• 1
    Scarpa R, Oriente P, Pucino A, Torella M, Vignone L, Riccio A, et al. Psoriatic arthritis in psoriatic patients. Br J Rheumatol 1984; 23: 24650.
  • 2
    Shbeeb M, Uramoto KM, Gibson LE, O'Fallon WM, Gabriel SE. The epidemiology of psoriatic arthritis in Olmsted County, Minnesota, USA, 1982-1991. J Rheumatol 2000; 27: 124750.
  • 3
    Goodfield M. Skin lesions in psoriasis. Baillieres Clin Rheumatol 1994; 8: 295316.
  • 4
    National Psoriasis Foundation. New research shows 1 million U.S. adults suffer from psoriatic arthritis: others may be at risk but not know it. Portland (OR): NPF Press Releases; May 15, 2002. URL:
  • 5
    Gladman DD, Stafford-Brady F, Chang CH, Lewandowski K, Russell ML. Longitudinal study of clinical and radiological progression in psoriatic arthritis. J Rheumatol 1990; 17: 80912.
  • 6
    Torre Alonso JC, Rodriguez Perez A, Arribas Castrillo JM, Ballina Garcia J, Fiestra Noriega JL, Lopez Larrea C. Psoriatic arthritis (PA): a clinical, immunological and radiological study of 180 patients. Br J Rheumatol 1991; 30: 24550.
  • 7
    Wong K, Gladman DD, Husted J, Long JA, Farewell VT. Mortality studies in psoriatic arthritis: results from a single outpatient clinic. I. Causes and risk of death. Arthritis Rheum 1997; 40: 186872.
  • 8
    Husted JA, Gladman DD, Farewell VT, Cook RJ. Health-related quality of life of patients with psoriatic arthritis: a comparison with patients with rheumatoid arthritis. Arthritis Care Res 2001; 45: 1518.
  • 9
    Tassiulas I, Duncan SR, Centola M, Theofilopoulos AN, Boumpas DT. Clonal characteristics of T cell infiltrates in skin and synovium of patients with psoriatic arthritis. Hum Immunol 1999; 60: 47991.
  • 10
    Costello PJ, Winchester RJ, Curran SA, Peterson KS, Kane DJ, Bresnihan B, et al. Psoriatic arthritis joint fluids are characterized by CD8 and CD4 T cell clonal expansions that appear antigen driven. J Immunol 2001; 166: 287886.
  • 11
    Nickoloff BJ, Wrone-Smith T. Injection of pre-psoriatic skin with CD4+ T cells induces psoriasis. Am J Pathol 1999; 155: 14558.
  • 12
    Steiner G, Tohidast-Akrad M, Witzmann G, Vesely M, Studnicka-Benke A, Gal A, et al. Cytokine production by synovial T cells in rheumatoid arthritis. Rheumatology (Oxford) 1999; 38: 20213.
  • 13
    Black RL, O'Brien WM, Van Scott EJ, Auerbach R, Eizen AZ, Bunim JJ. Methotrexate therapy in psoriatic arthritis. JAMA 1964; 189: 7437.
  • 14
    Jones G, Crotty M, Brooks P. Interventions for treating psoriatic arthritis (Cochrane Review). In: The Cochrane Library, Issue 3. Oxford: Update Software; 2001.
  • 15
    Brockbank J, Gladman D. Diagnosis and management of psoriatic arthritis. Drugs 2002; 62: 244757.
  • 16
    Griffiths CE, Clark CM, Chalmers RJ, Li Wan Po A, Williams HC. A systematic review of treatments for severe psoriasis. Health Technol Assess 2000; 4: 1125.
  • 17
    Mease PJ, Goffe BS, Metz J, VanderStoep A, Finck B, Burge DJ. Etanercept in the treatment of psoriatic arthritis and psoriasis: a randomised trial. Lancet 2000; 356: 38590.
  • 18
    Antoni C, Dechant C, Hanns-Martin Lorenz PD, Wendler J, Ogilvie A, Lueftl M, et al. Open-label study of infliximab treatment for psoriatic arthritis: clinical and magnetic resonance imaging measurements of reduction of inflammation. Arthritis Care Res 2002; 47: 50612.
  • 19
    Kraan MC, van Kuijk AW, Dinant HJ, Goedkoop AY, Smeets TJ, de Rie MA, et al. Alefacept treatment in psoriatic arthritis: reduction of the effector T cell population in peripheral blood and synovial tissue is associated with improvement of clinical signs of arthritis. Arthritis Rheum 2002; 46: 277684.
  • 20
    Breedveld FC, Dayer JM. Leflunomide: mode of action in the treatment of rheumatoid arthritis. Ann Rheum Dis 2000; 59: 8419.
  • 21
    Smolen JS, Kalden JR, Scott DL, Rozman B, Kvien TK, Larsen A, et al. Efficacy and safety of leflunomide compared with placebo and sulphasalazine in active rheumatoid arthritis: a double-blind, randomized, multicentre trial. Lancet 1999; 353: 25966.
  • 22
    Strand V, Cohen S, Schiff M, Weaver A, Fleischmann R, Cannon G, et al. Treatment of active rheumatoid arthritis with leflunomide compared with placebo and methotrexate. Arch Intern Med 1999; 159: 254250.
  • 23
    Emery P, Breedveld FC, Lemmel EM, Kaltwasser JP, Dawes PT, Gomor B, et al. A comparison of the efficacy and safety of leflunomide and methotrexate for the treatment of rheumatoid arthritis. Rheumatology (Oxford) 2000; 39: 65565.
