Psoriatic arthritis: clinical aspects, genetics, and the role of T cells

Efalizumab for the Treatment of Psoriatic Arthritis

Background:

Psoriatic arthritis (PsA) is an inflammatory arthritis associated with psoriasis. Efalizumab, a T cell-targeted, recombinant human monoclonal antibody, is approved for the treatment of adult patients with chronic moderate to severe plaque psoriasis. The effect of efalizumab therapy on PsA has not previously been investigated.

Objective:

This phase II randomized, double-blind, placebo-controlled multicenter study evaluated the efficacy and safety of efalizumab for the treatment of PsA.

Methods:

Patients were required to be on at least one of the following concomitant systemic therapies for PsA: nonsteroidal anti-inflammatory drugs, corticosteroids, and/or sulfasalazine or methotrexate. One hundred fifteen patients with active PsA were enrolled and randomized in the study. Of these, 107 were treated weekly with efalizumab 1 mg/kg or placebo for 12 weeks, followed by 12 additional weeks of open-label efalizumab.

Results:

At week 12, 28% of efalizumab-treated patients achieved ACR-20 response (a 20% reduction from the baseline in the American College of Rheumatology response criteria), the primary end point, compared with 19% of placebo patients ( p = .27). The safety profile was comparable between efalizumab- and placebo-treated patient groups, regardless of methotrexate background therapy, and no worsening of joint disease occurred with efalizumab therapy.

Conclusions:

Efalizumab was not effective in treating PsA; efalizumab therapy did not worsen PsA. The efalizumab safety profile does not appear to be altered with the concomitant use of methotrexate therapy.

Psoriatic arthritis and psoriasis: differential diagnosis

Psoriasis frequency ranges from 1 to 3 % in white population, and arthritis occurs in 10-40 % of psoriasis patients, representing a relevant health issue. Psoriatic arthritis (PsA) is an inflammatory arthropathy, associated with psoriasis, in which ocular-, intestinal-, metabolic-, and cardiovascular-related manifestations can variably coexist. In order to favor early PsA and psoriasis diagnosis, it is crucial to rule out other conditions that can resemble the disease and delay appropriate therapeutic approach. Therefore, the aim of this review is to focus on PsA and psoriasis differential diagnosis.

Psoriasis Arthropathy and HLA-B51: Report of 5 Cases

Psoriasis arthropathy (PsA) is a chronic inflammatory arthropathy characterized by the association of arthritis with psoriasis. Although the precise mechanisms of PsA still remain obscure, several genetic and environmental factors have been suggested to play important roles. HLA-B51 has been strongly associated with Behçet's disease; however, its association with PsA has not been documented. We describe herein five Japanese patients (4 males and 1 female) with PsA and positive for HLA-B51. The clinical forms defined by Moll and Wright revealed that the polyarticular pattern was noted in two cases, and oligoarticular, distal, and spondyloarthropathy patterns were noted in one case each. Positive rheumatoid factor was detected in one patient, and antinuclear antibody in two patients. The other HLA subclasses were A2 and A31 in 3 cases, respectively. HLA-B51 was detected in 5 out of 17 patients with PsA examined in our department; in contrast, HLA-B51 was not detected in 17 patients with psoriasis vulgaris. Our observations suggest that HLA-B51 may play a role in the pathogenesis of PsA in the Japanese population.

Psoriasis Arthritis

This article presents an overview of psoriatic arthritis, including the origin, genetic influence and immunologic factors involved in its evolution. The clinical features of psoriatic arthritis are also reviewed in this article, and a discussion of the diagnosis and treatment is included. We have highlighted the current psoriasis treatments, new biological therapies, and their use in practice. This paper reviews the efficacy of these agents, and the importance of their early appliance. The available published data on the efficacy of antimalarials, sulfasalazine, methotrexate, azathioprine and ciclosporin are described, as well as new data on leflunomide and other novel agents.

