapy is limited by spatial, financial, human, and time constraints on the part of the physician, as well as by the amount of time required by the patient. From the perspective of the cost-bearing institution, phototherapy has a good cost-benefit ratio. However, the potentially significant costs for, and time required of, the patient must be considered.

Characterization of intercellular adhesion molecule-1 and HLA-DR expression in normal inflamed skin: Modulation by recombinant gamma interferon and tumor necrosis factor

Lymphocytes bind to cultured keratinocytes that are treated with interferon gamma (IFN-gamma) and tumor necrosis factor (TNF). When the lymphocytes are preincubated with antibody to lymphocyte function associated antigen-1 (LFA-1), this adherence is inhibited. Because intercellular adhesion molecule-1 (ICAM-1) is a ligand for LFA-1, we studied the cellular expression of ICAM-1, as well as two other IFN-gamma-inducible antigens, (HLA) human lymphocyte antigens DR and DQ, in both normal and diseased skin. The modulation of these cell surface antigens by IFN-gamma and TNF with the use of short-term organ cultures of skin was compared with isolated keratinocytes grown in a conventional tissue culture system. While in normal skin, keratinocytes did not express HLA-DR, DQ, or ICAM-1, when organ cultures were supplemented with IFN-gamma, rapid induction of keratinocyte ICAM-1 expression occurred after 24 hours; HLA-DR but not DQ expression occurred after 48 hours. TNF also induced keratinocyte ICAM-1 expression (although to a lesser degree than IFN-gamma) but did not induce either keratinocyte HLA-DR or DQ expression. There was good correlation of keratinocyte expression of ICAM-1 and HLA-DR by IFN-gamma and TNF when the epidermis of the organ culture system was compared with the isolated keratinocytes grown in tissue culture. The presence of intraepidermal lymphocytes correlated extremely well with keratinocyte ICAM-1 expression but not with keratinocyte HLA-DR expression in psoriasis, atopic dermatitis, lichen planus, and mycosis fungoides. The intensity of endothelial cell expression of ICAM-1 correlated with the degree of dermal inflammation. We conclude that IFN-gamma, once produced by activated T lymphocytes in the dermis, may be of importance in lymphocyte trafficking in the epidermis by the induction of keratinocyte ICAM-1 expression. The use of the short-term organ culture system, in which there is inducible ICAM-1 expression, provides an experimental bridge between purely in vitro and in vivo investigations to further our understanding of the molecular basis for lymphocyte apposition to keratinocytes in the skin.

Psoriasis: epidemiology, clinical features, and quality of life

Psoriasis is a common chronic, recurrent, immune mediated disease of the skin and joints. It can have a significant negative impact on the physical, emotional, and, psychosocial wellbeing of affected patients. Psoriasis is found worldwide but the prevalence varies among different ethnic groups. It has a strong genetic component but environmental factors such as infections can play an important role in the presentation of disease. There are several clinical cutaneous manifestations of psoriasis but most commonly the disease presents as chronic, symmetrical, erythematous, scaling papules and plaques. The epidemiology, clinical features, and impact on quality of life of psoriasis are reviewed.

Infliximab for the treatment of pyoderma gangrenosum: a randomised, double blind, placebo controlled trial

Background: Pyoderma gangrenosum (PG) is a chronic ulcerating skin condition that often occurs in association with inflammatory bowel disease. There have been a number of reports of PG responding to infliximab, a monoclonal antibody against tumour necrosis factor α. Aim: In the first randomised placebo controlled trial of any drug for the treatment of PG, we have studied the role of infliximab in this disorder. Subjects: Patients 18 years of age or older with a clinical diagnosis of PG were invited to take part. Methods: Patients were randomised to receive an infusion of infliximab at 5 mg/kg or placebo at week 0. Patients were then assessed at week 2 and non-responders were offered open labelled infliximab. The primary end point was clinical improvement at week 2, with secondary end points being remission and improvement at week 6. Results: Thirty patients were entered into the study. After randomisation, 13 patients received infliximab and 17 patients received placebo. At week 2, significantly more patients in the infliximab group had improved (46% (6/13)) compared with the placebo group (6% (1/17); p = 0.025). Overall, 29 patients received infliximab with 69% (20/29) demonstrating a beneficial clinical response. Remission rate at week 6 was 21% (6/29). There was no response in 31% (9/29) of patients. Conclusions: This study has demonstrated that infliximab at a dose of 5 mg/kg is superior to placebo in the treatment of PG. Open label treatment with infliximab also produced promising results. Infliximab treatment should be considered in patients with PG.

Restoration of Collagen Formation in Photodamaged Human Skin by Tretinoin (Retinoic Acid)

BACKGROUND Topical tretinoin (retinoic acid) modifies fine wrinkles and certain other features of human skin damaged by exposure to the sun (photodamage), but histologic changes do not account for this improvement. In mice with photodamage induced by ultraviolet light, effacement of fine wrinkles by tretinoin is correlated with dermal collagen synthesis but not with histologic changes. We investigated whether collagen synthesis was reduced in photodamaged human skin and, if so, whether it could be restored by treatment with topical tretinoin. METHODS Biopsies of photodamaged skin from the extensor aspect of the forearm and skin from the buttocks, which had been protected from the sun, were performed on 26 healthy subjects. In addition, 29 patients with photodamaged skin were treated for 10 to 12 months with a daily application of 0.1 percent tretinoin cream (15 patients) or vehicle cream (14 patients). Skin-biopsy specimens obtained at base line and after treatment were assessed immunohistologically for evidence of dermal collagen I formation (collagen synthesis). RESULTS Collagen I formation was 56 percent less in the papillary dermis of photodamaged skin than in skin protected from the sun (P < 0.001) and was correlated with the clinical severity of photodamage (r = -0.58, P = 0.002). Treatment of photodamaged skin with tretinoin produced an 80 percent increase in collagen I formation, as compared with a 14 percent decrease in collagen formation with the use of vehicle alone (P = 0.006). CONCLUSIONS The formation of collagen I is significantly decreased in photodamaged human skin, and this process is partly restored by treatment with tretinoin.