  • 24
    Cohen S, Cannon GW, Schiff M, Weaver A, Fox R, Olsen N, et al, for the Utilization of Leflunomide in the Treatment of Rheumatoid Arthritis Trial Investigator Group. Two-year, blinded, randomized, controlled trial of treatment of active rheumatoid arthritis with leflunomide compared with methotrexate. Arthritis Rheum 2001; 44: 198492.
  • 25
    Scott DL, Smolen JS, Kalden JR, van de Putte LBA, Larsen A, Kvien TK, et al. Treatment of active rheumatoid arthritis with leflunomide: two year follow up of a double blind, placebo controlled trial versus sulfasalazine. Ann Rheum Dis 2001; 60: 91323.
  • 26
    Van der Heijde D, Kalden J, Scott D, Smolen J, Strand V. Long-term evaluation of radiographic disease progression in patients with rheumatoid arthritis (RA) treated with leflunomide beyond 2 years [abstract FRI0030]. Presented at the Annual European Congress of Rheumatology EULAR 2002, June 14, 2002, Stockholm, Sweden.
  • 27
    Liang GC, Barr WG. Open trial of leflunomide for refractory psoriasis and psoriatic arthritis. J Clin Rheumatol 2001; 7: 36670.
  • 28
    Reich K, Hummel KM, Beckmann I, Mossner R, Neumann C. Treatment of severe psoriasis and psoriatic arthritis with leflunomide. Br J Dermatol 2002; 146: 3356.
  • 29
    Cuchacovich M, Soto L. Leflunomide decreases joint erosions and induces reparative changes in a patient with psoriatic arthritis. Ann Rheum Dis 2002; 61: 9423.
  • 30
    International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (1996). ICH harmonised tripartite guideline. Guideline for good clinical practice (topic E6). URL:
  • 31
    Clegg DO, Reda DJ, Mejias E, Cannon GW, Weisman MH, Taylor T, et al. Comparison of sulfasalazine and placebo in the treatment of psoriatic arthritis: a Department of Veterans Affairs cooperative study. Arthritis Rheum 1996; 39: 201320.
  • 32
    Felson DT, Anderson JJ, Boers M, Bombardier C, Furst D, Goldsmith C, et al. American College of Rheumatology preliminary definition of improvement in rheumatoid arthritis. Arthritis Rheum 1995; 38: 72735.
  • 33
    Felson DT, Anderson JJ, Boers M, Bombardier C, Chernoff M, Fried B, et al. The American College of Rheumatology preliminary core set of disease activity measures for rheumatoid arthritis clinical trials. Arthritis Rheum 1993; 36: 72940.
  • 34
    Fredriksson T, Pettersson U. Severe psoriasis—oral therapy with a new retinoid. Dermatologica 1978; 157: 23844.
  • 35
    Kirwan JR, Reeback JS. Stanford Health Assessment Questionnaire modified to assess disability in patients with rheumatoid arthritis. Br J Rheumatol 1986; 25: 2069.
  • 36
    Finlay AY, Khan GK. Dermatology life quality index (DLQI)—a simple practical measure for routine clinical use. Clin Exp Dermatol 1994; 19: 2106.
  • 37
    International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (1994). ICH harmonised tripartite guideline. Clinical safety data management: definitions and standards for expedited reporting (topic E2A). URL:
  • 38
    Marguerie L, Flipo RM, Grardel B, Beaurain D, Duquesnoy B, Delcambre B. Use of disease-modifying antirheumatic drugs in patients with psoriatic arthritis. Joint Bone Spine 2002; 69: 27581.
  • 39
    Whiting-O'Keefe QE, Fye KH, Sack KD. Methotrexate and histologic hepatic abnormalities: a meta-analysis. Am J Med 1991; 90: 7116.
  • 40
    Paul CF, Ho VC, McGeown C, Christophers E, Schmidtmann B, Guillaume JC, et al. Risk of malignancies in psoriasis patients treated with cyclosporine: a 5 y cohort study. J Invest Dermatol 2003; 120: 2116.
  • 41
    Ujfalussy I, Koo E. Measurement of disease activity in psoriatic arthritis. Extended report. Z Rheumatol 2003; 62: 605.
  • 42
    Menter MA, Krueger GC, Feldman SR, Weinstein GD. Psoriasis treatment 2003 at the new millennium: position paper on behalf of the authors. J Am Acad Dermatol 2003; 49: S3943.
  • 43
    Wells GA, Tugwell P, Kraag G, Baker PRA, Groh J, Redelmeier DA. Minimum important difference between patients with rheumatoid arthritis: the patient's perspective. J Rheumatol 1993; 20: 55760.
  • 44
    Redelmeier DA, Lorig K. Assessing the clinical importance of symptomatic improvements. An illustration in rheumatology. Arch Intern Med 1993; 153: 133742.
  • 45
    Badia X, Mascaro JM, Lozano R, on behalf of the CAVIDE Research Group. Measuring health-related quality of life in patients with mild to moderate eczema and psoriasis: clinical validity, reliability and sensitivity to change in the DLQI. Br J Dermatol 1999; 141: 693702.
  • 46
    Mazzotti E, Picardi A, Sampogna F, Sera F, Pasquini P, Abeni D, IDI Multipurpose Psoriasis Research on Vital Experiences (IMPROVE) Study Group. Sensitivity of the dermatology life quality index to clinical change in patients with psoriasis. Br J Dermatol 2003; 149: 31822.
  • 47
    Cannon GW, Schiff M, Strand V, Holden W. Hepatic adverse events and other toxicity during treatment with leflunomide (LEF), methotrexate (MTX), other disease modifying anti-rheumatic drugs (DMARDs), and combination DMARD therapy: comparison to NSAIDs alone and adjustment for comorbidities. Arthritis Rheum 2002; 46 Suppl 9: S166.