Pharmacogenetic of antirheumatic treatments: clinical implications

Preliminary pharmacogenetic data suggest that germline genetic informations might be of value in individualizing disease-modifying antirheumatic drugs (DMARDs) therapy in various autoimmune chronic inflammatory diseases. Either DMARDs small molecules (DMARDs-SM) or DMARDs biological therapies (DMARDs-BT) might be selected for their lower toxicity or better efficacy based on single-nucleotide polymorphisms (SNPs) of genes governing the metabolism of drugs, or the response of immune cells to proinflammatory molecules, or the proinflammatory molecular activity of immune cells. Data available for one DMARDs-SM, methotrexate, suggest that a careful assessment of the SNPs of four enzymes involved in the folate metabolism allow one to construct a genetic index of toxicity (toxicogenetic index) that might be employed in daily practice to find the patient's most at risk. Only the full knowledge of the various gene polymorphisms controlling the phenotypic manifestations of the inflammatory-immunological milieu of each rheumatic disease will allow one to obtain the clear definition of a personalized medicine. Few different cytokine gene SNPs seem to be of importance in determining the susceptibility to diseases, or the aggressiveness of diseases. The role of genetics in affecting a possible clinical response to DMARDs-BT targeting specific inflammatory molecules or their receptors still has to be defined. However, the available data suggest that cytokine (and/or receptors) gene SNPs might indeed play a role in determining the biological effects, hence the clinical effectiveness of DMARDs-BT. Crucial to this aim will be the prospective analysis of clinical benefits and safety on the basis of the at baseline stratification of gene SNPs in each chronic inflammatory rheumatic disease before starting any new DMARDs-SM or DMARDs-BT.

Diagnosis and treatment of psoriatic arthritis

Psoriatic arthritis is a chronic, heterogeneous disease whose pathogenesis is unknown, although genetic, environmental, and immunologic factors play major roles. Psoriatic arthritis can follow an aggressive clinical course, and differentiating it from other arthropathies is sometimes difficult. Diagnosis of psoriatic arthritis is based on history, physical examination, the usual absence of rheumatoid factor, and characteristic radiographic features. At least 40% of patients with psoriatic arthritis develop radiographically detectable joint destruction; therefore, proper diagnosis and early treatment can have a significant impact on disease course and outcome. Understanding the pathogenesis of psoriatic disease has led to the use of several biologic agents that work by modulating T-cell signaling or by inhibiting key cytokines involved in inflammation, such as tumor necrosis factor (TNF). TNF inhibitors have demonstrated excellent efficacy in resolving skin and joint disease in patients with psoriatic arthritis and have been shown to be safe agents in various inflammatory disorders. This article reviews the diagnostic and treatment challenges of psoriatic arthritis as they relate to pathogenesis and burden of disease.

LEARNING OBJECTIVE

At the conclusion of this learning activity, participants should have acquired a more comprehensive knowledge of our current understanding of the classification, clinical presentation, etiology, pathophysiology, differential diagnosis, and treatment of psoriatic arthritis.

Clinical analysis of 21 patients with psoriasis arthropathy

Psoriasis arthropathy (PsA) is a chronic inflammatory arthropathy characterized by the association of arthritis with psoriasis. In this study, clinical, laboratory and radiographic signs of 21 patients (12 males and 9 females), mean age of 42.2 years old, with PsA were assessed. The clinical forms defined by Moll and Wright revealed that oligoarticular pattern was most commonly observed in ten patients (47.6%), followed by polyarticular (5 patients), distal (3 patients), spondyloarthropathy (2 patients), and mutilans (1 patient). Positive rheumatoid factor was detected in three patients and antinuclear antibodies in eight patients, suggesting the involvement of immunological disregulation in this disorder. Twelve patients were onychopathic, of whom 11 showed distal interphalangeal (DIP) joint arthritis. Based on radiologic observation, spur formation of the calcaneus (1 patient) and destructive changes of the articulatio coxa (1 patient) were seen, in addition to the findings such as joint space narrowing, erosive changes, resorptive changes and 'pencil-in-cup' appearances. Non-steroidal anti-inflammatory drugs (NSAIDs) were used in all cases for the control of joint pain, solely or in combination with immunomodulatory drugs such as bucillamine, sulfasalazine, methotrexate, cyclosporin, etretinate, and mizoribine. However, some of those drugs were often ineffective for the joint pain, while effective for cutaneous psoriasis. Immunohistological studies of the biopsied synovial tissues from two patients showed increased expressions of CD45RO and HLA-DR, suggesting that the vast majority of inflammatory cells are mature and activated T-cells. Parallel immunostaining using the involved psoriatic skin from one of the patients also showed enhanced expression of CD45RO, but less expression of HLA-DR as compared with its expression in the synovium. On the other hand, cutaneous leukocyte antigen (CLA) was abundantly detected in the inflammatory cells in the lesional skin, although less expressed in the synovium. These results are consistent with earlier observations suggesting a different subpopulation of inflammatory cells in the skin than the joint.

Modulation of bone morphogenetic protein signaling inhibits the onset and progression of ankylosing enthesitis

Joint ankylosis is a major cause of disability in the human spondyloarthropathies. Here we report that this process partially recapitulates embryonic endochondral bone formation in a spontaneous model of arthritis in DBA/1 mice. Bone morphogenetic protein (BMP) signaling appears to be a key molecular pathway involved in this pathological cascade. Systemic gene transfer of noggin, a BMP antagonist, is effective both as a preventive and a therapeutic strategy in the mouse model, mechanistically interfering with enthesial progenitor cell proliferation in early stages of the disease process. Immunohistochemical staining for phosphorylated smad1/5 in enthesial biopsies of patients with spondyloarthropathy reveals active BMP signaling in similar target cells. Our data suggest that BMP signaling is an attractive therapeutic target for interfering with structural changes in spondyloarthropathy either as an alternative or complementary approach to current antiinflammatory treatments.

Current and investigational treatment of psoriatic arthritis

Psoriatic arthritis (PsA) is now recognised as a progressively destructive inflammatory arthritis that can lead to joint deformity and functional disability. Early diagnosis and treatment with disease-modifying antirheumatic drugs (DMARDs) are necessary to control disease, particularly in patients with clinical factors and human leukocyte antigen markers predictive of progressive disease. However, there are few randomised controlled trials of the traditional DMARDs in PsA and none have demonstrated efficacy on axial manifestations or delay in radiological progression. The demonstration of raised levels of TNF-alpha in psoriatic skin and synovial tissue has provided a rationale for the application of biological agents in PsA. Furthermore, the recognition of the role of T-cell activation in both psoriasis and PsA has led to the therapeutic targeting of T lymphocytes, the results of which at this early stage are encouraging. This article reviews the studies of the most widely used traditional DMARDs in PsA followed by studies with leflunomide and the biological response modifiers, including TNF-alpha antagonists and T-cell-targeted therapies.

Lymphocytes expressing alpha1beta1 integrin (very late antigen-1) in peripheral blood of patients with arthritis are a subset of CD45RO(+) T-cells primed for rapid adhesion to collagen IV

We report that very late antigen-1 (VLA-1(+)) CD3(+)CD45RO(+) T-cells are selectively segregated from VLA-1(-) peripheral blood (PB) mononuclear cells (MC), in which CD3(+) T-cells are evenly CD45RO(+) and CD45RO(-), when PBMC are stained with a monoclonal antibody (mAb) to VLA-1 and passaged on immunomagnetic columns. In contrast, both VLA-1(+) and VLA-1(-) MC isolated from synovial fluid (SF) are mainly CD45RO(+)CD3(+) T-cells. VLA-1(+) MC formed 13 +/- 5.3% of MC eluting from columns loaded with PBMC of patients with seropositive rheumatoid arthritis (n = 6) and 2.3 +/- 1.6% of patients (n = 4) with other arthritides (P < 0.022). Importantly, only the VLA-1(+) MC from PB and SF adhered to collagen IV upon triggering with phorbol 12-myristate 13-acetate. Moreover, adhesion and migration on collagen IV were preferentially maintained in lines cultured from VLA-1(+) T-cells, and both were inhibited by mAb to the VLA-1 alpha1 I domain. These results suggest that VLA-1(+) CD45RO(+) T-cells in patients with arthritis could play a role in both systemic and local inflammation by rapidly adhering to collagen IV.

Development and early experiences of a Swedish psoriatic arthritis register

OBJECTIVES

To present a programme for a psoriatic arthritis (PsA) register (SwePsA) and to report the early experiences of a test period.

METHODS

Patients with symptoms and/or signs consistent with PsA or resembling PsA are enrolled into a follow-up programme, provided the disease duration at inclusion is not longer than two years.

RESULTS

Ninety-two patients were included into the programme during the test period. Sixty patients were classified as having PsA, 39 mono/oligoarticular, 19 polyarticular and two predominant axial. Thirty-two patients were classified as possible PsA. Thirty-two of the 92 included patients were followed for one year. Seven of 18 with mono/oligoarticular PsA had advanced to polyarticular PsA. Four of nine patients initially classified as possible PsA evolved into definite polyarticular PsA. Patients with polyarticular PsA had evidence of more severe disease than had patients with mono/oligoarticular PsA.

CONCLUSIONS

The programme was easy to administrate and not very time-consuming in daily clinical practice. The preliminary experiences emphasize the importance of early diagnosis and the need for reliable outcome predictors for this potentially severe disorder.

Current concepts in psoriatic arthritis

This review summarizes articles written about psoriatic arthritis in the past year. It concentrates on clinical and epidemiologic issues, pathogenesis and treatment, and updates the reader regarding new concepts in psoriatic arthritis.